TPI Setup questions

[GillBill]

I am looking to buy a TPI setup off ebay to put in my 388ci. How difficult is it to get TPI to run on a built engine. Any difference between maf and speed density in regards to tuning. I am putting this in my 1st gen, so insight is appreciated.

 

[dyeager535]

RyanB is a good source, he's done it on the first gens.

MAP is less forgiving of engine changes than MAF, but on a 388, you'd be insane not to tune right off the bat anyways. You'll need larger injectors than stock, no question. I can't emphasize enough, 350 spec parts do NOT flow enough as stock, to keep a 383+ alive. They *will* run lean, and can/will destroy the engine before you know what is happening.

What heads are you running? If you are running "old style" bolt pattern heads, a TPI *base* off of the '85-86 cars is what you'll want. No effort to make the base fit. The upper stuff (runners,plenum) you'll want off an '88+, which is when they got rid of the cold start injector, which was a bad idea. (the CSI that is)

'89 is typically considered the best year of the MAF setups, not sure that the '90-92 MAP setups had much improvement over those years. I haven't dealt with them firsthand, so you'll need to get more info on that.

Anything '89(I think it was '89, easy enough to find on thirdgen.org forums) and newer has VATS, the anti-theft stuff, so you'll need the PROM modified just to accomplish that, let alone getting the engine to run at it's peak.

To get tuning done right, you can pay to have it dyno tuned, send a datalog of your engine running to a tuner and have them burn you a chip (and repeat until right) or you can learn to do it yourself.

thirdgen.org forums are a HUGE source for TPI info, if you have any questions, typically its best to *search* over there before asking anywhere else.

 

[K5MONSTERCHEV]

Im selling my TPI, complete. Speed density system, fuel pump, harness and air cleaner. Check in the for sale forums.

 

[Hossbaby50]

Yes TPI will support a built 383 pretty well. If you want to achieve max high end HP then you will need to spend some money on aftermarket parts like bigger runners and a bigger throttle body but a stock TPI with bigger injectors and tuned will do a pretty good job of making a 383 run well.

TPI typically will only support good HP to around 4800 RPM and maybe a little less on a built 383. They will not flow enough air stock to support big HP above 4800 RPM so if you want max HP up there you need to do some porting or spend some money on aftermarket stuff.

If the 383 is built for lowend & midrange then stock TPI with bigger injectors will make your 383 a real animal. When I swapped TPI onto my 350 it woke the motor up ALOT. My lowend torque went WAY up along with my throttle response. My 350 is a 300hp crate motor and the TPI made the motor thrive and make way more power throughout the powerband. TPI is one of the best mods I ever did. I wouldn't change it for the world.

I personally run MAF TPI but that is because it is what I bought and it works. If I had the time and money to tune a MAP setup that would be awesome but the MAF runs well for me and it will stay for now.

MAP can have some problems with built motors especially if they have really lumpy cams. Research them both and find out if you have to much cam or if you haven't built the motor yet then build the motor with a cam appropriate for the injection setup you plan to run.

Be careful with early TPI. 85 & 86 weren't the best years. 87 and up were the good years.

Harley

 

[4X4HIGH]

Be careful with early TPI. 85 & 86 weren't the best years. 87 and up were the good years.

Harley

Unless i'm missing some info all the 1985-1989 were MAF systems using a 9th cold start injector and the only difference was 1985-1986 having the early style intake bolt pattern. 1990-1992 were MAP systems and the 9th cold start injector was deleted. Both systems from a camaro are batch fire and some of the corvettes got a sequential fire.

 

[Hossbaby50]

They are not terribly different but 85 had a different slower computer.

"The 1985 TPI calibration is contained in a EPROM (Eraseable Programmable Read Only Memory) and is a 32K chip. The 1986-89 ECM contains a 128K EPROM, 90-92 ECM's use a 256K EPROM."

85-86 used the big cap GM distributor where the 87+ camaro's and firebirds used the smaller easier to work on smallcap disty. Corvettes kept using the bigcap HEI. With the tall TPI manifold getting to the small cap HEI is still a PITA so the bigcap has to be harder to work on the the smallcap.

"All 85-86 systems used a GM HEI distributor. The connector for the distributor is keyed differently than previous model years. 87-92Camaro and +Pontiac systems use a small diameter distributor with an external coil."

85 also has a different wiring harness then the 86-89 cars with a different MAF burnoff relay setup.

All the quotes are from http://www.fuelinjection.com/portinj.html

If you were going to run MAF TPI the optimal setup (assuming older head style) would be an 85-86 manifold and an 87-89 TPI setup. The older 85 & 86 setup would work fine but they are just a little different and a little less desireable IMO unless the price is right.

Harley

 

[dyeager535]

I KNOW '85 you want to stay away from, '86 may be as well.

'85 used a separate MAF piece that is apparently so rare, it is prohibitive by cost or to find. (you can find reference to a piece that is attached to the ECM, thats it)

Cold start was gone in '89 for sure, maybe '88 as well.