Originally Posted by pbj
on my car it shift out of first by it self (thats when it is in 1) at 5500?
So if I understand you correctly, when you are in "1", your car shifts out of 1st at 5500? Into WHAT?
That'* not shifting out. That'* your differential shattering planetary gears and ejecting them through the casing.
To answer the rest of this, the best time to shift will be determined by the hp and torque curves of your respective engine, whether it be an L27, L36, or L67. Mods have an impact, too. Either a Gtech or a Dyno can be the best for determining this. Factory specs, if all else fails.