997gt3north

- the dyno was the same Mustang Dyno that AWE used ( they posted last week a link to their dyno pull of a customers white gt3)

- as I have dealt with AWE in the past, I phoned them (thanks Mike) to ask the key setting that must be input into the dyno (hp at 50mph) - we found out after we did our dyno pulls that we both used the same input (11.5hp at 50mph) - we actually phoned Mustang but they did not have the information, neither did Evolution Motorsport (they haven't dyno'd a 997gt3)

- unlike awe, we weren't able to rig up a fan that directly fed air into the intake (this may or may not make a difference)

- we used 3rd gear, I do not know what gear AWE used

- the car dyno'd 380 wheel hose power on 93 octane

- After we did 2 pulls on 93 octane, we added some 109 octane to bring the octane up to approximately 100 octane - we let the car idle on the dyno for 5 minutes to see if this would help the car adapt timing

- on the first and only pull on 100 octane, the car did the same hp AND threw a engine code (code P0503 - vehicle speed sensor "A" intermittent/erratic/high)

- with the code, I decided it time to finish for the day and head to the race shop that built my previous car (Fairfield County Motorsport in CT - they do lots of work on Porsche track cars)

- we examined the code, determined it was most likely the computer / PASM/TC system not liking only the rear wheels spinning at 100mph without the frount wheels moving

- we cleared the code and all was well on my 60mile drive home

- I later spoke with AWE and learned that they also threw this code when they dynoed their customers car

- also, PLEASE READ THIS, my driveway has a very, very small slope on it and the parking brake on my PCCB equiped car does not work, I had it fully engaged when I stepped out of the car for only a moment to grab my GPS unit from my other car for the trip up to the dyno, and the car started down the very slight driveway decline without me in the car!!!!!

Summary
1) if you dyno the car it will most likely throw a code
2) the car looks to be a 380-385 wheel horse power car with 500 miles on the engine
3) check and make sure your ebrake works

The dyno facility was at European Performance Labs (EPL) in CT - Tony (owner) does a lot of custom tuning on turbo engines (VW / Audi / volvo / porsche) - Tony is a great guy and I would highly recommend him if you have a Porsche Turbo car that needs tuning

GlennMc

Are you able to translate this figure to power at the flywheel please????

Thanks very much if you can




G.

997gt3north

I can say from my past dyno work I have done with Tony at EPL and all my experience with different dynos I have done on my other car is that there is no exact way to pin this down as every dyno is different and even the same type of dynos can have the shop set them up differently. This problem is further compounded by the fact that none of us will ever know if the true engine dyno numbers that the manufacture states are real / understated or overstated.

If Porsche's stated numbers are real (415 crank /engine hp) then taking the average of my dyno 380hp and AWE's dyno 386, then we get 383whp. Given Porsche's 415chp is 32 more than the wheel 383 then 32 / 383 is 8.3% drive train loss.

If Porsche's 415chp is really understated / a minimum, and is really 425chp, then drive train loss is 11% (more realistic).

If, as one of the biggest Porsche tuners believes, drive train loss for 2wd porsches is 17%, then 383whp translates to 448chp (to me this sounds too high from what I know about my other car)

If I had to guess, I would guess that engine dyno / crank hp is 10% higher than Porsche states = 420 to 425

Philip in AL

It is a safe bet to use a 12% DT loss. I would guess the crank HP to be about 440Hp to 445Hp.

MJones

Chassis dynos are an approximation of HP with slim to none calibration.
Different dyno mfg...different result
Different day...different result.
Atmospheric conditions (barometric pressure, ambient temp, humidly, altitude) will all effect results,
doubful that a local tuner will or can control as many variables as possible. (ie. intake air temp always 72° regardless of ambient temp)

Dyno rooms for engines (PAG) have the luxury to control and stabilize variables for consistant results.
For reference the altitude of Porsche Platz, de is 951 ft (290 m) where the final engine dyno figures are recorded.

