So stock 997.2 TT is listed by manufacturer as 500 hp and 479 torque (516 temporarily under SC boost)

I know when rated at wheel hp on a dyno, that's different though.

So what I'm wondering is what the stock numbers translate to when using same method as dyno graphs I see from ecu/flash mods.

For example, just got evomsit 565 flash done. See on dyno graph that it's output for max was 527 hp and 555 torque.

Couple questions then really:

1. What can I say is my listed or engine hp/torque based on above dyno numbers?

2. For easier apples to apples comparison, what does a stock 997.2 TT do on dyno?

 

Every dyno is different. How the run was setup, the conditions, etc. all influence the reading.

The only way to determine what your current crank HP is is to create a % drivetrain/dyno loss from a baseline dyno, which makes an assumption that the crank HP by Porsche is truthful. Even with this % drivetrain lost, your calculations may still not be accurate based on the condition of the run.

Don't get overly concerned about HP readings. A dyno is a tuning tool. Focus on the performance of the car - trap speed and 60-130, 100-200 km/h times.

 

To generalize:

Flywheel HP is for bragging...

Wheel HP is the only # that matters as it is representative of what power is actually hitting the road and what any "real" car guy will want to know.

 

I have a 2000 996 C2. After my original engine failed, I got a replacement engine from Porsche which the dealership tested and installed under warranty. I then had my car dyno'd at a leading foreign car specialist with a less than a year old Mustang Dynamometer. The factory engine specs were 296 HP and 258 ft-lb . the dyno results were 246.7 HP and 215.7 ft-lb without applying a weather correction factor. So for a 2WD C2 the powertrain loss was about 16.7%% for HP and 16.4% for torque.

So at the same percentage powertrain loss, the 527 HP at the wheel stated by EVOMSit will translate to 633 HP. Your AWD Turbo will have a slightly higher powertrain loss so the actual crank HP should be even higher.

Hopefully, these numbers give you a sense for the powertrain loss.

 

I could not agree more, I get maybe 510 AWHP from my EVOMS 700 mods. This is from many runs at two different shops. Depending on the dyno setup, multiplier etc., I can get you any number you like.

My car is far and away quicker than stock, so in the end I focus on the driving experience and let it go at that.......

 

think maybe I didnt express myself right.

Not looking for exact numbers, not looking for bragging rights - agree wheel hp measurements better.

Just trying to get a general sense of 'what kind of HP car I have when other people say I have a 500, 600, etc hp car' - and knowing those hp claims are likely not awhp.

Is it fair to say if in some temperature, ambient conditions, altitude, etc that a reputable dyno measured a car like mine (dont care it's not exactly mine either - just rough sense) with evoms flash at 527 awhp, that would imply something like ~650hp at the crank if you assume 20% dyno difference?

 

I remember a thread by Evoms stating they dyno tested their stock 997.2 TT and got 490 AWHP and 490 AWTQ. I believe this on original stock ecu tune which means Porsche under rated the .2 engine.

However, I've also seen other dyno #'s far less than what Evoms got.

https://www.6speedonline.com/forums/...ml#post2707455

 

TPC saw 460rwhp in Dynojet
Vividracing saw 444whp in mustang Dyno

 

Test your car on a Maha dyno. It's pretty accurate.

 

Couple of 6speed 997.2 turbo

AWE 473awhp/453awtq Mustang Dyno
Protomotive 500rwhp/513rwtq DynoPack

 

About 15% is what you can figure on a Dynojet.

 

15% less is what you can expect on a Dynojet dyno.

 

You got a good response from bbywu. Even the car manufactures have been fudging the numbers forever.

http://www.supercars.net/cars/349.html

VW quoted whp numbers for there 1.8ts to crank vr6 numbers because they didn't want to overshadow there premium line. You can run the car at different gears on a dyno and get different numbers hp and fuel economy and emission results. For the most part you can't trust a manufactures numbers. You will see magazines test drives that stomp oem numbers on the 0-06 and 1/4 mile for some of these reasons. But again don't trust magazines for other reasons >.>

My 06 mini S has a smaller pulley, flash, intake and exhaust. Stock its supposed to have like 160 hp. I believe it has 190 whp. Friends know its modified and ask how much hp it has I just say 190. Just because most of the people asking don't know the difference between whp or crank or even what torque is -_-; Beyond those stupid numbers it stomps my toaster driving friends with there 270 hp honda auto accords into the ground off the line and (while being safe and not breaking the law ^_^; ) and they are confused because they don't even know how much the car weighs, or even how a gear box factors into a how fast a car can be.

