gt37vgt

so is that real accounts of them breaking ?
i thoiught early 968's had cast pistons too and later forged ?genrally I'd be more concerned with that .
get some late rods or factoy turbo ones then you'l have bragging rights of all factory bits

333pg333

That's a fair point. My guess is that the failures have happened on racecars and the owner's don't document this on forums? There would also be some precedence in days gone by that now is just presumed as a 'given'.

95ONE

were you looking in the 944 threads or the 968?
The base of the Rods are thinner and known to bend/break.

95ONE

Here you go.. Best explanation right here on Rennlist.

Click here

Black51

I'm willing to bet if I click on that, it's gonna fire a million popup windows at me....

95ONE

no.. no it wont. It's a hyperlink straight to the thread that discusses this topic.

Black51

I'm not buying that sad puppy face look...

JDS968

Not sure why I'd want that bragging right? Nobody really cares what conrods I use except me...

333pg333

Either you know Bruce or you don't. In other words you're either joking or you haven't been around here a lot. No offence intended but you can trust him not to send you into a spamspin.

This is where his link sends you to:

https://rennlist.com/forums/968-foru...-968-rods.html

Duke

When I say low CR in this case I mean around 8.0:1.
I don't drive 600 bhp at the track, too much power for me to handle

I'll try to explain what I mean in a better way..
To reach ~ 600 bhp with a built 3.0l 16v you'll only need around 18 psi.
The only issues I see with higher CR is that you might be knock limited that forces you to retard the ignition into the EGT danger zone (cue Top Gun OST).

IMHO as long as you can get away without knock with a boost level and ignition values that doesn't induce too high EGT the higher CR the better.
Higher CR gives you better response, higher off boost power, lower boost at the same power level with lower IAT, more efficient combustion with less wasted heat etc.

But as discussed, you have to weigh in the maximum possible bhp of the engine. In my case, I'm not looking for more than 600 bhp and I want the best possible engine response with as low boost as possible. I chose 9.5:1 which have fulfilled my goals. I run Shell V-power 99 RON pump fuel.

If I had wanted 750 bhp, I would have taken another approach.

With that said, 600 bhp will always give you "issues" in a 944/968 no matter the CR

JDS968

I think I'd start worrying about cross-bracing the car at that point, especially at the trans mount point.

Chris White

Now that the weekend is over….a couple more thoughts!
Rods – the 944 rods are plenty strong, they will not fail – but they are also as heavy as boat anchors – and this will limit RPM and bearing wear.

Pistons – For the application that was suggested I would use aftermarket pistons as well as the aftermarket rods. You want the ability to survive the occasional knock and ping at that pressure. If you NEVER experience detonation then the stock pistons may last – but if you get any detonation then they may just fly apart.

Block – Once you get to the 600 crank hp neighborhood you may be getting into the power levels that flex the block. This causes greatly accelerated wear and other issues. OK for brief peaks but if you are building a track engine(road race track – not that quarter mile stuff) you will have reliability issues with the stock block.

The link to the super duper engine – 200hp at 5k rpm…..yeah, that’s what I want. I will applaud all the work they did but since I am not a person that measures engine performance in 8 second intervals….I have no use for it! Take all the work they did and compare it to a top fuel engine (its the same sport) and they come up about 6000hp short!

And finally – if the question is just ‘can it be done’ then the answer is yes. If the question is ‘is this the right solution’ then the answer is probably not. BTW- it would be easy to retime the cams to drop the effective compression ratio to a usable limit. Remember all the American muscle cars from the 60’s that had 11:1 street engines? The cams had so much overlap that the engines never actually made 11:1. The head design back then would not support 11:1 on street gas….

Duke

It might not be everyone's cup of tea, but I don't think you give that firm the credit they deserve. IMHO all engines on RL are kindergarten stuff compared to some of their builds.
Oh, and 200 hp at 5k rpm sure is a whole lot better for a track engine if it revs 11k+ rpm than any 944/968 engine build

evil 944t

This is 100% correct. Actually, for the 16v, I wouldn't go much over 9:1 and I wouldn't push that past 24psi.

Thom

Hmm... Spending such a fortune and involving such a debauchery of technology into an engine that certainly won't see much if any consistent road use and will probably end up being near undriveable pretty much belongs to kindergarten stuff.
What is this guy doing with his car once it's up & running and he's made his point after a couple of glory dyno runs?

As much as I appreciate that sort of shiny, super lightweight parts and the one-of-a-kind effort, let's keep real.