NineMeister

It has taken a long time coming but we now believe it was worth the effort as finally we get to install our first 4.0 litre race engine in our customers poor unsuspecting 964RS lightweight this week. The full spec of the engine reads something like:

* 9m/4T CNC windaged crankcases
* 9m/4T 80mm stroker crank (GT3 journal diameters)
* 9m/4T steel connecting rods (130mm crs, 22mm pin)
* GT3R oil pump
* 9m 103mm slipper pistons & barrel
* 9m/4T billet cylinder heads
* 9m/4T steel head sealing rings
* 9m head studs
* 9m race cams/springs/valves
* 9m individual throttle body intake system
* Motec M48 engine management
* 9m cat bypass

If I can get my account working properly I will upload some build photos soon, the most ineresting feature being the assembly of the crank/rods in the case, the design of the rods still clearing a stock oil pump even with an additional 1.8mm of swing on the crank - try that with a Carillo!

We are hoping to have the engine running tomorrow, so probably will have dyno results available early next week.

Christer

I don't think I want to read this. In fact, I might not even *call* you for a while.....

SimonExtreme

Colin

Can you reveal the name of the poor "victim"!

Chris M.

Go Christer, make that call!!
Anyone wanna guess the hp? I'll say 421 at the crank.
c

forklift

That is what I would do w/ the $1 mil from the other thread, plus have money left over for a few tires.

Geoffrey

Ohh, just a bit too late...I could be financially ruined if you had this a year ago...

SimonExtreme

Just one thought. It won't be a "matching numbers " RS any more. Having one of only a very few RHD RS's, I think I haved a duty to preserve the originality for future generations! Well, I have to find some excuse not to charge up to see Colin as my wife would probably cut off my "crown jewels" if she knew I was even reading this.

Repeat after me "My marriage is more important than more power; my marriage is more important..............."

cbracerx

H'mm - Post tuning I predict 425 @ crank

NineMeister

Since my current 3.82 litre race engine has posted over 420bhp/450Nm at the crank on our dyno I am hoping to see around 440bhp/460Nm depending on exhaust configuration, maybe even 450bhp with a custom set of headers.

Because this is the first one we built the RS engine with another set of 964 crankcases, so we still have the number matching engine available for "future proofing" purposes.

Heirsh

Now see. This is the sort of thing that is bad for the pocket book. Maybe I should buy a lottery ticket.

Looking forward to the results Colin.

Gary R.

I'll guess 452HP, and the engine cost of $1K per 10HP...

NineMeister

First light session on the dyno has found 400bhp @ 6800 & 430Nm @ 5000 at the flywheel on the stock cat-bypassed 964 exhaust. In comparison with the similar 3.8 engine in my RS there is a drop in torque up to 4500rpm and a steep power tail off above 7000, so since the only real differences in the spec is that my engine runs with 993 heat exchangers and a pair of 100 cell cats we are going to thy a different exhaust system first since I suspect that the larger header pipes of the 964 is reducing the exhaust velocity and affecting cylinder scavenging.

SimonExtreme

Colin

Are you going to try the 993 system or go straight to some custom headers. It will be interesting to see whether you can get anything extra with the 993 kit. I may be wrong (often am) but I wouldn't be suprised if you don't see that much gain but by using a complete custom system, you could well get a very significant gain.

I have seen this but on bike engines. We increased capacity but we were down on power despite everything else being the same and the fueling/timing being correct. I have always suspected that there reaches a point where, due to limitations on a particular exhaust system, you can actually go backwards in power terms (I hope this makes sense. I know what I mean but its hard to put into words!)

cbracerx

My empircal experience with the 964 exhaust (no surprise) on the same motor switching to 993 exhaust was a dramatic improvement. the 964 really choked things up. But my best example was a highly cammed 3.0 race motor I built. This required open exhaust to run even at all well. Adding any muffler, supertraps, etc just killed the motor performance _dramatically_.

Again, this is not news to any of you fine gentlemen. I'm _really_ impressed that you can get 400 with the 964 exhaust (sure the cat is gone but so what). Amazing!!!

Chris M.

I think they did this on purpose to leave room for improvement for the 993. Think about it; 231hp from the Euro 3.2 to 247hp for the 964 3.6? Surely they could get a lot more out of that engine. A friend's Andial '92 Cup dynoed at 275rwhp. No cat, no primary, no secondary...

c