Shift Points?

[Jay 02 TA ws6]

If I am driving my car right up to redline before I shift... right to about 5900, am I shifting too late?

My power peak is at 5400, it remains pretty flat until about 5700 when it begins to drop off...

...the reason I ask is this...

1999 Camaro SS with 319 rwhp, 331 rwtq ran a 13.15 @ 107 on a 2.2 60'

My best is 13.18 @ 109 on a 2.1 60'

It would seem to me that with more power, more torque, a better 60', and a higher trap speed... there must be something I am doing wrong that has to do with shifting.

Should I be shifting sooner?

[AmericanZ28]

Are you power shifting? What gear and RPM were you at when you crossed the finish line? I know that its ideal to cross the finish line with the engine almost at the redline, but Im not sure what gear that would be in for a T-56 and your particular gear ratio. Maybe you just need to practice ! J/K

[Jay 02 TA ws6]

No, I am not powershifting per se...

but if you watch the video (I know it is long) of my car club drag racing, I don't think you would look at my shifting speed as the problem...

There really isn't anything I can do with my current setup to make me cross the line near redline...

[fastTa]

Power-shifting is hard on clutches but is definitely the only way to shift at the track. It takes skill and practice but is well worth the effort.

You should be able to go all the way down the track witout your right foot ever lifting!

A lot of standard transmission owners assume they are shifting *quickly* by simply shifting hard. That is not the case. It is all about getting the clutch down just enough to aid in upshifting. The clutch pedal should not travel very far down at all.

C'mon I want to see a 12.xx in your sig Jay!

[Jay 02 TA ws6]

Originally posted by fastTA
...You should be able to go all the way down the track witout your right foot ever lifting!

C'mon I want to see a 12.xx in your sig Jay!

Oh man, you guys are bad for my wallet, lol...

I want to see it too!

How long can the stock clutch put up with this abuse? Especially with the higher than stock HP and TQ numbers I am making.

[fastTa]

I have a slight hunch that you will be in contact with a "SPEC" dealer in the very near future!

[Jay 02 TA ws6]

Originally posted by fastTA
I have a slight hunch that you will be in contact with a "SPEC" dealer in the very near future!

True... I was planning on doing the clutch this summer anyways...

I do have one concern though. I have only tried to powershift the car once... the time I did it, the shifter went into 3rd, but the trany stayed in neutral, and I had to RIP the shifter back out...

and what about my first question... do you think i should shift at lower RPMs too?

[fastTa]

I would shift at around 5900-6000.

Relatively speaking, it takes time for the energy generated by the combustion process to travel through your rotating assembly and additionally your drivetrain. You say your peak hp is generated at around 5400 rpm's. Well by the time you shift at 5900-6000 rpm that *peak* amount of hp is just reaching the wheels. So by shifting slightly past your peak hp not only are you giving the power time to reach the ground, you are using the additional rotating inertia generated by the higher revs to make the next gear pull just that much harder!

Hope that long winded explanation makes sense!

[Jay 02 TA ws6]

Sure does

[fastTa]

I think with a little more track time logged and reducing your pressure on the rears, you should earn a 12.

[Joe 1320]

You might even try a taller rear tire.

[KnightFire]

Our cars do not need to be power shifted, we have more than enough torque at lower RPMs to get you back in the sweet spot in a hurry! I highly discourage it, unless of course you love paying for new clutches and enjoy R&Ring them.

What gears are you running? If you know where you peak torque is, thats where you should be shifting. Why would you shift when your on the down side of the torque curve?


Just some food for thought



KnightFire

[Jay 02 TA ws6]

Originally posted by KnightFire
Our cars do not need to be power shifted, we have more than enough torque at lower RPMs to get you back in the sweet spot in a hurry! I highly discourage it, unless of course you love paying for new clutches and enjoy R&Ring them.

What gears are you running? If you know where you peak torque is, thats where you should be shifting. Why would you shift when your on the down side of the torque curve?


Just some food for thought



KnightFire

I have the stock 3.42 rear gears.

My torque peaks from 4000 to 4700... It begins to dive off at 5000... no way I should be shifting THAT early, right? I mean I am still making horsepower until 5400, and that takes a dive at 5700...

[KnightFire]

UGH! Posted that too early...yes you should be shifting at your peak RWHP NOT your peak torque RPM...GEEZ! Thanks for catching that.

Something that I'm not getting is that you had better numbers all the way around in the 1/4 mile than the car your comparing it too, yet it was slower in ET, the cars your comparing...did you run at the same track, same day, same weather conditions?

What gear are you crossing the traps in?

Your right on the money with shifting at 5700RPMs if thats where your RWHP starts to fall...some say shift a few hundred RPMs before that point...some say a few hundred after...its really a matter of trial and error.

KnightFire

[Jay 02 TA ws6]

Ugh... totally conflicting advice from Kevin at Knightfire, lol...

That Camaro SS was not at the same track and day, no... but he has the same mods as me, except for the headers and y-pipe, which are shown on PPC's dyno to give 25 more rwhp -- so those dyno numbers are right on the money.

Even though it wasn't the same track, day, etc... I still have a problem making sense of the numbers. I mean, your trap speed indicates your car's power -- so 109 to 107 makes sense. Your 60' indicates how good of a launch you had, and usually a tenth better 60' = 2 tenths better ET... if one track was downhill or something, I would expect his trap speed to equal mine... if he was running 13.1 @ 109 with the same HP and TQ numbers I wouldn't hesitate to pin it on different circumstances...

...but since everything adds up to not make sense, I gotta believe it has something to do with what I am doing after the launch.