Took off my axle-back (muffler) the other day. Drove around with just the mid-pipe back because I was curious to see, roughly, what it would sound like in-cabin and partially get use to what a cat-back might sound like. Anyway, I noticed while driving that shifting seemd to transition easier. I was wondering, is this due to the lack of back-pressure the muffler created or something else? My midrange also seemed to pull a tad harder. This is by no means a permanent thing, simply a curiosity filler. Don't really like how start-up sounds or idle (too hollow for me), but high end sounds decent and there isn't much drone.

 

 

It's probably a placebo effect.

 

maybe ^

 

the next big dyno to prove gains?...why not it will def change something lol...

 

4 posts and so far I've gotten "placebo effect".

Thank you...

I'm just curious if the lack of back-pressure will have any effect, I'm not a damn ricer looking for sound...so stop playing the stereotypical "not sure on the answer, but I'll jump on the .org band-wagon and bash because I don't know better" ****.

 

lol
+1

 

It's quite an increase in hp if you can acutally feel the difference from the pressure being freed up. I can hardly feel anything with an empty tank and full tank and that's quite some weight. Axle back delete can probably free up 2hp maybe? The y-pipe claimed to free up 20hp and it wasn't even a big difference hence why I would say the muffler back pressure is just a placebo effect.

 

I agree with you on the minimal (if any gains) an axle-back delete would result in. However, I am just wondering whether or not the new lack of back-pressure is partly responsible for the smoother shifting? I can't think of any other reason really...

 

my muffler broke right at the gasket a couple weeks ago. I drove around with the axle back off for a couple days.. didn't really notice any marginal power gains. The sound it made really was quiet. I was expecting something a little louder ha but with $10 and a little work it was back to normal.

 

Stupid.

And I remember reading that muffler off adds zero hp.
So..... I think you are just LOOKING for a reason for something to increase.

I can defiantly tell when I have a full and almost empty tank.

 

If any gains are marginal, that just goes to show our mufflers are not a major restriction in the exhaust.

 

I will back up your findings MIK3. I felt the same when my flange rusted off at the axle-back. I removed the rear section and shifting was smoother. My only assumption is that we no longer had the stock "valved" muffler, therefore we did not feel the two stage exhaust pressure change that stock OEM muffler produces.

I will also tell you, DO NOT LEAVE IT THIS WAY. I had a small fire start in the trunk AND my brake fluid was fried. Luckily, only melted a little of the black goo in the trunk and I had to power bleed my entire system to remove all the burnt brake fluid. can you say mushy peddle? No brakes? Eeeek!

 

i was thinking about this thread,..if it reduces back pressure...and if merlyn got dyno gains on a 3" catback,..which would reduce back pressure....speaking in terms of only a 3.5 not a 3.0...maybe some general thoughts are wrong,.. and the stock axel back limits slightly? lets say 8-10 hp? at best..just my .02

MIK3- do you have headers,..

 

I too thought of Merlyn's 3" prototype when doing this and how it might relate, as far as back pressure is concerned. And I currently do not have headers, but am on the verge of purchasing some Gen 3's from Brian here real soon.

Nismopc, that sounds pretty detrimental. So far, I've had it this way only for a couple of days, with a non-agressive driving style. How long did you have it off before noticing your damage?

 

Probably around the time when his brakes stopped working...

 

Haha...

...and when I began to smell some melting rubber!!!

Put a muffler back on or atleast run a straight pipe out so the exhaust is not pointed straight up at your brake line and the under carriage of the trunk.

Trust me!!!

 

ok so next time someone gets a dyno do muffler on then muffler off....no need to talk about it lol do it

 

Haha, looks like I caught it just in time! One of my brake line clips was completely liquified, but it seems as if the line itself did not sustain any heavy damage. Needless to say, my axle-back is going back on. Was fun while it lasts, but I savor my brakes far more than minimal smoothness in shifting.

Plus, my test-pipe is due Friday