Just installed my shift light, and wondering what is the best RPM for me to shift? Car is a stock 96 Z28 with either 3.42's or 3.73's.. I believe they're 3.73's going by gear calculators..

I have it set for 5k rpm right now. Is that ok? Any help is appreciated!

Thanks
Jeff

 

yeah 5000 to 5200. Anymore than that with stock motor and you are wasting time that could be spent in the next gear.

 

That is way too low of a shift point! The autos shift at 5700rpm, and from playing around with the shift points with my HPP+ on my last LT1 car, I know that lowering the shift points even lower on a stock car only hurts the ET. So 5700 is pretty much bang on the money for the right shift point on an LT1 with the stock cam/heads.

 

What Patman said.

-brent

 

What would they be for a bolt-on car? And does it matter where you set them whenever you go to WOT? I was wondering the same thing cause I have the HPP+ but I was going to wait till I ran it at the track then see if there's an improvement on times.

 

All right!! Thanks guys, I will raise it up a bit!

Thanks

 

to low? the stock cam makes peak power at 5200 rpm so anything above that is a waste of time. you can sit there and rev it higher if you want, but you will only be wasting time in that gear on the stock cam. put it on a dyno and see where it makes its power, when it hits 5200 the line will flatten out and stop going up.

 

Why are you hung up on peak power?

http://www.personal.psu.edu/users/b/...dyno/DYNO3.jpg

I'd rather run it up to 5800 and come into the next gear at 4k rpms where i have 239 hp in the next gear than shift at 5200 and drop to 3600 rpms where the car is only making 217 hp. Its AVG power in the gear that counts. You maximize the area under the curve by running past power peak if you want to look at it geometrically. Or, calculate your actual tq at the rear wheel for each gear ratio and shift based on that. You will get the same results.

I'm not getting into it anymore than that because there are whole hundred page posts on HP and TQ and optimizing them. Some people never get it anyways.

Maybe your shift points have something to do with only running 13.9@99 and when i had similar mods (full exhaust, tuning and 3.73s on an M6) i pulled down a 13.2@105.8 without much trouble in unfavorable DA.

With a stock car and programing i'd shift at 5800, with full exhaust closer to 6000.

-brent

 

Yea I would go with the factory redline (meaning right before redline). Its the best for it. I lowered my shiftpoints , and the car was shifting around 5200 rpm's. I increased them a little bit. And went from a 14.0 @ 99mph to a 13.8 @ 101 mph. So yes it did hurt the et.

Just dont go much higher then the factory shiftpoint. You dont want to run into valve float, and end up destroying your valvetrain over somthing that could of been prevented.

Once you upgrade your valvetrain then you can start testing the waters.

Mike

 

94formulabz is right on the money badblackta.... you want the highest AVG between the two gears, not shift at the highest point and be stuck with a way lower hp in the next gear...

 

I have the mods in my sig and kinda tested out this same situation. though my car is not stock, it is close enough. I was shifting at close to 6000 running 8.90's(1/8), I then lowered the shift points down to about 5700 and et dropped to 8.70's. Dropped down to 5400 and et was a little slower not much...but from all the changes I made that night, 5700 was almost right on the money as far as having the best et...in my car anyway. Anything much higher than that and you are just wasting your time on the stock motor and cam.

 

BadBlackTA your times are WAY off for the mods you have, eithger that 180K LT1 cant hold compression or you need to stop making it shift at 5200! Like everyone said you want the highest average power across your gears rpm range. All peak power #s are for is bragging rights, its all about the curve!