Red line problem

[z28 boy]

Hey fellas,
I put 3.73's in my 00 Z about 3 months ago. I also don't have the right tire size on my car they are to small. Well i noticed that when i would race it in D it would not go all the way to 6200 rpm it would do about 5700. I programmed the computer with the Hpp3 to the 3.73's and it fixed the problem. Now recemtly i programmed the computer to my tire size and the problem has come back. it only goes to 5700 rpm in D. I can make it go all the way if i manualy shift it but id rather not. Now my tire height is only 24in which is way short but i figured that having the computer programed with all the info that it would let it go all the way to 6200rpm. Any body have this problem? Or have any ideas what it is. My guess is the tires are way to small.

[FormulaLT1]

The 4l60-E isn't meant to shift manually infact you could cause some serouis damage by shifting that way and Our cars have been known for having the Tach climb slowwer than the actual engine is doing. If you do a google search you will find that alot of owner's have noticed this but since you stated it was operating normally without the tires adjusted I would say just program it back for the old tires I doubt it will be off by that much but I'm sure you can find out a exact number online

[z28 boy]

It still chirps the tires on the shift and everything it just doesnt redline the way it used to. So i don't know if i am losing power or the tach is just off like u said.

[FormulaLT1]

Just set it back for the old tire and see if it goes back to the way it was.

[Dober89]

Does it even make more power at 6200 than at 5700?? My car redlines at 5500 but the power stops climbing around 5000.

[z28 boy]

But when it shifts u want the car to drop u in the next gear right in ur power band. If u don't go high enough before shifting then u will land under ur power band.

[FormulaLT1]

Originally Posted by z28 boy

But when it shifts u want the car to drop u in the next gear right in ur power band. If u don't go high enough before shifting then u will land under ur power band.

Nicely put, I should be asking you for advice. But If your churping the tires on the upshift you must be hitting your next gear pretty close to your torque curve. although I would progam it down for the other tires and just set a mental note its slightly off.