Dave-T

I have a 94 LT1 6 speed car with a Vette Doctors head and cam package along with short tube headers, BB TriFlo exhaust and 3.92 gears. The Vette Doctors just swapped the short tube headers for TPIS long tube headers. They also swapped the stock cats for Random Tech 3 inch bullet cats. With the short tube headers the maximum HP was 361 @ 6100 rpm and maximum torque was 334 ft-lbs @ 4700 rpm. After the swap and some custom dyno tuning the maximum HP was 371.5 @ 6050 rpm and maximum torque was 356 @ 4600 rpm. Even though this was only a 10.5 maximum HP change and 22 ft-lbs maximum torque change the differences were quite impressive at lower rpm's. For example at 3500 rpm there was an increase of 15 HP, at 4150 rpm there was an increase of 22 HP and at 550O rpm there was an increase of 17 HP. Likewise for torque there was an increase of 22 ft-lbs at 3500 rpm, an increase of 28 ft-lbs at 4100 rpm and an increase of 24 ft-lbs at 5000 rpm. As far as sound goes, it seems as if the the exhaust may be slightly quieter. The resonance may also be slightly better. In any event the tone is different. Kinda of hard to describe. I am very happy with the results. Hope to get to E-Town soon. Thank you Carmen & Dennis at the Vette Doctors.

Dave

StealDads67

Sounds good to me :cheers:

Nathan Plemons

I knew there was a reason I went with longtubes over shorties.

I picked up 23 hp and 32 pounds of torque over my stock manifolds with no tuning. Of course I don't have ANY cats now either :)

Wasserott

When I swapped out the shorties for the TPIS LT Headers and Random Cats, I saw about the same impact on my 396. They also sound awesome!


[Modified by Wasserott, 3:39 PM 2/18/2002]

Nathan Plemons

Wasserott, you're gonna have to stop posting pictures of that color blue car, it might just get stolen. :) The vette I fell in love with 10 years ago was that color.

mackeyred96

Great job Dave.
You should be flying.
Thats alot more RWHP than I dyno'd.

95vettski

When I swapped from shorty headers to TPIS with NO cats I picked up 20rwhp and 15rwtq with no tuning to compensate. I'm sure dialing in the air fuel ratio would have netted some more power.
Your results are line with others, plus you won't wake up the neighbourhood by running high flow cats.
BTW, what are your cam spec?

95vettski

[QUOTE Thats alot more RWHP than I dyno'd.[/QUOTE]

I have a feeling he won't be able to 60' as well as you ;)

MSR

good to see some hard numbers, thanks for letting us know. i would've liked to see hp numbers vs the a/f before and after "tuning," though.

J Z06

With those numbers you ought to trap speed at LEAST 117MPH. Can't wait to see it run.

BrentDev

with the Zf6, using 17% loss, you should be over 430 at the crank. :cool: drool.

That is great to hear on your original block. I really want to get over 400 without doing a 383 or up. I'll wait until it totally dies to do that. Even with your shorties, you still had over 400. Man!!!! I need to look into that package. (and come up with some $$$$$ :cry)

I would love to feel my car with 400+ Gotta be fun.

GlockLT4

:cool: :cool: Hopefully someday I'll have $ to put some long tubes on with custom work to keep my cats (damn emissions)

Nathan Plemons

I don't think the ZF6 even has that high a loss. If you consider the factory rating of 300 flywheel to mean anything, you're only looking at about 10%. My car dyno'd 269 completely stock, and some dyno in the 270's.

But then who knows how accurate the GM rating was anyway.

Wasserott

When I pulled the cats off for true off road only driving, I gained another 10RWHP. Before I went to the big boy came that's in it now, the RWHP dynoed 425RWHP. I'm guessing it will be between 445 & 455 RWHP now. Cats off of course.


[Modified by Wasserott, 7:28 PM 2/18/2002]

88_vette

First let me say DANM. That's some nice power comen out of that car. I hope to have mine running long enough one day (HAHA) to be able to dyno. It is great to see the #'s. It's just as I thought. Long tubes do not give you that 30-40HP increase. The HP gain is right in line with the other two people I have seen hard numbers from. This makes 3 people that picked up around 10HP at the wheels. I'm not saying it's bad, just trying to figure out if the pain of messing with long tubes like I always have to is worth the 10HP.

He also did Cats, and tuning. So I'd say divide by three to give a real rough idea as to what did what. 10.5/3. That's 3.5HP per item. HMMM?

I guess it still comes down to personal op.

Nathan Plemons

Remember now, that's a 10 horsepower increase over shorties AND he still has cats. Personally I picked up 23 horsepower and 32 pounds of torque out of a motor that still has stock heads! The more air you move in and out of the motor, the more your headers will help.

True advertisers like to juice up their claims, but long tubes are well worth it.

REDGAR

Great Job Vette Drs and love the sound of your car Dave.

See ya soon

GlockLT4

I always say 15% manual, 18% auto. Now, some auto's will be 17% or 16% and some manuals will be 16% and some 14% ... but it's close enough. The auto should always be a few % higher because of the torque converter.

ASRoff

I agree with nathan its a good bang for the buck not to mention the weight savings you get with the heavy cast iron manifolds and cats removed.

Hammer

Dave,
Great numbers.

Please email me next time your car is going on the dyno. I would love to shoot over to the Doctors to see it run.

Jim