First post. Hello all. I'm thinking of putting EFI on old Comp boat

[Scott Russell]

First off, hello and it's good to find the site after having read a lot about it, and thanks for having me. From what I've read there are great people and a lot of great information on the site. 

Having said that, I'll dive right in. 

This question is for older Ski Nautique and Master Craft owners (and other comp boats) and when I say "older", I'm taking about the carburetor era boats and pre-throttle by wire EFI boats. The question is has anyone on the site updated an older engine to EFI with throttle by wire. Example: putting a Holley Terminator or HP or Dominator EFI system on an old Pleasure Craft Marine 351 Ford engine, or PCM 350 Chevy? 

As I'm sure some have guessed, the objective would be to run Zero Off on a "classic" competition ski boat. Just wondering if anyone on this site has done this? Keep mind I'm an avid drag racer with two, two thousand HP drag radial cars, which you can see on my FB page in my photo albums, as well pictures of my former Master Craft, old mahogany Chris Craft I learned to ski behind, and the fiberglass Chris Craft that followed the mahogany one. I've built and tuned my own cars since I was a teen and I'm an ASE Master Technician with private garage and dealership experience. There's not much I can't do as far as cars and trucks (and boats) are concerned. Both of my race cars are turbo cars with stand alone EFI systems (one has a Holley Dominator and the other is pretty dated with a F.A.S.T. XFI 2.0 system). So I know my way around stand alone EFI systems. Holley makes it pretty easy to convert from standard throttle cable EFI to TBW. 

I'm sure a few of the more knowledgeable folks are problem wondering "why ask us if you can do all that stuff?" The answer is because I never take for granted I know everything. If life has taught me anything, it's that all too often we don't know what we don't know. I haven't fooled around with boats in nearly 30 years. I hope to get reacclimated. 

What I really want to know is if any of you did this and loved it? or did this and ended up regretting it and wishing you'd just bought a nicer/newer boat with more power (standard out of the box). My thought is I build 400+ cubic inch Chevy or Ford small block with decent cam, cylinder heads and induction with EFI fairly inexpensively and put that in (for example a nice 93/94 Master Craft Prostar 190) and have a lighter boat with a fantastic wake for slalom that has more power than the new Nautique's 6.2L at a FRACTION of the cost.  

Thoughts?  

BTW, I'm located in Memphis TN. 

For those only interested in the technical question, you can skip all this below.

Since this is my first post, a little about me and how I came to sign up on a Water Ski site. I'm now 60 years old. I'm a Sr. Project Mgr for an Auto Parts Retailer that will remain nameless. I started skiing as a young kid after my dad bought a 66 Chris Craft Super Sport mahogany 17' run about (again pictures in my photo albums on FB) The story was that the previous owner had been jumping barge waves on the Tennessee River and broken a plank and just barely got the boat back on the trailer before it sank. After that it was put away without winterizing and block and heads cracked. My dad bought the boat in 1975 for $600, with the dual axle trailer. I was 12 at the time. My dad had the engine and trans removed by a marina owned by a family friend in Pickwick TN, and took the boat home to Jackson TN and we stripped the boat to the bare hull. LOTS of bags with stainless and brass screws and parts with masking tape with marker writing for where they belonged on the boat. We then thoroughly cleaned the inside and repainted it the same gray it had originally, and re-stained and painted the exterior. BTW, mop cord and copper paint is no fun at all on the bottom of a wood boat for those who have never owned or worked on one. From there my dad had the marina put a new Target Master (if anybody is old enough to remember those) Chevy replacement 350 in the boat and they got it running. 

I was 13 and it was time to put it in the water. My dad didn't know you had to fill a wood boat to the water line on the trailer and let it soak to swell the wood, so we began taking on water immediately when we were leaving the marina. We got it back on the trailer (barely) and drained it and took it back home for a proper soak. After a couple of test runs on the lake it was time for the first family outing with my mother, sister and father and my myself. At this point in my life I was basically part fish, as all I ever wanted to do in warm weather was swim. My dad had been a clown in a ski show in the summers between his years in college, so he was a good skier, but I hadn't learned yet. I was excited about the boat, and especially driving it, but was scared to try and ski. My dad and I had a pretty bad argument about it. I was standing on the back seat and he pushed me off the side and said "you can either let me help you learn to get up on skis, or you can swim back to the marina".  It might sound mean, but that was probably the greatest push my dad ever gave me started me on nothing short of an obsession with water skiing. 

I skied open water with friends till I was in my early 20's when I discovered the slalom course. I jumped into it like a maniac but quickly learned it wasn't as easy as it looked. I'd been watching a guy from Memphis who had a new (at the time) Ski Nautique who skied tournaments who hung out at the TN Tombigbee Waterway on weekends when he didn't have tournaments. Late in the evenings when the water would get slick, I'd see him making these WALLS of water, and then before that water could fall, a new wall of water would appear on the other side. I saw that for the first time in my late teens. I'd seen good skiers plenty of times thought I was decent, but this guy looked like a PRO. I tried to emulate what I was seeing and learned that the shorter the rope got and the faster the boat went, the bigger the spray I could make. After years of doing that in open water, when I got to a slalom course, I basically at the physical ability, but not the knowledge, or as I called it "the timing" of the turns to complete the course. I eventually started skiing regional amateur tournaments a few times a year and eventually ran 3 @ 38 off, but keep in mind, at that time I was 6'5" and 205lbs and in stellar shape. Now at 60, I'm still pretty much 6'5", but much heavier and WAY out of shape. 

After 3 knee injuries before I was 30 (all of which were scoped, so my orthopedist never had to open me up), and two children and too many other financial commitments, I sold my Master Craft power slot Stars and Stripes and I haven't skied behind any boat since I was in my late 30's. Fast forward to today, I just had my left knee replaced June 27th and the right will be replaced on Nov 13th.

