Does anybody know why the 91-92 TPI motors mysteriously have 5hp more than the 90 TPI motors?

 

Dual cats.

 

No..90's and 89's both have them too.

90-225hp
91-92-230hp

Anybody else have a guess?

 

I have a brochure for the 1991 Firebird line and it says 225hp for the 5-speed 5.0L TPI. I don't think there is a difference.

 

They did switch to lighter hypereuritic pistons.

 

Every aricle I've seen says 230 for the 91-92(5.0 TPI G92)

breaks down like this:
auto 5spd 350
1990 200 hp 225 hp 235 hp

1991-2 205 hp 230 hp 240 hp


Pistons sound about right.

 

Also they no longer used mass air flow sensors,they changed to speed density which eliminated the MAF bottleneck.

 

The 90 was speed density too.

 

That's funny because the brochure says for the 5.0L TPI with the 4-speed auto it has 200hp and 295lbs-ft torque. For the 5.0L TPI with the 5-speed it has 225hp and 300lbs-ft torque. And for the 5.7L TPI is has 235hp and 340lbs-ft torque.
But you really can't always trust what you read in brochures is true.

 

Some of the dealer brochures are printed before the specs are written in stone. I've seen this many times. I sold Pontiacs for 5 years.

 

90's had hypertecic... pistons too (or whatever they're called)

 

Auto 5.0 TPI equipped cars produced less power than the 5.0 5spd versions, not sure exactly why but Ive heard it was because the auto version received a milder cam, and the 5spd received the 350 cam, am I right?

 

Yeah the 5-speed received the L98 cam. The auto 305TPI got TBI manifolds, Y-pipe and cam.

 

I've seen both 225hp and 230hp ratings for the 1990 model year. But who really cares? 5 hp doesn't make any difference, right?

 

i thought this was covered a million times before. Doesnt the 90 -92 5.0 TPI Auto have the SAME cam as the 5.0 TPI 5 speed and the 5.7 TPI??? its the 85-89 TPI Autos that have the mild cam. I know the 90 TPI Auto has the smaller exhaust manifold, but i thought it had the 'good' cam.

 

Yes, you are right- except 85's had the "good cam"
and the 5500rpm redline- 90-92, curiously had the 5000 redline...

 

you guys are SO getting off topic.

 

YOU GUYS ARE HORSEPOWER FREAKS....OK I HAVE A QUESTION I BOUGHT A 1991 5.7L BUT USED MY 88 SETUP (MEANING MANIFOLD AND ANYTHING ABOVE THAT).. SO HOW MUCH H.P SHOULD I BE MELTING THRU MY TIRES???