sunset gun

+1 to Kevin.
Horsepower exists as a function of torque, so, in this case, sadly for the OP, the results are meaningless.
I believe the dyno shop owes OP a re-run, once they find the instruction book.

jazzwu

Actually it was STD correction. Mustang dyno would be decently lower thats for sure.

jazzwu

What's up. No why would these runs be bad? They're totally fine and shouldn't cause any issues if the operators know what they're doing.

I know an AWD dynojet not too far from you but their hours seem to be mostly weekdays. It's Precision Tuning shop.

The one I used was a rwd dyno so they had to disconnect my front drive shaft. Either way to dyno our cars I was told that most get dynoed on their rear wheels. I guess more for numbers and at higher speeds our rear wheels are the ones driving the power.

jazzwu

Thanks! A more optimistic dyno apparently but it is what it is.

Cleveland Porsche? of North Olmsted?

jazzwu

Guess I'll have to talk to the guys again.

bigrpowr

that is totally false. tq is a measuremant of horsepower at a given rpm. i own a dynojet , and have a pretty good grasp on how dyno's work , don't listen to those guys. AWD may be a little different but not in the mathematics , and they are wrong . horsepower is derived off accelration of the roller vs. load or speed . std correction can be a bit optimistic, but sae is not a fixed percentage to std, so it could be more , or less, dependent on the weather station . we use sae as it's the most dependable when dyno'ing a vehicle at different times and conditions . we can run our dyno with , and without torque input and the horsepower #'s are the same .

jazzwu

Thanks for your views and input. I figured something was up.

I didnt actually contact them so I'm good. It would be nice to know the torque numbers though so next time..

vbb

As long as the dyno is being used as a tool to measure gains and losses when modding or tuning, the raw numbers don't matter much. Dyno numbers can be debated ad nauseum, but remember, it is a tool. Use the same correction factors and try to tune in similar conditions. OP was trying to get a baseline and he did.

Ibanezgod

hey man, I've heard of precision tuning, haven't been there yet though. Just a general question. To Kevin's point, I get concerned due to the AWD nature of the car and using the rollers, etc. which is why I ask. If I knew of a shop that had specialized in all cars including AWD cars then i'd be up for a run. Not a fan of disconnecting the FWD though.

Hows the car been in the winter? Is this your DD?

jazzwu

The shop I used is Aim Performance in South Plainfield not far from you at all. Local actually. They specialize in building and modding porsches.

Car's been great and no its not my daily. I just drive when it's nice enough or decent enough outside. Love it.

sunset gun

re:bigrpowr-
"that is totally false."
"...don't listen to those guys."
"AWD may be a little different, but not in the mathematics, and they are wrong."
"horsepower is derived off accelration (sic) of the roller vs. load or speed."

I recommend you consult any ninth or tenth grade level science or, better, physics text book. There
you will discover the following scientific fact, expressed here by the noted John Baechtel in 1996 article he wrote for HotRod.net, explaining in layman's terms, the difference between torque and horsepower:

"Torque is the static measurement of how much work an engine does, while (horse)power is a measure of how fast the work is being done. SINCE HORSEPOWER IS CALCULATED FROM TORQUE
(caps mine), what we are all seeking is the greatest possible torque value over the broadest-possible
RPM range. Horsepower will follow suit, and it will fall in the engine speed range dictated by the many factors that affect the torque curve."
As to "AWD may be a little different, but not in the mathematics, and they are wrong." It's not
"mathematics"---it IS very basic science.

By your use of the word "they" in your post, I think you are disputing my thoughts, and those of Kevin of Ultimate Motorworks. Calling me wrong is not rare. Nor should it be. My socks usually match, but I ain't no genius. Kevin, on the other hand, is, if not a genius, one of the most respected, successful, and honored gentlemen in the Porsche business, here and abroad. You might want to study up a little bit before dismissing his knowledge as opinion.

bigrpowr

say what you will, but i dyno vehicles for a living and the HP # WILL not change with or without a tq reading. you can love kevin all you want, he's a great guy who steered me in the right direction on my build, doesn't mean he knows dynomometers, and the function of them. you , and he , are wrong if you think having a torque reading will affect the #'s . until you operate one yourself, please don't tell me where the bears **** in the woods , as you seem to have little to no basis or knowledge on the subject , minus riding the words of your savior to doom .

RJKflyer

Reading this increasingly heated post over a morning coffee...

Firstly, ca. 500 bhp, PS or SAE, at the wheels seems rather high for a stock 997.2, notwithstanding that Porsche may or may not be conservative. So, sorry, but that peaks my curiosity to put it politely - and may be why there is a challenge as to the accuracy of the process.

I won't go so far to say that the OP's car does not produce 575bhp or whatever at the crank, but I'd be very surprised. Unless it's been mapped unbeknown to him of course.

No matter what anyone says, thinks, or believes, a dynamometer of any description only has the physical ability to measure TORQUE. Power is derived as the rate of doing work. This is not to say in anyway that the power numbers are 'wrong', but point blank, they come from a calculation applied to a measured torque.

E.g. an electrical generator generates torque as a resistance to the turning motion of one electric or magnetic field within another. The speed with which it rotates then defines the power that can be consumed by the user.

TB993tt

To correctly measure your engine power like the Porsche factory do you need an engine dyno set up which can control the IAT and replicate the (known value of) IAT at maximum speed, this is achieved by lots of testing.

Engine dyno is calibrated by hanging a known weight at the end of a 1 metre rod, this gives you your Newton Metre calibration.

The engine is run up under load through the rev range with the engine being braked at certain rev points to get a correct NM reading (this is done with a computer program and in practice the engine is held fully loaded at each point for a second or so).

The resultant set of dots are joined up and that is your engine's torque curve. Simple formula converts this into the power curve.

Chassis dyno which "measure" hp by spinning up a drum in a few seconds ? - compare and make your own mind up

https://www.youtube.com/watch?v=dD8ruzuVOTU

longboarder

My bone stock 997.2 Turbo S made 501 AWHP and 536 AWTQ on Cobb's SoCal Mustang Dyno years ago.

These cars are monsters and run high 10's at nearly 130mph bone stock. They are clearly making well north of the advertised 530 crank HP.