How difficult to remove backboxes? For bypass
- Thread starter Dean26390
- Start date
Liverpool
It will depend on whether the clamps are rusted together like mine were. Which will require a bit of heat/sawing - and of course the new sleeved clamps to refit them.
My quote of £50 went to £100 then to £250 (with parts) - so didn't bother, and bought Rogue Diablo back-boxes for £600 instead.
My quote of £50 went to £100 then to £250 (with parts) - so didn't bother, and bought Rogue Diablo back-boxes for £600 instead.
It's a doddle, provided, as mmm-five says, the two bolts on each clamp are not completely corroded. If you plan on doing this job yourself, then I'd recommend that you lift the car up the day before you intend to remove the silencers and spray some "penetrant spray" onto the nuts and bolts on the clamps to give it a chance to loosen the crud on the bolts which should make them free to move when you apply the spanners. 
Whether it's worth saving £40 by DIYing, is all down to you. Personally, I like to do as many of the jobs on my car as possible for the satisfaction of being able to do them and the saved cash is a bonus, and it does add up over time.
Whether it's worth saving £40 by DIYing, is all down to you. Personally, I like to do as many of the jobs on my car as possible for the satisfaction of being able to do them and the saved cash is a bonus, and it does add up over time.Did one silencer last night, away out to do the other night.
As long as you can get the car up on axle stands it's not too bad at all. As Exdos suggests, get some WD40 or the likes on the bolts the night before and remove the next night. The bolts holding on the silencers to the mid section was badly corroded on mine, no way was a spanner going on, but using mole grips it was fine. One of the bushes is easier, the other is a bit of a pain, but a bit of patience it's fine. I found it easier to unbolt the bushings bracket from the floorpan with a loooonng extension bar.
Whatever you decide, just make sure you have new M8 bolts to hand, BMW want £3.70 each, or you can buy 5 from ebay for £2.19 including postage
You want M8 x 55mm.
http://www.ebay.co.uk/itm/121081465067?var=420127771562&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Give it a bash, very satisfying to do it yourself
G
As long as you can get the car up on axle stands it's not too bad at all. As Exdos suggests, get some WD40 or the likes on the bolts the night before and remove the next night. The bolts holding on the silencers to the mid section was badly corroded on mine, no way was a spanner going on, but using mole grips it was fine. One of the bushes is easier, the other is a bit of a pain, but a bit of patience it's fine. I found it easier to unbolt the bushings bracket from the floorpan with a loooonng extension bar.
Whatever you decide, just make sure you have new M8 bolts to hand, BMW want £3.70 each, or you can buy 5 from ebay for £2.19 including postage
You want M8 x 55mm. http://www.ebay.co.uk/itm/121081465067?var=420127771562&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Give it a bash, very satisfying to do it yourself
G
Dean26390 said:
I can't comment on whether it gives a better sound or not, I've not heard either in real life to compare. However, I know Exdos did a lot of data logging before and after with the internal mod and identified an improvement. Whether that can be picked up sitting in the seat I don't know, but it's what gave me second thoughts....
Drop machine monkey a PM, he may be able to help you
Dean26390 said:
I originated the internal mod for the Z4MC. Selectively removing internal parts and reconfiguring the layout removes the "reverse-flow" and allows the exhaust gases to pass "straight-through" the silencer, thus reducing the resistance to exhaust gas flow and therefore increasing engine performance. I have data-logged the performance gains produced from this mod and also when coupled with air-intake mods.
I have no idea of how much a suitable engineering/welding company would charge for modding a pair of silencers: I did the mod myself.
I've previously posted photos of the mod and also a link to a video showing my car being datalogged and the sound that the car produces under acceleration in 3rd gear to the redline. Do a search.
It's a piece of P, do it yourself but, as said above, make sure you have spare bolts to hand
DD
DD
The photo above is the way that Dalecan had his silencers modded.
The photo below shows a much simpler way of modding the boxes that I've devised, which will give "straight through" flow.
If you remove the centre perforated pipe and cut the inner side of the two other pipes (shaded in red) you can then weld some perforated sheet to join the two outer tubes (as shaded in green) so that exhaust gases can flow directly from the inlet pipe (on the right) to the outlet pipes (on the left) in this section of the silencer. After doing this, simply refill the section with the fibreglass that was removed and then reweld the outer skin. This leaves the neatest exterior appearance of the silencers.
The photo below shows a much simpler way of modding the boxes that I've devised, which will give "straight through" flow.
If you remove the centre perforated pipe and cut the inner side of the two other pipes (shaded in red) you can then weld some perforated sheet to join the two outer tubes (as shaded in green) so that exhaust gases can flow directly from the inlet pipe (on the right) to the outlet pipes (on the left) in this section of the silencer. After doing this, simply refill the section with the fibreglass that was removed and then reweld the outer skin. This leaves the neatest exterior appearance of the silencers.
Brilliant, thanks John, will pass that on to Machine Monkey. That does look a lot easier though, but probably the same result. I wonder if it will result in a different sound to Dalecan's solution. Is there no concern that air will try and escape out the single exist on the Y pipe and interrupt the flow, or will it always find the route with less resistance?
Just away to PM you about something else
Just away to PM you about something else
Just let me know witch way you want it done gwatson
They do stack well a bit dirty though!! Looks like i will be cleaning the hole things up for you!!!
They do stack well a bit dirty though!! Looks like i will be cleaning the hole things up for you!!!
Machine monkey said:Just let me know witch way you want it done gwatson
They do stack well a bit dirty though!! Looks like i will be cleaning the hole things up for you!!!
Will do Mat. They'll be collected on Mon.
Haha... don't tempt me to get the autosol out on them at the weekend for that mirror finish, I'm trying to leave my OCD days behind me
I'll give them a quick clean down though. The bottoms are fine as I sprayed them with black heat paint a few months ago, just the sides have 56k miles of road dirt.
Well its probably no bother to run a wire wheel over them. You could spray them all black and they would be all nice and clean then
