Recently i've been thinking of switching my car over to carb, how hard would this be to do? I think i've got a pretty good idea on how to do this but would there be any problems i would run into with the fuel or ignition systems that i may not have thought of?

 

Youll need to buy a non-CC dist., three way fuel pressure regulator so you dont dead head the pump, and obviously the carb. There will be little items and youll also need a carb intake if your using your stock tbi intake.

There is also a tech article on TGO about this.

As a side note, youll loose functionality with a carb and there will be little performance gain. The only gain really to be had is that a performance tuned carb will run leaner at WOT then the stock computer will. Reason for this is due to the need to run really rich to cool the cat and sap all teh oxygen out of the exaust so the cat doesnt burn itself up during extended high loads.

 

i am doing the same thing so i will just post here, didn't mean to hijack your thread. i have a 90 tbi all i wanna know is can i use the stock fuel pump and what kind of regulator do i need if i can use it. also where would i get it. thanks

 

Heres all you need to know:

https://www.thirdgen.org/newdesign/tech/carbswap.shtml

 

i got a question about the other electronics...will your gauges and everything still work when you switch to a carb or do you have to replace them with different gauges??

 

They don't go through the computer, so they'll work. VATS and digital speedometer are a couple of things that get in the way. And fuel pump activation (depending upon what you're starting with).

 

i have a Q...i'm a newbie....so dont laugh if my Q is stupid....but why would anyone want to change to carb?...i thought the TPI was better?...

 

because you can make a lot mroe power for cheaper with a carb....FI is good, don't get me wrong, but its so damn expensive to make big power....when you modify a FI motor you have to reporgramm the computer, costing around 500 bucks to get it running good...a carb, you just buy parts, and adjust the carb and timing...its quite simply...carb=simplicity and cheap FI=for guys with the need for speed and money

 

I switched from tpi to carb a few years back and i have a friend going through the swap now.

i prefer carb cause my knowledge of FI sucks and the same with my friend.

 

oh....thanx for clearin that up...i have a 86 camaro 305 4bbl an had always thought that EFI was the path i was gonna have to go to make big numbers.....i'm a newbie so....i'm lost in muscle performance...

 

your carb should be good for 500hp now as it stands, with some tweaking of course.

 

GOOD MAN!!!!!!!!!!!!!!!

 

The issue is airflow.
If you convert to carb, you can use any intake manifold
you want. The stock tbi or tpi intakes , restrict airflow.

 

Im gonna make the swap just because ive grown up with carbs and when it comes to cars, I just dont trust computers.

 

Im gonna have to agree with ya on that one I'd rather have carb than mess with all the dam wires on that injection

 

Doing this myself for a lack of knowledge but...

Fuel pump activation and VATS was brought up!?!?

I have a 1991 TPI car and need to know if my fuel pump will work and if VATS will disable the car when I remove the ECM.

 

From what I understand, neither will be a problem as long as you keep the ECM in place. It won't do everything it used to do, but will continue to do those things.

If you have problems, check the tech articles linked from the thirdgen.org homepage for VATS info.

If you rewire the fuel pump, the power should be routed through the oil pressure switch for running operation. You can hook a parallel power path through the starter solenoid for starting priming.

 

so to wire that fuel pump in you just splice your gas line wherever you want to install the pump, connect each end of the gas line to each end of the pump and secure with the proper clamp/fitting, and wire the pump into the oil pressure sending unit?? do you just splice connect protect? where do you locate the afpr? fuel pressure gage?

 

Are you talking about using the existing in-tank electric pump, or an aftermarket in-line electric pump?

Most people mount the AFPR to the inner fender in the engine compartment and run braided line to the carb. You can mount the fuel pressure gage most anywhere you want, using a regulated port or somewhere in the line up to the carb.

 

im talkin about an IN-LINE pump as in non in tank. i cant imagine just wiring this to a positive and i dont remember reading about this in the efi to swap article.

 

If you use an in-line electric pump, you should first remove the in-tank electric. There's a sticky that details a good way to modify the pick-up.

The existing in-tank electric wiring can be used for an in-line electric. Keeping it wired through the engine-mounted oil pressure switch is a very good idea for safety reasons.

 

ok thanks