I did a search and was surprised to not find anything on this topic, so I hope this thread is okay.

So I spotted this https://www.thirdgenranch.com/catalo...1cabb9cdf54c68 at thirdgenranch for a great price and thought it might be a fun little project. With everything listed there, what else would I need to convert my carb to TPI? The only modifications done to my engine are the smog/air pieces have been removed.

Would it be "worth" it? Would there be any initial power gains? Getting tired of always fiddling with this old quadrajet all the time (yes, its been rebuilt numerous times, yes I am using Cliff's book and stuff).

 

You would need a high pressure in tank pump. Not a bad deal.
You would also need to elongate the center four holes of the intake.
You might need to get the memcal reprogrammed depending on its origin.
You need a o2 equipped exhaust manifold for the drivers side or a o2 bung welded in. Maybe a heated o2 if you run it in a bung. Efi offers easy start and better fuel economy and more torque for tpi.

 

Ive thought hard on doing the swap myself being I have a complete system off a previous car of mine stashed away and damn it does look cool sitting on top of the engine bay. TPI can be finicky though and probably more so than a quadrajet or TBI in my past dealings with them anyways. May give you some torque gains but I doubt horsepower unless you go ahead and swap to a warmer cam, better exhaust, etc that the factory TPI already had as compared to the LG4 cars from the factory.

 

I would think it'd be easier to revert to a non-computer Qjet and vacuum advance distributor, and make it work. TPI is a good setup, but it has certain limitations.

I sure wouldn't give money for an early TPI setup. 89 is about the minimum year I'd consider. 85 TPI systems have a lot of goofy issues, and they get better every year until about 1989. 89-92 are all pretty well sorted.

You're pretty much looking at replacing the fuel system, all the way from the tank to the rubber lines from the fuel lines to the TPI fuel rail. Alternator bracket is TPI specific in 85-87 too. To get the same power as a TPI car, you'd need the entire TPI exhaust system, flat top pistons, better cam. The intake itself is really only good for torque and emissions, maybe a little efficiency.

 

Consider this: http://fitechefi.com/products/30003/

Self-learning EFI fits on a 4BBL intake manifold. Plus they have 4 fuel system options, so you don't have to convert your tank.


http://fitechefi.com/products/31003/
http://fitechefi.com/products/40003/

 

i did this swap years ago on my 86, converted to 92 speed density style TPI with accel base and runners and a holley 52mm throttle body. the reason for this was i was tired of smelling like fuel after getting out of the car and wanted to supercharge it.

with the 305 i had out of an 88 formula that i rebuilt with world product s/r torquer heads and a crane roller cam and D1sc procharger i made 380hp/420 ft lbs to the wheels.

i pulled that in favor for a 6.0 ls motor... the tuning on TPI is lacking and i just could not get it where i wanted it.

 

Never have had an issue getting a Speed Density TPI system running where I wanted it to run tune wise.

I have run Speed Density (MAP) setups on both the 165 and 730 ECMs. There are modified versions of stock coding for both. The 749 code from the Typhoon/Syclone runs a 2-bar MAP sensor right from GM and the modified code can run a 3-bar. You can real time tune the OBD1 stuff much more cheaply. The OBD1 stuff also has ECM hacks with commented dissasemblies available. You can look at every bit of the code and know exactly what is going on within the ECM. The revised version of the Typhoon/Syclone code even allows for wideband closed loop.

 

i was running a 7730 with the $59 code using a 3 bar map. it ran like a raped ape full throttle but idle and driveability is where it was lacking. i experimented with the wideband closed loop control and was not happy with that either..


i already have hptuners pro, i had done some tuning on my vette with long tube headers and a cold air intake, there is no turning back now, so much better and easier than the old stuff.

 

I have used many softwares on many different vehicles. I still prefer TunerPro even on my Express vans 0411 when I still used the 0411. The only thing I would use HP Tuners for is to dial in the VE and Spark Tables. For everything else I used TunerPro. With HPTuners you cannot even do the simple task of enabling lean cruise.

However that being said, by far the easiest to tune vehicles have been real time tuning my Nissans with Uprev. They are MAF based with factory widebands.