That said, while I was laid up for a week after the first surgery, I found the TWBC channel on YouTube and my interest in water skiing has been rekindled (to put it mildly). I've watched so many tournaments that I hear Tony Lightfoot in my sleep haha. While the tournaments were great, the real nostalgia kicked in when I found Marcus and Jen's channel for Flow Point Method. Seeing those collegiate tournaments and the joy of those kids took me back to my younger days. 

To this very day, the most calming and happiest memory I have is spending the day on the Tombigbee Waterway and Skiing till dusk with 3 or 4 friends. But the best part and the part that will forever be etched on my brain was the vision as I cruised the boat at around 25 mph from the Bigbee back to our dock at Pickwick as the sunset chased us home ....     I would just watch everybody talking, worn completely out physically, rehashing the day, and it was a feeling of complete and utter contentment that I have yet to find anywhere else in my life. To this day if I'm having a rough day I can find a quiet place, close my eyes and picture that setting and it calms me. 

I have no delusions of grandeur about skiing as I have weight to lose (which can and have done multiple times in the last 10 years, not to mention a LOT of physical work to do before I even attempt to get on a ski again, but I'm determined to make it happen and make skiing my path to maintaining better health and fitness into my senior years. Not to mention my adult kids missed out on all the fun when they were young and it would great for them to finally understand first hand my love of the water before they get to my age. 

[Mastercrafter]

Skipping to the bottom..

 

You need to use an e-controls ECU to run Zero Off so you’re pretty limited there. I put an Ilmor 5.7 in a 1991 Prostar and it was a blast.  
 

Perfect Pass works with anything cable-operated and is certainly much easier and cheaper if you just want a decent speed control. 

[skimtb]

Sounds fun as long as you pick the right hull, especially if you are getting back in the game and will be at longer ropes / slower speeds.  Unless you are gonna start at 32-34mph 28-32 off, and shorten from there…

To put a lot of work and $$ into a hull that doesn’t ski as well for your needs just leaves you with a hot rod boat.  Cool, but not necessarily a hot rod SKI boat.  

 91-94 Prostar is good for longer lines, slower speeds for the era.  91-93 are carb.  I think the good nautiques started in ‘97, most were FI already.  The previous nautique hull wasn’t great as slow speed / long lines in my experience, others may differ. Malibu also good 97+, not sure about before. 

Not sure on classic 80’s boats, but I presume not as good as the newer ones…

Maybe some other guys can help you with a list of target hulls to look for.  
 

post pics!

 

[BraceMaker]

@Scott Russell as mastercraft inserted its not that ZO only works with throttle by wire boats its that Zero Off is a product of E Controls Technologies and E Controls Technologies is the maker of the engine management software used by all the boats.

I've opinioned that E-Controls needs to come up with their own throttle body system to repower these old boats but that isn't their market.

Holley etc. don't run E-Controls so no shortcut to ZO there.  There should be one but sadly no.

[rawly]

Welcome to the sight. I looked at the length of that introduction you gave us and figured I’d wait for the Readers Digest version to come out. Then I figured I’d scan it very quickly. I thought maybe I’ll come back when this episode of Spraymakers is over ,  but when I saw the part about your dad being a clown in a ski show , I figured I pause The Boys and join you at the campfire. What a story. Takes me back to my beginnings and how I knew I had to learn how to do this when I first saw a good skier.  Man I hope like hell you are a real dude and not what came up when you entered WATERSKIERS BSing AROUND A CAMPFIRE into GPT Chat 🤣.   You will get your answers and become a better skier if you hang out around here. Welcome 

[Scott Russell]

1 hour ago, skimtb said:

Sounds fun as long as you pick the right hull, especially if you are getting back in the game and will be at longer ropes / slower speeds.  Unless you are gonna start at 32-34mph 28-32 off, and shorten from there…

To put a lot of work and $$ into a hull that doesn’t ski as well for your needs just leaves you with a hot rod boat.  Cool, but not necessarily a hot rod SKI boat.  

 91-94 Prostar is good for longer lines, slower speeds for the era.  91-93 are carb.  I think the good nautiques started in ‘97, most were FI already.  The previous nautique hull wasn’t great as slow speed / long lines in my experience, others may differ. Malibu also good 97+, not sure about before. 

Not sure on classic 80’s boats, but I presume not as good as the newer ones…

Maybe some other guys can help you with a list of target hulls to look for.  
 

post pics!

 

I tried to post pics but it appears I can't upload, only hyperlink? All mine are posted on FB and it wouldn't accept the URL.

[Scott Russell]

43 minutes ago, rawly said:

Welcome to the sight. I looked at the length of that introduction you gave us and figured I’d wait for the Readers Digest version to come out. Then I figured I’d scan it very quickly. I thought maybe I’ll come back when this episode of Spraymakers is over ,  but when I saw the part about your dad being a clown in a ski show , I figured I pause The Boys and join you at the campfire. What a story. Takes me back to my beginnings and how I knew I had to learn how to do this when I first saw a good skier.  Man I hope like hell you are a real dude and not what came up when you entered WATERSKIERS BSing AROUND A CAMPFIRE into GPT Chat 🤣.   You will get your answers and become a better skier if you hang out around here. Welcome 

I appreciate it. I'm not sure what qualifies a real dude, but most of life from 15-25 is blur. Thankfully I got away from a bad lifestyle. Don't get me wrong, I had a blast but I don't think I'd have lived long if I'd continued like I was going. I worked hard and played hard and enjoyed it till the last year or so. I've ended up fairly successful professionally, but I wouldn't recommend the path I took to get here. There are much easier ways that would have gotten me here sooner. Hopefully the folks here can help me to learn what passed me by while I wasn't skiing the last 28 years. 

[Scott Russell]

2 hours ago, Mastercrafter said:

Skipping to the bottom..

 

You need to use an e-controls ECU to run Zero Off so you’re pretty limited there. I put an Ilmor 5.7 in a 1991 Prostar and it was a blast.  
 

Perfect Pass works with anything cable-operated and is certainly much easier and cheaper if you just want a decent speed control. 

I didn't realize perfect pass was cable operated. Good to know. I've only looked at ZERO Off so far. 

