Spirited driving on the streets I let the tach hit redline and hit the clutch and bang out the next gear. I know on my two bikes that I race the optimal shift point is not redline and I was wondering what is the optimal shift point on my 997? Is it in fact redline?

 

I have a Softronic flash and all performance parts (without the LSD and LWFW ... have not installed yet)

 

Shift just before a rod lets go.......just kidding Pm Ed (Northvan997) and ask him.....he runs his car at the track

 

ED... where are you? I know your lurking around here somewhere!!

 

LOL, yes I am lurking around.

I guess I missed this post.

I shift at the top of the power band, it is a feel/sound thing for me. I don't watch the tach, I just shift when I feel it is time...difficult to describe. I will say that it is a bit of re learning with the LWFW, it gets up there really quick.

 

I agree with the feel/sound thing, I guess im asking where is the technical powerband end or die off? I can only imagine when I get teh LWFW... I heard it just redlines with no effort!!

 

It depends on what kind of driving you are doing? Sometimes it makes sense to pull past your power peak closer to redline to not drop out of the powerband in the next gear.

 

The max HP and torque are quite high on this car, I am sure that I am at or near the max RPM when shifting. I have even over revved a few times on the track

 

First I have to say that the tach on these cars are slow in 1st gear. I start reaching for 2nd when the needle hits 6800rpm, when I make the shift the tach is still going up..and I have seen sometimes 7500rpm. Also coming out of a car that redlined at 8250 (E46M3 with software) I hit the revlimiter a few times when I first got the car I'm like..Oh, 7k rpm I still got time then bogggg! Anyway for the best times you obviously don't want to be bumping on the revlimiter. As for the rest of the gears I hit it right at about 7krpm..so when I make my shift I am right at 7200-7300rpm. These cars with the VarioCam really like the upper rev's.

Dave

 

997 torque curve is flat between about 4200 rpm and 7000 rpm. Therefore shifting near redline will keep you at the peak torque.

 

There are so many variables. Like Ed said "it is a feel/sound thing" as much as anything else.

Personally I'd rather change to suit the track and the situation than for optimum revs. So long as you're in the right sort of rev range that generally works.

Only been doing this stuff for 30 years though so like everyone else I'm still learning...

 

The theoretical best shift point is where torque x gearing will give you more pull in the next gear up than torque x gearing in the gear you're in. As the torque curve falls away at the top of the rpm band this point will eventually be reached but I don't have enough info to do the math and work out if that point is below the rpm limit.

If this point isn't reached before the limiter cuts in, then the best shift point is at the moment the limiter is grazed.

Any mods you have on the car will also make a difference. In particular, sport cats let the car hang onto more power (hence torque) at the top of the rev band and can move the theoretical shift point upwards

 

look at the web site "when to shift"