Has anyone put a turbo on a 944s2?

Bluegrass2 · 11-11-2005, 09:05 PM

I have a 944s2 that is a monster out of the hole but needs more horsepower. I have thought about turbo charging. Not sure how the engine will respond. Has anyone put a turbo on a 16 valve engine car?

todd951 · 11-12-2005, 07:12 AM

I've heard of 968's being converted to Turbo, but they normally use an 8V head when they do the Turbo conversion. I'm not sure how much different it would be for an S2.

AaronM · 11-12-2005, 08:09 AM

Just remember that to do it right you'll need new rods and new pistons. Also, you'll have to lower the compression a lot to avoid detonation under boost (factory turbos are 8:1 CR) which means you'll lose some of your hole-shot. And you'll need a full engine-management system since the S2's DME won't be able to handle the turbo so I hope you're good at programming a MegaSquirt system.

WaA420 · 11-12-2005, 08:41 AM

Quote:

Originally posted by AaronM
Just remember that to do it right you'll need new rods and new pistons. Also, you'll have to lower the compression a lot to avoid detonation under boost (factory turbos are 8:1 CR) which means you'll lose some of your hole-shot. And you'll need a full engine-management system since the S2's DME won't be able to handle the turbo so I hope you're good at programming a MegaSquirt system.

Why would you need new rods?

AaronM · 11-12-2005, 11:39 AM

Quote:

Originally posted by WaA420
Why would you need new rods?

Turbos used forged connecting rods to deal with boost pressure. Doing a turbo conversion right would mean replacing the NA cars' cast rods with the turbo's forged rods.

Most cars would need a new crank as well, but all 944/968 series cranks were forged according to the sources I've found.

WaA420 · 11-12-2005, 01:34 PM

'86 951's have the forged rods while '87-'88 951's share the n/a rods. Then '88 951 s and the '89 951 have an entirely different rod that I believe is forged as well. The rods that are in the S2 will work just fine to turbo charge.

Fast951 · 11-12-2005, 02:27 PM

To turbocharge the S2, you have 2 options. 16V turbo or 8V turbo.

The 16V turbo will cost much more and will be fairly diffcult as most parts must be custom made.. Parts unique to the 16V: Exhaust & intake manifolds. Custom 16V pistons to lower the compression. You will have to sleeve the block in order to get low CR pistons..

The 8V will be much simpler as you can use many parts from the 951. You can use the 2.7L 8V head MY89 944NA, or a modifed (water passage) 951/944 8V head. You still need custom pistons to lower the compression.. (You can actually get away with using the 3L 16V pistons, as when used with the 8V head CR is low enough to get away with it.. Using the stock S2 pistons is not a good choice, but will work marginal performance..
When using 8V head, you might be able to find pistons to work with the Alusil block.. Andial had few sets, not sure of availability any longer.. If you cannot find the low CR pistons for the Alusil block you will have to sleeve the block and get JE or similar pistons..
When using the 8V head, you can use the 951 header, crossover & intake.

Both 16V or 8V require the 951 left motor mount, and intercooler. 951 rods can be used or aftermarket ones. S2 rods are not a good choice for a turbo application..

The S2 DME works fine, just need to reprogram it. Of course, larger injectors and higher fuel pump is needed..

This is nothing but a brief description to what is involved.. Plan on spending serious $$ especially if you pay for labor..

AaronM · 11-12-2005, 10:30 PM

Quote:

Originally posted by Fast951
The S2 DME works fine, just need to reprogram it. Of course, larger injectors and higher fuel pump is needed..

This is nothing but a brief description to what is involved.. Plan on spending serious $$ especially if you pay for labor..

How will the S2 DME provide the KLR functions? Does the wiring harness even provide for a KLR? It has to monitor boost pressure somehow and without a KLR the regular DME can't do that, can it? Not sure if you can rig a way for it to monitor manifold pressure even with re-programming.

Bluegrass2 · 11-14-2005, 04:42 AM

Thanks to all of you, this is good information. Iwas under the impression that
I could put on a thicker head gasket, get a stand alone system, turbo and an exhaust off of a 951. I didn't think that the S2 rods and crank are too weak.

AaronM · 11-14-2005, 05:55 AM

Quote:

Originally posted by Bluegrass2
Thanks to all of you, this is good information. Iwas under the impression that
I could put on a thicker head gasket, get a stand alone system, turbo and an exhaust off of a 951. I didn't think that the S2 rods and crank are too weak.

Well, you technically _could_. It's just a bad idea.

