88blkiroc

Is it possible to use a TBI setup with a turbo? This would be on a 350 motor in a 93 Chevy 1500. Id imagine you'd need a 454 TB with the bigger injectors (90lb?) But how would you adjust the fuel flow for the boost? Use a MAP sensor and tune the computer or would you need some sort of piggyback fuel computer? I'm not talking about huge boost though. Maybe 6-8psi. I have a couple spare turbos and a welder to make up an exhaust manifold. Just kinda dreaming here but if its doable without too much messing with electronics, I may give it a swing. What do you guys think? Ever been done before? Thanks for the input

mzoomora

iTrader: (31)

There are other FI systems for TBI's, so you would just find out what they use for fuel. You can get a lot of fuel out of a TBI with an adjustable regulator, and the 454 units flow decent air also (670 stock, more with an injector spacer and without the factory spacer ring) You should be fine with 6-8.

TurboGibbs

iTrader: (6)

I happen to know someone who could help you out. The tuning process is much more difficult than with OBD2. It takes a lot of patience. Contact Brian @ tbichips.com and tell him Mark Howard sent you. He would be the best person I know of and have personally delt with with the OBD1 mods. We are currently working on a naturally aspirated 383 of mine. He has done blown tbi's in the past and now has a very good business going.

kbracing96

iTrader: (26)

I did it on a 91 S-10 with a 2.8 TBI V-6. Same concept, just a smaller motor. I put 4.3 injectors in the 2.8 TB and used a rising rate fuel regulator to increase fuel pressure for boost. Worked good for 6 lbs of boost and pretty cheep. I had about 700 bucks in that whole turbo setup. Let me know if you have any more questions about the setup.

88blkiroc

Cool. Thanks for the advice guys. I figured that would be about all I'd need but I wanted to make sure. Somebody else on another site was talking about a booster pump for the system too. Anyone know what hes talking about? Also, I forgot to mention this before but I will be intercooling this system as well.

Mzoomora - What are the injector spacers and factory spacer that you are talking about? Sorry for the newbie question but I dont have any experiance with TBI. I'm used to dealin with TPI on my Camaro.

kbracing96

iTrader: (26)

You probably will need an in-line booster pump. TBIs only run about 14 psi fuel pressure and you will need to get it up to about 26-28 psi depending on boost to add enough fuel. If you go much over that the injectors will lock shut and not fuel. Its kind of tricky to tune. My stock intank pump on the S-10 would only get it to about 18 psi. The one I uses was made by MSD and was around $80 from Jegs I believe.

Another problem you will have is a small about of fuel will leak/be pushes out around the throttle shaft under boost because the injectors are before the shaft. I just lived with it, its makes a little mess on the intake and you smell gas once and a while, but there is a fix for it. Basically, you have to drill a small hole up from the bottom of the TB to the shaft and then drill a matching whole down into the intake about a 1/2 or so and then drill a hole from the side of the intake in to the hole you drilled coming down from the throttle shaft. Then you JB weld a small, 1/8 tube or nipple in that hole and plumb it to the TBI hat so it will be pressurize the throttle shaft will boosted air which will have a little more pressure that the air in the TB do to pressure drop. This will seal it you and you won't get the fuel leaking. Make since?

TurboGibbs

iTrader: (6)

On my 95 383 I have a 255lph pump in the tank and i'm running 19psi pressure with gm 454 injectors(90pph) on a Holley 670 cfm tb. I was running the holley injectors but they would not function well above 15 psi. So I had to put a gm injector pod on it with the 454 inj and an adjustable fuel pressure regulator. In my opionion I wouldn't bother with intercooling it with only 6psi of boost. The tbi acts much like a blow through carburator in the sense that the air gets cooled in the intake by the vaporizing gas. Multiport injection engines don't have a chance to cool the air because of where the fuel is injected. It works just like Meth injection but better. That same cooling effect or lack of it with MPI is why those motors respond so well to cold weather and carburated engines arn't effected as much. Like I said before email brian @ tbichips.com and he can tell you everything you want to know about tbi and get you tuned for the turbo.

88blkiroc

So should I go with the in-line booster pump or should I just put in a stronger in-tank pump?

LVSTOGOFST2002

iTrader: (3)

i have a high performance in tank tbi pump, with no use for it. I bought it for my hp 350 in my 93. it's the 20-46psi unit from turbocity, if it'll do you any good, pm me about it. It's brand new, in the box. i also have a pressure regulator, and a injector pod spacer. ( used ) for sale. i have a few other goodies laying around too ( headers and such, might make things real easy for your fabrication process, they're edelbrocks tubular exhaust system, but i'm missing the y pipe, so..... hard to sell, but maybe perfect for someone like you, fabbing things up, they're a midlength type header, they exit a little lower than a stock manifold )


here's the link to the pump.

http://www.turbocity.com/product_info.php?products_id=4

NXRICKY

iTrader: (1)

Right now I have a fuel plate that adds the extra fuel needed.. It uses 2 80 lbs. injectors. Standalone computer, contains map sensor, and a few other thinkgs(built into the plate), like linking to a wide band etc, and a mini fuel rail....
Let me know if you want to see the pics.
You will need a bigger pump and a bypass reg,(fmu to raise fuel psi), TBI trucks and 15psi is not much to play with.
Ricky