You know there is a thing called red line, its clearly marked on the stock tach. Need you really ask how high it can rev stock?

it has a lot to do with clearancing inside the motor as well, your side seals are natually warp due to inertia and leak some compression off, so at redline not only are you past your intake and porting "sweet spot, but your loosing compression too.



you always want to shift at your peak horsepower, and hopefully the upshift will land you in your peak torque. The only time that it would ever be beneficial to run past your peak horsepower, is if your already in your top gear and don't have the option to due so.



Not to mention the rapidly increased wear that occurs at high rpm and internal wabbleing and warping that can junk your whole motor.

[quote name='1300ccTuner' date='Apr 1 2005, 05:29 PM']ok for my non turbo s5 im getting my racing beat road race exhaust and custom piping from a shop. should i get 2 inch piping done or 2 1/4 piping. im probrably going to have them weld it to the stock mufflers until i get more money for a better exhaust. no cats because i got the air pump to open my 56 ports.




[/quote]

the road race header has dual outlets right? if so I would just hold their diameter back if i were designing the exhaust, but since your going to have a muffler shop bending pipe, you may want to take a step up inside to make up for the restricitons that those bends create.