Ok, your at an autocross, you do your first run, do you shut the car off as soon as you get back, do you let it idle? for how long? or do you just leave it on until its your turn to go again???

Thanks.

 

at the driving school I attended (road course, 15 minute sessions) I idled my car for ~5-8 minutes before I shut her off

 

I let her idle for 5-10 minutes with the ac on, so both fans would run

edit: That's for road racing At auto-x, maybe 3-5 minutes with the ac on

 

Off. But I turn on the manual fan switch.

After 3rd or 4th run, I open the hood for a minute.

 

if it's hot out....i turn it off. if it's really hot out, i turn it off and open the hood. if it's ******* hell on earth, i turn it off and open the hood and turn the fans on.

generally, i turn it off.

all of this assuming that BEFORE you ran you allowed the engine to reach optimal operating temperature.

 

I let it run on a summer day about 5 minutes with the hood up In the winter maybe 1-3 minutes.

 

Since my Tacoma doesn't have an electric cooling fan (mechanically driven off the water pump) I let her idle for about 3-4 minutes with the hood up and heater on, then shut her down and leave the hood up until it's time for the next run. She's always up to temp by the time I'm staging to the start from grid.

 

My Miata was getting past half way on the temp gauge...I tried a few different things - running it with the heat on, off with fans on and hood open, just completely off. Seems like the most effective is off, hood open with fans running..maybe let it run for 1-2 mins after your run.

 

I turn it on about 5 mins before the first run and keep it running until the timer shuts it off about 5 mins after the last run. Oh and on hot days I also bring along a water sprayer for the intercooler (and for the front tires if running the Azenis). And to my delight, I've also never seen more than 190F water temps with the talon even on the hottest days here in atlanta and even though I keep it running at all times.

 

let it run for a bit seems to be the concensus here?

 

I turn mine off. Not like it's at redline for a full minute, and even if it was, that's nothing on the engine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by garados &raquo;</TD></TR><TR><TD CLASS="quote">I let her idle for 5-10 minutes with the ac on, so both fans would run
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AC makes the car run hotter. If you run your blower with the temp dial on hot than that would help dissipate heat.

After I autox I usually drive the car back slowly to my parking or staging spot and turn her off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lyrikz &raquo;</TD></TR><TR><TD CLASS="quote">do you shut the car off as soon as you get back, do you let it idle? for how long?</TD></TR></TABLE>


i guess that is where my mechanical water and oil temp guages come in handy....after the run, i let it idle down for 30 sec-minute or so, then shut it off. i keep tabs on the temp (as my car runs the best from 170-180 degrees) and start the car if i need temp, or leave it off, sometimes opening the hood if too hot. you cannot go by the factory guages, as most time they aren't anywhere near accurate.

 

The key is that running the engine keeps the water pump running, so idling for a little while keeps the flow moving.

My other hobby is off roading Jeeps. Many people have cooling issues since we swap larger-than-stock into old Jeep CJs(I still have a stock AMC 304 :-) and radiators get pacekd with mud.

A lot of people like to turn off the engine, but leave electric fans running. Keep in mind, all thats doing is cooling the antifreeze in the radiator.

The engine itself is hot. Hotter than the antifreeze. The coolant in the block stops once you turn off the engine, which stops the water pump. Coolant temps in the block & head passages get very high, 300 or more degrees ins't unreasonable.

Best to let it ilde for a few minutes just to keep the coolant flowing.

Its no different than the same thing the automakers have been saying for years.. if you overheat, leave the engine running at idle and turn on the heater. Its to prevent the coolant from sitting in the block and getting really hot.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lyrikz &raquo;</TD></TR><TR><TD CLASS="quote">Ok, your at an autocross, you do your first run, do you shut the car off as soon as you get back, do you let it idle? for how long? or do you just leave it on until its your turn to go again???

Thanks.</TD></TR></TABLE>

This is very car and temperature dependent. If you have a turbo car then always let it run for awhile. The Camaro drivers all let their cars run - they cool off faster running then off - go figure. I let my type r run for a few seconds if its hot and let it run if the outside air temp is cold. Some people are concerned that shutting it off will allow the intake to heat soak.

 

My concern is not holding the brakes down or setting the parking brake after a run... which typically ends in a very tight stop box.

 

thanks for all the replies, seems general consensus is to just leave it running for a minute or two before shuttin it down.


Thank you.

 

One other item, the Honda water pumps tend to start really working at about 2k-3k rpm. If you really want to cool the car down quickly, bring the revs up to that level for a minute or so. More throttle opening also tends to help prevent heat soak in the intake manifold, which is what really kills your power.

C_A_T

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PupaScoopa &raquo;</TD></TR><TR><TD CLASS="quote">My concern is not holding the brakes down or setting the parking brake after a run... which typically ends in a very tight stop box.</TD></TR></TABLE>

Is this really a concern in autocross? I know it is for track events, but you don't get that much heat into the brakes during an autocross run...braking hard 3-5 times doesn't seem like it would get the temps that high, especially since you're not braking from that high of a speed in the first place.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by manveer &raquo;</TD></TR><TR><TD CLASS="quote">

Is this really a concern in autocross? I know it is for track events, but you don't get that much heat into the brakes during an autocross run...braking hard 3-5 times doesn't seem like it would get the temps that high, especially since you're not braking from that high of a speed in the first place.</TD></TR></TABLE>

I'd tend to agree with you. Unless you have some really high-speed/hard stops in your AutoX the heat in your brakes should be negligible.

Oh and I let it run a few minutes and then turn it off. If I get a few runs in a short period of time I run it a few minutes, then pop the hood. Does it do much? I don't know. Does it make me feel better? You bet!

 

What does turning the fans on do when the engine is not running?

that water is not circulating through the block..
the effect of cooling the water in the radiator to cool the engine will only have slightly useful effect if any at all

 

let it run for 5