924 turbo og 944 turbo - longevity of turbocharger

[Ole Petter]

Hi, I am thinking of buying a 924 turbo.
The turbocharger does't have water-cooling av the later 944 ones does. Will this give longevity problems?

The reason for buying a 924 is because of its now + 30 years of age. The insurance and road tax is very much less for that where I live. I already own a 911 and my son has a 1984 924 in great condition. The 924 is a great little car. I hope a 924 is even more so

Thankful for advice.

[wild man]

Obviously the lack of water cooling will result in shorter jevity than a water cooled unit. The best way to stretch that out is to not run it hard very often. And when run hard, "baby" it for next 5 minutes, especially before shutting it off. I had 2 924's, and I was under the impression that they only went to 1982.

[924RACR]

Yes - they can be harder to keep happy. What wildman said, make sure to give it time to warm up (oil temp, which is always slower to come up than water temp) before getting into the boost, and likewise some cool-down time after running, to let the turbo cool.

Using synthetic is mandatory, as well; when the 931 (924 Turbo) came out, they weren't in common use, and so use of regular/dino oil in the turbos contributed to early failure.

Consider looking into a Turbo Timer, which will run the engine after you key off, to help with cooling.

Another option, if you're real aggressive, would be to upgrade the center section of the turbo to a watercooled unit from another car, like an Audi... this would of course require a turbo shop to build it up for you.

FYI, the 2.0L 924 continued to be sold into 85 in the EU - they only stopped bringing it over here in '82.

Yes, the turbo is all the fun the NA should've been...

[wild man]

Good info in the previous post. But here is an idea:

Being that the 931 turbocharger is a K26, it might not be all that difficult to convert it to a water cooled unit, by simply swapping out the center section (and installing a rebuild kit, while you're in there). It should be possible to do it yourself, just be sure to mark the nut, shaft, and wheel for proper alignment when re-assembled. Plumbing in the water lines is what would require some creative thinking.

And BTW, I do happen to have an extra water cooled K26/K27 center section available.

[Rasta Monsta]

But then again some 951 racers run disconnect the H2O systems on their K27 units.

[J1NX3D]

i thought it was Rasta that did it, maybe it was ideola or someone else... but yes, the 944 k26 watercooled housing is a direct swap for the 931 no watercooled housing. plenty of discussion about it on 924board.

[J1NX3D]

Originally Posted by wild man

I was under the impression that they only went to 1982.

Originally Posted by 924RACR

FYI, the 2.0L 924 continued to be sold into 85 in the EU - they only stopped bringing it over here in '82.

I think RoW continued until '85, not just EU. it could be with the US marketing of the 944 and power difference between the US spec 24 and 44 that they stopped the 924 in '82 for North America.

I see some '85 924's come up locally every now and then... lol, eg just now: Porsche 924 1985 for sale - TradeMe.co.nz - New Zealand

[wild man]

Originally Posted by Rasta Monsta

But then again some 951 racers run disconnect the H2O systems on their K27 units.

In my book, racing = cooking, especially when it comes to the exhaust system and turbocharger. So in my wildest dreams, I cannot fathom why they would even consider depriving it of it's cooling supply. Racing or not, I'd NEVER consider it! It just seems like such a cruel thing to do to. But I suppose that they have fat enough wallets not to be concerned about how many they go through.

[Ole Petter]

I agree. It does sound strange to run a water-cooled turbocharger without the water cooling. But racers always let their engines cool down before shutting off... Maybe that is the real trick.

Modern oils may make a lot of difference?
And thinking of it - the turbochargers of the 911 variants ran without water-cooling until the 996. And I never heard of any issues with the oil-cooled turbochargers on those cars...? Hmmmm

[petrolhead611]

Hi, I think you'll find that the 924 turbo continued to sell in Italy thru 1984 due to their punitive tax laws for cars of over 2 litre engine capacity, whereas it was discontinued in 1982 in ROW. The second generation 924 turbo surely had the water-cooled tubo, did it not? The other advantage of 1981 and later cars was the fully,rather partially, galvanized bodywork.

[J1NX3D]

Originally Posted by petrolhead611

The second generation 924 turbo surely had the water-cooled tubo, did it not?

sadly no. it was introduced on the 944 turbo.

[924RACR]

Oh, BTW, as for water-cooled housings on-track - no need, as you can enforce warm-up/shutdown procedures, so it's not worth the added complexity for a racecar.

One of those things Porsche had to learn in making the transition with the technology from the racecars to the street cars...

[Rasta Monsta]

Yeah, I sorta feel like the 951 setup is really only intended to save the turbo from stupid owners (run the crap out of it and then park it). Water cooling does its most valuable work after shutdown, and really does very little while running.

[Porch]

Water cooling is nice as an OEM solution, but in the real world lots of people run turbos without water cooling. Invest in a turbo timer and you'll never have an issue (except with people like me telling you "your car's still running!")