Dave Keeper
Dedicated Member
- Joined
- Dec 20, 2014
- Points
- 28
Looking at de-backboxing my 2.8. Just want it louder really!
Anyone done it?
Anyone done it?
De-backbox
- Thread starter Dave Keeper
- Start date
Dave Keeper
Dedicated Member
- Joined
- Dec 20, 2014
- Points
- 28
No just take the back box off and put some nice tips on that's all really!
Been looking on YouTube and some seem really good but then some seem pants lol
Been looking on YouTube and some seem really good but then some seem pants lol
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zedonist
Guest
Just buy a straight through cat back system, there are a few available
smartbear
Zorg Legend
- Joined
- Jun 6, 2014
- Points
- 83
it will sound great with this mod but i wouldnt do it, been reading on the z4forum about people doing this & it makes the cars lose a fair bit of power (proven on the dyno) there is to little back-pressure & the engine doesnt like it!
While I was out having a quick cob web blow in the Zed this morning.
Someone cut open their back boxes (Z3M), and removed some some of the baffles within them through the hole in the top. Can't remember if this was done to lighten them, make them louder or make them more free flowing (or all the above). The hole was then welded back up again so when the exhaust is refitted you can't see it's been "tweaked".
Been racking my brains and I think it may be @Aceman - sorry if it wasn't you Ian
Someone cut open their back boxes (Z3M), and removed some some of the baffles within them through the hole in the top. Can't remember if this was done to lighten them, make them louder or make them more free flowing (or all the above). The hole was then welded back up again so when the exhaust is refitted you can't see it's been "tweaked".
Been racking my brains and I think it may be @Aceman - sorry if it wasn't you Ian
Quote Pingu....
"I had a spare exhaust system, so I thought I'd have a look inside. The first thing to note is that it's a double-skin exhaust."
"Under the double skin was this"...
(RH Silencer)
"Here's a diagram showing how the exhaust flows"...
"Main entry pipe is fully open in Chamber 1, perforated in Chamber 2 and sealed from Chamber 3".
"Secondary pipes are perforated in Chamber 1, perforated in Chamber 2 and fully open in Chamber 3".
"Exit pipes are sealed from Chamber 1, sealed from Chamber 2 and perforated in Chamber 3".
---------------------------
"I have de-restricted the exhausts by removing the secondary pipes and removing the perforations on the exit pipes"...
(LH Silencer)
"Here's a diagram of the new exhaust flow"...
(RH Silencer)
"The inner cut-out was welded back in place, then sealed with exhaust repair paste. The system was tested to a pressure of 8 bar. The outer cut-out heat shield was attached using exhaust repair paste, then painted using high temperature exhaust paint".
"Finished result"...
(LH Silencer)
"All the modification has been done to the top of the silencer and none of this can be seen from under the car".
"I can't objectively tell you what the improvements are, but it does sound slightly "fruitier" and a little bit less of a screamer at mid-revs".
"There is less engine braking and the engine seems to rev more freely".
Pingu.
"I had a spare exhaust system, so I thought I'd have a look inside. The first thing to note is that it's a double-skin exhaust."
"Under the double skin was this"...
(RH Silencer)
"Here's a diagram showing how the exhaust flows"...
"Main entry pipe is fully open in Chamber 1, perforated in Chamber 2 and sealed from Chamber 3".
"Secondary pipes are perforated in Chamber 1, perforated in Chamber 2 and fully open in Chamber 3".
"Exit pipes are sealed from Chamber 1, sealed from Chamber 2 and perforated in Chamber 3".
---------------------------
"I have de-restricted the exhausts by removing the secondary pipes and removing the perforations on the exit pipes"...
(LH Silencer)
"Here's a diagram of the new exhaust flow"...
(RH Silencer)
"The inner cut-out was welded back in place, then sealed with exhaust repair paste. The system was tested to a pressure of 8 bar. The outer cut-out heat shield was attached using exhaust repair paste, then painted using high temperature exhaust paint".
"Finished result"...
(LH Silencer)
"All the modification has been done to the top of the silencer and none of this can be seen from under the car".
"I can't objectively tell you what the improvements are, but it does sound slightly "fruitier" and a little bit less of a screamer at mid-revs".
"There is less engine braking and the engine seems to rev more freely".
Pingu.
- Joined
- Nov 27, 2012
- Points
- 98
- Location
- Swadlincote / ashby de la zouch
- Model of Z
- Z3 cosmos black ltd edition
I've always wondered what the zed would look like with a nice set of retro thrush side pipes.....cobra style
Dave Keeper
Dedicated Member
- Joined
- Dec 20, 2014
- Points
- 28
Don't think I'll be doing that lol I had a go of a Robin Hood track car and was deaf in one ear for two weeks!!!
Think I'm just going to cut the back box off and chuck some pipes on her ! Then take it from there! If it's no good I'll put on another small backbox!
Think I'm just going to cut the back box off and chuck some pipes on her ! Then take it from there! If it's no good I'll put on another small backbox!
what about de-cat and K&N air filter, that will give her a bit of umph but not too much ;-)
Yep I have done this too but haven't got around to finishing it yet. It is quite difficult to do as the Z3M backboxes are made out of stainless steel so you need inox cutting wheels for the angle grinder and then it is still pretty hard. I have one silencer done and the other just needs welding back up. Pingu did his around same time I started mine but he finished his although I don't think he totally gutted his. Apparently it has quite a significant performance increase for the ///M's and does make then a lot lighter too.
Z
zedonist
Guest
Have a read of this. Doing the mod to the Z3M won't give you any more power, only change the noise of it, you need to move away from a baffled box altogether
http://www.paraglidingteam.nl/PPGTechnics/sound and noise/Mufflers/1155795969.pdf
http://www.paraglidingteam.nl/PPGTechnics/sound and noise/Mufflers/1155795969.pdf
DivideBYZero
Zorg Guru (I)
It's quite a common mod on the E92 M3. I've had mine done with two of the perforated sections straight piped, but it's also not a baffled system. Sounds amazing, I love it. 
lmrdave
Dedicated Member
I've got a butterfly valve to bypass the back box, so you can chose either loud or quite at the touch of a button.
I believe it's called an exhaust cut out. I've been looking to import a couple from here http://www.badlanzhpe.com
The sound is rediculously loud, I think this mod is best done with a solenoid valve so you can open and shut the bypass. But it does sound awesome.