Exhaust back box/silencer modification

[MartinP]

Hi All,
This is my first post. Bought my 2006 3.0si Convertible in July and have been enjoying it a lot. Have moved over from the TVR club (11years) having owned a Chimera and 2 Tuscans. Its such a pleasure to now have a car that starts every time and is properly engineered!

The one thing I do miss however, is the sound of the TVR. Granted, the Speed 6 is a very different note, but it was an event every time it started up. The Z4 is too conservative for me.

So having read a few posts about modifying the back box and owning a mig welder/angle grinder, I thought I would seek out a second hand silencer and give it a go.

The exhaust I have bought matches the one on my car, but looks a slightly different to the one modified in this thread.

https://z4-forum.com/forum/viewtopic.php?t=88783

When looking down the inlet and outlet pipes, the seem to turn at 90degs.

I think there was a new design in 2005/6ish and the welds are not as obvious as those in the above thread. I wondered if anyone has hacked apart the same version of the silencer, to save me cutting mine apart in a less than idea way.

Many thanks,
Martin

 

[Mr Tidy]

Hi and welcome to the forum, Martin.

The one in the link you posted is for a pre-facelift 3.0i (the facelift was early 2006), which is why it looks different to yours but sadly I can't offer any other advice.

Luckily my car already had a custom cat-back exhaust fitted when I bought it!

But we'd like to see your car.

 

[MartinP]

Here she is

 

[road warrior]

Like many I always wanted a TVR, but the silly prices and the unreliability always kept me away, I suppose the noise it made couldn't compensate for when it wouldn't make that noise.... so welcome

 

[MartinP]

So the 1mm angle grinder discs were received last week and tonight I set about cutting open the silencer. I got lucky and didn't cut anything critical/structural. Beginner's luck! Here are the photos of the internals....
HEALTH AND SAFETY WARNING: I couldn't find my paint spraying face mask, but wished I had it. The glass fibre wadding was knackered, so I quickly bagged it up and sprayed the exhaust down with water, whilst hiding my face in my jumper. Nasty stuff and very bad for your lungs.

 

[MartinP]

If you want to see the wadding removed and how dirty a job it is: https://youtu.be/phvJxHUcwUs

I'm assuming the area with no wadding is a resonator??

 

[MartinP]

Got into cutting the pipe this evening. I ordered some poly 50mm flex pipe 200mm and 180mm lengths with 52mm ID collars for £20 delivered. Was a pig to get them out due to disc size and grinder bumping into other pipes/structure. I added a few angled cuts to the collars of the poly flex and bent round one of the existing pipes (where it was perforated) and they fit really well. Just need to clean the areas where I’ll be welding, get some exhaust putty and seal it back up.

Any advice as to where to get new wadding, or should I reuse the existing stuff?

Also, should I put the baffle plates back in?

 

[thecookie125]

Good work so far! Have you seen the DLV backboxes on here? A forum member basically does exactly what your doing then welds it all back up, they sound great because you loose the drone that you would typically have with a straight pipe etc.

 

[MartinP]

I think it was his post that inspired me to have a go!

 

[craigbeal]

I would have personally just removed the back box entirely and had pipes straight through which is the most common option. less weight again and a better sound

https://z4-forum.com/forum/viewtopic.php?f=2&t=109709&p=1586366#p1586366

 

[Smartbear]

I would have personally just removed the back box entirely and had pipes straight through which is the most common option. less weight again but more drone

https://z4-forum.com/forum/viewtopic.php?f=2&t=109709&p=1586366#p1586366

I’ve fixed that for you, no need to thank me
Rob

 

[craigbeal]

Very good.

People talked about drone but yet I’ve had my n52 3.0si and my friend his 3.0i m54 and neither drone :|

He had a custom made replacement back box before removing the back box entirely... now that did drone!!

I would say his m54 sounds much better than the n52 with the delete. Lots of back fire crackles !

 

[MartinP]

This evening’s welding. Haven’t welded for a few years, so quite happy with the result.

New e-glass arriving on Tuesday, so will weld up soon. Can’t wait to hear the difference!

 

[limitedslipdiff]

thats crazy work could you not afford a decent exaust system it looks like u opened a can a beans

 

[oiler]

Besides keeping your muffler shell and tips, I can't see what the difference is between what you have done and or a muffler delete??

 

[True-Blue]

Besides keeping your muffler shell and tips, I can't see what the difference is between what you have done and or a muffler delete??

Pipes within box still vent into a now larger chamber, not the same as a straight through pipe

 

[MartinP]

Besides keeping your muffler shell and tips, I can't see what the difference is between what you have done and or a muffler delete??

Pipes within box still vent into a now larger chamber, not the same as a straight through pipe

That right, removed a pair of vents= less sound attenuation, and removed the convoluted route of the exhaust gasses = better throughput of exhaust gasses. This may improve power responsiveness, but I’m not banking on it.

 

[MartinP]

Before:
[youtube]UXXdpliah8Y[/youtube]
After:
[youtube]M-0k9rDY5TY[/youtube]

Its still not loud enough! I've done exactly what member ducklakeview has done, but there are no pops and bangs and it doesn't sound anywhere near a nice as his video in the original. I wonder if the centre silencer is different on the M54 compare to the N52 in mine? Anyone have any thoughts/experience? Thanks.

 

[LittleZ4]

The m54 gives a deeper note than the n52. I reckon you'll get more pops and bangs with a back box delete. I got rid of mine and as soon as it's nice and hot it pops and bangs pretty much on command.

 

[Carteen]

Old post but did you put the wadding back in the box ore just a part of it?