Patrick Krause

In the states, the weight problems are because of the saftey standards for road cars and the luxury items buyers want today. If they were able to stip the cars down to the saftey standards of the past, etc., they would probably be lighter...just a thought.
Look at the jumps in weight from the 70's to the 80's. In one of my pcar books they make reference to the saftey standards, weight issues.
PK

hansi1

What's going on there is that it bears out what I said earlier.
"All other things being equal", similar cylinder displacement size results in similar rev limits. That is, Ferrari engine with a swept volume of 480cc/cylinder has a rev limit fairly close to the BMW engine with 530cc /cyl..

But the proviso "all other things being equal" is important.

A lot more factors come into the equation:

- The effort put into maximising the rev limit depends on the application.
An F1 engine is tuned for max power at max revs, with no regard for low-end torque, because F1 cars are not driven much at the low end of the rev range.
An SUV engine would need high lugging torque at low revs, but would hardly ever be driven at max revs, so a high rev limit is not a priority.
An engine with a very high rev limit and very high torque at low revs has yet to be developed.

- The bore/stroke ratio. Long stroke means high mean piston speed for a given engine speed and swept volume. There is limit to the possible max mean piston speed, which depends on the quality of lubrication and piston ring and cyl. bore materials, among other things.

I could go on and on..... There are books on this subject, so I won't.

Spizz Oil

If the 996 is a flat six and the 998 a flat eight, will the 997 be a flat seven?

Spizz

hansi1

The odds on a 997 being a flat seven are as good as on a 998 being a flat eight!

Rassel

Hehe
So that makes my 993 a flat three!

Sean

I was told yesterday by a Porsche salesman that the 997 would only be produced for two years as a transition model, then the platform would switch to the 8-cylinder 998. First time I've had a Porsche salesman tell me so (though I still have my doubts).

hansi1

You have to ask yourself, how likely is it that Porsche would tell a car salesman in Alabama its confidential product plans three years in advance. On a " need-to-know basis", he's very likely to be at the front of the line, right?

I bet that, whilst well informed on the 998, he couldn't reliably tell you when you could take delivery of a 997, right?

TIS330ci

2 years? its going to take 2 years just for the 997 turbo to some out.