msiminoff

I have searched through all of the posts here about cat-back exhausts and replacement mufflers. There is a definite consensus that with my 4" exhaust, a cat-back system is not necessary and of course there are lots of posts about having a "louder" exhaust and avoiding "drone"...

But what I haven't seen is actual data supporting claims of increased torque and/or HP. Has anybody done a before/after dyno test with any of the replacement mufflers? What were the *REAL* gains (if any) and what RPM are you seeing them at.

Thanks
-Mark

msiminoff

So based on the the fact that this post got zero responses... Am I to assume that there are no real HP/torque gains available by replacing the stock muffler with an aftermarket one on an otherwise stock '05 CTD ?!?!?!?

jmccart

I have read manyh tech articles where they dyno before after a muffler install, they always get mo
re power. Do ya' want noise or no?

mikelr

Mark,
I know that you are asking for "real" dyno proven results and unfortunatly I can't provide you with that.
I can say however that my 07' woke up considerably after dumping the stock exhaust system and installing the 5" turbo back with 51" Donaldson muffler.
The power when the truck was stock would nose off around 2400rpm when rowing through the gears. With the new exhaust I can feel a bit more pick up but what is more notable is that I have to watch the tach because the truck will run up past 3000rpm and it will pull till the ecu defuels. Obviously the truck is breathing much better and the fact that it is still pulling beyond the piont it used to with the stock exhaust would equate to a higher HP number on any dyno.
BTW, there is absolutely no drone with this setup.

TexasCTD

My truck bone stock from the factory dyno'd 280/528 on a dynojet in the summer heat.


After adding an AFE Stage 2 air intake and 4'' straight thru Magnaflow muffler and no cat......it dyno'd 277/549 on the same dyno a year later.

To answer you question directly......You will probably see no gains by doing an exhaust upgrade alone. However, once you add boxes/downloaders etc. the air and exhaust mods will help things flow better.

The exhaust mod is basically a "supporting" mod and doesn't add power in and of itself. That is my experience anyway.

Now with the Smarty on level 9....mine dyno'd recently at 466/922. Hope that helps.

mikelr

Cut out that MBRP muffler and strap on a Donaldson.

TexasCTD

Maybe you could try having your exhaust tip extended to see if that helped. Also, maybe a turndown tip?

MikeyB

The only real gain to be had with a high flow exhaust is a slight drop in EGTs.
Neither intake or exhaust will increase power on a stock truck, but it does help when going for higher hp.

MikeyB

rjm022

big rig shops sells donaldson mufflers. look in your local phone book for a peterbilt, kenworth,etc dealer/parts dept. i paid around 60.00 bucks for mine alittle more than a year ago.