gcb951

So,
I have obtained an early pre 1985.5, 944 NA block and I am wondering if it can be used for a turbo swap. I have a scored #2 cylinder on my stock 951 block.

I have been told that the oil feed line to the turbo feed must be tapped into the counter balance shaft housing. Also, I would have to use the oil pan from my 951 for the turbo oil return line.

But is that all? Can't be right? What about the water pump and sensors? Will my 951 wiring harness work?

If anybody can give me an idea of the possible problems I might run into that would be great. I don't know if I should even try to use this block. Any info would be awsome. Thanks.

Porsche-O-Phile

Several people have done it. It ain't much more complicated than you mention as I understand. Some transplanting of sensors and wiring (and the head & pistons), but that's it. The blocks are identical IIRC.

gcb951

So,
Maybe I can use this NA block after all? Does anyone have any specific information on what I will have to do?

Porsche-O-Phile

PM Danno. He's running one in his car right now.

KuHL 951

I think that the early blocks had slightly smaller oil passages than later blocks. I know they have been used before but I have no idea if the size restriction is a negative or not. At least you'll have a spare set of forged rods to sell.

gcb951

Yea,
I also heard that the oil passage ways are smaller. I don't know if that will make for poor lubrication of the turbo.

How do I PM danno?

Keep the advise coming guys, really appreciate it.

KuHL 951

He's hard to reach sometimes but you can reach Dan through: http://www.gururacing.net/

Helstrm

The tap for the turbo oil line is already in the balance shaft covers. There is a plug screwed in. I would not try to change the covers unless you have to because they are machined parts. No gaskets...

The oil pan is the same. If you look at it there is a plug where the return line goes.

gcb951

Hold up,
I thought the hole for the oil feed line on the counter balance shaft wasn't put on all the blocks till 1985.5? And your saying the oil pan is the same too on an early (1984) block? Im confused. Please keep the info rolling in. Thanks.

Helstrm

They are on 2 of the blocks I have.. Maybe this was different on some models..

eclou

You need to use your old turbo pistons though

Porsche-O-Phile

I wasn't aware of that. Perhaps on later '85 models? There were some 951s that were produced for Europe in 1985 and even a couple of prototypes that rolled out as early as 1984. I'm not sure if / when they'd have retooled the production of the upper balance shaft housings and oil pans to include the turbo line connections. Anyone know when they did it for the water pumps for the extra cooling lines? Maybe they did all this at the same time. . . Anyway good question; I'll look at my early '85 (Callaway) and see if I can see whether there are connections there. If so, that'd sure be nice! Hmmm. . . Sequential twin-turbo setup? Hmmm. . . You know if those connections ARE there it means I could always add a second turbo over there. . . Hehehehehe.

Jfrahm

The blocks might have different tolerance group bores so check that. With the wrong tolerance group the pistons will not fit. And you do need the turbo pistons or I suppose you could dish the NA pistons. You could use the NA pistons as-is if you wanted more off the line snap but less overall boost tolerance, as it would raise the compression ratio (and make the combustion chamber smaller.)

-Joel.

Porsche-O-Phile

Running with the stock 9.5:1 n/a pistons in a turbo (951) setup has also been done with good results. The n/a pistons are admittedly cast metallurgy and not as strong as the forged 8.0:1 951 pistons, but IF (big if) you are very diligent with your tuning and keep the setup within stoich. you shouldn't have problems, even with higher-than-stock boost levels. There are ricer guys running around with 10.0:1 and higher stock compression ratios running 25+ psi of boost. It's all in the tuning. The disadvantage to the higher-compression cast pistons is if you DO happen to run lean, things will go south a lot more quickly and with far more disasterous consequences. Where a forged piston might "take" a momentary bout with detonation, a cast piston could shatter. That's not to say forged pistons are indestructable - they're not, but they might be able to weather some abuse that an n/a cast piston wouldn't. More reason to make sure your tuning is spot-on.

I have NOT heard of a turbocharged version of a later n/a engine (with the higher c/r) nor of a Euro-spec turbocharged n/a engine. Again, it probably could be done, but your tuning better be perfect before boosting it up. Or add some toluene to your fuel mix. Or methanol. Or all three. There's ways to do anything - doing it "right" and carefully is important unless you have extremely deep pockets. These cars can drain a bank account faster than a boat if you're not somewhat diligent.

Good luck! Keep us posted.

gcb951

Well,
I would be using my 951 pistons (8.1). So I won't have to worry about over boosting because of high compression pistons. I just wanna know if I can use the early pre 1985 block to put all my turbo stuff on. Will everything bolt up? Will my new updated water pump fit? Are all the oil feed fittings already on? Will my wiring harness work? Are all the sensors the same? Considering I got this 1984, 944 block for $150, it makes it a very cheap fix for my bad #2 cylinder on my stock 951 block.....that is....if it will work.