Strip Poker 388

Here is some picks of what CMI did on mine


http://www.offshoreonly.com/forums/s...ighlight=bungs

onesickpantera

It wasn't their system. It was a re-flash of the stock MEFI 3 system for the whipple along with larger injectors, fuel rail and a couple other small components.

29scarab

Appreciate that 388!!

Outdrive1

I changed my injectors with the Vortech, I also had the bung welded in the header for the wide band o2 sensor so it could be tuned on the fly while running. AZSM did the work. No mechanical failures in 100 hours. Last winter I put new heads and a new cam in it. I also re did the entire fuel system with Aeromotive stuff (filter, pump and regulator). The bung on the headers is a great place to adapt a pyrometer after testing, I would also add a fuel pressure gauge.
As for just bolting the system on and running it? I would say no way. You need the ECM remapped and it would be best to tune it in real world conditions and not just mail it to someone. The stock injectors are about 43lbs (I think)?? I think they put 55lb injectors in mine. I also notice that if I adjust the regulator below 47lbs at idle the knock sensor goes crazy and temps start to get high on the pyrometer. The stock system is only good for about 43lbs even with the new regulator. You may need an after market pump.
Fuel management is the key, maybe at 4 lbs you can live with 43lbs of fuel pressure and stock injectors as long as you have the map sensor changed and reprogram the ECM. I would also set it up so that the rev limiter stays at about 5500 max. I'm running mine at 5500 but it's propped for about 5200. Those motors seem pretty happy at 5200, although you can make a ton more hp closer to 6k, unless you put some money into the rotating assembly, heads and lifters I wouldn't turn it that high. You motor has a roller cam but the valve train is just stamped junk.

chase n us

To get back to the stock fuel injector on the whipple 502, I had two different places flow test the stock keihin fuel injectors and their optimum operating range is 45 psi-53 psi. If you go with more pressure the coil on the injector will not open the injector properly and then you will have a lean out situation. I have an adjustable regulator on my fuel rail and fuel pressure gauges on my panel. The Mefi 3 and the stock injector will provide a reliable fuel pulse of up to 13 milliseconds which seem's to be adequate for applications up to 600-650 HP 5Lbs of boost. If the demand calls for any more injector pulse time the drivers in the computer can't handle the load and fail to provide the needed signal to provide the amount of fuel the engines require. So to answer the question Ray is definately right on when he say's "NO". If you are looking to make much more power than 600-650 HP then you will need something more reliable. That is why the New F.A.S.T system seem's to be the way to go next time with injection or just go back to the basic's with a nice Blower Shop blower with a big Carb.

29scarab

I think once it was all said and done on the dyno with my engine it came out between 40 to 43 psi for fuel presure to feed the Whipple and the engine injector rail. That was with the new aeromotive pump and regulator.

Just got a call that my fitting for my return line back to the tank was ready at the fab shop. I might be tuning tonight.

onesickpantera

Well, I originally started this thread cause I had a chance to pick up a used side mount. It had the older computer system and secondary injectors that would not work with my MEFI 3 system. I contacted Jim at ASM and he stated that bigger injectors, a reflash of my ECU, fuel rail etc is the best way to go.

I really didn't want to go this far but the bang for the buck is great especially when you can find a used one. I only want 500-550 hp so I would be running 3-4 lbs boost. But I have to admit all these supercharger posts I read with tuning problems, melted pistons, broken valvetrains, etc scares the hell out of me!

chase n us

It should scare you unless you have a continuous open check book. I think the best advice you can get is to take your whole package to a reputabe shop, spend the $700-$1,000 for the dyno tuning and you will have minimal problems.

onesickpantera

Exactly! And I don't! My thoughts were to get the sidehanger, add the larger injectors, fuel rail, get the ECU re-programmed and add a Powerdex AFX moniter.

But on second though maybe I'll just add some exhaust and get the prop labbed!

Pat McPherson

Smart Choice!
You don't need a supercharger to get to 500-550HP anyway.
Buy some good exhaust and get your prop tweaked by BBlades.
Enjoy the boat for the rest of the summer.
If she's not quite fast enough , do your engine work during the winter.
Head work, cam change, and a reprogrammed ECU from Tyler Crockett or Mark at Precision EFI will get you over 500HP from your 502Mag.