Exhaust replacement - is this a dumb idea?

[Felixlamb]

Hey guys,

Hope you're all coping as well as you can during all this.

Lockdown boredom has got to me and I need a project to work on before I go mad.... I'm looking to get a more aggressive noise out of my exhaust. Unfortunately my car is on a PCP agreement so I'm limited with what modifications I can do to the original parts.

What I had been thinking of doing is either getting a more free-flowing backbox or to take the insulation out of my current one. But both options would require cutting and welding the original exhaust, which I'd rather not do.

An alternative to this which has sparked my interest recently is there are a few full OEM exhausts (cat back, as that's where the join is and therefore won't require any pipe cutting or welding) on the fleabay going for the cheap. My idea would be to take the insulation out of the eBay exhaust backbox, weld it up, and swap that exhaust in. Then when the time comes to return my car to BMW I can just swap the original one in. Obviously this is a massive oversimplification, and I'm probably in over my head.

Also, is it possible to take the exhaust off without first taking off the lhs strut brace?

Example pic of full exhaust for reference


Please tell me this is a bad idea so I can think of doing something else stupid instead

Felix

 

[Smartbear]

Have you tried leaving the exhaust valve open permanently?
Rob

 

[BeardyJon]

I’m sure I read a thread from someone who did something similar with an E85 back box and he said he wish he hadn’t done it cos of the drone it caused.

 

[Smartbear]

I’m sure I read a thread from someone who did something similar with an E85 back box and he said he wish he hadn’t done it cos of the drone it caused.

Can’t be the same thing as the e85 doesn’t have an exhaust valve! Sounds more like he had the rear silencer cut off which can (unsurprisingly) cause drone.
Rob

 

[Felixlamb]

Have you tried leaving the exhaust valve open permanently?
Rob

Hey Rob, yeah I did the golf tee mod a few months ago.
I guess my thought process is even if I don’t like the end result I can still revert it completely.

 

[BeardyJon]

I’m sure I read a thread from someone who did something similar with an E85 back box and he said he wish he hadn’t done it cos of the drone it caused.

Can’t be the same thing as the e85 doesn’t have an exhaust valve! Sounds more like he had the rear silencer cut off which can (unsurprisingly) cause drone.
Rob

No I was referring to the process of cutting the backbox open and removing the insulation. Someone on here did that, I’m sure.

 

[Nictrix]

When you say the car is on PCP do you mean that basically you are leasing the car and handing it back once the agreement is finished?
If so, its not your car to do anything to and you may be responsible for paying to have the car returned to standard when handing it back.

 

[Anonymous]

When you say the car is on PCP do you mean that basically you are leasing the car and handing it back once the agreement is finished?
If so, its not your car to do anything to and you may be responsible for paying to have the car returned to standard when handing it back.

Tsk tsk..you are such a stickler for these minor issues..

 

[Felixlamb]

When you say the car is on PCP do you mean that basically you are leasing the car and handing it back once the agreement is finished?
If so, its not your car to do anything to and you may be responsible for paying to have the car returned to standard when handing it back.

Hence why my original post mentioned that I didn’t want to modify the standard parts...therefore meaning it would be standard when handing it back as I could just refit the original exhaust...

 

[mcbutler]

Its not yours, best to leave alone..

 

[Silverzedtom]

Not worth it in my opinion, presumably you would declare the changes with your insurance, then you have discrepancies against the lease contract and that could easily leave you or ultimately anyone you left behind in a sticky situation after an accident. Sounds ridiculous, until it happens!

 

[R60BBA]

If you were to modify the original backbox from the top I highly doubt BMW would notice. (As the welds wouldn't be seen from below).

However, any exhaust modification may breach your finance agreement.

Nevertheless, lots of people on PCP modify their exhausts and still obtain successful warranty claims...

 

[sunnydays]

As long as OP is not planning on running methanol injection, with hybrid turbos, and a tank of NOS in the trunk, I doubt they will care / notice.