From reading the boards, I have gotten the idea that there is a significant difference between the early TPI and late TPI. Could somebody tell me the changes, and if they make a big difference. I am just wondering because I have the opportunity to but a TPI from an 87 or 89 305, with all the goodies for only 300$ and put in my 91 RS.

Is this worth it if in good shape?

Thanks

 

the differance is that 90-92 cars use speed density while 89 and back use a MAF setup. Different people like both setups. Speed desnity is nice cause u dont have to mess with a MAF so ur free to run your intake anyway you want. The drawback is that SD cars are really sensitive to modifications. You have to get a new chip burnt for almost every modification you do to the engine.

MAF cars biggest drawback is the actual MAF sensor. When u make real big HP numbers the MAF can be a restriction to airflow. But thats around 450-500 HP. The nice part about MAF cars is that they can adapt somewhat to modifications so a new chip isnt always neccesary. MAF cars are also better at figureing out what kind and how much air is coming into the engine and adjusts accordingly. Thats why GM went back to a MAF in 94 I think.

 

Is this just the TPI or is it a TPI w/ computer and wiring harness? OK deal for just the intake (if complete), smokin' deal if you got a 'puter, harness, and intake.

The MAF TPI's have a cold start injector (84 to 89?). The 90-92 intakes won't have the cold start injector.

84-86 have a standard bolt pattern, the 87 have the exhaust cross-over bolt at a different angle.

 

From what I understand, this is the whole unit, computer, intake, plenum, etc etc. I haven't seen it yet so I don't know the condition of it all because it is a friends friend type of deal.

 

90 to 92 cars are speed density (they calculate the amount of air going into the engine). 89 and earlier cars are MAF cars (they measure the amount of air going into the engine). This was stated before. Now, for the cold start injector, the last year for the cold start injector was 88, not 89. So the 89 are the only year for TPI with MAF and NO cold star injector. Not having the cold start injector also meant a change in the runners, no big change, but keep that in mined if you order runners for it. 89 to 92 runners are the same, even though 89 are MAF and 90-92 are SD. Hope this helps.