Raceboy

16v turbo makse MUCH more power at less boost level, especially in Porsche case. You can buy, modify and try your a$$ off with modifiyng 8v 951 but you still have crappy cylinder flow and basically crappy power from that boost. 16v turbo needs much less boost to achieve same power and S2 and 968 pistons have proved themselves to withstand bunch of boost. Rods are other story and they should be changed out to 951 ones.

Black Arrow

Are the rods for the 951 better than the s2 rods? Whats the difference?

Raceboy

Yes, 951 rods are stronger than S2 and 968 rods.

George D

Most 951 roda are forged, but some are cast.

Are you asking why not just turbo a S2 car, or take a S2 motor and build a 3.0 turbo for a 951? If you mean turbo an S2 car, you can't go past 8psi of boost using the stock internals. Not cost effective based on the end results.

SFR has a proven supercharger system for the S2 and 968. Better bang for the buck.

The S2 and 968 block are almost identical. This is what most use to build 3.0 dedicated turbo motors. We only use the block and coat the cylinder walls. Everything else from the crank up is dedicated for forced induction. Forged rods, custom or factory Mahle turbo pistons, etc.

George

Raceboy

It's a proven point already that thicker headgasket mod works with 3.0 engines allowing decent boost (up to 18-20 psi) and spectacular power numbers. Markus951 968 engine was STOCK sans Cometic headgasket and 951 rods and made 567 hp @ 1.35 bar.

Olli Snellman

That's correct.
I choose another way. I have a 951. Bought a S2 block &crank and most likely i am going to have a S2 head too. Wössner turbo pistons, finnish made rods, E30 M3 throttlebodies etc. etc. I can make this here in Finland, because 951 is already a turbo charged car. If i start withS2 it's not possible here... Odd regulations.

George D

It's a proven point already that thicker headgasket mod works with 3.0 engines allowing decent boost (up to 18-20 psi) and spectacular power numbers. Markus951 968 engine was STOCK sans Cometic headgasket and 951 rods and made 567 hp @ 1.35 bar.

Markus changed the rods. This is not a stock S2 motor. With a piston change he would basically have a 3.0 like what I'm talking about in the first place. If Markus changed the rods he pulled the motor and went through everything but the pistons. Because he used the stock pistons, he had to lower the compression using a thicker headgask. This motor is basically a 3.0 conversion tubo motor, sans the piston.

I'm assuming that the original intent of this post was to not have to pull the motor and basically do a rebuild.

George

NZ951

The problem I see with using a thicker HG to reduce compression to run more boost is that the factory squish clearance goes totally out the window. You could take some cc out of the head while porting and reduce compression a little while there. I would still think if rods allow you can run way more than 8psi. Hmmmm the S2 must be incredible prone to det otherwise.

NZ951

Yes intent is to buy a stock S2, bolt on necessary parts to turbo without doing bottom end.

Other questions will be around valve springs pressure I guess...

George D

That will be expensive. I would look for a bolt on used blower kit. The new kits are around 6K, but give you STOCK 951 turbo performance.

Go to www.speedforceracing.com and you can see some dyno runs and such.

George

NZ951

I dont think it would be that expensive to turbo an S2, but hey depends how you go about it and if you can do it yourself.

AL951

That is true. If you could do your own work ,cost will drop like a rock.

I know most people here usually go for the 968TS replica engine, but if you are all read spending 10-12 gs for this, why not just go all the way and get maximun bang-for-the-buck by keeping it 16v .

Regards,
AL

davepnola

Markus told me he is using the stock studs, washers, and nuts with 3.2mm cometic head gasket . He has had no problems yet. I plan on trying the same setup. Will the stock rings work or are the turbo model rings different material ? I would love to use the turbo pistons, but 2000.00 savings goes a long way in this setup. My other worry would be the vario cam chain and pads setup. I know I will upgrade the chain to the heavier duty version. His version is completely stock chain and pad setup.
My real interest is tuneing vario cam with boost. That should really increase the torqe curve.
Heck 9.0 compression tuned at 12lbs boost should put close 400rwhp. Whad ya think ??

Raceboy

My point was that with engine management and some sanity 400 hp is easily achiveable from stock S2/968 engine. Yes, head-gasket change is a must.

We've talked in and out for hours about this squish issue with Markus before he decided to try head-gasket mod, and whoops! it worked. His engine is not anymore detonation prone due to "ruined" squish. If he'd pushed 2-2.5 bars through his motor, yes, then it would count a lot.

It's better to not machine the expensive head or pistons (they get weaker).

And expensive? Heh, I'm not going to tell you yet how much cash I've put on my 2,5 16v turbo engine but it aint big money Everything can be done if one has a little knowledge and common sense.

NZ951

What do you mean your HG mod worked?