Shift points

[LPEZO6427]

I have wondered about the best shift points in the ZO6, but I dont know the gear ratios or have a dyno chart (what i need to figure them out). does anyone know the ideal points or have any other info.

[IceSabre]

When being a little aggresive I usually go at 30, 60, 92, 128, ??

Just jump in and go... when you hit 6300-6500 or so shift.

Stock it has a pretty good torque curve that works with redlining (max tq before redline... plenty of good area to work with).

Of course I am no racer, so others will probably know better

[LPEZO6427]

you want to stay within an rpm range where the transmission is delivering optimum torque before and after each shift....this stuff truly helps in a drag...whether racing or going for times...i am convinced that it does because mathmatically it only makes sense. I really want to figure them out for someones z06 and then have them try it and let me know the results. kinda like an experiment....

[PowerShifter]

LPEZ06427,You could take the torgue and multiply by gear and rpm to come up with the highest torque at the drive shaft after the shift but you allso have to deal with the fact that if you hit the rev limiter at 6600 the recovery time in the ecm is to much. I have seen little differance 62-64 shift higher seems to be better but that pesky fuel cut off is very tough power shifting any higher. If you come up with a solution I'am all ears. Do you have an LPE 427? I read your inquiry as to a stock Z06? Ric

[LPEZO6427]

No i dont own one, it just happens to be my favorite LPE car right now. I dont have a zo6 however my father does. so i ahve been around them. as far as shifting goes though i do know you are correct about driveshaft torque, but you must also take in account the rpm loss from each gear. then from there you compare the driveshaft torque with the rpm and gear before and the rpm and gear after. after that you will find the smallest difference in torque loss even if it is like -5 or soemthing like that.That is how you choose your ideal point. Suppose this....hypothetical of course.... suppose we have a car that after all the math does this from 1st with gear ratio of 2.20 to 2nd with a gear ratio of 1.66. Now the brake torque is given through a dyno chart that i dont feel like typing

RPM Brake Shaft RPM Brake Shaft +/- torque
6000 300 660 4527 330 548 -112
6200 280 616 4678 330 548 -68
6400 255 561 4829 325 540 -21
6600 240 528 4980 315 523 -5
6800 190 418 5131 310 515 97
7000 160 352 5282 310 515 165



As you can see in first gear you would want to shift at 6600 RPM because that is where the car loses the least and gains the least or in essence is closest to 0. That is why I am asking for someone's Z06 dyno chart that is willing to try out these shift points for me. I am just curious on the difference it actually makes. I know mathematically speaking it should make a marginal difference of about 3-4 tenths of a second at the most. I dont know if this helps or not but i gave it a shot.

[LPEZO6427]

Well powershifter i just read your profile and odds are you probably new all that....sorry about the wasted space...i should be seeking advice from you...i am only 18 dreamin of a crotch rocket

[PowerShifter]

It's good that your thinking and reading books it can only help. You allso have to learn a bit more about real word dynamics of driveing a Z06 with engen managment in the real world. Good luck.Ric

[LPEZO6427]

my day will come.....hopefully

[pmontelo]

Shifting just before you hit the rev-limiter is about perfect for these cars. You end up at the following RPMs after each redline shift:

shift to:
2nd = 4600
3rd = 4559
4th = 4615
5th = 5544
6th = 4400 (... a brick wall without major mods)

[LPEZO6427]

powershifter....you say you have a 67 camaro that does 8 somethin....what do you have in that and how did you make everything mesh together to make it so quick

[LPEZO6427]

well at the redline you are more likely to reach more of your peak horsepower which does not accelarate your car...what you want is focused around torque...generally however they are at higher rpms....but at the redline you will have little torque and depending on where the rpm change is it might not be too efficient

[Roger Ramjet]

Originally posted by LPEZO6427

I know mathematically speaking it should make a marginal difference of about 3-4 tenths of a second at the most.

WOW! Do you really mean .3 or .4 sec for each shift?
Let's see, .3 sec per shift - 3 shifts per run - 0.9 sec ET.

I think the best performance comes from knowing where peak HP occurs. Then use the gear change RPM drop/2 to find how much over peak HP you need to run. However, the HP curve for the LS6 is so flat out to the red line that the fuel cut off becomes the liniting factor.

[LPEZO6427]

know not each shift overall....well i dont know about the vette never run one...sounds to me like it likes to accelarate with horsepower..but that doesnt make sense to me...horsepower is how fast...torque is how fast you get to that fast..why do you think peak horsepower is at high rpms...because you are running the engine as fast as it will go putting out as much as it can thats where top speed comes from...max torque however lay in the 3500-5000 range or usually where the rpm loss ends up...not trying to be a jerk..i just dont understand...maybe its just the car..like i said i have never run one before

[pmontelo]

Originally posted by LPEZO6427
well at the redline you are more likely to reach more of your peak horsepower which does not accelarate your car...what you want is focused around torque...generally however they are at higher rpms....but at the redline you will have little torque and depending on where the rpm change is it might not be too efficient

Short shifting these cars isn't really effective because they have a *lot* on top. 4600 RPM is about the perfect place to be after the shift, right in the sweet spot of the torque curve. If you shift earlier, i.e. 5800-6200, your 1/4 mile times will be slower than if you take it right to the redline.

If you ever get the keys from your dad, you'll probably find that out the first time you drive it... the car revs faster than you will be able to react to it at first.

[LPEZO6427]

i understand what you are saying but i dont mean to be implying short shifting because that is not what i mean....it is all abotu torque loss btween rpm differences...it could happen anywhere..moreover in the higher rpms like you said..