well i just installed a new fuel pump and a slp lm2(this thing is fawking loud ) last night (had a flowmaster before) so now i just cant take off like i used to. higher rpms are more productive(used to die out at 5000) but i just cant spin tire like i use to. the cat is gutted from what i can tell pops real bad when letting off any way to get my lo end power back. hi flow cat, gears , tune, any suggestions would be helpful

 

A new catback shouldn't result in a power loss. Is the car in good mechanical tune?

 

well it ran great before the new catback but i dont know for sure when the last time there was new plugs and wire installed i was going to put new stuff on when i put the headers on what else should i ck. the fuel pressure is good maybe dirty injectors i believe one of the injectors is leaking

 

I actually noticed a small power loss after my LM install. I can only feel it in overdrive at low RPM's, but there is a slight acceleration hesitation only in this situation. I never felt any loss of low end. I just sort of figured this loss of power was from the difference in exhaust backpressure (i went from stock to LM), but it never really bothered me much.

 

When I got my new bigger muffler installed I too lost some of my low end. From my understanding this is pretty normal. I am changing to a 3:42 rear end anyway. I have an A4 too. My setup is in my sig

 

Less backpressure makes you faster in the upper RPM but less pep from dead stop. More backpressure makes it a little more responsive on the low end, but chokes the motor up high.

That is my experience with my cutout vs stock exhaust.

 

Yep that's what gears are for muahahaha

 

http://www.uucmotorwerks.com/html_pr...torquemyth.htm

 

I agree with this somewhat, but feel this guy didn't write the bible on exhaust.

I do know how my car has reacted to exhaust changes, and vice versa from capping it and uncapping it.

 

The difference is far more likely because of velocity changes or turbulence (An increase of backpressure in many instances) than it is from "backpressure".

 

well gears it is then
thanks