hansi1

Nope!
If you disregard Detroit iron, smaller individual cylinders mean lighter pistons and conrods which mean higher revs without increasing stresses to the point that everything falls apart!

hansi1

brh986

In practice I have not seen that to be true at all.

Patrick Krause

Look at Ferrari...
360 Modena 3.59 ltr V8 400hp
575 Maranello 5.75 ltr V12 515hp

A flat 8 with a 3.8 ltr would work with a much higher redline, much more hp. Probably wouldn't have to change the dynamics of the 911...
Just a thouht

PK

brh986

What does this prove? The only thing I notice is that the smaller displacement v8 with less cyllinders has a higher output per liter (probably ways less to). The 575 is also barely faster than the 360 in laptimes and teh GT3 bests them both. What does one thing have to do with another?

GrantG

More cylinders for the same displacement means smaller pistons with shorter stroke - so there's less reciprocating mass. So, it's easier to rev alot higher with a 4L V-12 than with a 4L V-6. Ferrari used to make 2L motors in 4, 6, and 12 cyl motors and the V-12's were the highest revving of the bunch (and the straight 6 was next). There is an optimum displacement for an individual cylinder in order to maximize power. I believe it's in the 300-350cc range. This is why when Formula One changed it's capacity limit to 3.5L, most of the manufacturers chose to use V-10 motors instead of V-8 or V-12. Now the rules dictate a V-10 but that used to be discretionary...

brh986

It seems to me of current production street cars the more cyllinders you have the lower the redline. Look at a civic vs a viper.

hansi1

brh 986,
You are looking at this the wrong way if you are going to compare an 8 liter V10 and a 2 liter 4 cylinder engine to arrive at the conclusion "more cylinders = lower red line".

The swept volume of each Viper piston will be almost twice that of each Civic piston, and it's the heavy weight of the Viper piston, as well as the longer stroke each piston has travel through, which causes its red line to be lower, not the number of cylinders.

Pistons are not well informed. They do not know how many more there are in their own block. They each individually decide of their own accord the rev limit they want to stop working at.

If you compare a three liter V10 Formula 1 engine (300 cc per cylinder), which revs to almost 19000 rpm, to a 3 liter V6 (500 cc per cylinder) which might be capable of running to 7000 rpm if well designed, you'll see that your conclusion doesn't hold water.

If you want to restrict the comparison to production cars, you still could not compare a big straight six to, say, a ferrari V12 of approx. the same cubic capacity and still arrive at your conclusion, because the multi-cylinder will outrev the large-bore clunker by a large margin.

Civic to Viper is not a good comparison anyway. One is efficient, the other isn't. You guess which is which.

hansi1

brh986

Yea I see the error in my logic now. Where is there a straight six of the same displacement as a ferrari v12 to use for comparison? BMW's 3.2L inline six does fairly nicely with 8,000 rpm redline doesn't it? Ferraris' 575M has a 5.75 liter V12. 5.75 / 12 = .4791 3.2 / 6 = .5333

I'm pretty sure the 575 has an 8000 rpm or lower rev limit. WHat's going on there?

Koda

No you mis-read my post...If Porsche were to built a V8 or F8 that was 200lbs more that the current F6 as someone else suggested it would be heavier than the Z06 motor...My point being I don't think (or at least I hope) a modern Porsche 8 would be 200lbs heavier than the current 6.

Bob Rouleau

On the more cylinders versus rpm issue - consider the F1 engine. V10 which redlines around 19,000 RPM.

brh986

He already said that. What about the M3 vs 575M?

GrantG

As far as I remember the M3 and 575M both redline at about 8k. Similar redlines because they have similar cylinder sizes (about 525cc for M3 and 480cc for 575M). The Ferrari is more of a torquey motor (much more displacement), so it hasn't been tuned to be quite as peaky and rev crazed as the m3 which need to wring out every last hp from its small 3.2L. The race version of the 550 revs higher...

Baron009

Hmmm, well I'm sure the Porsche Engineers will figure out something good, whether it be a flat 6 or a flat 8.

PLEASE GOD, NO V-8 THOUGH

Like Rassel, I hope they don't turn the 911 into some rocket that lacks character and handling capability. They really need to STOP making the car bigger and heavier. Save weight, but keep the body rigid.

Haha, true, the new one has some serious ghetto booty. With the 998 they should go mid engine I think. If they are actually coming out with a sedan that is to be the 928 succesor, I see no reason why they can't cut out the 2 rear seats and go mid mounted with the 911.

brh986

I really don't understand that either. You would think with all the light weight space age newer technology brings along the weight of cars would be going down significantly now but instead it goes up. That's just wrong. Why does a GT3 weigh more than any of the sport models they've made in the past? Makes no sense!

jecey

TIS330CI,

Are we talking about computers ?
When I read some comments like yours, I immediatly think about the computer industry ... " ...wait till the new Pentium 5 with 4 Ghz and 64 bits ..."
come on guys, where is the passion.