Building Barefoot 196

[coosafooter]

PCM has recomended that I use the stock transmission and prop that is on the boat now and just plug in the new 6.0L. They believe it would make it a 50 mph boat.

[coosafooter]

Just got off the phone with Arizona Speed & Marine I think they may can tune another mile per hour or two out of the 330 HP PCM.

[TRBenj]

If you figure out how to edit the PCM fuel mapping curves, that would be something. Starting from scratch would be a real process. Once you crack that though, the options for upgrading a 350 Chevy are endless.

Dropping in a 409hp 6.0L would get you beyond 50mph for sure. The TSC2 (no gate) with the 375hp 6.0L is knocking on the 50mph mark. The 409 in a TSC3 with the gate up is good for 52-53. You'd have to go to a bigger prop (668) to keep it off the 5600rpm rev limiter, though. Not a cheap upgrade, either!

[coosafooter]

I have been looking at every angle, guys who understand the ECM mapping tell me that they cant believe that someone has not done it already. The CAT motor will have programers looking at marine engine market more than ever.It cant be all that hard, unlike cracking into a new vette. Do you know someone with the 6.0 set up in a 196 ? Those speeds would open up revisiting the barefoot plate again, would have some speed to use up mashing down that roster tail into a nice table. Bill at ACME would love the challenge to get the prop right.

[Mikeski]

I looked into remapping the MEFI 4b on my 2005 EX330, mine is pre-cat. I did replace the stock exhaust manifolds with aluminum high flow units Revolution Marine. The runners and collectors are considerable larger than the stock units. Not sure if they will fit under a dog house, they increase the width by about 2". The offshore guys have some off the shelf maps for the MEFI controllers. If you get it close then put it on a computer you can tune it. The PCM unit is locked, you will need to wipe it clean and start from scratch. I actually found another MEFI 4b controller on craigslist that somebody had used on a sand rail. I bought it and kept it in a drawer for 2 years then ended up reselling it. These are very common controllers. If you search the serial number you can determine what controller you need. I would also suggest you reach out to 2gofaster in this forum. I think he might have experience with these controllers. Remap the fuel and timing curves, run premium fuel, and change the exhaust manifolds. You can probably squeak another 30HP out of the stock motor. Push the stock mill for all it's worth, if you blow it up then you have a good reason to replace it.

[TRBenj]

I looked into remapping the MEFI 4b on my 2005 EX330, mine is pre-cat. I did replace the stock exhaust manifolds with aluminum high flow units Revolution Marine. The runners and collectors are considerable larger than the stock units. Not sure if they will fit under a dog house, they increase the width by about 2". The offshore guys have some off the shelf maps for the MEFI controllers. If you get it close then put it on a computer you can tune it. The PCM unit is locked, you will need to wipe it clean and start from scratch. I actually found another MEFI 4b controller on craigslist that somebody had used on a sand rail. I bought it and kept it in a drawer for 2 years then ended up reselling it. These are very common controllers. If you search the serial number you can determine what controller you need. I would also suggest you reach out to 2gofaster in this forum. I think he might have experience with these controllers. Remap the fuel and timing curves, run premium fuel, and change the exhaust manifolds. You can probably squeak another 30HP out of the stock motor. Push the stock mill for all it's worth, if you blow it up then you have a good reason to replace it.

Mike, good info! I assume you mean that you can squeak another 30hp out of the stock motor without playing with the fuel and timing curves? That seems plausible. If you can get some decent working curves to support upgraded parts, the sky would be the limit. I would think it would be pretty easy to build a 400-450hp 350 based motor for less than the cost of a 6.0L upgrade.

I have been looking at every angle, guys who understand the ECM mapping tell me that they cant believe that someone has not done it already. The CAT motor will have programers looking at marine engine market more than ever.It cant be all that hard, unlike cracking into a new vette.

I say go for it! I know someone who will be tinkering with a GT40 based EFI set up before too long- it would be great to have someone knowledgable on the Excal as well. If you can figure out what works (both hardware and software) then you could build a pretty mean engine.

Do you know someone with the 6.0 set up in a 196 ? Those speeds would open up revisiting the barefoot plate again, would have some speed to use up mashing down that roster tail into a nice table. Bill at ACME would love the challenge to get the prop right.

I do. My uncle has a '04 196 (TSC2) with the 375hp 6.0L, which we've GPS'd at 49.9. My father has a '09 196 (TSC3) with the 409hp 6.0L (cat). That boat has actually seen glimpses of 56-57 on the GPS, but its sort of a special example. 52-53mph on that set up is more typical. Ive only played with a few props on that boat, but nothing has worked as well as the stock 668. Ive tried a lot more props on my '90, and have worked extensively with both Eric from OJ and Bill from Acme.

It would be interesting to see what you would propose for a plate on that hull. I still dont see how a plate is going to have a big effect on the rooster beyond what the hydrogate can do. At least not without pushing the nose down to the point of being dangerous.

Whats the coosa reference in your screen name?

