t/adreams

iTrader: (1)

I gave a search a whirl, found *some* info, but nothing as detailed as I'm looking for. I have an '88 TBI T/A and am wondering if I can use the block I have and convert it to a TPI setup without pulling the engine.

I'd like a list of parts that are needed, and if its worthwhile power wise considering the car will still be running with the swirl heads (unless it is necessary to change them too for a TPI conversion).

Thanks for your time!

Z2EIGHT

Honestly, I don't know what TPI I does, and if it involves lots of parts and becomes expensive... you could build a 350. I heard its cheap.

Kevin91Z

iTrader: (1)

Yes its possible to change the intake, replace the computer, and repin the wiring harness while the engine is in the car. My dad did it on his old '92 RS. There is a tech article on this site that helps, but its old and outdated now. You can search for posts on this swap by myself and my father Dyno Don.
The car went from 158 RWHP to 176 RWHP, and 220 RWTQ to 290 RWTQ, using the same camshaft, heads, and exhaust manifolds as stock, but the cat-back was changed to a stock 2.75" from an 85 IROC while it was still TBI. Gas mileage also increased a little, like half a MPG.

t/adreams

iTrader: (1)

Now THATS what I'm looking for!!!! Thanks, I'll be searching out your family's thread. Any idea where you posted it?

Ogre91

t/adreams, I am looking for this answer too. I will share what I find.

blizzted

when you guys find please let me know as well.I am doing the same thing but im replacing the 305 with a 350 in my car,I was going to stick with the tbi but after the price of boring out the tbi,getting new injectors and other nickel and dime stuff i just went to ebay and got a complete used tpi with a puter for 200 bucks,Now heres what i wanna know can the tbi harness still be used but modified,also what sensors if any will interchange such as map,ecm and also the dist.,and the fuel pump will have to swaped out im sure....

DerrickB4C

im alos looking to go from a 305 tbi to a 305 tpi. my donor car is a 1988 t/a tpi can i use the 1988 stuff on my 91 camaro?

sully91rs

Hmm, I haven't done this, but I do know that the TBI fuel pump is way too weak (around 14 psi) to fuel TPI (needs around 36 psi). So on top of the TPI swap, you'll need to upgrade your fuel pump.

five7kid

iTrader: (14)

Pressure is a function of the restriction produced by the regulator. A TBI pump may produce 35-45 PSI, but it won't be able to keep up with the required flow at that pressure. So, it is true that you need a different in-tank electric pump, but not for the reason stated.

The TBI can be changed out with a TPI, but the heads and cam of the TBI engines weren't as good as the TPI engines. The best way to do the swap is to change the complete engine (or at least the heads and cam along with the rest of the TPI stuff), harness, and computer.

You should be able to use earlier TPI equipment in a later chassis.

Kevin91Z already answered the question about using the TBI harness on TPI - yes, it can be done, but you have to "repin" it. Easier to just get a factory TPI harness.

sully91rs

Thanks for clearing that up.

blizzted

Heres a link to a web site i ran across today it has tons of great info on it

http://sethirdgen.org/tpi1.htm

DerrickB4C

great link