DIY Turbo Timer

[fspGTD]

At part loads and idle loads, a Diesel has EGTs much lower than gas motors do... so less turbo timer duration is required.  I find that EGTs on my 1.6lTD after extended idling, will even drop below 200 deg F.

I only very rarely think there would be a need to idle a street-driven VW TD longer than 1 minute before switching off the motor.  The worse case scenario would be, you're going WOT up a mountain pass for minutes, engine is smoking hot borderline overheated, and you take a rest stop exit coming to a parking space almost immediately after the freeway.  For that kind of scenario, I'd say say use common sense, maybe manual idle the motor a little bit longer before switching on the 1-minute (slow-glow relay) timer.

I have not even rebuilt my old Garrett turbocharger, which came along with the 1.6lTD motor from a junkyard car of unknown history, engine was rebuild but turbo was not... and I have not experienced any turbo related problems whatsoever.  I attribute that to the (1 minute) turbo timer being used as needed, and also use of synthetic oil (Mobil Delvac 1, 5W40.), which can take a lot more heat than mineral oil.

[Turbo DS]

Get a good/fast responding EGT gauge....  a lot will be revealed as far as proper turbo timing time.  Also, I've done some anaylsis with an infrared pyrometer; a short time is generally all it takes.  Do not forget, a diesel nearly always has a ton of excess air in the exhaust mass, further cooling down hot parts as compared to a gas engine with its throttle mostly closed at idle.

But if you desire 3 minutes, go for it  :wink:

[andy2]

I also just use my fast idle/advance to bump up the rpm a bit and after pounding the engine I have found that it takes literally no more than 1 minute for the EGT's to drop to a low that the engine would idle at anyways.Just my 2 cents  

[QuickTD]

I have found that it takes literally no more than 1 minute for the EGT's to drop

Be careful shutting down by EGT readings alone. I find that even though the EGT's drop to 300ºF in less than 1 minute, the manifold/turbine housing are still storing considerable heat. If I shut my car down after a hard run when the pyrometer hits 300º, then wait 30 seconds and turn the key back on, the guage will often read 600º or more. The heat from the manifold soaks back into the probe after the engine is shut down. The thin probe out in the middle of the exhaust stream is the first thing to cool down, the manifold and turbine housing take far more time...

[andy2]

Good point Quick TD,my pyro"Banks" doesn't use any voltage so it reads with the key off and I usually don't pay attention to its readings when the engine is off,however I've never seen the temp go back up after shutdown. Also noticed that if I do some higher rpm downshifting before I park it really gets the exhaust to cool down fast.Does the exhaust temp differ much at "idle" in respects to pre and post turbo or are they pretty equal  :?: has anyone ever had a dual pyro setup to monitor such differences (at idle) :?: