Turbo Cool down Questions

[nozzano22]

Hi all,

When you refer to cool down driving, how do I know if it is cooling down? is it RPM based? I typically drive slow in my residential neighborhood the last 1/2 mile or so to my house, but it is hilly.

Also, I find typically when I get to where I am going I slow down to park, or take a moment or two to park and shut things down. If just a few mins of slow driving will do great, otherwise it is the timer from Hector.

Also, looking at the Turbo Timer but have a question. With my Saturn I would notice a much reduced Coolant temp when the A/C was on as this started an Electric Fan and cooled the radiator more. Is the PT the same way? Seems to me that just letting the car idle could build up heat without air movement through radiator. Does the A/C kick on the radiator Fan?

Thanks

Mike

[PTGT_Boy]

For normal non-agressive driving, you don't really need a cool down period.

However, because you drive around hills going home(not sure how the steep the hills are), I would suspect your using some amount of boost going up the hills and probably a good idea to give it a cool time period. The cooling period would be more dependent on how steep the hills are.

The electric fan will automatically turn on when the engine bay reaches a certain tempature, turning on the A/C is not necessary. In addition, the PT turbo is coolant/oil cooled, having the electric fan will do little to cool the turbo charger. The cool down periods are to cool off the turbo charger than to cool down the engine.

[JPMS GT]

PTGT's got it Mike. I have a 1/2 mile cool down to my place too. I just make sure the fan isn't running before I shut it down. Another good idea I heard here is turn off the air conditioning for that last half mile and you wont get moisture (mold and mildew) in the ducts. Good cruizing!

[AlmondTurbo]

I do some driving in and across the Sierra Nevada mountains in California, so I'll offer this example. Climbing, and using boost, I want to pull into a turn-out for a scenic photo. I'd leave the engine running. If I was on a long down grade and wanted to stop for a photo, I'd shut off the engine. If I were stopping for lunch on the upgrade, I'd let the engine cool for 2 or 3 minutes. It's hard to believe how hot the exhaust manifold, turbo (hot section), and exhaust headpipe get on a long grade.

[mcruz]

I always pop the hood when I get home and leave it up for a couple of hours. Don't know if this does any good but I figure it can't hurt.

[brenner]

The purpose of the cool-down is to let the tubo disapate heat and to ensure that its spinning slowly so leaving your hood open for a few hours after its shut off does nothing. I installed a pyrometer on my GT and i let it idle before i shut it down until the exhaust is under 800 degrees. normal driving around town usually doesnt get the exhaust very hot unless your always in the boost, it usually stays between 8-900 degrees, but if you get it into the boost its over 1000 degrees very quickly, and going down the highway at 60 its 11-1200 degrees. So your best bet is to always allow a minute or two before shut down if you've been driving easy for the last 5 minutes or so since the exhaust (and turbo) disapate heat pretty quickly.

[Gear_Head]

brenner, a little off topic here, but where did you install the EGT probe. I installed at the top of the down pipe under the 02 housing. Didn't want to deal with removing the turbo/exhaust manifold just to catch the metal filings.....

[PTGT Redman]

I use my EGT and let it drop below 800 b4 shut down. I ocassionally pop the hood cause the bay gets so damn hot and venting the heat I figure will reduce thermal damage especially over time and to sensitive stuff along the firewall.
I put my EGT probe on the downpipe too. It's not bad and for what I use it for it is helpful.

quote:Originally posted by brenner

The purpose of the cool-down is to let the tubo disapate heat and to ensure that its spinning slowly so leaving your hood open for a few hours after its shut off does nothing. I installed a pyrometer on my GT and i let it idle before i shut it down until the exhaust is under 800 degrees. normal driving around town usually doesnt get the exhaust very hot unless your always in the boost, it usually stays between 8-900 degrees, but if you get it into the boost its over 1000 degrees very quickly, and going down the highway at 60 its 11-1200 degrees. So your best bet is to always allow a minute or two before shut down if you've been driving easy for the last 5 minutes or so since the exhaust (and turbo) disapate heat pretty quickly.

[redrum]

even after the cool down, i also open my hood to exhaust heat out of the engine room. it is very warm there and opening the hood can not hurt whilst the car is out of the rainy seattle weather.
redrum
03GT

[JPMS GT]

Whilst, redrum? I haven't heard that since my last trip through the Forest of Dean! [^]
John