I sure your guy is dealing with Mark at Precision Marine in La. He did mine and it runs flawlessly . He is real good at programing the ecm's. He does them for alot of the top marine engine builders out there.
We dynoed my motors there and he mapped them on the dyno . His base map he already had was very close . just a little rich on the bottom. I also had the bungs put into my tail pipes for Mark to fine tune . It is so close I have not made it back down there to play with it any more . It runs so good now why mess with it. Its safe and I haven't touched it all summer

I would recommend he dynos it with your fuel system,your normal gas you run and try to run the water temp the same as it would run in the boat .Cold



I had CMI put the bungs in mine . Being a dual wall tube tail pipe I didn't want to take a chance on a leak .

Ck out my thread on the Whipple build up.

http://www.offshoreonly.com/forums/s...ad.php?t=90540

Good luck and let us know what it does

Rob

STRIP,

Great thread! I have stainless marine exhaust. I will have to do some checking as far a Oxygen sensor goes. The ECM was reprogrammed when I bought the Whipple system about 4 years ago. The engine is now a 509 cid with a bigger cam. The ECM was sent back to Dustin once we got the new cam spec.

My engine builder is a lil' pestimistic of big numbers on the dyno. I was looking for around 640 to 680HP. Its been so long since I've had a bigger engine built.I'm not sure of the HP capabilities of the engine. I'm using the stock pulley on the Whipple. I was told I could make some bigger numbers going with an 1/8 smaller pulley creating more boost.


What do you guys think??

Thanks!!

My previous engine had a 3.3 whipple carbed. 502ci canfield AL heads, solid lifters, 580 lift. I can't remember the rest, but it made 760HP on 93 octane at 8 Ibs. I would think your engine builder is being conservative. You should be able to make more HP, but then again your drive probably won’t last too long.

Once again, I feel you should use an ECU that can be tuned on the fly. We charge $700/day for dyno time. It gets real costly to sit around while ECUs get sent around the country for reprograming. JT

I'm sure everyone would like to have the power to program on the fly, but the cost of that setup stops most people. If you have a cheaper alternative I'd like to hear about it. My complete fuel management system was several thousand dollars. I'm glad I did it, but most people don't go down this path.

What boost are you at now?

What cam?

So your motor started out as a 425hp 502 mpi?

Rob

Mark did a great job reprogramming the ECU for our HP500EFI supercharging system. Once in the boat, all he had to change was the IAC opening rate to compensate for big pitch, five blade props (stalled when put into gear at first). These engines ran all this summer in poker runs without incident. We were prepared to do "in the boat" programming if required, but it wasn't necessary, at least in this case (32 Skater).

I think the dyno operator should have O2 sensors on the dyno headers. You can see them on Mark's CMI headers in this photo. That way you can get the A/F ratio very close on the dyno under many diferent load conditions (RPM vs. MAP). Not only for steady state conditons, but for many different acceleration runs (eg. 2000-2500, 2500-3000 etc.). If Owens can't program the ECI himself, the current A/F readings would be a big help to whoever reprograms the ECU.

TOMCAT,

I think you have the Skater I saw at Victory. Sweeet ride. Owens sent the ECM off today and Mark should have it tomorrow. I hope he can get it close. I had a lot off problems with blower surge around the docks before. We were having to tweek the secondary throttle blade a bit to get some of the surge out of it. It was still a pain in the ASS around the docks with in and out of gear and turning the hydraulic steering on it.

The O2 sensor is mounted on his headers in the dyno room. I didn't use it when i put the Stainless exhaust on. Could have that been a problem with the engine before by not using it with the Whipple??

I want all of those issues gone. I still think there will be some tweeking needed once I get it back in the boat. If needed I guess I will make a run to Louisiana.

I appreciate everyones input on this thread.

Thanks,
Shawn

[QUOTE=29scarab]TOMCAT,

I think you have the Skater I saw at Victory. Sweeet ride. Owens sent the ECM off today and Mark should have it tomorrow. I hope he can get it close. I had a lot off problems with blower surge around the docks before. We were having to tweek the secondary throttle blade a bit to get some of the surge out of it. It was still a pain in the ASS around the docks with in and out of gear and turning the hydraulic steering on it.

The O2 sensor is mounted on his headers in the dyno room. I didn't use it when i put the Stainless exhaust on. Could have that been a problem with the engine before by not using it with the Whipple??
Shawn,I have a similar application to yours. I had Tyler Crockett dyno mine with his laptop hooked right into the mefi ecu.We made just shy of 950hp uncorrected using merc ecu,modified lower mpi intake,stock upper plenum and throttle body.On the dyno we used his cmi's with wideband 02 sensor and egts. I am using Stainless marine hi tq 3's,I tapped a metric hole into the manifold near # 8 cylinder underneath where its NOT water jacketed,no bung,just a hole w/metric threads. We re-tuned mine on the water 6 weeks ago,the afr's on dyno were 11.2-11.8-1,as installed in the boat they were closer to 10-1. Unless you go to a aftermarket ecu/efi system(I didn't) then Your best bet would be to have the guy dynoing it be the guy tweaking your ecu AND then re-tune it as installed in the boat.A tuner is forced to set your fuel curve a little rich if programming a ecu without seeing whats hapening at the motor. My boat ran much cleaner,smoother and used noticeably less fuel after re-tuning it in the boat,maybe Mark can get it close enough for you to finish dynoing it then you can take it to him for a final tune on the water, Smitty

Can Tyler get it close in the boat without EGT or O2 Sensors?