[slowbird]

We just took our street car to the chassis dyno today. We got 312hp at 5750 and 301tq at 4500. The numbers seem to be off to me since we run mid 11 in the quarter. It was done on a Mustang dyno. But we had a good time and learn some. We did a 1/4 mile run on the dyno to and showed a 14.4 at 108mph but we filled the shop with tire smoke and I had to put it into high right off the bat because the tach went straight to 6000 and would not fall until i got it into high. Everyone there thought we would be around 250hp so at least we surprised them with our Pontiac.

75bird 7.41 1/8mile at 92mph street car
73Ventura 11.88 at 113 streetcar
69GrandPrix 12.64 at 107 tow car
65GTO 10.14 at 129 tri-power dragcar

[David Jones]

Having just done the same on mine, I'd say there was a dyno problem.

http://kurtspontiac.homestead.com/DavidJones69GTO.html

[slowbird]

The tire smoke only came on the 1/4 run. None of the hp pulls had tire smoke. One thing that I am pleased about is the tq falls off very slowly after peaking.

75bird 7.41 1/8mile at 92mph street car
73Ventura 11.88 at 113 streetcar
69GrandPrix 12.64 at 107 tow car
65GTO 10.14 at 129 tri-power dragcar

[burch]

My car put down around 330hp on a Mustang dyno, two days after it ran [email protected], with no modifications in between. Race weight was around 3800lbs.

I agree on the high-stall converter making the numbers funny. Look at Goatman's recent dyno results vs the numbers he ran at Norwalk a couple weeks later.

[slowbird]

Thats what I thought but I can now go around and tell the new Mustang owns that our car makes 312hp to their 305hp and see if they want to race for money. I have the dyno sheet to prove that im not lying. Last time out in the 1/8 mile we ran 7.39 at 92.25mph.

75bird 7.41 1/8mile at 92mph street car
73Ventura 11.88 at 113 streetcar
69GrandPrix 12.64 at 107 tow car
65GTO 10.14 at 129 tri-power dragcar

[head #96]

I would say those #s are quite abit off the mark, for an 11sec car.

Building a fast stock appearing street car.
homepage http://home.mchsi.com/~vroman6

[slowbird]

We just took our street car to the chassis dyno today. We got 312hp at 5750 and 301tq at 4500. The numbers seem to be off to me since we run mid 11 in the quarter. It was done on a Mustang dyno. But we had a good time and learn some. We did a 1/4 mile run on the dyno to and showed a 14.4 at 108mph but we filled the shop with tire smoke and I had to put it into high right off the bat because the tach went straight to 6000 and would not fall until i got it into high. Everyone there thought we would be around 250hp so at least we surprised them with our Pontiac.

75bird 7.41 1/8mile at 92mph street car
73Ventura 11.88 at 113 streetcar
69GrandPrix 12.64 at 107 tow car
65GTO 10.14 at 129 tri-power dragcar

[basketcase70gto]

Yea, It looks to be about right for the manual trans cars. I was just saying that on the same dyno mine is only 34 hp more than his and weighs about 600 lbs more and runs 1.2 sec and 10mph faster than his. That must be some magic horsepower to make that much difference.

[brian damian]

Chassis dynos are good for bench racing..there
are so many variables unless the dyno operator
has it set up properly,there is no way to insure
accurate numbers.also it will not take into effect any type of "ram air" or scoped air
once the car is in motion.my 3400 lb lemans
ran best of 7.03 at around 95.5 in the eight.
the chassis dyno said 366 rwhp with 28" slicks.
loss from the loose convertor,soft sidewall and the auto trans..let the track tell you the bragging numbers.

[basketcase70gto]

I have a chevelle that has run a best of a 11.49@118. The car weighs about 3650 with driver and is traction limited to a 1.77 60ft. At the Car Craft show in St.paul Mn. The car made 364hp at 6000 and 394lbft at 4200. The stall convertor and auto trans really seem to screw up the #s. And the add 20% for the drivetrain loss is b.s. There was a bunch of guys there with their engine dyno sheets and with a auto trans the losses were more like 38-39% and the manuals 20-22%. Another friend has a 351 to a 68 mustang that will be in the nov. issue of car craft in the dyno proven combos article. The car has a four speed and made 330 hp to the wheels and last week ran a 12.70@108 on street tires and through the mufflers just like it was on the dyno.

[Goathead]

That sounds more like an 11 second car than the dyno does...somebody is way off...



http://www.dannys65gto.com

http://kurtspontiac.homestead.com/dannys65gto.html

[Goathead]

There is no way those #'s are correct for an 11 sec 1/4 mile car unless you car weighs about 800 lbs with driver...

I'd ask for a recount....or make sure that track that you are running the 11's at is'nt a 1/8 miler...



http://www.dannys65gto.com

http://kurtspontiac.homestead.com/dannys65gto.html

[SLOW 77]

Your friends hp in the Mustang sounds correct; y 01 Ram Air put down 337/356 and ran 107.7 mph in the 1/4; so that mathces what I have run, and I think my car wieghed 3550 with me in it.

My 77 put down 417 rwhp and has pulled a best of 99 mph in the eighth at 3600#'s so yours are probably right in line with mine as well. I know for a FACT I can hang with a stick shift car making 535 rwhp and 500+ rwhtq from 20-120mph so I know that my car dyno's low; it is no big deal to me as long as it runs the number at the track. I have also raced my brothers Supra before and he put down 525+rwhp and my car would stay side by side.

[Fake Goat]

If you were seeing tire smoke, you were not getting a good grip on the rollers of the dyno, and therefore were not getting accurate HP numbers. The dyno operator should have seen that and backed off the throttle to regain traction.

On the dyno chart, do you see what would appear to be a smooth upward curve, then a SHARP dip? If so, that dip could be where your tires lost traction. It doesn't have to be a deep dip. If no dip, you may have been spinning right off the line. Can't believe the dyno operator didn't see the tire smoke and know it wasn't an accurate run

----------------------------------------------------------------------------------- It is better to remain silent and be thought a fool than to open your mouth and remove all doubt.