3.3 Shortstroke on a 964 case

[Axel84]

Got a 964 engine with an SC crank and rods - it needs a rebuild anyway so why not mak something fun out of it.

Using the case and CRANK - how would you build a high rev screamer?

AT Power ITBs
EFI
What cams?

can the valvetrain cope with 8500 + RPM?
will the crank be as good as a 66 MM on high revs?

[Evan Fullerton]

Well I’m building a similar engine but kinda going the other way.

3.0L crank
3.2L case
GT3 oil pump
100mm LN cylinders
997 GT3 130mm Ti rods
Xtreme big valve heads

I’m not planning on reving it to the moon though. Shooting for ~7000rpm peak power and not a ton of drop of up to 7500 to 8000ish. Looking for a super flexible wide powerband.

We will see how it works with 993VRam intake and 993SS cams.

To really rev it to the moon, GE100 cams and some flat slides would probably be the ultimate setup.

[winders]

Flat slides are not as good as a quality set of butterfly ITBs. The are not good at partial throttle…butterflies out perform them at anything but wide open…and a set of AT Power ITBs are 99% as good wide open.

[Evan Fullerton]

Agreed…….. but for an engine built to be exciting and rev, nothing like one that only really works at WOT.

[winders]

You get the best of both worlds and none of the downsides with the AT Power ITBs. They work incredibly well with my Xtreme heads on my race engine...

[Axel84]

so my engine with Rehardened rocker arms, GE100 cams, AT Power ITBS - JE pistons and flowed cylinder heads - what are talking

330-340 bhp? 100 bhp/litre? Revs to .. 8000?

[winders]

Go with CP pistons…

[Axel84]

ok.

[winders]

Also, find someone that you can trust to spec out the engine for you. Someone that knows what works together and what doesn't. You aren't going over 8000 RPMs with stock rods. Heck, I am not sure that it is a good idea to go over 7500 RPM with stock rods. It depends on what pistons and cylinders you choose to use as well. If you are going to 8500 RPM you will need forged rockers...and the Pauter rockers won't work.

[Axel84]

likely only go to 7700ish, and yes will be new custom rods.

[blue911rsr]

Don’t spin a old sc crank that hard.it’s going to break in half.

[Axel84]

thought the SC cranks were ok!

[Evan Fullerton]

I think it all depends. I have been successful spinning a VW T4 motor in a 914 with stock crank, rods, reused stock rod bolts, and Chinese cast pistons to 7500 regularly and occasionally 8000+. Porsche parts are definitely superior to 50 year old VW Parts.

It’s all a matter of risk and expected lifespan.

[Usafmike]

CP makes a great piston

[stownsen914]

I'd not heard that SC cranks couldn't go to 8000. The earlier 70.4 mm stroke 2.4-2.7 cranks are known to have a resonance issue above 7500, but SC cranks are dimensionally different even though same stroke. I thought they'd solved the issue?

[Axel84]

According to henry Schmidt supertec on here they are good to just below 8000 ��