So we have a variable cam system which should help the motor breath better up top and I looked at several dyno sheets and the torque curve flattens out a bit. It would seem that a relatively stock motor could make some more hp by going to 7 or 7.5k
So why is redline so low, I've hit the limiter a couple of times already, I'm used to shifting around 7500 in my previous life.

 

I'm with you, regarding previous cars with higher redlines. Ours can be raised with a tune, but, of course, there's a lot of debate on whether this is a prudent move without fortifying certain engine components.

For my part, I don't drag or track my car, so I can live with the factory spec. Even if it makes first gear pretty much useless.

-V

 

the car was de-tuned as was delivered. which probably explains why it's so easy to tweak more power out of them.

many of these have 1.2 tunes ( or even more ) and a raised 7200 limit without adverse effects

 

Redline is generally dictated by piston speed which is a factor of crankshaft stroke. Reciprocating mass; rod small end, pin and piston are a factor as well. Conservative redlines greatly extend motor life.

 

The valve train of a 996TT can not take much more then low 7's. You can modify it to take more with upgraded parts to take 8g but that will cost you.

 

Our peak torque happens at around 4.3-5k rpm... after that there is a small hp creep, but not much. It basically flat-lines. It is very turbo dependent, but usually with the k16/k24 you'd be shifting before redline.

Lots of tunes raise the redline to 7200-7500 if you don't bounce off of it a lot. Every time you redline the ecu records it!

 

So this is basically a drawback to a boxer/flat6 design?
Are the rods relatively longer than a comparable inline 6 cuz I looked at the crankshaft comparing it say a 2jz and it looks significantly smaller


A flat torque curve is what you want in a high rev'ing motor and we have the elements to breathe well up top.


I was just kinda surprised it was so low from the factory when looking at what other high performance Japanese and Italian motors rev too.

 

Porsche appears to have tuned our cars for bottom end torque. I'm sure this is partly due to the cams, valves and heads in general. Given this our torque curve drops off significantly. Due to gear multiplication, it does help to rev a little higher than the factory redline, but not much, because torque begins to drop off too fast.

If they had designed the head to flow more at higher rpm's than we would have lost spool and bottom end torque. It's all about compromise. I would love to have the top end pull that my Supra used to have, but I use the additional bottom end torque every day.

I'd be curious to see what the power curve would look like with some GT3 cylinder heads.

Later, Steve

 

^This.

 

that makes perfect sense. always wondered...

 

You want high revs, buy a GT3.

 

ummm because rpm = ruins peoples motors

 

Peak torque will break a motor way more than rpm. By the time you are wound up that high your not even making power anymore. Every motor I've seen blow happens before 4500 rpm.

 

Different engines are designed to have different hp/rpm ranges. You can get a Honda S2000 if you want to shift higher - but then you'll be parking a Honda every day. I wasn't surprised by the redline - it was right there on the tach before I purchased them.

 

Think of usable rev range instead of peak rpm.

From 3k up to 7k the engine pulls like a freight train. That's a 4000rpm range to have fun with.

The S2000 engine pulls from 6k to 9k. Only 3krpm of fun.
My old elise pulled from 6k to 8.5k. Modified with a SC, pulled from 4k to 8.5k, that was actually pretty good.
An RX8 from 8.5k to 9k (and even then, it doesn't really pull) lol

I can't think of many cars with more than 4000rpm of usable power.

I'd say our car make great use of its powerband.