4 barrel throttle body with gm computer?

[4554x4]

I have built a big block Olds motor that would be capable of about 450 horse power, if I can get enough flow thru the throttle body.

I am using the 454 chev throttle body. it is equipped with a 4l80e overdrive trans that is controlled by the computer. It is installed in a 74 chev 4x4 that i use for towing.

With the configuration i have now it pulls pretty well off the line but runs out of steam pretty quickly due to not enough flow thru the small tbi. It would run much stronger with the quadrajet carb, but I love the easy starts and throttle response with fuel injection.

Does anyone make a 4 barrel tbi that would hook up to the GM wiring harness?

[Six_Shooter]

While there are 4 bbl throttle bosdies out there, most of them seem to use less than desirable injectors and many seem to fail.

A friend of mine has made a few 4 bbl throttle bodies by cutting apart and welding some 2 bbl throttle bodies together.

He runs the injectors in series and requires no modifications to the ECM to drive them.

His personal car is a '71 Olds Cutlass with a pretty stout Olds in it, making north of 400 HP, and 500 Ft/lbs, he's also running a 4L80E. He is using the 16147060 PCM to run the show.

[4554x4]

I would love to see that setup! Have you access to pictures or a way for me to contact him?

[4554x4]

I have checked the ECM, it is a 16147060. Can someone modify a PROM for this ECM?

[RobertISaar]

with that kind of motor, it would be wise to invest in your own PROM burner/emulator.

[EagleMark]

That motor is only going to tune if you learn to do it. You are not going to get a mail order chip to do anything more than run... even then this type engine or truck should be done on a dyno. You will need much time to get er done on the street. Even then you will find so more on a dyno. Wide band O2 sensor tuning is really the way to go.

The new Delphi injectors in the Holley 4 Barrel TBI are good but the old ones are fishing sinkers. Then you need to modify your ECM to run them properly.

I have tuned a 440 Mopar engine with a 454 TBI unit on the 7747 so yours should be better.

Tuning does not happen overnight. If you are not preparred (like me) when you start and don't have time? Find someone to hands on tune your car. Yours? Not a lot of comercail options in the country that would even try... I started learning these in 1987 when the first TBI truck came out.... did conversions for 10 years... had a built in chip tuner I worked for so never needed one then got 4 years into tuning on web and about 12 vehicles.... I learn something new each day.

Your TBI is probably running out of gas way before it runs out of air.

Have you recorded any data from the ECM? How about fuel presure? What injectors are in it? What's the cam specs @ .050 ?

If these guys help with your ECM tuning (I'm only experianced in old school EFI 7747) I would help you learn and tune that. It would end up being a great write up for a starter for others in future.

[Six_Shooter]

I would love to see that setup! Have you access to pictures or a way for me to contact him?

I should be able to get some pictures. I know sometimes he's a bit reluctant to share some things with the general populous.

There is no easy way to get a hold of him, because as much as he loves EFI, he hates computers, I do his tuning for him now. lol.

He was running on a mail order tune from a popular TBI tuning company, but since he changed the cam over the winter his old tune was no where near right, it was a drastic change. A couple hours of street tune and it runs better than it ever has according to him.

He's using the same PCM as you are, so yes the tuning can be changed. I just typed a 9 instead of a 4 earlier in the PCM service number.

The best thing you can do is get some of the equipment to tune. The original PROM can be replaced with a new EEPROM, which makes changes easier and quicker to make, you can also use an Emulator to tune while the car is running, I find this to be the best method, since you get to see the changes in real time and not need to shut the vehicle down each time you want to make a change. The time saved pays for itself IMO.

[EagleMark]

I stand corrected they can be run in series, I knew that but not in Parrelell. The one I saw done fired and injector right front and left rear and so on. This may have worked with a simotanious four barrel but filled the rear throttle bores on his progressive linkage...

[Six_Shooter]

Yes, progressive linkage would also require progressive control of the secondary injectors.

[4554x4]

Eaglemark, You have asked some good questions. I will research fuel pressure cam specs etc. I will need some equipment to record data. Where can I find this equipment Emulator etc?

Ant thought to running two tbis on a dual quad intake? I do have the intake manifold and it would look cool!

[gregs78cam]

Where can I find this equipment Emulator etc?

Ant thought to running two tbis on a dual quad intake? I do have the intake manifold and it would look cool!

As far as Emulators go, I feel if you can swing the cost the Moates APU1 is the cats meow. Does almost everything a average tuner would need.

Two TBIs on a Dual Quad would look something like my set up. It's do-able, just have to work through it. You can check out my thread for more info.

[4554x4]

gregs78cam, I dig your setup! I like your adapter! I think I will do that instead of using the old school dual quad intake. I believe that my performer intake will flow better anyway.

Much of the info here is just what I need. It will be quite an education for me. This site rocks!

[gregs78cam]

Thanks. A common plenum adapter is a little easier to make a single IAC work unless the the Dual Quad has both TBIs mounted to a single plenum. But a dual quad will make it easier to fit an air cleaner. In a truck you should have plenty of room to do any type of air cleaner setup you like. There are pros and cons. To make mine work there were quite a few items that I had to machine and weld to make work. I will get some detailed pics today and update my thread with all the procedures and parts I had to make in order for it to work. I should have taken pics while I was making everything, but oh well. I didn't know if there would that much interest in how I did everything.

[Six_Shooter]

I know the 16197427 PCM has no problem running a pair of IACs. I haven't tested that with a 16147060 PCM though, but I can't see the IAC drivers being any different.

[4554x4]

I know the 16197427 PCM has no problem running a pair of IACs. I haven't tested that with a 16147060 PCM though, but I can't see the IAC drivers being any different.

Perhaps I dont fully understand the statement, forgive me if I dont. Wouldnt it run just fine using only one IAC instead of both?
I picture splicing the injector wires together, using only one IAC and TPS.

I definately have much to learn. Would it be possible to have too much CFM available, like over carb'ing or would the programing take care of that?