Bluegrass2 · 11-14-2005, 06:16 AM

Quote:

Originally posted by AaronM
Well, you technically _could_. It's just a bad idea.

Ha, point taken.

legion · 11-14-2005, 07:49 AM

I believe Powerhaus did a 16v 3.0L turbo.

IIRC, they had custom low-compression pistons, and had to fabricate custom intake and exhaust manifolds. (951s use 2-bolt flanges on the exhaust side, S and S2s use 3-bolt flanges. Not sure about the intake side.)

Spook · 11-16-2005, 07:08 PM

Also to add, the Vario cam ( 16v) will need to be eliminated so that the valve timing is no longer enabled. Increased valve timing = blowing the engine. As has been said, can be done, much more than meets the eye. Stay with an 8v, less headache and less on the bank account.

AaronM · 11-17-2005, 05:54 AM

Quote:

Originally posted by Spook
Also to add, the Vario cam ( 16v) will need to be eliminated so that the valve timing is no longer enabled. Increased valve timing = blowing the engine. As has been said, can be done, much more than meets the eye. Stay with an 8v, less headache and less on the bank account.

I think that VarioCam was only on the 968.

Bluegrass2 · 11-17-2005, 06:25 AM

yup, I have no Variocam. This sounds like too big of a project for me, so I might just focus on a nice flowing exhaust and chip. I have already dropped Web ground cams in but no exhaust or fuel management yet.

Fast951 · 11-17-2005, 04:52 PM

Quote:

Originally posted by AaronM
How will the S2 DME provide the KLR functions? Does the wiring harness even provide for a KLR? It has to monitor boost pressure somehow and without a KLR the regular DME can't do that, can it? Not sure if you can rig a way for it to monitor manifold pressure even with re-programming.

On the 951 the KLR deals with knock, controls boost and send teh signal to the boost gauge on the cluster.
Anytime you modify a 951, you remove the factory cycling valve, and go to manual boost control. So this is not needed for the S2 conversion. The S2 cluster has no boost gauge, so a second KLR functionality is not needed..
That leaves knock control.. Doesn't the S2 come with knock control?

So there is no need for the KLR.. If someone to use the KLR, they will need the 951 DME and wiring harness... which may be an overkill for this conversion.

The S2 crank is fine for turbocharging, it's the same as the 951/944 crank, just a different stroke.

AaronM · 11-17-2005, 06:15 PM

Quote:

Originally posted by Fast951
On the 951 the KLR deals with knock, controls boost and send teh signal to the boost gauge on the cluster.
Anytime you modify a 951, you remove the factory cycling valve, and go to manual boost control. So this is not needed for the S2 conversion. The S2 cluster has no boost gauge, so a second KLR functionality is not needed..
That leaves knock control.. Doesn't the S2 come with knock control?

So there is no need for the KLR.. If someone to use the KLR, they will need the 951 DME and wiring harness... which may be an overkill for this conversion.

The S2 crank is fine for turbocharging, it's the same as the 951/944 crank, just a different stroke.

Won't it still need to monitor manifold pressure somehow though? I mean, how will the S2 DME know how much boost there is to adjust fuel flow accordingly? Or is it possible still to just control that according to the AFM?

thelowestone · 11-19-2005, 08:34 AM

can you not just suction mount the afm 'mount before the compresse housing" and reprogram ecu for use with bigger injectors and be done as far as detonation and such you can manually tune around it if you know what to look for

Fast951 · 11-19-2005, 06:53 PM

Quote:

Originally posted by AaronM
Won't it still need to monitor manifold pressure somehow though? I mean, how will the S2 DME know how much boost there is to adjust fuel flow accordingly? Or is it possible still to just control that according to the AFM?

Why would you need to monitor boost? Load is measured based on AFM (or MAF) over RPM. There is no need to monitor boost in the DME, however you should have a boost gauge.

AaronM · 11-19-2005, 07:04 PM

Quote:

Originally posted by Fast951
Why would you need to monitor boost? Load is measured based on AFM (or MAF) over RPM. There is no need to monitor boost in the DME, however you should have a boost gauge.

I guess I'm just overthinking. I had thought that the ECU would need to read manifold pressure and compensate for boost with increased fuel. I mean, you can have the throttle wide open and the AFM maxed out and still not be on full boost pressure meaning that there would need to be enrichment past what the AFM calls for as boost builds. Then again, at WOT it's full rich anyway now that I think about it since the TPS bypasses the AFM at WOT...

Never mind, I think I see now.