We just completed an engine swap in an 87 Iroc. we pulled the stock 305 tpi out and put in a standard bore 350 w/vortec heads and a scoggin dickey tpi lower. we put in a comp cams roller cam 487/495 lift 264/270 duration and accel 24lb injectors. we are using the stock plenum, runners, fuel pump and regulator. it is a factory 5 speed with the factory 3.45 rears. we had street and performance burn us a chip to those specs, but with their chip installed the car will not start. it tries, but as soon as you let off the key the fuel pump stops and the car dies. we put the factory 305 chip in and the car starts right up and runs good, but not up to it's full potential. this is my first attempt at messing with a tpi car, so I am lost. any ideas? are any of you from the Wichita Kansas area that may be able to give it a look?

 

Sounds like you got a chip with VATS (anti-theft) enabled...and your '87 doesn't have VATS. Give Street & Perf a call.

 

ok found the problem, the chip they burned was for mass air and we have speed density or visa versa. now new question, what is the difference between mass air and speed density?

 

a different ECU and different sensors MAF for mass air flow and MAP for SD

 

So exactally which one am I working with? and which one is better?

 

what year TPI setup are you working with? 86-89 is MAF and 90+ is speed density. As far as which is better thats a matter of opinion. Some people say SD is best for performance, and some people will argue MAF is. Either way its still TPI and they are both pretty similiar as far as their restrictiveness to flow in the upper RPM band, and their ability to make a good deal of low RPM torque.

 

I just reread your first post and noticed your working with an 87 iroc, assuming its the TPI setup from that car your working with, the MAF chip should work, I second the idea of it possibly being burnt to include VATS. Call and ask them.

 

I called and talked to them, they said that vats was disabled. but they told me it was burned for speed density. so we have to send the chip back and they gave us a phone number of another place to call for the correct chip. thank you for all of your help. maybe if I have to do more of theese I will look into learning to burn my own chip cuz this can get expensive.