I havea 85 roc with a Lb9 engine..how does that compare to other thirdgen engines..thanks

 

U actually have 1 of the better 305 TPI's. This was the 1st year for them in the Camaro and it was the best cam that an LB9 Auto would see during the Third Gen. With 215HP and 275TQ, it had 25 more HP than the next LB9 Auto's would, but it also had 10 less TQ than that milder cam that was used after 85.

 

but, and here's the kicker... the 85 TPI setup is a nightmare... Most early TPI cars I've seen around here have various reliability problems that I attribute to GM's adventure into port fuel injection. Not to say that it can't be made to work well, just that over time as things start breaking down, the MAF thirdgens run into rather significant problems.

 

Yeah 85 had a better cam than 86, but that is the only advantage. 86 to 89 had a faster computer and a better MAF sensor. 89 was the best of the MAF cars since GM got rid of the troublesome cold start valve. They did this by changing the injector pulse width during cold conditions to deliver more fuel through the 8 main injectors. As far as an 85 TPI car goes, you got the better cam, but you have the worst TPI setup.

 

While I will agree that 85 MAF weren't good, that doesn't say anything about the 86-89's. The 85's had a digital output Delco MAF, while the 86-89's had an analog output Bosch MAF. They got better, and in 89 especially (89's had a better chip also) as in the previous post. I have an MAF car and I can say that it never gives ANY problems or inconveinences, except for being changed 1 time. Its stock 89 MAF needed to be replaced 11 years later, and runs just as good as before again. I know on the TPI and V6 boards there are others with similar good experiences with them.

 

Don't forget that in 85 the cam was still hydralic- in 88 they all went roller-hyd camshafts- a little better