[rawly]

Just listen to Spraymakers and try to apply it to your skiing. Erasing bad habits is hard , but if you’ve seen 3@38 , you can get back there with the modern skis and available coaching. 

[BraceMaker]

57 minutes ago, Scott Russell said:

I didn't realize perfect pass was cable operated. Good to know. I've only looked at ZERO Off so far. 

PP is a slackening device when the servo pulls tight your throttle cable works 100% like factory.  but as the servo feeds out slack the throttle arm on the carb (or throttle body or potentiometer) goes towards idle pulled by the return spring. so you just swap out the brass fitting on the end of the throttle cable and install the servo unit then install the dash and computer box and click in the wiring.  couple splices for power and tach and done.

[Horton]

I'm not a mechanic and can't really speak mechanic talk but re-powering older boats or ZO hardly exotic.

[Dano]

Pretty sure PP has a DBW option as well.  If you know what EFI system you are going to install and understand how the parts and programming work.  I’d think it would be possible.  You might have to talk to PP directly to work it out.  They are very knowledgeable and helpful.  I have several friends using PP dbw systems and they work very well.  In my opinion they are very close to zo. 

[swbca]

11 hours ago, Scott Russell said:

I tried to post pics but it appears I can't upload, only hyperlink? All mine are posted on FB and it wouldn't accept the URL.

Go to Facebook, right-click on your photo and select "save-as" and then browse to your desktop to save your photo to your desktop.  Then rename it to a short normal file name because Facebook creates a huge file name for your photo.  Keep the .jpg file extension when you rename. Then it's possible your photo is too big for BOS.  

If you already have your photos on your PC or get them from Facebook, if they are too big for BOS, Follow the steps below to resize an image in Photos on Windows 10 or 11:    Best quality is to resize to 600 pixels wide because that the max size displayed by BOS.

Step 1: Right-click on the image and select Open with followed by Photos. 
Step 2: Select the Three dots icon located in the app's top-right corner. 
Step 3: Select Resize on the drop-down menu.

Edited October 3, 2023 by swbca

[jpwhit]

10 hours ago, Dano said:

Pretty sure PP has a DBW option as well.  If you know what EFI system you are going to install and understand how the parts and programming work.  I’d think it would be possible.  You might have to talk to PP directly to work it out.  They are very knowledgeable and helpful.  I have several friends using PP dbw systems and they work very well.  In my opinion they are very close to zo. 

This is my understanding of the situation. They did at one time, but the patent suit settlement between Perfect Pass and Zero Off divided the market between ZO covering all DBW applications and Perfect Pass covering all Mechanical throttle applications. Basically PP had patents on mechanical throttle and ZO had patents on DBW. So PP discontinued their DBW support. 

[ReallyGottaSki]

Welcome

I share your enthusiasm for such projects

However show me someone who put EFI on an old std engine to fix runability,  I'll see someone who also finally improved their fuel filtration like they should have done decades prior.

Like you,  I also am a fan of light hull, snappy engine. 

in my case heads, Cam,  intake and ss logs on a well used 1350hr shortblock has amazed anyone who has gotten a ride or pull.  Same carb, its had, still no dull spots. its seamless as efi.

Just a pv change upon getting it 25 years ago 

frankly deep slalom starts are 15% throttle or less otherwise i get complaints

the ski experience is other-worldly, from 26-36 mph,  for the peanuts to the proficient adults

Still have no need to to efi.  efficiency is off the  charts too, boat uses 2/3 the fuel of contemporaries

This particular boat is offline now, Hull is getting new bones over the next year, and also address the side spray @35 off, and get ppw/zbox. aim is further refine this retromod 

If you build/keep the boat light i don't think you need to be at 400",  

 

boat has seen 52.5, but i think one side of the hull was getting unstuck, boat has no business above 50

it hits 20mph within its own length plus one big step.

 

[BraceMaker]

15 minutes ago, jpwhit said:

This is my understanding of the situation. They did at one time, but the patent suit settlement between Perfect Pass and Zero Off divided the market between ZO covering all DBW applications and Perfect Pass covering all Mechanical throttle applications. Basically PP had patents on mechanical throttle and ZO had patents on DBW. So PP discontinued their DBW support. 

 

That but also even if you get a DBW module, which they are for sale from time to time including on great lakes skipper its not like there is a standard for it to communicate with Sniper EFI.

The wiring pin out for them is; RQST is the request line, when the PP module engages that's the signal from PP to the ECM, the ECM when it detects the request then the STAT line gets voltage and the PP display beeps to confirm engagement, and then from there the VGOV is the RPM level return.

How you would get Sniper to communicate with it?  I have no clue that'd be an entire extra layer of programming.  I'm sure it has some input/output for cruise control maybe?

 

[Dano]

DBW upgrade kits are listed on their website.  

[Scott Russell]

22 minutes ago, ReallyGottaSki said:

Welcome

I share your enthusiasm for such projects

However show me someone who put EFI on an old std engine to fix runability,  I'll see someone who also finally improved their fuel filtration like they should have done decades prior.

Like you,  I also am a fan of light hull, snappy engine. 

in my case heads, Cam,  intake and ss logs on a well used 1350hr shortblock has amazed anyone who has gotten a ride or pull.  Same carb, its had, still no dull spots. its seamless as efi.

Just a pv change upon getting it 25 years ago 

frankly deep slalom starts are 15% throttle or less otherwise i get complaints

the ski experience is other-worldly, from 26-36 mph,  for the peanuts to the proficient adults

Still have no need to to efi.  efficiency is off the  charts too, boat uses 2/3 the fuel of contemporaries

This particular boat is offline now, Hull is getting new bones over the next year, and also address the side spray @35 off, and get ppw/zbox. aim is further refine this retromod 

If you build/keep the boat light i don't think you need to be at 400",  

 

boat has seen 52.5, but i think one side of the hull was getting unstuck, boat has no business above 50

it hits 20mph within its own length plus one big step.

 

That's great information. Thank you.

