Hello everyone. I've built this motor for forced induction, originally with a 8-71 roots blower in mind, but have decided to put twin T04E Garrets on it. It already has the 7747 as it's a 88 Chevy truck and was wanting to know if I use a 3 bar MAP sensor can I be able to have the VE and Advance tables accomidate accordingly? I'm planning on a moddest 15 PSI of boost (not to sure how much air flow that will be) and that is right with-in limits of the 3 bar MAP sensor.

If I can do it responsibly then can I get some advice as to how to change the code which is $5D I believe to work right? I'll be using WinALDL to log and the Motes Ostrisge EPROM Emulator to tune on the fly. I have a Turbo Talon that is going to be putting down 600 WHP and I think it wouold be a total shame to have a motor that is twice it's size not be able to at least match it. I tune my Talon via ECU (as I hate piggy backs) and with it I'm able to change a lot of things to do what I want. Like I'm using the EGR Soloniod output for a PWM to activate my alcohol injection and other crazy stuff that I never thought was possible with a stock ECU. OK I'm babbleing now. So yeah any help from those that know the GM ECU as I don't yet, and maybe from some that have gone forced induction on the TBI system.

Thank you,
Maglin

 

It's a lot easier to just go with a 7730 or 7749 ecm depending on injectors and $58 code. You get quicker aldl and code already set up to support boost.
There was a post a while back on repinning a 47 to a 730.
I think only one person has successfully used 1 bar code with a 2/3 bar sensor. And it was 730 8d IIRC. And he isn't a beginner DIY promer.

I'm gathering parts for a single t70 set up and going to use a 730 with $58.

 

Your problem is going to be fuel, at best the biggest injectors you can get are 90 lb/hr,and with those cranked to a real high fuel pressure you may be able to feed 400 hp, no way you'll feed 600. Also no way to use a 2/3 bar sensor with 747 without really doing some wild stuff. You need to swap to a 730 or 749 and run 8 big injectors, then run the $58 code, it's all set up for boost.

 

Maglin,

I have a 7749 available if you're interested. BBMonteSS comments regarding adequate fuel supply is probably the biggest obstacle you're facing. Joby on this forum and the Crossfire Forum has also supercharged his Vette. You may want to discuss his strategies.

 

Dominic,
So this is basicly doing a TPI swap? Do you have everything needed ie. Harness, ECU, Manifold and TB? I know about the injectors and I know where I can get some Bosh 1600 cc injectors fairly inexpensively. I'm going to try and stay under $3.5K as a budget for this porject. Since I already have the turbo's I just need the ECU, Manifold, and TB and the rest I can pretty much fab personally.

If TPI is the way to go then I'll just mount the Turbo's backwards for shorter pipe routing and pull the intake air from a reverse cowl pretty much right at the back of the hood. I have a few intercoolers laying around and I'm sure I have one that I can make fit. I'll PM you about your set-up.

Thank you everyone for the comments. I'm very very new to GM ECU programing. Been playing with the DSM ECU for 8 months now and have that just about down pat. Still learning some HC11 programing so I can try to totally convert a ECU from MAS to SD which is what all forced inducted cars should run. Harder to tune but once tuned they perform the best. ie... boost leaks pose no problems to SD systems as it's all off MAP anyways..

 

I have a similiar question about a project I've been working on. I have a 355cid all set to go for a 6-71 blower. I was thinking about running multiple throttle bodies on top instead of carbs. Is this possible with a 7747, or do I face the same problems as turbos?

 

Sorry...computer posted twice

 

Maglin/SB406,

You may want to visit this site. Joby is a pretty sharp guy.

http://web.telia.com/~u60505093/index.htm

 

You *could*, with a min amount of work do that. BUT, it would be as much fun to drive as a concrete truck.

There are two Speed Density non N/A codes, the 58 and 8F. The 8F is about as complex as you can get. The 58 is what was used in the Syclones, and the Source Code for it is available, plus a patch to make it 3 bar. Not to mention the schematics for the unused outputs is available on line.

If you want to run the 58 code then you'll need to run a 730/749. The 747, and TBI will have a hard time being used in a 600 HP application.

I'd suggest a 730/749, 58 code, and 60 PPH injectors, done port style.


This also applies to the 6-71s guys questions. With the throttle bodies on top of the blower, and MAP sensor below the blower, it doesn't matter how many TBs you use.