Is a decat on a Z4M an option?

maupineda · Post by **maupineda** » Wed Mar 08, 2023 5:27 pm

Ed Doe wrote: ↑Mon Mar 06, 2023 12:48 pm
Vanne wrote: ↑Sun Mar 05, 2023 11:58 pm lots of decat options for z4m, just not for 100 pounds..

https://www.hackengineering.co.uk/produ ... ipes-z4-m/
That price is absolute f*cking robbery for a pair of pipes!!!

Then this car is not for you. Parts can be very expensive. This is not the usual cheap and cheerful Japaneese car. Wrong selection for low cost motoring

jontZ4M · Post by **jontZ4M** » Wed Mar 08, 2023 6:38 pm

TomK wrote: ↑Tue Mar 07, 2023 8:10 pm Yes, where the 'X' is. I put a supersprint x-pipe on mine (already had their fairly loud 'race' back boxes) and the volume change was pretty extreme, I think my car went from measuring ~92dB @5000rpm to ~98dB static. Had to go back to stock for track day compliance, but I was happy, it was far too loud with the SS X-pipe. I have stock cats btw.

Ah that makes a lot of sense.

OK so the plan now is the following:

1) repair the cat section (not sure how yet) and refit.

2) modify/replace the X-section and rear mufflers to get the volume up. Either a new cat-back Supersprint set up, which will cost around £2000. Or modifying the OE cat-back system to remove the middle resonators and replace the mufflers with free flow units.

Thanks all.

Ed Doe · Post by **Ed Doe** » Wed Mar 08, 2023 6:49 pm

maupineda wrote: ↑Wed Mar 08, 2023 5:27 pm
Ed Doe wrote: ↑Mon Mar 06, 2023 12:48 pm
Vanne wrote: ↑Sun Mar 05, 2023 11:58 pm lots of decat options for z4m, just not for 100 pounds..

https://www.hackengineering.co.uk/produ ... ipes-z4-m/
That price is absolute f*cking robbery for a pair of pipes!!!
Then this car is not for you. Parts can be very expensive. This is not the usual cheap and cheerful Japaneese car. Wrong selection for low cost motoring

Lol behave mate, I don't care what car it is, a bit of bent 304 stainless pipe is not worth 900quid unless you're a certifiable clown.

I'm not getting into a dick waving contest over who's spent what on their cars but I'm fairly sure I've had the bigger end of the engine bills from an s54, I'm perfectly aware of and prepared for the cost of ownership.

jontZ4M · Post by **jontZ4M** » Wed Mar 08, 2023 7:01 pm

Ed Doe wrote: ↑Wed Mar 08, 2023 6:49 pm I'm not getting into a dick waving contest over who's spent what on their cars but I'm fairly sure I've had the bigger end of the engine bills from an s54, I'm perfectly aware of and prepared for the cost of ownership.

Not me sadly, my wife will cut my balls off if I spend too much on car that never gets used. I'll find a way of making it affordable.

TomK · Post by **TomK** » Wed Mar 08, 2023 7:10 pm

maupineda wrote: ↑Wed Mar 08, 2023 5:27 pm Then this car is not for you. Parts can be very expensive. This is not the usual cheap and cheerful Japaneese car. Wrong selection for low cost motoring

Says the man with H&R coilovers

Ed Doe · Post by **Ed Doe** » Wed Mar 08, 2023 7:12 pm

jontZ4M wrote: ↑Wed Mar 08, 2023 7:01 pm
Ed Doe wrote: ↑Wed Mar 08, 2023 6:49 pm I'm not getting into a dick waving contest over who's spent what on their cars but I'm fairly sure I've had the bigger end of the engine bills from an s54, I'm perfectly aware of and prepared for the cost of ownership.
Not me sadly, my wife will cut my balls off if I spend too much on car that never gets used. I'll find a way of making it affordable.