Honestly, I'm not interested at all in making the boat fast, or if it has a choppy idle or not. It sounds like you understand that cam durations and tight lobe separations that provide the choppy exhaust note we know and love isn't conducive to stump pulling torque in the 2500-3800 rpm range where our boats typically operate and need torque. The reason I was entertaining the larger CID was because long stroke is where the torque is. And believe me, I get what your saying about low throttle inputs for deep water starts. I had an 81 power slot Prostar that was bone stock (240hp) and it was more than enough to overwhelm a skier doing a deep water start at wide open throttle. 

The embarrassing fact is, I've been away from skiing for 28 years the whole concept of speed control in ANY form is foreign to me because of the era when I was a hardcore skier. Not to sound like an old fart, but "in my day" (haha) we just tried to maintain the boat path and hand throttle while checking the speedos as best you could. The whole speed control thing is cheating haha. Just kidding, but it IS something I didn't know existed until watching YouTube videos the week after my knee replacement at the end of June this year. 

In tournaments I kept hearing Tony or the pros commentating with him about the "zero off setting" the skier had chosen for a pass. The first time I heard it I thought: zero off is a damned 75ft rope ... what the .... but then I learned that it was speed control. When I finally learned what Zero Off was it got me thinking about how new boats have new EFI systems, which means they have TBW rather than a cable. I've converted a couple dozen cars/trucks from carbs to EFI, and I was an early adopter of stand alone (aftermarket) EFI in the late 90's when most were afraid of it. I know my way around several aftermarket systems very well. 

TBW is more simple than most people realize. The throttle is a 0-5v potentiometer and at idle the voltage output is sub 1v range and wide open throttle is 5v. That voltage signal goes to the PCM (or ECM in an OE application) and the PCM takes that input and creates a waveform that goes out to the 12v actuator motor on the throttle body. The throttle body has 6 wires, a power and a ground for the 12v signal to the motor, and 5v power wire and ground to two throttle position sensors and then each TPS has a signal wire to return throttle position voltage information back to the PCM. If either of the TPS sensors fails, you get a check engine light and the vehicle goes into limp mode until the PCM sees both TPS sensor outputs again (it's a safety redundancy thing). The throttle and the throttle body/actuator are remarkably simple. The voodoo is in the creation of the wave form created by the PCM that translates the peddle position (or throttle in a boat) sensor output to the wave form voltage that makes the throttle blade move in accordance with the movement of the throttle.

In a car/truck, traction control overrides the pedal position (driver input) and makes changes to the position of the throttle blade based on a variety of factors, but usually most notably wheel speed in relation to vehicle speed and it will use the vehicle's ABS sensors for wheel speed input and the speedometer input vehicle speed.

Zero Off is doing a variation of what traction control does in a car/truck, only it's using a GPS speed input, which is converted to a voltage signal. You set your desired speed in Zero Off and Zero Off will only allow the throttle blade to open to a point where your set GPS speed is met, overriding the throttle position setting the boat driver has set. The beauty of doing this with TBW is that the actuator motor is extremely reactive to voltage inputs, so if the boat loses speed, the Zero Off system is probably sampling the GPS speed input (just guessing) thousands of times per second. That's how finite the control is. So when the skier pulls coming out of a buoy and boat wants to slow, the throttle will react instantly (in thousandths of a second increments) and then when the skier goes into their edge change and decelerates into the next buoy, it will throttle back based on the GPS speed signal and so on and so forth. The settings in Zero Off that the skier chooses are simply defining how quickly or slowly the throttle blade reacts to speed changes and much or how little delay it reacts with. 

The aftermarket EFI systems like the Holley Dominator, Haltech, Fuel Tech, etc., have all added software for TBW that is tunable, so I see no reason that I couldn't put a Holley HP system with GM throttle by wire (for example) on a 427" small block Ford and use Zero Off for speed control. Put that in an older lighter hull with a great wake and you'd have a boat that would perform (from a skier's perspective) as well if not potentially a shade better than a new $130k boat.  

But here's the sad part. I'm 60 now, and my skiing will likely NEVER be up to a point where precision speed control through the course is a concern for me, so all this is probably not worth doing anyway, at least not for me. However, I do plan to retire to a ski community of some sort, and it would be nice to have a boat that could be used for regulated tournaments that people would WANT to ski behind. From that standpoint it might be worth doing. From a hot rodders perspective, it would just be a fun challenge to see if I could build a boat on a budget that could be pretty easily duplicated that would actually (really) perform on par, or a tick better than today's cutting edge wonder boats. 

[BraceMaker]

@Scott Russell

I think you basically are putting the cart before the horse.

The tournament regulation sort of allows you to use a vintage boat but practically speaking doesn't you basically would need to have a recent late model boat to pull anything that people are going to want.

 

But from a ZO perspective from what I can tell they've put part of their control software into the head unit and part of it into the ECU so that neither aspect stands alone their engine management certainly isn't just taking a potentiometer input from the head unit.

[Horton]

@BraceMaker

just to clarify - I know some folks with relatively vintage boats with a current technology engine plus zero off and the boat skis great. Now I think what you're referring to is perfect pass in which case, yes, you're exactly right it's not a good practice boat and certainly could not be used in the tournament

[BraceMaker]

@Horton ski great yes.  Live in a ski community with other boat owners and pull an event?

[Dano]

@Horton If you are referring to older versions of PP on boats that are not running well, or propped well. I would agree with you.  But the latest DBW versions of PP on a good running boat are very good.  It’s not ZO but it’s very close.  Even boats using the servo throttle control can be tuned to work quite well.  I do ski tournaments, I run the same buoys behind ZO as I do behind my old 89 Centurion with stargazer zbox.  Maybe it’s different for guys running -38 or shorter but for me PP is an acceptable practice boat. For a project like this one here I think PP might be his best option when trying to make it work with an aftermarket EFI system. 

[BraceMaker]

I'm just trying to be clear with expectations because I personally agree if you could take a late 80s early1990s era boat and drop a throttle body on it and plug in a ZO head unit and be off to the races I think that would be something a lot of us vintage ski boat owners would but I think Zero Off purposefully designed their system to make that difficult to impossible. 

