I have a 305 TBI in my 1992 RS. Ever since I bought it the fans have always turned on early and I switched from a 160 degree stat to a 180 and not knowing what fan switch it had on it I installed a 200 degree fan switch and it changed nothing. The fans still turn on at 160. I've lived with it for 3 years so it's not a huge deal but thought I throw the question out there if anyone knows as to why this would be. Oh, it also has a hypertech streetmaster chip in the computer. I do not have the stock chip for it, as the previous owner did not have it anymore. Let me know what any of you think. Any and all suggestions are appreciated.

 

Sounds more like a "Thermo Master Power Chip to me. Went on line at Jegs racing and they are suggesting a 160* thermostat with that chip because its programed to turn your fan on at 160*.The Street Runner is not.

1) The Street Runner™ Power Chip is designed for daily street driving or competition in unmodified vehicles using a stock thermostat.


2 )The ThermoMaster™ Power Chip is designed to be used with a 160° or 180° PowerStat thermostat.


Popular applications include:
1994-81 Buick/Oldsmobile Car
1993-81 Camaro/Firebird/Corvette/
Impala SS/Caprice
1995-84 Truck/SUV V6/V8

 

how much was your posi unit does it work good i wanna put 3.73 posi in my firebird what do u think good to buy?

 

92firebird 305, Im going to send you a PM so we dont steal his thread.

 

A TBI would be a single fan to start with.

A TBI single fan is controlled (temperature wise) by the fan switch only, aftermarket PROM doesn't affect fan operation.

 

I have both the ThermoMaster and Street Runner and swapped them both out to check and it doesn't matter which is installed and the same result. And it is also true that the TBI fans are controlled by the fan switch and not the computer so I had also debunked that years ago. I figured when I replaced that fan switch with the 200 degree switch that it would fix my problem and it doesn't seem to matter what I do, when it hits about 160 the fan kicks on. So wierd. It's tolerable but I'd rather it run correctly.

 

I sent you a pm