Zink57

One day at a car show...(Crystal Cove, NB,CAL).. met up with Jeff Bietzel who told me a story of the "real" reason that the 1989 Turbo TransAm Pace Car had it's numbers underrated at 250hp/345lbs. Jeff Bietzel is the founder and CEO of PAS Inc that built/tested/certified the Turbo Trans Am project back in 1989..as well as the Cyclone and Typhoon turbo cars..... The story goes... during the early stages of testing and production...the TTA componants had to be certified for warranty coverage purposes... PAS was getting grief from the Turbo Hydromatic people regarding their insistance that they would not sign off on warrantying a platform that outputted more then 350 lbs of torque for their TH200 tranny. Jeff went on to tell me that they were met with the challenge of dynoing lower output #s..and the primary way they achieved this was to run hot air through the intake of one of their test cars---thus is how the "lower" numbers were achieved and this is how PAS was able to by-pass this warranty hassle with the Tranny people....

Thus the story about the Corvette getting it's feeling hurt and political reasoning for lowering the TTA numbers might make for good reading..but it appears that there was a more direct issue involved in the decision to underrate these cars. Low 13s with 250 hp is indeed pretty imaginative

auto_cran

That makes sense.

I never understood when sources state regarding the 250hp rating for the TTA : "The generally accepted explanation is GM's unwritten rule which states no passenger vehicle shall have a higher horsepower rating than that year's Corvette. In 1989 the Corvette was rated at 255 HP."

The Corvette did NOT have 255 horsepower in 1989. It had 240 horsepower, unless you got option G92 - the performance rear axle which also added less restrictive mufflers and bumped horspower up to 245.

So, in 1989, the Corvette had 245hp, and Pontiac rated the TTA at 250hp - breaking GM's "unwritten rule".

The transmission/warranty issue makes more sense.

Thanks for the info!


Chris
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1989 Pontiac Turbo Trans Am #760 (1804 miles)
1988 Chevrolet Corvette 35th Anniversary #1941/2050
1983 Delorean DMC-12
1985 Kawasaki Eliminator ZL900

Kevin91Z

iTrader: (1)

Everyone has thier own version of the story, and every one is believeable.

Also, the TTA's didnt use a TH200, they used a 2004R.

Zink57

Everyone has their own version of the story...

but only one story is correct. I would rather take the word of the PAS CEO and founder..then some "theory" from a source that nobody can validate. There's really no reason for Jeff Bietzel to tell me tall tales about the TTA... afterall...he isn't trying to sell the car to me...I already am the owner One of my buddies told me that I should have taken a pick of Jeff standing my my TTA to help "substantiate" the "story".. A picture would have been nice only for one reason... for my personal collection. There's no need for me to use a picture of the guy to prove anything. I met him, he told me, and it's as simple as that. As a car guy...I thought it would be cool to share with other car guys.. Since there is so much misinformation about these special vehicles..this is my contribution to the car culture. No ego motivation or validation being sought here...really ...in fact... if people would choose NOT to believe this story... the better... I would actually prefer being the ONLY one who knows this fact about my own car and a piece of it's production history.

GTADave

Interesting!!!!!

- Dave

Zink57

What's provocative...is if the TTA was getting pressure from the supplier of the trannys about the "torque" rating... being held below 350 lbs... I am wondering why the GNX was allowed by GM to be rated at 360 lbs? I didn't have a chance to ask Jeff this point...as I didn't think of it at the time...

Apparantly...in addition to GM/PAS engineers taking the lessons from the Grand National program to work out the top 20 bugs when developing the TTA... it appears the vendors were doing some of this too on their side of the fence to protect their interests--in this case warranty paramaters. I am sure GN enthusiasts, from their modding...probably broke a few of these stockers and the Turbo Hydromatic management was taking steps to protect their interests...

1989GTATransAm

iTrader: (3)

Looks to me that when they made a "hot air" car out of the TTA the dyno numbers came up 345FT/LBS. No reason to fine tune the hot air as they were under the limit and close enough.

TTA 1387

I've been saying its been warranty reasons with Hydramatic for years. Its nice to see I actually knew what I was talking about

Its just one of those things that gets spread like the use of FWD heads to fit between the strut towers. I guess if you read it enough, you believe it.

Xophertony

i have heard abou the tranny thing before. (to be honest i thought the corvette thing made more sence) nice to know the REAL story. thanks for sharing.

-future TTA owner

Kevin91Z

iTrader: (1)

Ok, I'll bite. What's the true reason for the different heads?

3.8TransAM

Actually that is the reason for the heads, but only part of it.

The narrower heads let them bring the exhaust/headers in and that allowed a downpipe to fit from the turbo and out the bottom.

It wont happen when attempting a swap using a Grand National 3.8T. I hung it in the engine bay once as a joke when my 383 was taking too long :-)

later
Jeremy

TTA 1387

Mainly for the use of the stock TA A/C. The stock GN heads fit fine but way too close to the A/C.

Another reason was they just flow better than the old 3.8 heads.

nick418

I used to believe it was a corvette reason why they underated the #s. Ever heard of a Callaway Corvette? Those were low production number cars but they would walk all over a TTA in everything. Which i believe wouldnt have to do with the corvette then either.

If you want to compare them:
You would then compare the Callaway Corvettes with the TTA.
And the Regular Trans Am to a Regular C4 L98 Vette. thats what i think.

But intresting..

TTA 1387

I would tend to think that a $26K option to get the turbo should walk away from a $31K car. Kind of hard to compare a car that was twice the price of the TTA. Should have been better!

Comparing prices though, TTA vs regular production C4.