 

Could that be due to the PP/ZO agreement?  Sure but I doubt it, I don't think PP could complain if you could buy a sniper EFI from Holley and a ZO head unit retail plug em together and run it.  I think this has more to do with ZO driving a market on new boats and the difficulty in retroing that back.

[MDB1056]

@Scott Russell - summary - unless you are going to ski tournaments at a high level you do not seen Zero Off. Stargazer PP will servie you just fine

[UWSkier]

2 hours ago, Dano said:

DBW upgrade kits are listed on their website.  

There was a 1-2 year period in there where manufacturers were switching over to DBW but didn't support Econtrols.  The 2006 Malibus come to mind.  They had DBW throttles on those boats, but supposedly only the '07+ supports the Econtrols ECU swap and ZO.  A ZO 2006 Response LXi would be a phenomenal boat.

[tjs1295]

@Scott Russell If I had your mechanical knowledge/ability, I'd buy a decent hull from the past 30 years, put perfect pass in it, and go skiing. It will still be something nicer than you ever had. If you want to mess with the engine along the way, that would be great. EFI or carb? Sounds like you could try both on the same engine with your setup/skillset. I don't know how the ski communities work, but if you need to provide a boat to fit the needs of others, just cross that bridge when you get there. In the meantime have fun with a perfect pass boat. On the other hand, if money is no object, then something from 2024 with 6.2 liters, and zero off. 

[Jody_Seal]

I have  complete GT-40 for sale. running condition.. Add stargazer and Zbox you have the whole package for an EFI project.

[Scott Russell]

16 hours ago, BraceMaker said:

PP is a slackening device when the servo pulls tight your throttle cable works 100% like factory.  but as the servo feeds out slack the throttle arm on the carb (or throttle body or potentiometer) goes towards idle pulled by the return spring. so you just swap out the brass fitting on the end of the throttle cable and install the servo unit then install the dash and computer box and click in the wiring.  couple splices for power and tach and done.

No question that sounds like the best way to go for an older boat for the least amount of work to implement speed control. 

[Scott Russell]

3 hours ago, BraceMaker said:

@Scott Russell

I think you basically are putting the cart before the horse.

The tournament regulation sort of allows you to use a vintage boat but practically speaking doesn't you basically would need to have a recent late model boat to pull anything that people are going to want.

 

But from a ZO perspective from what I can tell they've put part of their control software into the head unit and part of it into the ECU so that neither aspect stands alone their engine management certainly isn't just taking a potentiometer input from the head unit.

I guess it's good that most tournaments have dedicated NEW boats that skiers prefer, but it seems a shame that the older boats are basically just obsoleted and put out to pasture once the pros get acclimated to the latest and greatest the industry has to offer. I get it, but I hate it for the older boats, especially the ones that had really fantastic wakes for the shortest line lengths. I know pretty much NOTHING of how hulls are designed, but common sense would seem to indicate that the lighter the boat, the smaller the wake. But again, I know nothing of hull design, so that may not be true at all. 

I see what you are saying about proprietary engine management.

I'm wondering what ZO would potentially use from the engine management system? The only other input I can think of would be engine rpm, or maybe shaft speed if the boat has an underdrive trans like the Nautiques do these days.. A simple ignition tach signal can provide engine rpm, and there are any number of hall effect sensors that could provide shaft speed data if ZO required it. In drag racing we use ignition timing to control power output. Actually, in a blower car, timing is all the power control you have on the fly, but I have a hard time picturing a mass produced engine with a 7 year, 1000 hr warranty using timing retard to control boat speed when the throttle will do the same thing because of the prop be under constant load. I'm wondering what else from the engine management system would ZO need to set speed? 

I'll be digging around seeing if I can find a wiring diagram to see what the connectors from ZO to the engine harness are referencing. Either way, it's interesting to learn more about. I'm thinking GPS speed for the actual speed the boat is moving, and a feedback loop between the ZO head unit and throttle body are really all you need in a boat. If engine rpm equated to the exact speed of the boat, I'm not sure why you would need GPS at all, other than validation.

The whole point of traction control in a car/truck is for an algorhithm using wheel speed vs vehicle speed to bring wheel speed back into line with vehicle speed so traction is re-established (or not lost to being with). It bypasses the peddle sensor's output signal and uses the traction control software's instruction. There is super sophisticated traction control that incorporate shock sensors, suspension travel sensors and engine rpm vs driveshaft rpm, but a boat has none of those to read. 

I'm thinking in ZO the head unit simply bypasses the throttle input once the throttle is applied beyond what is needed to reach the programmed speed and at that point the software is ZO is using the throttle body to keep boat speed constant based on the GPS input the engine management system is just along for the ride. Once activated, the throttle only works when below the ZO programmed speed. My understanding is that once you get the skier planed off at a lower throttle setting and you throttle up for the pass, you activate ZO and physically put the throttle wide open and ZO controls the speed from there and the throttle voltage output is removed from the equation. But when you drop the throttle manually below the set speed, the potentiometer in the throttle takes back over.

Again I'm just thinking this through this from automotive perspective, so I could be way out in left field. It just sounds to me like the engine management system is passing the control of the throttle body over to ZO when activated and ZO passes it back to the engine management system when the throttle is below what is required to maintain the speed set in ZO. If that turns out to be true, then an aftermarket PCM that can operate TBW should be compatible. Regardless, it'll be fun to figure out what will and won't work. 

[Scott Russell]

2 hours ago, tjs1295 said:

@Scott Russell If I had your mechanical knowledge/ability, I'd buy a decent hull from the past 30 years, put perfect pass in it, and go skiing. It will still be something nicer than you ever had. If you want to mess with the engine along the way, that would be great. EFI or carb? Sounds like you could try both on the same engine with your setup/skillset. I don't know how the ski communities work, but if you need to provide a boat to fit the needs of others, just cross that bridge when you get there. In the meantime have fun with a perfect pass boat. On the other hand, if money is no object, then something from 2024 with 6.2 liters, and zero off. 

