Have any of you guys (or girls) installed an aftermarket muffler and noticed a DECREASE in torque?

I installed a Magnaflow 14468 on my L, and maybe it's my imagination, but I seemed to have lost power!

 

I don't have an L, but feel your pain. I have a 2001 4x4 and when my custom catback (flowmaster SI/DO) was installed, I noticed a loss in low end torque. It does, however, seem to have gained power in the mid to upper end. I do love the sound, though. Now I have to figure out how to gain back that low end torque.....and mabe pick up some more...Magnacharger, maybe?!?!?!?...too expensive for my blood.

 

If you're really concerned, you could design a butterfly valve system to decrease exhaust flow @ low RPM.

 

Interesting approach, Corpsie... I think I have learned to live with it, though. I'll probably get the supercharger, once I have the money. If not for the power, just for bragging rights.

 

Did you both go to a 3" system? If so, that's the prob.

 

The pipe from the y-pipe to the mufflers is 3". Then from the mufflers out is 2.25".... I am sure the loss in backpressure is the problem, but I have dealt with it....

 

I installed a Magnaflow on my L and couldn't see a difference either way. No gain-No loss.

 

I took off my Gibson Sweptside si/so 3" & put on a Flowmaster delta flow 50 series si/do 2.5" pipes out the back & I lost ton's of low end torque/power. Needless to say that I have my Gibson back on. Next time I do my exhaust I will leave the stock pipe & just replace my muffler with something Highflow & put a sweet looking tip on it.

 

Without back pressure, your boost just fills the exhaust system at lower rpms. With a positive displacment blower your full rated boost occurs somewhere around 1800-2000rpm, your motor isn't using that much air (1.5 CFM per HP) so instead of the back pressure holding the boost pressure in the cyilnder (packing in tightly), it flows freely into the exhaust.

I don't think any muffler will add much in the way of HP to a L, they have a real effective system already, sound, well you can get that, and still maintain good back pressure.

For the street go for the torque, hp will net better trap speeds, however everything is a trade off., and unless you race it alot, why would anyone trade the feeling of the giant silent hand pushing you into your seat!!

My Stang runs a factory 4 cat pipe, (no mufflers) out of the hole its awesome, I'd never trade that feeling for anything. Sure I'm chokeing it to the tune of 25 hp or more, but with an AOD and 3:55's, I run a low stall converter 2400rpm, it drives great on the street.

 

I just installed a FM 50 SUV muffler with the stock tailpipe. This was recommended by Flowmaster. I lost some low end power. I am thinking about re-installing the stock muffler.