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Advertised TTA horsepower

8

89MNTTA

Well-Known Member
Okay......I've seen a few different numbers...........(Jim, Jared, George, Jan).................what's the real rating from Pontiac? Is it 250 hp & 340 tq? Or something else???
 
I have a dyno print from PAS stating they found 375 at the crank!! That means about 301HP to the wheels. Keep in mind the vette that year was 255HP and GM said to Pontiac.. Buick killed corvette sales when the GN's came out so let's not do that again. Keep the HP rating under 255 so they went with 250 for the press. And people with money would go to their local GM dealer and say.. I want to buy the fastest car in GM's inventory. So they would tell them that was the vette so they didn't loose sales!
 
These cars are well over 300 HP. Just look at the MPH in the quarter around 101-103 mph for the stockers with a 3400 lb car.

- Dave
 
I've always heard that the true rating was 301 too. I saw somewhere on the net, when googling Turbo Trans ams that someone put one on a dyno (there was pics too) totally stock with crappy gas put down 295 hp. The real shock and I believe it based on my experience as well as witnessing a close friend with a Buick GN that these cars win races with brutal torque. The same car in this article put down 413 ft pd of torque on the same dyno, same pull.
That's what wins races. Especially street races. If you hook that kinda torque up or even still spinning all over the place your still bound to run off from most cars out there, nevermind when you start modifying things. See ya ZR-1
smileyTTA.gif

:WOOT:
 
Thanks, Adobe ImageReady. Oh yeah, I should add to the above that at the same dyno/car show there was a 69 Trans Am Ram 3 or 2, not sure. Anyway it was the TA from 69 that had some monster horsepower, it put down like 435 ft lbs.
The TTA has got to be one the highest rated torquey cars from all of the years Firebirds where produced.
 
Last edited:
DaveGershon said:
These cars are well over 300 HP. Just look at the MPH in the quarter around 101-103 mph for the stockers with a 3400 lb car.

- Dave
Click to expand...

Duly noted, I realize they are underrated.........I was just wondering what the 'advertised' horsepower was.......:)
 
A 1969 Trans Am would have either a Ram Air III engine, or the round port Ram Air IV engine.
I don't know the figures right off hand, but 455 SDs Trans Ams/Formulas had some monster torque.

:beach:
 
The story goes that GM had an unwritten rule that no GM car had more horsepower than the Corvette. Since the '89 Corvette had 255HP, Pontiac rated the TTA at 250. GM supposedly got 301 HP on their dyno. Somewhere on line I've seen PAS dyno results that were even higher. It also said a TTA lapped Indy at 158 mph and hit 171 in the straight.
The 455HO I had years ago in a 71 TA was rated around 480-490 ft/lbs of torque. The SD was a stronger motor but the rating system was changed by then. (net instead of gross).
 
hey guys, i just put my car on a dyno, and at stock boost it read 198hp, this led to an arguement about the dyno reading low, and i used this forum as a reference. sooo i have a question. when it was said that the stock car made 301hp to the wheels, was that at stock boost?
 
echostatic said:
hey guys, i just put my car on a dyno, and at stock boost it read 198hp, this led to an arguement about the dyno reading low, and i used this forum as a reference. sooo i have a question. when it was said that the stock car made 301hp to the wheels, was that at stock boost?
Click to expand...

To my knowledge, stock boost from the factory is 16.5 psi. :)

Did you record the boost during your dyno runs?
 
stock boost is 16.5? thats about what i hit in 1st gear with boost set to factory, then when i hit 2nd gear the highest my boost is is 11lbs... is that normal?

i got 198hp/319lbs of torque at 11lbs of boost, and 292hp/360lbs of torque with 20lbs of boost.
 
I could be COMPLETELY wrong on this, but I saw on Spike tv's Powerblock when they tested a project corvette. So when they added the turbos they had to set the dyno so that it would create load in order to get the turbos to work correctly. I'm thinking it's kinda like when you rev the car in neutral it doesn't create boost. No exhaust energy is being created, no load. This could be the deal. Go to the track and get some real world times on the car. :cowboy:
 
sverble said:
I could be COMPLETELY wrong on this, but I saw on Spike tv's Powerblock when they tested a project corvette. So when they added the turbos they had to set the dyno so that it would create load in order to get the turbos to work correctly. I'm thinking it's kinda like when you rev the car in neutral it doesn't create boost. No exhaust energy is being created, no load. This could be the deal. Go to the track and get some real world times on the car. :cowboy:
Click to expand...

no there's load on all dynos, although I hear dynojets aren't ideal for turbo cars. I'm also going to assume that he was getting the pressure readings from driving one the street. Your car shouldn't drop either way (dyno or street) when the car shifts, infact most cars creep a little bit up compared to what they get in first gear. Do you have a scantool? It's tough to really say anything without having any readings because there's soo many different things it could be.
 
echostatic said:
hey guys, i just put my car on a dyno, and at stock boost it read 198hp, this led to an arguement about the dyno reading low, and i used this forum as a reference. sooo i have a question. when it was said that the stock car made 301hp to the wheels, was that at stock boost?
Click to expand...

I would expect around 260 at the rear wheels at the stock boost level. The rule of thumb is about 15hp per 1 lb of boost.

- Dave
 
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