I have many many years of drag racing experience with carbs, so that's always an option. My old stars and stripes purred like a kitten with a factory installed Holley 600 vacuum secondary carb. I could spend the money on a new or newer boat, but to be honest, it's more rewarding to be using something I built myself, or at least tweaked to my liking. I have about 25 years experience with stand alone EFI and I really enjoy working with it. Again, not out of necessity, I just enjoy it. 

In reality, I don't yet know how hard I'll be able to go at 60 years old, so I may never really need ANY kind of tournament speed control haha. I'm just enjoying learning something new and planning my next project. 

I appreciate your thoughts. Thank you. 

[Scott Russell]

2 hours ago, UWSkier said:

There was a 1-2 year period in there where manufacturers were switching over to DBW but didn't support Econtrols.  The 2006 Malibus come to mind.  They had DBW throttles on those boats, but supposedly only the '07+ supports the Econtrols ECU swap and ZO.  A ZO 2006 Response LXi would be a phenomenal boat.

Different servo motors will generate different rpm with the same 12v input. That's where the difference is. Both the motor and the gearing of the motor (there are gears behind the cover on a DBW throttle body) of the motor to the throttle shaft have to be inline with what the ECM expects. Otherwise the throttle will either stay behind the actual throttle input, or constantly overshoot it. That's why I was talking about using stand alone EFI. Those parameters can be tuned to suit in aftermarket EFI systems whereas they are fixed in the programming of an OE ECM.

What I'm thinking is that as long as you have the same throttle body, or at least the same servo motor and gearing as ZO would expect if it were plugged into in a compatible Ilmor ECM (for example), there shouldn't be any issues getting ZO and the throttle body in sync. The wild card is getting the throttle body with specs ZO is designed for. Trust me on this, marine specialty engine builders are using OEM sourced parts. They just build all the parts necessary to adapt them to a marine application (water injected manifolds, etc.). All you have to do is get a part number from a ZO compatible throttle body and go from there. Worst case you could build your own throttle body to emulate the specs of the expected throttle body to "trick" ZO into thinking it's connected to a compatible throttle body. It just depends on how deep in the weeds you are capable (and willing) to go. 

[Scott Russell]

3 hours ago, BraceMaker said:

I'm just trying to be clear with expectations because I personally agree if you could take a late 80s early1990s era boat and drop a throttle body on it and plug in a ZO head unit and be off to the races I think that would be something a lot of us vintage ski boat owners would but I think Zero Off purposefully designed their system to make that difficult to impossible. 

 

Could that be due to the PP/ZO agreement?  Sure but I doubt it, I don't think PP could complain if you could buy a sniper EFI from Holley and a ZO head unit retail plug em together and run it.  I think this has more to do with ZO driving a market on new boats and the difficulty in retroing that back.

GPS speed control is nothing new. In drag racing, Shannon Davis at Davis Technologies owns a number of patents related to using it in wheel speed management systems in many different forms of motorsports. I've dealt with him for about 15 years and have quite a bit of his wizardry on both my race cars. Now that I think about it, he might be just the right person to look at what I'm trying to do and expand his product line. Making a boat maintain a constant speed while external forces are applied would be child's play for him. Hmm ...     The only issue I see is that all the super serious skiers seem to already either have or have access to new or newer boats already. If there was a market for this and everything isn't already patented, this could really become a reality. I need to make a phone call ... 

Edited October 3, 2023 by Scott Russell
left out a word

[Scott Russell]

9 hours ago, swbca said:

Go to Facebook, right-click on your photo and select "save-as" and then browse to your desktop to save your photo to your desktop.  Then rename it to a short normal file name because Facebook creates a huge file name for your photo.  Keep the .jpg file extension when you rename. Then it's possible your photo is too big for BOS.  

If you already have your photos on your PC or get them from Facebook, if they are too big for BOS, Follow the steps below to resize an image in Photos on Windows 10 or 11:    Best quality is to resize to 600 pixels wide because that the max size displayed by BOS.

Step 1: Right-click on the image and select Open with followed by Photos. 
Step 2: Select the Three dots icon located in the app's top-right corner. 
Step 3: Select Resize on the drop-down menu.

Sorry for my confusion, but you are saying I can upload an image (properly sized) straight from my computer to BOS? and not have to post it through a host site? Just want to make sure I understand what your saying. 

[swbca]

20 minutes ago, Scott Russell said:

Sorry for my confusion, but you are saying I can upload an image (properly sized) straight from my computer to BOS? and not have to post it through a host site? Just want to make sure I understand what your saying. 

You can drag your files from your computer into your post as shown below.

Edited October 3, 2023 by swbca

[Scott Russell]

19 minutes ago, swbca said:

You can drag your files from your computer into your post as shown below.

Got it! I just did it, but since this thread was already getting pretty long, I started a new one with the pictures. Thanks for the assist. Much appreciated. 

[03RLXi]

@Scott RussellI don't think it's what ZO takes from the engine management but what the ZO gives to it, or more specifically how quickly it gives the more power less power signal to the engine. With throttle servo motor and carb or basic EFI there's more time delay involved and there's no direct engine feedback. 

In my opinion for having fun and non tournament skiers it really does not matter. For lower end tournament skiers it probably also doesn't matter, but it's a 'feel' sport so the skiers tell themselves it's does matter and likely many even convince themselves that's why they don't ski pro level. LOL, spoiler, that'd not be why and it's actually them, not the boat, or ski, or rope, or vest, or shorts that holding back their scores😂

[Scott Russell]

46 minutes ago, 03RLXi said:

@Scott RussellI don't think it's what ZO takes from the engine management but what the ZO gives to it, or more specifically how quickly it gives the more power less power signal to the engine. With throttle servo motor and carb or basic EFI there's more time delay involved and there's no direct engine feedback. 

