your engine is designed to run under load not freely. when you rev your engine there isn't efficeient load on it and can damage it

 

How does load effect the engine? Makes all the world for a turbo.

 

if your engine is not uder load it does not make alot of pressure out of your exhaust(as you know) this means that excess gas can get into the exhaust and ignite in your catalitic converter. Gas ignition in your exhaust melts the ceramic emission filter, which then makes the car run like having potatoes in the tailpipe. also if you rev your engine with no load is it has much less restraint. so if you rev up to redline and then let off it can still ecced redline because of the accelreation of the crank. a rev limmiter only cuts fuel or ignition it dosent slow the crank itself(as im sure oyu know)

When hot, reving the engine when not in gear can also cause vibration wear and damage. Car engines were designed to be reved under load( in gear, driving). When it is freewheeling( in nuetral\park) the engine can speed up too quickly, because it does not have the mass to balance and push against, causing it to vibrate violently and at the extreme break.

 

Thats some good info (assuming no one can counter it), thanks!

So theres no gain with the cai? Some are telling me no theres none at all, and some are telling me theres a little gain, but nothing noticeable.

 

So if its not noticeable, how do you know its a gain? Why spend $300 for something that gets you nothing? If you want sound, just get a 2.75" U bend of aluminum piping and a filter and you have the same thing.