Shorter engine life of turbos...question

Does this apply to all turbos to the same degree as it does to the aircooled ones? I'm wondering if a water cooled turbo can expect half (or less) the engine life of a water cooled normally aspirated car, or if this halving of engine life applies specifically to aircooled models where heat is such a factor. Clearly turbos will have a shorter life than normally aspirated cars, and the question is only to what degree depending upon engine make.
And if this is so, then a Japanese High rpmer should have a shorter life than a high torque style car like a carrera...should, but do they?

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Kurt B
1984 911 Carrera Cabriolet
75 914 1.8

Kurt I think all things being equal you are probably correct. The problem is in moving from the general to the specific. My 911 turbo will probably last quite a while some abused 3.2 may die a early death. I work with a kid who is running the S out of a eclipse turbo. I don't think the car will be around much longer. The thing the jap motors have on their side is better manufacturing technology. They can build to tolerances today that were only available to the high end hand assembled cars of the past like our older 911's. That said, the affordability of the jap turbos also means they are more likely to be treated cheap too. I think the high end ones like 300's and supras probably got better care by their owners. My 300 was a great GT ride,good for a quick coast to coast in climate controled comfort.

david 89 turbo cab

It stands to reason that ANY turbo version would not last as long as its N/A counterpart. You are putting 30% or more added stress on the engine as well as a lot more heat. Modern technology may keep a high revver going past 100K if the owner doesn't thrash it and keeps the maintenance up. I would immagine that diligent maintenance and a light foot will increase the life of both high strung and boosted engines. Synthetic oil also has a hand in increasing engine life. It will be interesting to see the longevity data on the 993TT and the 996TT as time goes by. Both these engines have benefitted from modern technology so it should be a fair comparison. As for the older tubos (930) vs 911, heat did play a bigger part in an early death. The N/A 74-77 cars show this as a real problem as well. I hate to say it but it looks like their are a few very good reasons for the 911 to go with water cooling instead of oil.

[This message has been edited by RarlyL8 (edited 10-21-2000).]

Kurt,

i posed a similar question to a friend of mine a while back who is a Bosch engineer. i was talking about the 1.8t VW engines, and about a few other turbocharged "hand grenades". i wondered why people would buy such a motor if they knew that it would be problematic and costly.

well, we talked for a while and i learned a lot about turbocharged engines, and how they can be made to be just as reliable as Normally Aspirated ones. he had looked at quite a few turbo designs and explained that if you can keep the excessive heat down, and keep the turbo lubricated... then the turbocharged engine should last just as long as the Normally Aspirated one. the newer Japanese turbo engines have a very nice method of keeping the turbo cool, and this prolongs it's life greatly.

every time you want a larger or more powerful turbo, remember you will be needing a larger oil cooler. also you will need a better method of keeping the engine cool in general... maybe a lower temperature oil thermostat could help too.

one of the BIGGEST enemies of a turbo is the engine and exhaust heat that bakes the turbo after the heat is shut off and the engine is no longer circulating coolant around the turbo. one of the big differences between the newer and older turbocharged cars is that the newer ones keep coolant circulating past the turbo after the engine is shut off.

hopefully within a few years, we will see the air bearing turbochargers come down in price and be more realistic for sports car applications. the air bearing turbos are right now only being used in heavy equipment such as semi trucks and other industrial gear. they are supposedly the BEST because they are the lightest, they spool up the quickest, and they also do not need oil to keep them lubricated! exciting development indeed!

in the meantime, the best thing to do to prolong your turbo engine life is to keep it cool. keep the engine well lubricated with high quality synthetics also. if exhaust heat is a problem, then consider getting your header and exhaust jet-hot coated. keep your engine clean, and make sure that if you've been running hard for a long time... you give the engine a while to cool down after a hard run. we HAD a 931 a while ago. excessive engine heat destroyed the turbo and killed the car at only about 80,000 miles. too bad, nice car really. oh well!

obin

Some additional info on long lived engines. You probably have seen many examples of this on the road. In the early to mid eighties, Mercedes made a 5 cylinder diesel turbo, model was the 300D. High compression, no intercooler, good oil cooler, lots of oil, and tons of them still on the road. In 1998, I rode in an 84 300D from Philly to D.C. that a lawyer acquaintance bought new. 425,000 miles, regular maintenance, no rebuild. My '83 300D has almost 200,000 miles.
Last year one of my employees drove the car and the radiator started leaking. In order to limp home, he continued to drive, stop, add coolant, drive, stop, add coolant. This probably would have worked in a normally aspirated car, but not the turbo.
I bought a used head for $100 and had a machine shop redo it. New radiator $140, a good used turbo $100. Total repairs about $1,100.
I expect another 200,000 to 300,000 out of this turbo charged high heat motor. It is water cooled, but air cooling is sufficient if done right. I wouldn't worry about turbos and long life if they are well designed ,well built and well maintained. Like most Porsches.
David

While I do not own a turbo 911, I worked for as a mechanic at a Saab dealership for a few years and worked with ALOT of turbos. Based on what I saw in those cars, I never saw what seemed to be decreased engine life or engine failure due to any sort of wear that could be attributed to pressures on the engine from turbo boost. I did, however, see a tremedous difference in the earlier turbos which were oil cooled only, and the later ones which were oil and water cooled. The oil only operated a very high temps, and once the engine was shut off, basically cooked themselves into failure at around 60-70K. The later ones (oil and water) ran much cooler and I never saw one fail, even well into the 6 figure mileages. It seems, that if an engine is built from the ground up to be a turbo, or at least well modified to take the turbo beating, it really does not decrease its life. If, however, you bolt a turbo onto an engine that was not designed to handle the heat or boost pressure, I can see how this would be a problem. I would assume that the engineers at Porsche probably did their homework, so you major concern is most likely keeping the turbo as cool as possible so that it does not fry itself so quickly.


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Nick Shumaker
1982 911SC Coupe

Nickshu:
"The oil only operated a very high temps, and once the engine was shut off, basically cooked themselves into failure at around 60-70K."

this is EXACTLY what killed our 931! Porsche's newer turbos are much better built and have much better cooling, so this sort of thing is a thing of the past.

before we got our Porsches, i fell in love for a gorgeous Maserati Biturbo. i always loved Maseratis, and this one was just too good to pass up. i didn't buy it however... it was the first car that i ever heard of in which ALL the enthusiasts said "great car... but don't buy one!"

apparently, the twin turbos on that car are consumables like oil, gas, and spark plugs. it eventually eats gigantic holes in both your patience and your bank account. too bad really, as they are gorgeous looking cars.

obin

I was in the market recently and was torn between a 3.6L and a 3.3L turbo -- I ended up with a 91' C2 and am I glad after reading the responses you received. I had no idea most air cooled turbos were down and dirty after 100K. I plan to put a LOT more than that on my 3.6L. Sounds like we're better of tricking up our present engines. However, those trubos are a ball to drive!! Thanks for asking the question

Both NA 911's and 300TD's are subject to self-destruction in the hands of idiots like the infamous Bill Gates! He burned-up the engine of a '76 911 and a 300TD by just filling them up with gas and driving with great abandon ... ran them BOTH out of oil in the '70's! Guess you could say he could afford disposable cars.

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Warren Hall
1973 911S Targa