911 SC engine upgrade. What would you do?

[Nick Triesch]

Or buy a 2017 Mustang GT with 435 H.P. with 6 speed. And leave your cool Porsche alone.

[Josh D]

Originally Posted by sorien

I think that when it comes to Cams, CIS is the limiting factory is it not?

CIS and the pistons that accompany it. In other words, you can't just replace CIS with carbs and run any cam you want. Once you start narrowing the lobe centers or add too much duration and lift, piston to valve clearance becomes an issue due to the piston dome shape of the CIS pistons.

[Vereeken]

Originally Posted by Url

Vereeken, I'm an SC owner from Belgium as well

Who will do your engine build? Everything or will/can you assist?

I'll be following your adventure closely (Will you create a thread on PP?) as I'm looking to have my engine rebuilt in the coming years as well and was asking myself the same questions!

I will not start a separate thread. I will do 0% myself. I have another car that needs attending to if I want to go race again...

My engine builder is an old school guy(only porsche and he stops at 993). I can share the name by PM if you ever need it.
The problem (if you can call it a problem) is that he is not very adventurous and very sceptical about any claimed gaines....So he is not the guy to hot rod your engine.

[Vereeken]

Originally Posted by Nick Triesch

Or buy a 2017 Mustang GT with 435 H.P. with 6 speed. And leave your cool Porsche alone.

I am a sucker for mild performance gains unseen to the naked eye....

When I was a kid I used to pump up my bicycle tires to the point of explosion just to get the minimum amounf of drag. Nobody could see that my bum was hurting.So you see the issue....

[jons911]

A little late to the party, but I figured I would summarize some points echoed in some of the responses here for others that come looking for 3.2SS advice.

- 3.0 SC came stock with 95mm p/c's with the cylinders having a groove on the top for a sealing ring, and the pistons had a 22mm wrist pin (US stock CR 0f 8.5:1, EUR stock CR 9.5:1 or 9.8:1 can't remember)
- 3.2 Carrera came stock with 95mm p/c's without the ring grove on the cylinder, and the pistons had a 23mm wrist pin (don't have a 3.2 so never learned what CR those ran)
- The bump in diameter to 98mm is usually complemented by twin plugging since the higher CR pistons usually start to block the flame path (pictures located earlier in thread), resulting in an inferior burn (although I have read of plenty of people running single plugs). It is also usually complemented with a higher octane rating fuel for further protection against detonation. 91/93 here in the US is usually enough for normal operations.

The 3.2 95mm cylinders are what you need if you want to bore out and replate for 98mm as the ring groove is too close to the cylinder wall on the 3.0 95mm cylinders. I picked up a fresh set of bored and plated Mahle cylinders for $1300 whereas to buy new Nickies from LN is $3700 ($4780 with JE pistons). Also, JE makes pistons designated for the SC vs 3.2 Carrera. Even though the pistons are the same size/design, they made them with different wrist pins to accommodate the two engines.

My build plan is a little less adventurous with 98mm p/c's, JE 10.5:1 CR, and twin plug. Depending on emissions, I may backdate the exhaust to SSI with M&K Sport 2/2 exhaust.

Hopefully someone will find this useful.

[tcsracing1]

all very useful information!