As the saying goes 'my biggest fear is that if I die my wife will sell my cars for what I told her they cost'

My top end let go on a trackday with my wife 6 months pregnant with our first child.... It was touch and go as to whether the car was fixed and sold, I juuuust managed to swing it

maupineda · Post by **maupineda** » Wed Mar 08, 2023 7:23 pm

TomK wrote: ↑Wed Mar 08, 2023 7:10 pm
maupineda wrote: ↑Wed Mar 08, 2023 5:27 pm Then this car is not for you. Parts can be very expensive. This is not the usual cheap and cheerful Japaneese car. Wrong selection for low cost motoring
Says the man with H&R coilovers

Whats is left of them are just the front strut bodies to retain the height adjusting ability. All else is different components.

beanie · Post by **beanie** » Wed Mar 08, 2023 7:50 pm

Ed Doe wrote: ↑Wed Mar 08, 2023 6:49 pm a bit of bent 304 stainless pipe is not worth 900quid unless you're a certifiable clown.

Couldn’t agree more, it’s outrageous. In fact, in the spirit of the 2020’s, I’m offended by it.

I’m sure any half competent exhaust place could knock a set up for 1/3rd of that.

jontZ4M · Post by **jontZ4M** » Thu Mar 09, 2023 5:23 pm

beanie wrote: ↑Wed Mar 08, 2023 7:50 pm Couldn’t agree more, it’s outrageous. In fact, in the spirit of the 2020’s, I’m offended by it.

I’m sure any half competent exhaust place could knock a set up for 1/3rd of that.

Yup this is what I'm looking at at the moment, trying to get quotes from bespoke exhaust fabricators to see how much a modified cat-back could be made up for.

jontZ4M · Post by **jontZ4M** » Thu Mar 09, 2023 5:26 pm

I've send this email off to a couple of companies just to see if it's possible and how much it will cost:

I want to modify the cat-back section of the exhaust to make it louder and more free-flowing.

There are pre-made aftermarket options, like Supersprint cat-back, but that costs around £2000.

So I'd like to see if a custom solution can make it more affordable.

The OE exhaust is stainless steel with these cars, so I was wondering if you can modify the OE system? Chop out the resonator and replace with pipe. and replace the rear mufflers with louder mufflers?

Would this be possible? Or do you only do custom from scratch?

If so, do you need the car or can I just drop the exhaust off?

plenty · Post by **plenty** » Thu Mar 09, 2023 6:56 pm

I've got a cheap catback system for sale: viewtopic.php?p=1963228#p1963228

jontZ4M · Post by **jontZ4M** » Fri Mar 10, 2023 4:11 pm

plenty wrote: ↑Thu Mar 09, 2023 6:56 pm I've got a cheap catback system for sale: viewtopic.php?p=1963228#p1963228

Yup I'll take this. DMing you now.

Ed Doe · Post by **Ed Doe** » Fri Mar 10, 2023 6:04 pm

jontZ4M wrote: ↑Fri Mar 10, 2023 4:11 pm
plenty wrote: ↑Thu Mar 09, 2023 6:56 pm I've got a cheap catback system for sale: viewtopic.php?p=1963228#p1963228
Yup I'll take this. DMing you now.

Can't decide if I'm pleased or disappointed - I'd been bloody tempted by these for weeks, but trying to be sensible and not spend money on stuff I don't need right now - so one the one hand a blessing in disguise that you've bought them, but I'm still disappointed at not having them myself

jontZ4M · Post by **jontZ4M** » Fri Mar 10, 2023 6:36 pm

Ed Doe wrote: ↑Fri Mar 10, 2023 6:04 pm Can't decide if I'm pleased or disappointed - I'd been bloody tempted by these for weeks, but trying to be sensible and not spend money on stuff I don't need right now - so one the one hand a blessing in disguise that you've bought them, but I'm still disappointed at not having them myself

I'm glad to save you the money Ed!

jontZ4M · Post by **jontZ4M** » Fri Mar 10, 2023 6:39 pm

Ok Guys - I've just had a closer look at the cat section of exhaust. I've cleaned up the welds and I can not find any obvious leaks (I got to say those OE welds are amazing! I'd love to be able to weld like that).

Tomorrow I'm going to refit the cat section and run the car to see if the blows re-materialise. With hinesight, I should have paid more attention when the exhaust was still on the car.

The question I have is: how tight do we do those four bolts that join the headers to the cat section please? Can't find it in any of the diagrams (surprise surprise)

Thanks.

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