mikew968

I am seeing as much as 4 mph speed drop at the end of the back straight at Mid Ohio from the morning to the afternoon. How do I figure out where this drop is coming from? I am assuming it is both the "launch" coming out of the keyhole as well as some engine performance drop?????

Thanks,

zedcat

How much ambient temp increase do you see from AM to PM? That is probably the driver to lower engine performance. Should be able to see that with just a speed vs distance overlay from your data logger- presume you have AIM or Vbox or ?

mikew968

V-box and Garmin. Temps were probably hi 50's low 60's to the low 80's in the afternoon.

sonorous

I don't know the answer here but your symptom sounds similar to the reason why Porsche added the side window intakes on some Clubsports and why the new RS has the feature built in. Just throwing it out there...

thuggo

Thats exactly what it is. Road Atlanta in the Summer.....on the back straight going into turn 10 you can see a big diff in top speed from morning to afternoon. I mean you are talking 20+ degree difference in intake temp alone. The normal intakes on the GT4's suck ***** for feeding cool air on the track.

carbondan

Can higher octane fuel counteract this?

thuggo

It didn't for me. Race 100 Octane didn't make a lick of difference on Power vs Good 93 Octane from what I could see. *shrugs*

Chris P Lewis

No..

Chris P Lewis

You can compare intake temps assuming the Vbox is set up for it. You will see the intake temp and ambient temp track with the intake temp about 15 F above the ambient. It's Physics... and you are driving a thermo pump.

tcsracing1

these cars are known to get slow in the heat. The computer is retarding the timing to protect the motor in the extreme heat.
You can install a flash to help curb it.
The side window air intakes are the best fix however.

We ran the car in IMSA 2020 and were basically the only team left running a Cayman due to the lack of performance in the heat and a ****ty BoP given in the cold of february.
2021 allowed the car to run with a good BoP and side air intakes but the engine still struggled in the heat.

The new Cup motor really helped out this seaon however a ****ty BoP is once again on the car.

RobT 394

While this is normal, a cold air intake kit will drastically reduce the heat soak you are experiencing. Have a brand new kit ready for install if interested. PM me.

thuggo

Ya I'm going to go with...lol it won't help.

RobT 394

Dont blame you! The price is not for the faint at heart. Here is a link to the kit as FYI. Well made, and still cheaper than PMNA. https://teambgb.com/pages/carbon-fib...ke-kit-981-718

thuggo

I thought you were talking about something else, yes the SRO Intake kit....will make a huge difference. And the BGB is much better made than the PMNA one.

RobT 394

Getting fresh air to the motor will do more for the car than just about any other upgrade. Somewhat free HP as it is not invasive.