People ask me how much hp my turbo has and I say 480. After an exhaust, intercoolers and tune my local tuner thinks I'll have 550 whp +. Sounds reasonable. I will probably google awd crank hp loss for a 997 turbo and multiple that number with that other number to get my I am having drinks with my friends that want to be impressed with big numbers that don't know **** about cars number. Honestly I don't care if my gf's brother in law believes if I have 600 or 650 hp and wants to compare it to his stock v6 convertible mustang's sticker hp. Its all bull ****.

 

This is one of the most interesting topics you'll run into in the bench racing online forum world. I have probably driven 200+ passes on different dynos with my cars over the years.

There are 3-4 popular dynos you will generally see out there - Dynojet (typically 2WD, but there are AWD versions out there), Mustang, Dynapack, and Mainline seems to be gaining a lot in popularity now with more and more performance oriented AWD cars being available.

I've seen Mustang dynos that read "high" (I call them very optimistic), as well as Mustang dynos that read low. Typically a 2WD Dynojet is going to read higher than any AWD dyno, but there are exceptions. The Cobb Tuning Mustang dyno in the Dallas, TX area is extremely optimistic and great if you want to put down a big number.

The reason various dynos of the same type will read differently include temperature/humidity (more on that in a minute), initial setup and calibration, configuration changes made by the owners, etc. One of the reasons I like the Mainline dynos so much is that they don't use the typical large drum, but rather apply braking to the rollers that can be precisely measured. Instead of applying the dyno brake to slow down after the run, you can lightly brake the vehicle down to a stop without worryl

It's a lot more simple to dyno a normally aspirated RWD car. Think Corvette. You only have one roller, temperature doesn't affect the engine out put nearly as much, etc.

Turbocharged AWD cars are one of the more difficult combinations to get right. The correction methods (which can be chosen by the operator) may be STD, SAE, and a bunch of other methods not really needing to be mentioned for discussion. Fiddling with smoothing, corrections, etc one can still manipulate to a small degree what the final numbers and curves look like. Neither SAE or STD correction really work right with turbocharged vehicles when the temperature is very far off from the reference temperature. A general rule of thumb is that if it's very cold, your numbers will be artificially inflated. If it's very hot your numbers will be on the lower side of what they might otherwise be. If you want to get the most accurate reading you should dyno as close to the SAE reference ambient temperature of 77 degrees F as possible.

The best way to figure out how much power your making is as mentioned above, make a 1/4 mile pass and use the trap speed, 60-130 times, etc. and weigh your car. If you're at the drag strip pull off onto the scales and get the exact weight with you in it. How much fuel you have in the tank also significantly affects the weight of the car, keep this in mind. Of course how well you drive plays into this, but a Tiptronic or PDK car will give extremely accurate results this way.

Most performance car enthusiasts ONLY reference dyno wheel-horsepower numbers to describe performance. A relatively safe guesstimate for the 911 turbo is to subtract 20% for driveline losses. Most cars seem to make anywhere from 400-420whp stock (9971.1). I've been surprised in the Porsche world how common it is for the professional tuners to reference crank horsepower numbers. That's actually interesting, because unless they are actually running on a real engine dyno, they are running on a chassis dyno and then adding ~20% to reference a calculated crank horsepower number based on a calculated wheel-horsepower number. Doesn't seem all that scientific, but I realize that a large number of Porsche owners are more into driving their cars and having fun with them than worrying about how everything works.

 

+1, Rix. Now, here's another spanner in the works: Parasitic losses, from transmission, clutch,diff,axles, brake discs, wheels,tires, plus power steering pump, alternator, AC, etc. etc., ARE NOT LINEAR. That is, at lower speed, parasitic losses are much higher than at say, eighty mph, and also are lower at an 80mph cruise than if accelerating through 80 to some higher level. All of the above is/are complicated by the average dyno's 40-60mph cooling fans, and their placement. Best situation, seems to me, is most conservative standard (SAE), consistent set-up of the dyno by an ethical technician, and as many runs as possible in any given situation.
Many Europeans hold the Maha dyno out as God's own tool. Oh stop. It ain't magic. Physics, even at RS Tuning, work almost the same There as Here. Yes, there are better and worser dynos. DynaPacks, for instance, add so many truly silly variables to the mix that they reduce themselves to the most base level tool. You do get what you pay for. Do you still really really need a factor to hang your hat on? Okay. Be conservative. For a 997tt, on a Dynojet, DynoDynamics, or Mustang 500SE, you may use 14-15%, with my blessing. And at your own peril.