In my opinion for having fun and non tournament skiers it really does not matter. For lower end tournament skiers it probably also doesn't matter, but it's a 'feel' sport so the skiers tell themselves it's does matter and likely many even convince themselves that's why they don't ski pro level. LOL, spoiler, that'd not be why and it's actually them, not the boat, or ski, or rope, or vest, or shorts that holding back their scores😂

I agree on all counts. I'm more of a "I sucked because I suck" kinda guy 😆 

And I seriously doubt I'll ever need any such "tournament level" technology. My PB was run 29 years ago and at age 60 its doubtful I'll ever get back to that level. That said, I did it with mostly 35 year old technology, but I'm 6'5", which is kinda cheatin anyway 😄 I'm fascinated with the new boats and new equipment but at the end of the day ya still gotta get around the bueys. 

[jpwhit]

5 hours ago, Scott Russell said:

Different servo motors will generate different rpm with the same 12v input. That's where the difference is. Both the motor and the gearing of the motor (there are gears behind the cover on a DBW throttle body) of the motor to the throttle shaft have to be inline with what the ECM expects. Otherwise the throttle will either stay behind the actual throttle input, or constantly overshoot it. That's why I was talking about using stand alone EFI. Those parameters can be tuned to suit in aftermarket EFI systems whereas they are fixed in the programming of an OE ECM.

What I'm thinking is that as long as you have the same throttle body, or at least the same servo motor and gearing as ZO would expect if it were plugged into in a compatible Ilmor ECM (for example), there shouldn't be any issues getting ZO and the throttle body in sync. The wild card is getting the throttle body with specs ZO is designed for. Trust me on this, marine specialty engine builders are using OEM sourced parts. They just build all the parts necessary to adapt them to a marine application (water injected manifolds, etc.). All you have to do is get a part number from a ZO compatible throttle body and go from there. Worst case you could build your own throttle body to emulate the specs of the expected throttle body to "trick" ZO into thinking it's connected to a compatible throttle body. It just depends on how deep in the weeds you are capable (and willing) to go. 

The ZO head unit does not interface directly with the servo on the throttle body. The eControls ECM reads the data from the throttle pedal position sensor (PPS) and it directly controls the throttle body serve motor. The ZO head units talks to the ECM via the CanBus interface and it can send commands to override throttle control. For safety reasons, the ECM will only allow commands to alter throttle controls within the range of zero throttle up to the current reading from the PPS. So if the driver moves the throttle lever to say 70%, the ZO commands can set throttle between 0 and 70%. If the driver returns the throttle lever to idle, the ZO cannot control the throttle at all. 

[DW]

Scott, as many have posted to end up with ZO it takes the econtrols ECU to be compatible with the ZO system.  ZO and PP Stargazer do use GPS as the throttle control strategy, the older PP system used engine speed to control the throttle position.

As for the EFI question separated from ZO, ski boat owners that has tried and posted about an EFI conversion (mostly all trying the Sniper) have given up over not getting it to work.  Maybe it's just those that posted and there are several running around but I have not seen a single conversion post that ended in a happy marriage.  Given your expertise a carb should be fine and you have a few options, typically a Holley or Weber (which is same as Carter AFB or Edelbrock).  Just don't run one too lean, marine engines run richer to stay alive as they are always under load. (and that may be the issue on an EFI conversion, the O2 signal / existing calibration really does not richen the mixture enough, IDK).  

As for an older boat, no question they can be improved.  Removing weight, relocation key components to move the CG forward will improve the wake along with some hull enhancements to correct the deficiencies of any of the specific hulls (side spray on an older Prostar as an example).  Moving CG forward counters an aggressive weight reduction program and in my example project improved the tracking.

A quick read of your thread, you have to decide what is your priority in your hobby, we can easily help you spend money.  From what I read you are looking at two paths   1. build a really nice older ski boat that exceeds the original 240 hp performance level and has a functional speed control or    2. spend a fair chunk of change to end up with a ZO speed control boat either new hull or old.  For item 1, an SBC can easily be build in the 385-400 hp range that offers plenty of torque and drivability to pull up a skier, boarder or footer.  Marine cam or torquey truck cam is what you should settle on.

[Horton]

if you're not skiing tournaments and do not have your eye on super short ropes an off-the-shelf Perfect Pass system is a no-brainer. I wouldn't even bother with a more modern stargazer system.

Disconnect the secondaries on your stock Holley carburetor and go ski.

 

[buechsr]

10 hours ago, Horton said:

if you're not skiing tournaments and do not have your eye on super short ropes an off-the-shelf Perfect Pass system is a no-brainer. I wouldn't even bother with a more modern stargazer system.

Disconnect the secondaries on your stock Holley carburetor and go ski.

 

PPass doesn't make classic anymore.  You have to get stargazer.  Unless you're speaking to Zbox specifically?  Stargazer is a simpler install too.  No hull drilling.

[Jody_Seal]

I want see Horton do a video on disconnect of Holley secondaries!!

or better yet installing the secondary cam and secondary diaphram that does not allow the secondaries to crash in..

 

[Scott Russell]

11 hours ago, jpwhit said:

The ZO head unit does not interface directly with the servo on the throttle body. The eControls ECM reads the data from the throttle pedal position sensor (PPS) and it directly controls the throttle body serve motor. The ZO head units talks to the ECM via the CanBus interface and it can send commands to override throttle control. For safety reasons, the ECM will only allow commands to alter throttle controls within the range of zero throttle up to the current reading from the PPS. So if the driver moves the throttle lever to say 70%, the ZO commands can set throttle between 0 and 70%. If the driver returns the throttle lever to idle, the ZO cannot control the throttle at all. 

So is does work precisely the same as stand alone EFI systems. Thank you, that is excellent news. 

[BraceMaker]

3 minutes ago, Scott Russell said:

So is does work precisely the same as stand alone EFI systems. Thank you, that is excellent news. 

I think what he stated is that it works opposite of stand alone systems?  

[BraceMaker]

@DW issue with that is the best time to install an EFI is right after you make sure its running perfectly on a carb, not when you're having running concerns.

