Whats your setting ?

 

If the Autotimer feature on my HKS sets it greater than 2 minutes, i let it go for that long, otherwise, 2 minutes.
~Tom

 

I got my greddy set at 3 minutes. Weather i drive for a minute or not, i always cool it for 3 minutes. When i'm at the track, i set it to 5 minutes.

 

1.30 if im comin under normal slow driving, if im gettin on it in the least 2 min with hood up and fans on...@ trac 5min..mabe more

 

it all depends on how hard you ran it. if you didnt really get on the boost, you dont have to set it for as long.

 

I just set my greddy timer on auto high. but start it at 2 minutes.

 

It really depends on my temp and how I was driving before hand. If you drive easy right before you get to where you're going there is no need to use the timer. In fact it can do more harm than good. Think about it, if your turbos aren't excessively hot your just letting your car run with no air flowing over things to cool it down. Thus you're just cooking your engine. Things like rubber hoses, pumps and batteries don't like that. However if I just came off the track, 3 minutes min.

 

Usually 3 minutes is best. If you have been getting on it all night then id say let her sit for about 5. If you just went to get some groceries and back, then I'd just set it for 1:00 maybe 1:30.

 

O minutes..... I've observed that my car's water temperature (with an SR Ultimate radiator) peaks at rises to 210-215 F if I leave it idling long enough.

As a general rule, I try to have the water-temp at or below 195F before I shut it off. My procedure is to drive off-boost (10"+ vacuum) for the last two-three minutes, to get the temperature down below 195F. I also turn on the cooling fans a few minutes in advance (the well-documented fan-mod). I shut the car down immediately after coming to a stop and leave the fans running for 10 minutes.

By this procedure I've noticed that my manifold temp rises to about 215F about 30 minutes after shutdown, but it cools off quickly to below 180F within a couple of hours!

Bottomline: No need for a turbo timer - just cool the car on the road before shutting it down.

 

I never set mine for less than 2 min. Typically 3 min though.

 

I thought the idea behind turbo timing was to allow the car to gradually cool down so it prevents cracking of the manifold? If you cool it off quickly, doesn't that make it more prone to cracking? I'm not saying what you're doing is wrong, I'm just asking questions to learn more...

 

Manifold cracking due to quick cooling? I don't think that'll happen from the fans or from driving off-boost for a couple of minutes.

Rememer the goal is to cool the turbos as much as possible before the car is shut down. I believe that the technique I've described above works best.

You can always test how your car responds to idling after being run hard - does the water-temperature drop or not. You can then decide if you want to use a turbo-timer or not.....

All of this discussion assumes that you have a working water-temperature gauge (either an after-market one, or a linearized stock gauge).

 

Normal driving is set to 1:50 and when I street race 2:00 hood popped and when I drag 5:00-6:00 with hood popped and two fans at high speed

 

10 seconds can't let it idle to long when your running 4 11's (spark plugs)

 

30-40 secs normal, 2-3 mins after driving hard

 

seeing as how I usually coast to a stop while parking or getting into my carport, I usually allow no more than 1 minute for the same reason as bbr1.

still need to do that damn fan mod tho.

 

30 secs when driven normally..1-2mins when driven hard.

 

I cool for 2min for regular drriving 3min for gettin on it alittle and 5 at the track.

Jeremy

 

I must be timing too long b/c I time mine for more than 4 minutes on hard driving and 2-3 minutes on regular driving. I just time until the red glow on my turbo goes away. Maybe I'm just paranoid.

 

Metals can fail if subjected to heat cycling although I think the materials used in the construction of the exhaust components are selected with consideration for their operating environment.

My understanding is that letting the engine run for a period of time at idle was originally intended to feed oil (cooler oil) to the bearings to prevent "coking". Coking occurs when oil is heated to a very high temperature and breaks down causing particles of carbon to form. If you've ever removed the valve cover of a higher mileage or neglected conventional piston engine then you've probably seen these particles on the top side of cylinder heads or inside the valve covers. It's that black gritty (abrasive) stuff. Now imagine what black grit does to bearings. That's right it tears 'em all to hell.

Turbos on the 3rd gen are lubricated and cooled with oil, and additionaly cooled with engine coolant circulated through the housings. Older turbo equipped vehicles usually had only the lubricating engine oil as a means of cooling. I would say that the problem of coking is probably not that prevelaent in later model cars which use dual methods of cooling, but I do have a turbo timer. And I have noticed the temps rising and the fans coming on (and I don't have the fan mod) when the car was idling on the timer. Sometimes I use the timer to warm the car up to operating temp.

For that reason I suggest, and use bbr1's procedure often. And personally I don't think the turbos ever really get dangerously hot unless you're in moderate to heavy boost for extended periods. As for the person that had the turbos glowing red--I would take that as an indication of some type of problem (most likely exhaust).