I just bought a TPI system at a swap meet (Intake, runners, throttle body, plenum, fuel rail, injectors, and computer)it has 1987 stamped under the plenum, I am guessing that this is the speed density unit. That is about all that I know. I have read the TBI to TPI tech article (good info). Here are my questions:

what is the difference between the early TPI and the later TPI ?

Which harness should I buy and where ?

What is the RPM range on a stock TPI system ?

I will be installing this on a 350 (10 to 1, 218-224 duration @.050 495-503 lift hydraulic roller cam, edelbrock aluminum heads 2.02-1.60, 3.42 gears, custom chip, and SLP 1 3/4 headers. Can I use the stock base and runners with this setup ?

I'll take any comments on this set-up and what works best on a TPI set-up, thanks for the help.

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1990 RS Camaro 305 TBI, 700R4 Tranny, 3" cat back system with flowmaster muffler, Edelbrock strut tower brace, rear panhard bar, and torque arm, Spohn subframe conectors and lower control arms, all polyurithene bushing under the car, KYB gas adjust shocks and struts, March underdrive pully system, Taylor 8mm plug wires, Accel super coil, K&N air filter
Hypertech chip
GM Aluminum driveshaft
3.42 Zexel-Torsen Rear end with superior 28 spline alloy axles, and Summit aluminum rear end girdle, Killer sound system, Many new mods to come (swap to 350 comming soon)

[This message has been edited by sbrice18fan (edited August 24, 2001).]

 

Earlier style has 9th injector can't remember which yr that was dropped. Also used a MAF setup. Stock TPI redline rated at 5500 rpm...... probably a little earlier.

Matt

 

OK, the cold start injector was dropped in 1989. The SD TPI intakes had fins on the top of the plenum stop back near the drop that goes down toward the front of the plenum...the MAF TPI plenums had fins that came several inches further forward. SD TPI systems were first used in 1990, not 1987. Stock TPI systems will drop power off sharply at 4500 but some cheap mods can be made to help.You could use the stock base and runners, I would think the intake base would fit your heads but check them to be sure. 1987 and later TPI intake bases used a different bolt pattern than 1986 and ealier units. The base needs porting on a healthy 350 at least, as well as the plenum opening, you should be able to find info about that on this website. A set of siamesed runners will help if you plan on making power up until around 5750 RPM, LTR's help until around 5000, of course every system is different. Siamesed runners tend to lessen the ramming/tuning effect of the stock TPI, since the 2 runners are opened up into a single larger one...increasing flow but lowering velocity. SLP runners are by far the cheapest runner new for $250, but really could also use additional porting. They slightly lower low-end torque in favor of a stronger and flatter midrange up to around 5750 RPM, give or take a few. LTR's have a lower powerband, but can still flow well for higher RPM's (not as much as siamesed) and they improve low-end. You could get by resonably by porting the base and plenum, but make sure you replace the runners and port-match sooner or later...as far as harnesses go, Painless sells a harness, but I have personally heard it's a pain in the *** , also TPIS has one, but they're known for wallet raping customers. I would probably go for either the painless or pull one from a junkyard. Also what color are the injectors? 305 TPI units and 350 TPI units were identical except for injectors. 350's had 22# injectors, 305's had 19# injectors, and the chip has to be programmed for them.

If you plan on putting this setup on a motor make sure your porting and parts choices reflect that and the intake works with the heads and cam in the same powerband...bone-stock TPI on a healthy longblock will starve it for air and restrict HP.

 

Wow !, thanks for the info. Anything else that I should know, best parts, parts to avoid ?

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1990 RS Camaro 305 TBI, 700R4 Tranny, 3" cat back system with flowmaster muffler, Edelbrock strut tower brace, rear panhard bar, and torque arm, Spohn subframe conectors and lower control arms, all polyurithene bushing under the car, KYB gas adjust shocks and struts, March underdrive pully system, Taylor 8mm plug wires, Accel super coil, K&N air filter, Hypertech chip, GM Aluminum driveshaft, 3.42 Zexel-Torsen Rear end with superior 28 spline alloy axles, and Summit aluminum rear end girdle, Killer sound system, Many new mods to come (swap to 350 comming soon)