howardchen416

Recently acquired a Cobb AccessPort AP3-POR-015 which comes with a rather comprehensive data logging feature.
Collected some performance data of my '21 GT4 (w/ Soul Valved Exhaust + OAP and BMC Air Filter) following the vendor instructions and got some pretty interesting/impressive results. This being my first attempt not sure how reliable the data is, nevertheless thought it was worth sharing. A somewhat surprising observation is the recorded peak torque of 371 ft-lb at ~3k RPM compared to the Cobb map notes (Stage1 Octane 93) with peak at 314 ft-lb at 4.8k RPM. The full list of AP loggable items may be found here. Your thoughts are always welcome. Thanks and Happy New Year!

DFW01TT

I wish I'd have paid attention when I put my Cobb tune on.
I could have measured between stock and then the Flat 6 OAP's.
The Cobb tune will ruin your gas mileage, because you'll always have your foot in it.

planolemans

Do you know what gear the car was in when the data was logged? Mechanical advantage can change the curves.

howardchen416

It was straight 3rd gear according to the vendor instruction, after the the car has been warmed up to normal operating temperature.

monochrom3

Impressive what Cobb has been able to extract from the 4.0

flynlo

With due respect to Cobb, it might have something to do with Porsche purposefully stifling the output of this engine to keep its place in the brand hierarchy.

howardchen416

Yes, the full list of AP loggable items may be found here.

howardchen416

Actually, I was surprised by the recorded peak torque (371 ft-lb at 3k RPM) and power (446 HP at 7k RPM) figures as they appear optimistic compared to other published 718 GT4 numbers.

TXshaggy

Yeah, those numbers appear to be all gooned up…especially the TQ both peak and range.

howardchen416

Tend to agree except these numbers appear to be direct readings from the ECU through the OBD interface and not interpreted by the AP device. Isn't that the same way these numbers are retrieved during a dyno session?

TXshaggy

No, a dyno measures work directly at the wheel/hub.

There is a HP/TQ graph back of your OM. Think peak TQ of 309/317 plateaus much higher

planolemans

Third gear is surprising to me. The third gear ratio is 1.41 to 1. So you will have some mechanical advantage in your data. I would have thought that fourth gear at 1.13 to 1 is the one you would use.

Nevertheless, I was really impress with the power gain I felt when I installed the Cobb tune in my gt4.

howardchen416

That was Cobb's official measurement and yea I take that should be more accurate.

howardchen416

In my case, think the PMC air filter contributed a fair share too.

planolemans

I also have the BMC filter. I did not feel there was much gain with just the BMC filter. The tune really made a difference in my case.