[coosafooter]

I looked at the plate again today, the way a barefoot plate works best is to be a extension of the hulls running surface. The idea is to clean up the waters surface that has been distrubed by the prop, has nothing to do with the shape of the wake as in wakeboarding, in other words try not to push the bow down. They are fixed in position and set to the bottom of the hull with a straight edge. Some boats may set up .125 below flush. The plate needs to be some where aruond 14'' to 18'' wide. I think for one to work on the 196 it will have to be bent with a break press into the profile of the bottom. I sure hope that the boat could be tuned and increase the top end to 49 mph, my one foot problems would be solved. But the plate would rob 2 mph off the top end so here we go again. Coosa is for the Coosa River.

[coosafooter]

Also the length of the plate is close to the width. Special example 56 -57 mph what are you talking about?

[81nautique]

Also the length of the plate is close to the width. Special example 56 -57 mph what are you talking about?

Don't go there Tim, they'll never believe you, LOL

[TRBenj]

Ha, have we been down this road before, Alan?

Dad's boat: http://correctcraftfan.com/ccfboat/

Thanks for the explanation of the plate, but Im still confused. If the intent is to simply extend the hull and not force the bow down, what causes the 2mph loss? Ive always assumed the lower speed was because the plate has a downward tilt (like a trim tab), that both smooths the rooster and pushes the bow down. Is that incorrect? If not, the hydrogate does the same thing.

[Miljack]

My $0.02 on the controller. I tried to have someone program my MEFI4 from my Python engine, and they couldn't do it. They had to "wipe" it clean, and then installed their program, and it wouldn't even cycle the fuel pump. I was lucky in that I was able to get the stock program put back on the controller. I used a guy down in the LA area who has a good reputation with the Ram Jet crowd of hot rodders using the GM 350 Ram and 502 Ram's in their various hot rod projects. Basic consensus on these engines is that they come from GM with a VERY heavy fuel mixture. I know that PCM "changes" their tune, but the GM engines going in cars are using a "marine MEFI" controller.

Can we get a "backdoor" way to open the code? I know for my engine, it's WAY too rich and could benefit a bunch from a clean up of the fuel curve. I know that PCM considers their tuning proprietary, but, how much of a secret do they have in that program? I'm with Tim on the tuning of the Excal, should be easy to get into the 400-450 hp range with not too much work and running good fuel...

[coosafooter]

Barefooted three days in a row before this cold front came in today, no surfing boats to be seen any where ! Friday we took off the spark arrestor just to see if it restricted the flow of air, the motor hit the rev limiter. 47.5 MPH but with footer in tow 46.5 MPH.

[Mikeski]

MilJack,

I suggest you work with somebody that knows marine motors, not a car motor guy. I completely agree about the fuel curve being very fat. I confirmed this in a discussion with Ray Layton from PCM when he was checking out my Revolution Marine exhaust manifolds at the Nautique reunion in Vallejo. I told him a was a little worried about the motor pulling in more air and leaning out the mix. He said not to worry.

When I was ready to pull the trigger on my Dart small block based 409 I was going to have Larry's Engine build it for me. I spent a little time discussing the build with Larry, he knows his stuff. I would trust him to program a open MEFI controller for you. The key is just getting it running. Once it is running you will need to pull it up on a computer and tweak it.

Everybody I spoke with confirmed the PCM computer is under hard lockdown and PCM is not giving anybody the key to their program running this motor. You should be able to get a program designed for a mercruiser motor on your controller and get it running. There are several toggles you can choose from like bump start (tap the start and it holds the starter on till it starts). The guy programming your controller must have been a rookie and forgot to turn on the fuel pump output. Search the internet for these controllers, plenty of good reading available. I read some negative reviews about poor customer service for AZ Speed so I steered clear of them when I was in the market.

The guy that sold me the Revolution Marine manifolds also told me how I could easily add the O2 sensor bung. Just needed to find someone that could plug weld aluminum. I would suggest you get O2 sensors on your motor run it in closed loop mode to help you dial it in if you reprogram it. Once it is dialed in you can save the settings and pull the sensors so they do not get fouled from moisture (put the motor back in open loop mode). That was my plan.

Last advice - don't mess with the factory ECM, buy another new or used one and play with it. They are so easy to swap you can do some tests A/B, send it back for tweaking, etc. That was my plan.

[Mikeski]

Here's a quote from a tuner's forum thread:

I've check 4 MEFI controlled engines, 2 had the Mefi3 the other 2 had the mefi4 controller and all 4 were so rich, they would not even register on my gauge's, until after I flashed them with a properly tuned bin file.

I know Mercury does this so they want have pay for rebuilds, on these so called racing motors.

[Miljack]

Mike,
thanks for the feedback, I may reopen this project over the winter. The guy I used has a company called "OBD Diagnostics" down in the LA area. I found him through one of the sites where the GM "RamJet" engines and tuning was discussed quite a bit. He told me he had a "marine" program if he couldn't crack the password on the PCM controller.
I'll get in touch with Larry's engines and check around for a controller. Now that I think about my controller, I'm pretty sure it's a MEFI3, and if you want to control via "closed loop" you would need the MEFI4 controller.

thanks