Thanks. I'm curious to know how they manually figured the TQ numbers without an rpm pickup. Or even how the HP graph was accurately calculated. Oddly...their graph for the Cobb software shows a pretty smooth TQ curve.

Finding a good rpm pickup on these cars is tricky, and can drastically change the tq numbers on the dyno. In the early 997.2 days, we found that our tq numbers were sky high until we realized we were using the wrong one.

 

OP, all of these dyno values are worthless. None are even remotely within reason.

If you are in SoCal why didn't you just go to Cobb to dyno at their facility? They know how to dyno a 991TT and your results will actually make sense.

By the way didn't we race at NoFlyZone?

 

Dynojets are capable of calculating horsepower from vehicle speed.

The math to calculate torque from horsepower and vehicle speed is really quite simple and should be pretty common knowledge to most calibrators or dyno operators. I posted this same information in a different thread about a week ago. It is all just a relationship between variables. The key part in this was Nigel being able to record datalogs with the Accessport to get the variables needed. He pulled the logs off and sent them to me via email. Doing this would not be possible with other equipment that doesn’t allow the consumer to log. Keep in mind we can log at 40+HZ so the sample rate is extremely high.

We need four variables in total to find RPM and the resulting torque:
- Vehicle Speed (dyno supplied)
- Horsepower (dyno supplied)
- Vehicle Speed (log supplied)
- RPM (log supplied)

Using vehicle speed and RPM from the log we can now calculate our speed ratio. Speed ratio is the relation of RPM to vehicle speed. In 4th gear, from the log I uploaded here, shows the speed ratio of 4th gear to average out to be just over 52RPM/MPH. I use 52.08 in my calculations after reviewing several samples over the course of 3 logs for Nigel’s particular car. To put this in practical terms you would simply take that ratio and multiply it by your speed to get your RPM.

E.G. You want to find the rpm of your car in 4th gear at a vehicle speed of 87mph given the speed ratio for 4th is 52.08rpm/mph:





4530.96MPH is the RPM you are at in 4th gear at 87mph.

Using this speed ratio constant and the shared variable of the dyno vehicle speed and logged vehicle speed you can easily use Excel to calculate all RPM values of the dyno runs.

Using those RPM values you can then calculate torque using that new RPM value and the horsepower output from the dyno. Horsepower and torque have a simple relationship.




We have horsepower and now we have RPM which is all we need to find torque!
Attached is a spread sheet in Excel with the Cobb Stage2 Run 3 as well as our competitor's Stage2 Run3 using the data I got from Nigel. These runs produced the most power of their respected baseline session. You can look through them yourself.

No smoke and mirrors here folks, lift the veil and see that is all just good old fashioned data! We are much too talented of a group and take tremendous pride in what we do. We aren’t going to risk our personal reputation and that of the company by making bogus claims to make a quick buck. We are out to produce a kickass product and judging by the converts and Cobb’s sales in the Porsche market overall, the majority of you agree it is kick *** also.

This was a straight up apples to apples test performed by a customer at a 3rd party dyno. This test was performed on a linked Dynojet 424linx. Results are results, and gains are gains. The beauty of data is that it doesn’t lie.

In this particular case our competitors tune had that dip and the Cobb didn't, not quite sure why that is odd? Just because it wasn't in our competitors favor? That is what the car did on that tune, on Cobb's it didn't. Pretty simple really. Perhaps on that competitors tune there is a torque limiting table that was touched which resulted in the throttles starting to close or detonation which resulted in a large timing reduction. I can't tell you for sure why it was there because basic consumers can't log their tunes on this particular competitors product. All I can say is that it was fixed by simply flashing on the Cobb Stage2 map.

Thanks again guys for reading! More dyno plots below!
-Jon


Data for days

 

Dyno Plots from the .drf files Nigel sent me.


Cobb Best vs Competitors Best with calculated torque:




Cobb Best vs Competitors Best:




Cobb Worst vs Competitors Best:




Cobb Best vs Competitors Worst:




All 3 Cobb Runs:




All 3 Competitors Runs:
-Note the dip is present in all three



All Runs:


All Runs with run conditions:

 

Thank you so much Jon in helping to make sense of the files sent. Such a worthwhile endeavor as I was able to dyno and compare both tunes on my car apples to apples with no other change.

The value is in the hard data and having the ability to determine what helps or not in achieving results.

 

How was it driving Nigel? Have you had a chance to stretch her legs more?

 

Enought of dyno numbers, everybody know Cobb put more whp than giac lol
For me is time to see track and vbox numbers... Mine w COBB and Fabspeed did 7.2 on 60-130mph

 

Went to the track tonight and hit my first 6.99 ET. I am beyond thrilled! Traps were a consistent 100 to 102 and I ran back to back to back. Beat two decent drag cars but was really racing to better my 60' and improve MPH. Really impressed with the new tune. Mid range and areas where Id previously felt hesitation or a "flatness" in the power band are no longer. Id lived with this characteristic for so long I actually came to believe it was normal. She now pulls extremely hard throughout the full run in roughly 70-80 degree temps. I've circled my runs on the slips below.

 

Something is still off.

Those times are slower than my times in the dead of summer with only GIAC Stage 2 tune and exhaust.

 

Agree. The 1/8 mile trap seems slower than stock. If this the same car I think it is, it was faster with the GIAC tune when I raced it back in May.

If OP is not the car In the first race of the vid below, then I apologize and will leave the thread. But I think it is. If you look at the first 4 races, OP does a decent job of keeping up with me. Then I run heads up with a built/upgraded turbo 703 wheel GTR and decimate an SLS BS and Ferrari F12. Those are indicators that I'm making well north of 600 wheel. OP must have been making somewhere in the 530-540 wheel range to keep it relatively close. The GTR is a very well documented car owned by Raphael and has lots of dynos to prove the mods/power.

Here you go:

 

Well it's a TT not a TTS, I assume that is the case from the OP's handle and at first I thought the hp numbers were low in the first plot but I just figured that is because it's a TT. IMO this shows the TT can be tuned up to a stock TTS but it won't tune to the levels a TTS will.

 

Was that on pump 91 or with race gas?
What were your previous ET and trap?

 

It also has a stock exhaust.

 

He's running a 3" Speedtech with 200cel cats. It's a couple posts down from the top.

You still going to the track today?

 

I understand all of that, but without having data-logged the GIAC tune, how were they able to extrapolate the TQ curve? That's all I'm asking...