I got pulled over last night at about 1 oclock in the morning. I was doing somw spirited driveing and i then saw these lights go off behind me and thought o $h!t, but when i pulled over i shut the car down right away and put the keys on the dashboard. I do this to show respect to the officer ( trying to get out of ticket ) but now i am wondering if my car is feeling it. Is it ok what i did or should i have let the car cool down.

 

i thought about that when they told me that you had to kool it down, and im all like well wont the officer think your planning to drive away? but i dont know, sorry i couldnt answer your question but i think its ok ever once in a while, like if you do it by accident.

 

you should read up about turbo's because in simple terms a turbo is a fan spinning really fast, which creates heat, if you drive hard then go park the car the fan blades on the turbo are reaaly hot, turning the car off will let the blades warp. Thus letting the turbo spin to cool it down, this way it keeps the blades in the right shape.

 

yes

 

all of that shutting down and putting key on dash is unnessesary ,well i turn my car off now but when i get the evo and install a turbo timer it wont be going off when i shut off the ignition if i happen to get pulled over like many things in life that isn't supposed to happen

 

Its not a good habit, but it should not cause any damage unless you were to race the car, shut it off and keep going in that cycle constantly. Cool down and warm up are precautionary measure for your car. Similar to a low fat diet for our bodies. Can we eat junk food constantly without heart disease? Yes. People do it every day and live as long as others. But to be optimal, one should watch what they eat. Treat you car like you would treat your body.

 

As long as the car was still warm when you started it back up you'll be fine. The cooling process is to prevent coking of the residual oil in the turbine casing. By letting it sit at idle the turbo stops pulling oil into the housing and while still heated up it drains out the oil it pulled in during driving. The point is to not let it cool down with the oil in there. 5 minutes the cop is gone, car is still hot, start it up and let it idle when you get home. It's just going to recirculate that oil again but it will be hot and it will be just as if you let it cool down the first time.

I believe this is the theory behind coking but anyone can correct me if I'm wrong.

 

This is crazy how people take a snippet of info and build in their heads a complete fabrication...
1) there is no oil in the turbo housing..oil is fed to the bearings on the impeller shaft, that gets hot through heat transfer from the exhaust impeller and the air compression side of the turbo.
2) the reason for the delay before you shut your car down is so the oil pump can continue to pass cooler oil over the impeller shaft bearing, and thus cool the impeller shaft and bearing to a temp that will not cook the oil that will be left after the oil pump has ceased to circulate oil around the motor
3) It has nothing to do with warping the blades as one of the previous posts suggests
4) And yes you can damage your turbo if it is hot enough with one accidental fast shut down....although the damage may not be evident immediately

 

One or two hot shutdowns with synthetic oil are probably not going to damage the turbo so relax. I won't repeat Limey's excellent description and just add that common sense works just as well as a turbo timer.

I replaced the stock turbo on my 114,000 TSI Talon and there was a small amount of coking but nothing that degraded the turbo performance. I have always followed simple rules such as:

- allow a 3 minute cooldown after a 30 minute or more run on the highway.
- allow a 2 minute cooldown after spirited driving

Normal driving does not require a cooldown. That is it and it worked for me. Turbo timers and BOV's seem to be the first two complete wastes of money for new EVO's. IMHO.

Speedlimit...

 

Not sure if I would use this analogy .... plenty of "human garbage cans" or should I say "fast food junkies" out there driving evo's I'm sure. Think of it this way ..... how many girls can you pick up at the drive through window in an evo? Wouldn't want to miss out ... would ya now?

 

I was regurgitating what someone else told me. Like I said, correct me if I'm wrong. I've never had to replace a turbo in any car with the exception of upgrading. But even still the stockers were just fine. Just remember to let it idle for some amount of time before shutting down.

BTW, you're the first to explain it like this in the many years I've been around turbos. Not saying you're wrong just the first to explain it in one of many different ways.

 

Evilutions comments wrapped-up with Limeys and Speedlimits are good info for people new to turbo cars.

I wouldn't lose any sleep over the situation you described especially since you fired her back up and continued to drive afterward. Synthetic oils can certainly take more heat than conventional petroleum oils, but even Synth oils like Mobile 1 use a petroleum based carrier and are still succeptible to heat break-down and coking.

I appreciate speedlimits comments about turbo wear and inspection after many miles of use. When I shelled my engine in my Syclone at 74k miles, I found that my stock turbo had no coking at all, and end-play tolerances were excellent. I have 96k on the turbo today and it is still singing along nicely.

This may be repetative but these are the things I think insure long turbo life:

1) No cold spool-ups (I think this contributes to most new turbo failures than anything else). This is why an oil temp gauge really keeps you safe.
2) Consistent oil changes w/synthetic oil every 3000-3500 miles. Regardless of it slippery nature or high heat tolerances, synthetic oil is still going to get contaminated with combustion by-products. This contaminant is not heat tolerant like the original synthetic oil.
3) Plan your drives and make sure you give yourself time to cruise and cool-down before stopping. The flowing air will act much quicker to cool the temps than sitting still letting the car idle with a turbo timer. Again an oil temp gauge helps because many factors will determine how quickly temps recuperate.

Speedlimit - I am glad you commented on the turbo timer. None of my turbo cars were ever equipped with a turbo timer, and yet none ever experienced any turbo problems. I personally view turbo timers as functional gadgetry schwag. They do work, are cool to look at, can certainly be great conversation pieces, but are not really necessary. Maybe ok for some, but not a priority in my book.

BTW- I am not looking for a flame war..but just felt like piling on a bit to help provide a counterpoint to the many posts extolling the unquestionable virtues of turbo timers.

 

Most of the good stuff has already been covered, so I'll just summarize and add my little bit to the end.

(1) Synth oils are MUCH less prone to this coking problem we've all been warned about. Don't fret it.

(2) DSMs have been running these turbos HARD as HELL since '89 and I can't recall more than one or two cases where people have claimed a coking problem. Granted, I don't dissect turbos daily and I'm sure those that do will have seen more than a couple in their day, but it's not a huge, consistent problem and I don't think it really has been since those ****ty Ford turbo days of '85-'89 or so. I used to own an '84 Ford EXP turbo...what a HEAP!

(3) If you like Corky Bell, his comments suggest (actually I think they even just flat out state this, but I can't recall for sure, so I'll say suggest) that water cooled turbos are water cooled for this very reason...to prevent coking. Oil is going to drain from the turbo fairly quickly, but the water system is full all the time. As the water cools, it also moves through the system, helping to remove heat from the turbo.

I've beat on 16Gs and 20Gs and various other turbos for the last 6-8 years and have never once used a turbo timer and have never once had a coking problem. I don't think it's a legitimate concern any more. Of course, after a hard and heavy session on the road course, I let it idle a few minutes in the pits, but I don't pay it a second thought on the street.

Thomas Dorris

 

Thanx!!! the info i have been getting from this forum is great!!!

 

I usually just take it easy the last couple minutes of a drive and turn the A/C on. I've noticed with the A/C, it will kick the fan on and off for short intervals here and there. It can only help with the cooling I would think.

After spirited driving though...I dont mess around. Its usually at least a 2-3 minute cool down for me.

I was religeous with turbo cooling on my old spyder gst.
Well...I went through 3 turbo's in 150k miles in that thing anyways. Those T25's were pieces of ****..

But those old DSM turbo's like the previous poster said above were already tweaked from the factory. I bet the 16g will have a longer life. Its about time they fitted the right turbo for the 4g63 here in the US..