///Mous3

Gents,
What's your take on why Porsche sticked with 3.6L for the GT3 and RS? What kind of upgrade will it take to built a 3.8L engine from C4S to rev 1000 more rpm?

MJSpeed

The 3.8 in a C4s is not even close to being the engine the 3.6 is...

stout

+1, though that's not to say the 3.8 C4S motor is a BAD engine for what it is -- esp. if it's got X51.

Generally speaking, I don't think you'll see PAG up displacement when it can get enough power to satisfy the marketing department's desires out of an existing displacement.

Look at 986/987 2.7-liter cars. First 217 hp (2000), then 225 (2003), then 240 (2005), then 245 (2007). Or 964/993/996/997, which have all hung around at 3.6 liters in base trim, going from 250 hp to 325 hp with time. In fact, 996 went down to 3.4 to begin with, but still made 296/300 hp.

In the case of 997 GT3, 3.6 has been enough to get to 415+hp from 380 (2004), which was up on 360 (1999).

We'll see 3.8 at some point, but the real reason to go to 3.8 is for more torque along with more hp. What we won't see is Porsche throwing away the last bits of development potential prematurely.

I just wish it would "fix" engines and start concentrating on weight. Even little losses would make me so very happy.

With the world going the way it is, this is where we need to go... and better sooner than later.

pete

krC2S

agreed given the difficulty in putting much larger engines in rear-engine layout at least given technology available now porsche will up the sizes of engines very slowly

hopefully their inability to put much bigger engines and make huge power gains for future generations
will force them to focus on weight and other things

GrantG

the 3.8L wetsump cannot hold a candle to the 3.6L drysump. The relative prices tell the story - you can buy 3 or 4 3.8's for the price of one 3.6L GT3 motor from Porsche. Now, it is not difficult to increase the GT3's displacement by increasing the bore of the bolt-on pistons and cylinders. Porsche could do it easily if they wished...

///Mous3

So what are the changes from 3.6L of 996 GT3 to that of 997?

Bluehinder

Right on what Grant said. Apples and oranges.

GrantG

Relatively minor: Lighter reciprocating parts for higher redline (8,400 vs. 8,200 and a bit better breathing intake and exhaust - 415hp vs. 381hp). The 996GT3 motor was already a masterpiece of performance and endurance, so any improvement is only improving the legend.

Mad Manx

The GT3 engine was developed from the GT1 race engine.

stefan einz

And indeed Porsche have done this; witness the 3.8 litre engine in the new 997 GT3 RSR.

Manthey Racing in Germany have also built a 3.9 litre version of the GT3 engine. It was used in their VLN race car (a high modified GT3 RS race car) to great effect. I've also driven a road going GT3 Mk2 with this engine installed. It was incredible, with an astonishing amount of torque, but dare I say, around the Nordschleife where I drove it, it was almost too much (certainly for my modest skills)!

As to the original question, I think the answer is because the 3.6 litre engine is so exceptional in terms of power and reliability already. My Mk2 engine was dynoed by Manthey Racing after they had breathed upon it at 425 bhp - and it has run faultlessly for 25,000 miles at that level of tune. (MR's dyno is used by Porsche - it is very reliable, unlike some.) Even the 997 GT3 has yet to reach the full potential of the engine. Personally, I rate it as the finest "mainstream" engine on sale today.

Kind regards

Steve

frayed

The current motor is a balanced/blueprinted version of the prior motor. Everything gone over and lightened to sustain higher revs and breath better.

As already stated, when will pag go with a 3.8L drysump motor, hopefully a bored (not stroked) 3.6L?

I'm sure they will. But I think people get too transfixed on power. The car already makes more than you can reasonably use on the street, and on track, faster laptimes will come from lighter weight and improved handling rather than another 30 hp.

eclou

Or they could do something really insane and turbocharge it

GrantG

But then it would be called the GT2 and cost twice as much

frayed

Or add AWD, PSM, 250lbs and make weekend heroes on the track.

eclou

You forgot the LED turn signals and rear wiper, and 9 oil pumps