Time spent at 100% throttle in Autocross/Endurance

[umngopher]

If some of you guys would be willing to share the time your vehicle has spent at 100% throttle around Endurance and/or Autocross the past couple of years.

I realize there will be variance so if you would be willing to include the year, MI/CA/VIR, engine, and time, I would appreciate it.

Thanks

[Jay Lawrence]

For our F4 turbo with ~70kW and ~100Nm, the range is about 5-15%, heavily dependent on driver. Note that this value includes rev-matching too. I imagine for the single teams the value could be somewhat higher.

[bob.paasch]

With our 36 kW CFR450X we're at full throttle 15-20%.

Edit: Just looked at the logged data for endurance at MIS last month, looks like we were at full throttle about 20% on that course. There was a lot of lap-to-lap and driver-to-driver variation.

[Scott Wordley]

Between 10-20%, even with massive wings, so still majorly grip limited, and over powered.

[nowhere fast]

Originally posted by Scott Wordley:
over powered

I disagree. If you spend x% of a lap at 100% throttle then additional power will increase your speed for ~x% of the lap.

That said, the low amount of time spent at 100% throttle suggests that bigger gains in lap time may be available elsewhere.

[Thrainer]

Scott, is that a car with traction control and full-throttle upshifting, or without?

[Jay Lawrence]

As a point of interest, our 5-15% full throttle relates to a car with 100Nm at about 7500rpm, where 75% throttle gives something like 97% power, so the 5-15% is a little less meaningful. That is in a car with TC but no full-throttle upshift.

[Scott Wordley]

Nathan, thats my point, in our view better to spend your resources working on things to improve your speed over 85% of the lap rather than the 15%, which consequently shrinks if you are successful.

The "elsewhere" you are talking about is cornering, braking and combined cornering acceleration. All these modes can be improved with more grip through the generation of downforce.

Thrainer, this is with traction control but no full throttle upshifts.

[Boffin]

600RR 240-250kg car on 6" hoosiers.
No traction control. No launch control. Cut spark not working on these runs

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Blanchard (Professional Driver) during his fastest autocross.
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Blanchard During endurance
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Matty (team leader, 2nd fastest driver) during endurance
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[Boffin]

Originally posted by Scott Wordley:
Nathan, thats my point, in our view better to spend your resources working on things to improve your speed over 85% of the lap rather than the 15%, which consequently shrinks if you are successful.

I echo Scott's sentiments.
As much as we used to have guys coming in wanting to work on engine, I used to steer them away from it, as they will do a lot "engineering" on another section of the car, and it's more beneficial for the car as well.