If you cannot make your boat run on its carb its not going to run well on aftermarket EFI.

[Horton]

@Jody_Seal I don't know maybe I'm using the wrong terminology. when I was a kid whenever we got a new boat the first thing we did was remove a little c clip off of a post on the side of the carburetor. then we would slide the connected arm off that post. the result was the secondaries wouldn't kick in slalom. we would of course reconnect it for a jump. My memory is clear. my description may suck.

[Scott Russell]

11 hours ago, DW said:

Scott, as many have posted to end up with ZO it takes the econtrols ECU to be compatible with the ZO system.  ZO and PP Stargazer do use GPS as the throttle control strategy, the older PP system used engine speed to control the throttle position.

As for the EFI question separated from ZO, ski boat owners that has tried and posted about an EFI conversion (mostly all trying the Sniper) have given up over not getting it to work.  Maybe it's just those that posted and there are several running around but I have not seen a single conversion post that ended in a happy marriage.  Given your expertise a carb should be fine and you have a few options, typically a Holley or Weber (which is same as Carter AFB or Edelbrock).  Just don't run one too lean, marine engines run richer to stay alive as they are always under load. (and that may be the issue on an EFI conversion, the O2 signal / existing calibration really does not richen the mixture enough, IDK).  

As for an older boat, no question they can be improved.  Removing weight, relocation key components to move the CG forward will improve the wake along with some hull enhancements to correct the deficiencies of any of the specific hulls (side spray on an older Prostar as an example).  Moving CG forward counters an aggressive weight reduction program and in my example project improved the tracking.

A quick read of your thread, you have to decide what is your priority in your hobby, we can easily help you spend money.  From what I read you are looking at two paths   1. build a really nice older ski boat that exceeds the original 240 hp performance level and has a functional speed control or    2. spend a fair chunk of change to end up with a ZO speed control boat either new hull or old.  For item 1, an SBC can easily be build in the 385-400 hp range that offers plenty of torque and drivability to pull up a skier, boarder or footer.  Marine cam or torquey truck cam is what you should settle on.

As I mentioned in response to few other commenters, the reality is that at my age, it's probably delusions of grandeur to think I'll ever get back to 38 off, or to really need speed control, other than for personal use through a course for giggles. I could just go buy a boat that has ZO, but this is really about my love of building cars. I enjoy setting a goal and I enjoy the build as much as I do driving the finished product. Just being realistic, I'll probably never REALLY need anything as exotic as ZO, but it would be pretty cool if I could show others how to convert older boats to EFI and even to ZO(?) on a budget. 

I've been a car guy since before I was old enough to legally drive. I made my first pass down a drag strip before at 15 years old. I always did automotive side work to fund my racing habit, and after my divorce in 97 I joined the auto industry as a technician. Then a shop manager, then a dealership tech (Chevy and Cadillac), then a service writer, and eventually a major auto parts retailer where over the past 24 years I've worked from being a counter guy, to field management, to several roles in the corporate office where I am a Sr Content Project Mgr today. During all that I've been building and racing cars. I do my own engine building, most of my own fabrication and welding, and I do all the suspension setup and tuning. 

I've converted old muscle cars to several brands of EFI, including FiTech, FAST EZ EFI. I've raced both ProCharger and Turbo cars using Classis FAST (over 20 years ago) and FAST XFI 2.0 (which the gray car in the pictures still has today), and Holley Dominator EFI, which is what is on the Reef Blue twin turbo car in the pictures. Converting a carbed boat to EFI is the least of my concerns. I just have a newbie fascination with all this speed control stuff for skiing. None of this existed in the 70's and 80's and early 90's when skied. I would seem an interesting challenge to potentially figure out how to break "the proprietary code" so to speak of the ZO system and not only do it for myself, but enlighten others as to how (potentially) simple it may be(?)  

[BraceMaker]

30 minutes ago, Horton said:

@Jody_Seal I don't know maybe I'm using the wrong terminology. when I was a kid whenever we got a new boat the first thing we did was remove a little c clip off of a post on the side of the carburetor. then we would slide the connected arm off that post. the result was the secondaries wouldn't kick in slalom. we would of course reconnect it for a jump. My memory is clear. my description may suck.

The secondary thing was more about how they closed vs. how they opened.  

 

@Scott Russell I mean do it but remember there have already been lawsuits and settlements so if you're doing it commercially best of luck!

[Scott Russell]

1 hour ago, BraceMaker said:

I think what he stated is that it works opposite of stand alone systems?  

In stand alone systems that are using DBW, the PCM receives a 5v signal from the pedal position sensor, the PCM then translates that to a 12v waveform which is what is used to determine throttle blade position. OEM systems work the same way. The variables are in the motor used in the TB and the gearing used to connect the motor to the throttle blade, and the wave form generated by the ECM. In stand alone systems (the higher end ones like a Holley Dominator for example), you can set the wave form any way you like (to match various different types of DBW throttle bodies). From what he said, ZO is cutting the pedal position sensor out of the equation when it is active and the throttle is above the position required to maintain the speed set in ZO. Traction control in the production car works the same way. When wheel speed and vehicle speed don't match, the pedal position sensor is bypassed and the traction control algorithm takes over until wheel speed matches vehicle speed (that's a VERY simplified explanation, but you get the idea). ZO is interrupting the PPS signal much like traction control does in a production car. Just like when a car's traction control is active and the pedal sensor is ignored until vehicle speed matches wheel speed, when ZO is active, as long as the throttle is above the throttle potentiometer position required to maintain the set speed, the throttle position is ignored, until such time as the throttle position is physically moved below the position required to maintain the set speed (as he said, for safety reasons, which makes good sense). Hopefully my explanation makes sense. 

[Scott Russell]

1 hour ago, BraceMaker said:

@DW issue with that is the best time to install an EFI is right after you make sure its running perfectly on a carb, not when you're having running concerns.

If you cannot make your boat run on its carb its not going to run well on aftermarket EFI.

THAT is spot on advice! Many an EFI conversion nightmare has begun by NOT follow that advice.