GT3 KSA

Dumb question but my stock GT3 today went on a dyno (Mustang Dyno) and the numbers were extremely low on all 3 runs. I am wondering if the Dyno place did something wrong.


When a 991 GT3 is put on a dyno should it be dyno-ed on 4th, 5th gear or other? Both gears gave horrible results. I am waiting for him to send me the results via email but figured, I'd ask so that after I put on the mods I am sure we run it in the right gear although I will probably do some in 4th and 5th since he did two today in 5th and 1 in 4th just to get the delta.


He also mentioned my AFR shows the car is running extremely lean, which he thought was bizarre for a stock GT3. If I am not mistaken he told me over the phone 260 WTQ (pretty close I guess to where it should be) and 322 WHP (seems very low to me).

RealityGT

Mustang's typically read a lot lower when compared to say a Dynojet. Since it is a load based dyno, you won't see any hero #'s.

Post up the chart with the environment variables, and correction used.
-Also was your car heat soaked at all prior to the pulls?
-How much cold air was being rammed into your intakes? (Big fans, and how many of them)
-What was your DA, baro, humidity... etc..

All these play roles in how your car performs when tested.

Regarding which gear. I'm not familar with the PDKS gearing, but you would want to test in the closest 1:1 ratio gear... Likely 5th or possibly 6th on the PDKS.

You want an accurate measure of Power? take it down the strip.. traps speeds will tell you alot about your motor.


Finally, it's just a #.. Dyno's don't really tell the whole story.. they should only be used as tools for tuning and displaying the delta's between changes.

GT3 KSA

email from the dyno operator below in " ", my question is was it supposed to be run at 4th, 5th or 6th gear? I read somewhere on line 6th gear is closest to 1:1 ratio but wanted to double check


"Pleasefind attached the dyno runs, the highest number of HP was when we did a 4thgear run, the rest are done on 5th gear.

TheAFR was averaging between 13,7 and 13,8 which i personally think its reallylean.

ithink due to the weather today it affected the dyno pulls numbers. where whenit is hotter the ECU automatically starts to pull and reduce timing which givesyou less power to sustain safe running engine"


here are the graphs for the 3 runs, 2 done in 5th and 1 done in 4th

robmypro

When you floor it does it scare the **** out of you? If so, it puts out enough HP.

GT3 KSA

That was very helpful, thank you!

robmypro

LOL Sorry man. Slow day.

fbirch

Mustang dynos do read lower, but there's no way a 991 GT3 should read that low on any dyno. Something is amiss - either the dyno setup or the car. I'd try another operator to see if the low readings are replicated

Mech33

Did the operator use a PIWIS to put the car in dyno mode? If not, that is probably your issue... too much ECM intervention due to the oddities of the dyno environment confusing the car.

GT3 KSA

Not many places to Dyno in Riyadh, Saudi Arabia + it is too late now since I shipped the car yesterday to the shop (3 hours away) to put the akra. race line exhaust / headers installed.



I saw a few videos online where all 4 wheels are strapped, I noticed in these two videos 1 in 4th gear and 1 in 5th that only the rear wheels were strapped, can this be why my numbers appear so low?

Charles@dundonmotorsports

If the car is in limp mode, meaning only 2wd dyno and no PIWIS 2 tester, the car can be made to rev out to redline but it is limp mode. I had originally done this and its a flat lazy tq curve and revs to 9000 but i think we only made 275whp.

If they put your GT3 on only one set of rollers running it RWD then yes it will not be a correct dyno, if they did all 4 then it may be ok. Mustang Dyno's do usually read less than dynojet, and those are usually 370whp AWD, so 330whp on a mustange AWD dyno may be ok.

Again, dont worry about the number, worry about the change before and after.

robmypro

I know on the surface my comment seemed worthless, but what I was really trying to say is, how quick is the car? Because most reviews I have read or watched say the same thing. This thing is fast. Now that won't tell you anything absolute, but if your car is really only putting out those numbers, I would think it would be pretty sedate.

If it pulls hard, probably just a dyno issue.

GT3 KSA

Charles - what is the right gear to dyno in though, is it 3rd, 4th, 5th or 6th?

GT3 KSA

The car is hella fast but just want to make sure i am dyno-ing it correctly

RealityGT

Learned something today.. thank you, sir!

Charles@dundonmotorsports

In theory the gear the dyno is done in shouldn't matter. Al this talk of 1:1 is just myth.

Generally the engine will be more consistent in higher gears as you don't want the engine to rev out too fast. I try to stay under 1000rpm per second but 5-700rpm/second always seems more consistent. I have dynoed these cars in Pdk mode doing a pull 2-3-4-5th gears. In all of those type of pulls 5th gear always made the post power and the most consistent and 4th was usually 2-3whp behind 5th. I dyno in 4th gear because it is more real world and 5th does 166mph which pretty much no one does except a few on huge tracks.

The lower gears make less power because the engine has to accelerate everything up to speed faster and it takes more HP to accelerate the flywheel transmission axles brake rotors wheels dyno rollers from speed A to speed B. There is more HP available at that speed so the car accelerates faster but there is more loss as well.

I can post a multi gear dyno run in a little