i have 1200 hp engines with whipple 8.3 L superchargers and a pair of 1050 carbs,i am running msd ignition and will keep it,not wanting the computer to control timing,but am thinking of going to efi at the end of season.i know nothing about efi,but am a fast learner.i have been watching this thread and it looks like haxby is on top of this,haxby,would you be interested in putting a package togeather for me to install,and if so,can you give me a rough estimate on cost per engine?

I've done the final in-boat tune of my SC'd 572's that are running MEFI-5 controllers. Builder developed the maps from scratch, and they are right on under power. I've had to get in and mess with idle, load anticipate, and stall-saver parameters to dial it in.

You have to have the Technical Pro software to really do anything with the MEFI-5, so that severly limits most people, and keeps the tuning in the hands of the shop. The basic software version lets you do most of the main fuel and spark tables, but locks you out of the specialized functions. If I had to do it again, I probably would have gone with MEFI-4, since although the MEFI-5 has some amazing features, I'm not utilizing hardly any of them in this application...

I am running a FAST wideband O2, with one probe per motor, and was getting 11.8-12.0. The cruise was a bit fat on the original setup, so I leaned the 3000-3500 range out a bit to get around 12.5. I guess this agrees with Dustin's advice, assuming my A/F is off by 0.5.

I just searched for mefi5 tuning program and found that mefi burn now sells it-HOLY smoke-THAT is going to change the WHOLE game around here!!!
http://www.obd2allinone.com/sc/toplevel.asp?cat=73

I talked to Bob 8 or 9 months ago about that, and he was going to give me a heads-up when he released it. Guess I got left off the mailing list...

You can run dual IAC's with an adapter harness. I believe that's how the unit that Whipple sells is set up? However, I have yet to find an application that needed a dual IAC after proper idle tuning. Even with big props and a 1.25 ratio. The Holley ecm will also allow you to run a PWM IAC that moves a lot of air with very quick response time like the Hitachi unit Merc uses. You can tune the IAC for your engine combo as well. There are several options for converting a roots deal. You can run one or two T-bodies or a hat with injector rails, or throttle body injection. Rootz EFI has a pretty clean setup. The Holley system will run any of these setups. If you're around 1000hp or under, the twin EFI t-bodies are the cheapest way to do it and only run 22psi fuel pressure so you do't need a monster pump either. I set these up inline and blocked off one of the IAC's for clearance. The only problem is there's no more blower surge unless you program it in.

Take a look around at what kind of setup you want run for rails, t-bodies, etc and I'll be happy to price out a system to run it.

BDS, Rootz EFI, Kinsler, Hilborn, etc.

Its cool that there is now software for mefi5 BUT I was under the mistaken impression that the 555 motorola was the same as mefi5 and unfortunately its NOT, Smitty

Haxby,
That looks like a pretty low profile setup. Who's throttle bodies are those? Where are the injectors?

That is a clean setup.
Rick

Yes, I had a gross conceptual error there too. Somehow I'd been led to believe there were similarities between Mefi5 and PCM555.

Holley, in the throttle body above the venturi's.