GlennMc

I had my MKII GT3 (with manthey K410 upgrade) dyno'd at a well respected place in the UK

It is a Dyno Dynamics RR, and i think these are known to be one of the best ??

Anyway, i had it dyno'd twice, there with approx a 4 month gap between each run...

Both times it showed 417.6BHP at the flywheel, it takes all things into account apparently.

I'm no expert, but was impressed with the exact same figures at different times..

We always talk flywheel figures over here for some reason, but i understand it is not an exact science due to the transmission loss as stated above.


I had heard that the new GT3/RS should be around 420-430, so that sounds about right.


I will hopefully get the RS Dyno'd in a month or two, but was wondering how many miles needed on the car before it should make full HP.
I.E. it's still only on about 300 miles, so would i be correct in assuming tht it would probably not make it's best figures yet ??


Cheers

G.

Z06

They have a correction factor..... When we compare rwhp & rwtq we look for the numbers to be corrected...for reasons you mentioned.

So the only way to compare dynos is to get the numbers from the dyno test that are corrected plus you would be using a gear that is one to one..which is not third (1.64)and the closes gear would be fifth 1.06 ratio.

997gt3north

there is no way i would dyno the gt3 in 5th gear - at least on a mustang, 4th gear in the gt3 speed wise would be close to shutting the dyno down - 5th gear the car would be starved for air and crazy

i dynoed the car at 400 miles - i'm old school - drive it like you stole it - as long as the oil is up to temp and it is ready to go - let it rip

1/2 the guys say baby it for 1000 miles, 1/2 the guys say once the oil is up to temp let it rip - you pick

Z06

I don't know what the max speed would be on a dyno but if your going to compare numbers to others it's done 1 to 1.

Why would it be starved for air in fifth gear?

997gt3north

- 5th gear at 8400rpms in the gt3is 178mph or 287kph
- there is no way a sane dyno owner will let you go this speed on a dyno (if they do, leave immediatley)
- when you are travelling 178mph into the bus stop at watkins glen, the airflow into the engine cannot be replicated by fans purchased at WalMart that Dyno onwers use

frayed

Huh?

The dyno doesn't know whether you are redlining in 2nd or 5th. Engine speed is the same.

997gt3north

- you should think about what you write before writing it
- a dyno is a machine that has specs that it opporates within
- 2nd gear for a gt3 moves the dyno rollers at 137kph / 85mph versus 5th gear in the gt3 which is 287kph / 178mph
- also, you do understand that a car consumes air in combination with gas to create power and that the air required to move a car at 178mph is much more than required to move a car at 85mph
- in order to get peak hp/tq, the a/f curve requested will be in the range of 12.0 (my dyno showed porsche's ECU requesting 12.25 at peak tq)
- if you dyno your car in 5th gear at 178mph at 8400rpm good luck getting the dyno not to shut down and good luck getting your a/f ratio to be anywhere close to 12.0

my911rs

The air consupmtion of the engine should be a function of engine speed and load, not speed. The GT3 can develop 10 or so more HP at full speed due to ram effect. this would not show on a dyno. Quite possibly doing a test in 5th gear is not advisable for wear and tear reasons and maybe safety, but in pricipal peak HP can be determined in any given gear, and the air consumption would be the same regardless of the gear selection.

frayed

gt3north, I wish I could take a hit of WTF you are smoking. See post 13.

Have you ever run a car on the dyno through gears 2 through 5? Rotational limits on the dyno I get. More air at the same rpm on a loading dyno in third vs. fifth, such that the car is starving for air? My car at redline in third is fine but at redline in fifth will be starving for air? Uh huh.

A.Wayne

You are assuming that you will have positive pressure in the intake. i highly doubt this proper high flow ventilation, is all that is needed to work . If your dyno has walmart fans then i would run , but not at the 178 MPH Speed on the dyno . Anyway , you would need to use the gear that is closet to 1:1 it might be 4th or 5th i'm not familiar with the gt3 gear ratios.