Turbo Life vs. cool down

[Thermo1223]

Turbine speeds AFAIK are in the neighboorhood 10-15k at idle and possibly depending on the turbo 75-90k at full tilt. I could be wrong though, I am trying to remember this all from an SAE paper.

The momentum is greater the bigger the turbo but still nothing compared to a semi or cat engine. The engine size also plays a factor, Cummins, PS, Duramax guys have it great with nearly 4 gallons of oil to absorb heat from the engine & turbo. So I wouldn't really worry, like the banks site said, it is mearly a myth now but had merit in the past.

If any one should be concerned it should be small diesel owners since we only have 4 3/4 quarts capacity.

Then again we have extremely tiny turbos with VNT tech so it makes the heat load much easier since boost can be more tightly controlled.

I only leave my TDI idle on the highway rest stops for a bit, never in town since I sit and idle at every light anyway. Even then it is only 1 min unless we are only stopping for a bathroom break or it's winter then I just leave it run.

If I turn it off in 30F wheather with 5 mins there is no heat left in the engine, at least on it keeps everything somewhat warm.

 

[Junior]

Turbo speeds are engine, turbo and application specific. We see speeds around 150,000 at full govonor break HP and exhaust gas temperatures as high as 1300F.

You are certainly not hurting your turbo by letting it cool down some. But, I don't have the knowledge to quantify how much or to know what the optimum temp is.

 

[1sttruck]

The owner's manual for my Dodge diesel states to let it idle for a few minutes if pulling off of a highway with load, where temps will be highest at altitude on a grade. No extended idle is needed for low speed / no load conditions. I always let mine idle at least a bit, less than half a minute or so, and end up doing the extended idle when travelling and pulling off of the highway for whatever.

 

[Steve S]

Junior what application see 150,000 rpm seems high.

 

[Thermo1223]

I agree with 1sttruck, only in apps where your towing or constant highway speeds do I see a need for a slight cool down otherwise just a waste of fuel.

 

[Junior]

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Junior what application see 150,000 rpm seems high.

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The company I work for builds off road equipment using Cummins engines. 80,000 to 200,000 is pretty typical for most turbo applications.

 

[DiEseLjunKy]

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I gave up using any turbo temp gauges in my semi's since about '92. Just wasn't worth cluttering up dash with temp gauges for turbo, diffs, and tranny anymore with high quality synthetics.

Oh... if this seems foolish, I have NEVER lost a turbo in almost 20 years of driving approx 130K miles a year and putting 1.4 million miles on my last semi, a '96 with Cummins N14.

A lot of what is said here is true... the time is takes to get thru a couple of lights on the street and pulling in to park will cool the turbo. Unless you are on a hard pull, at high power, etc. and then just reach over and turn the key off, you will probably not have a turbo cool down problem.

With the new variable vane, computer controlled turbos, the risk of turbo cooking is not nearly as big a problem as it was 2-3 decades ago. Take a look at this from Banks... especially myth #7:

http://www.bankspower.com/tech_TD-fact-Fiction.cfm

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I'm also a trucker and have to agree. From my experience turbo timers are a complete waste of time and money. A little common sense is all one needs. The time is takes to get thru a couple of lights on the street and pulling in to park will cool the turbo. Unless you are on a hard pull, at high power, etc. and then just reach over and turn the key off, you will probably not have a turbo cool down problem. That about sums it up. It's what I always do and I've never had any cooked bearings.