Autocross Question

[NickCats]

Ok, I have a stupid question. I am attending my second autocross this Saturday and I was wondering if it is bad for the car to run it in the high rev limits when the car is cold ?

For regular day to day driving, I make sure the temp is in the 180 range before I wind out the gears. In an autocross, since the car sits for awhile and cools down, then when it is time for your run you are basically pushing high RPM’s in 1st and 2nd for about a minute or so, is this bad for the engine ?

Thanks,

Nick

[Perfectlap]

good question!
I don't think I ever really looked at the temp during an autox, or maybe I did and it never registered. usually i turn off the engine while waiting on the qeue.
Sometimes during the autox I will leave the 'paddock' and take a drive around the venue to warm up the tires a bit. I doubt it makes a huge difference but since they were R comps I figured maybe....

In the morning I always short shift when first starting up the car but its usually up to temp in no time.


but revving any engine that's cold is not good in the long run.

[FrayAdjacent]

It is definitely better to run the engine at temperature, especially if you're pushing it hard. The engine oil viscosity changes as temperature increases - it flows better. You need good oil flow when you're pushing it.


I can't say it will really HURT the car if it's not warmed up, but I will say it's better to have it warmed up before pushing it hard.

[ChrisZang]

same here:
I made it an habit of mine to start the car and let it idle before the driver's meeting (you never know if your run group goes first). And between runs I let the engine idle.
Don't ask about the average gas mileage I get out of an Auto-X

[986 Girl]

Originally Posted by ChrisZang

same here:
I made it an habit of mine to start the car and let it idle before the driver's meeting (you never know if your run group goes first). And between runs I let the engine idle.
Don't ask about the average gas mileage I get out of an Auto-X

At one event I remember driving an hour out to... got 31 mpg on the way there...

... and then a whopping 9 mpg while participating. Hehehe.

[Rodger]

Nine MPG?! Pshh.....I got 5.9 at my last one! Nice fast course....

I always warm mine up and sustain the revs around 3000 to really get things flowing prior to pulling up to the start.

[kabel]

I always let my cars come up to temp before running them at autox rpms. Just seems like the right thing to do. And it sound counter intuitive, but I run the ac between runs (if back to back) I noticed the water temp runs cooler with the ac fans running.

[LuisR]

I would also recommed warming up your engine before autoXing. You do NOT want to run high revs with your engine cold!!!! I did my first autoX earlier this month and i was told by many Boxster drivers to just ket the car idle in between heats, remember that you want as much lubrication as possible!!!!

[NickCats]

Thanks for the suggestions, guys !

Nick

[racer_d]

Another one in favoring of letting the engine reach operating temps before (ab)using it

Also remember that there is an excellent chance that if the coolant/water isn't up to temp, then neither is your OIL. The OIL is more important to make sure engine parts aren't starved of warm oil. The actual water temp being cool likely isn't a problem, since the coolant is used to COOL the motor, not heat it, but its temp is indicative of the overall engine temp.

[Sammy]

I always turn the car on and allow it to come up to temp before I take off. I usually keep an eye on how many cars are ahead of me and with about 5-8 cars to go I start the car.

[Sammy]

Oh and don't forget to let the air out of your tires (down to 5 psi) and ride with the parking brake on! (can't have a non S without race tires beat me on Saturday)

[MNBoxster]

Originally Posted by LuisR

I would also recommed warming up your engine before autoXing. ...was told by many Boxster drivers to just ket the car idle in between heats, remember that you want as much lubrication as possible!!!!

Hi,

That's true, but letting it idle is the worst thing for it. Both the Coolant and the Oil Pumps are Crank Speed dependent. At idle, they're not flowing very well at all. Excessive idling kills most engines because of this. Better to shut it down and then start it before your next runs and give it partial throttle to get the Oil and Coolant really flowing...

Happy Motoring!... Jim'99

[Bavarian Motorist]

Before running, I just leave my engine on till it warms up. No biggie.

[Perfectlap]

Originally Posted by MNBoxster

Hi,

That's true, but letting it idle is the worst thing for it. Both the Coolant and the Oil Pumps are Crank Speed dependent. At idle, they're not flowing very well at all. Excessive idling kills most engines because of this. Better to shut it down and then start it before your next runs and give it partial throttle to get the Oil and Coolant really flowing...

Happy Motoring!... Jim'99

yep^ ever been to the motor pool at a police station? The cops have their cars idling for hours a day. They have to change their oil every week and the mechanics are always rebuilding engines.
This makes feel better when I jump in the car and drive off without more than a minute of warming up...speed dependent.

[Bavarian Motorist]

Originally Posted by MNBoxster

Hi,

That's true, but letting it idle is the worst thing for it. Both the Coolant and the Oil Pumps are Crank Speed dependent. At idle, they're not flowing very well at all. Excessive idling kills most engines because of this. Better to shut it down and then start it before your next runs and give it partial throttle to get the Oil and Coolant really flowing...

Happy Motoring!... Jim'99

Thanks for the tip

[986 Girl]

I'm embaressed to say this, but I never even considered letting the car run for a little bit before doing a run. Now having thought about it for, oh, half a second, it makes perfect sense. Good advice to keep in mind for this season!

:blush: