I'm pretty much getting tired of my TPI setup. I can never get it to run right and I failed emissions terribly. I have decided I want to go carbed because I like the tunability. What I have planed is nothing big something along the lines of an Edelbrock Performer Intake and an Edelbrock performer 600cfm, I want to be able to pass emissions. What kind of power differences could I expect switching over to a carb? Also what is the easiest fuel pump solution? Thanks for any help.

Well I read just about all of the posts on the swap and I think I have everything figured out. My only questions that remain are , am I gonna feel any power difference. I already bought a Performer Intake and a 1405 performer 600cfm carb. Also I wish to retain my Air system, Is that controlled by the ECM?

You can tune a TPI engine just as easily, it only requires different tools. However, because the '85 setup was one-year only, its a bit more difficult.

Power is subjective. You'll have more power above 4500 rpms, but you'll have less torque from idle to 4000 where you need it on the street.

As much as some of the more old fashioned guys don't want to hear it - fuel injected is superior to carbureted in everything except the price of tools required to tune it, and price in general. You will not be able to retain the air system, you will not be able to retain the computer controlled EGR system, or the EVAP canister. If you're dead set on going carb'd (which It seems you are since you already purchased everything), I would purchase a book on turning for economy and performance. If you car wasn't tuned for the camshaft you put in, then you'll definitely feel a power difference once you get the carb dialed in. As kevin said, not so much low end, but deffinitely top end.

Well I already passed my evap test and visual, They just need to do the road tests.

Don't get me wrong I don't have anything against fuel injection in general. In fact the TPI system was the initial reason a I got this car. But I figure I would rather save up and do and entire LTI swap. Like it was mentioned the 85 is a a PITA, I can't do anything with it.

You could convert it to a later '86-88 ECM.

Thats what I have been trying to do for the last 6 months. I can never find a correct ecm. Just this weekend I went to the Boneyard and found three gutted Irocs and 2 gutted Z28's. They every bit of evidence that the car was a TPI. Everyone always beats me to them. All the ones I find online are ridicoulusly expensive.

I would need the ECM and Prom form a 350
I need the ESC module
Knock sensor from a 350
22lbs injectors

Random wiring and relays. I don'y mind doing it but I can't those parts all at once.

On another note, Would this work if i used my existing TPI fuel pump?

http://cgi.ebay.com/ebaymotors/ws/eB...m=350013569527

Go to the parts store and buy the ECM and knock sensor, go to GM and buy a prom to match the ECU, Summit racing for the injectors. Possibly a custom prom tune for it to run properly or to get more horses.

While I'm at it I'll buy a supercharger, a nitrous kit, forged pistons, eagle crank, some trickflow heads, etc... Its not that easy man. I can't just go to the parts store and dealer and buy parts.

You can use the stock fuel pump but you need a bypass regulator, I used the mallory 4309 and it worked like a champ.

Buzzman1

I would not use a regulator for the swap... do it right and get a carb pump. i have the same regulator and cannot get the pressure steady enough. There is crazy pressure spikes.

anyone wanna buy a mallory 4309? lol

I was thinking about using a regulator, and I didn't think it was a good idea. I actually did the swap already, and I filled up the carb and it fired up. It runs so smooth. I am pretty happy with the results. I will post up some pics soon. For the fuel pump I am gonna use a stock carb pump and I bought a fuel sending unit for a carbed car. I'll do that swap tomorrow.

In another thread someone mentioned the possibility of my cam not having the Mechanical fuel pump Lobe. Anyone know the difference from Car to Car?

I think they changed cam designs in 86 and went to the roller cam which I dont think has the pump lobe. Threw my old one out or I would check...as far as the pressure flucuation with the 4309 I had that too but only a little bit and it seemed like when I got the crappy battery out of the car it seemed better. I dont know if the battery was too weak or what but the 4309 works perfectly for me.

Buzzman1

crap.....

I have a holly blue pump on the shelf, i guess ill try that next.

So i got everything done. and wow am I impressed. My car will actually pull through 4500rpm now. It seems to jump after 4500rpm now instead of running out of breath. My exhaust tone is actually nice.

I think I'm gonna start enjoying my car now.

yeah mine too ...the car pulls right through 4500 like it was nothing ...going to the track next week and the slip will tell but seems a lot quicker. as this was a difficult project I got a great sense of accomplishment doing it correctly.
Buzzman1

TPI is good for low end torque and thats about it... I shaved .5 switching from HSR to carb.. if the TPI is out of tune you might as well go carb.. I can tune carbs but I don't know anything about prom tuning so it was a no brainer to go carb I like them better and properly set up they can hit as hard as FI and make more power.. I would throw a performer RPM intake on it and depending on your gear ratio/stall converter a holley 650 double pumper would be best performance, an edelbrock 1405 or even a quadrajet (if you know to tune them) would all work well. You will also need a vacuum advance distributor..

if you have to pass smog though I would get a Performer EGR intake, and a quadrajet and hook my vacuum advance to ported vacuum and have all the AIR stuff hooked up as well as a functioning cat you should pass smog no problem.

It's also good for reduced emissions and improved fuel economy.

If your car is '88-newer, carb isn't an emissions-legal choice.

who drives a third gen for emssions and fuel economy?


then why did 88 monte carlo ss have carbs... might just be in california

Im doing the same swap but with a 355ci and cam, Glad to see it works. What did you cut from the TPI harness?

I didn't have to cut anything. I pulled the entire harness out of the car.