Is a decat on a Z4M an option?

[Ed Doe]

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' :lol:

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 :lol:

 

[maupineda]

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 :rofl:

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

 

[beanie]

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]

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]

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]

I've got a cheap catback system for sale: https://z4-forum.com/forum/viewtopic.php?p=1963228#p1963228

 

[jontZ4M]

I've got a cheap catback system for sale: https://z4-forum.com/forum/viewtopic.php?p=1963228#p1963228

Yup I'll take this. DMing you now.

 

[Ed Doe]

I've got a cheap catback system for sale: https://z4-forum.com/forum/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 :lol:

 

[jontZ4M]

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 :lol:

I'm glad to save you the money Ed!

 

[jontZ4M]

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.

 

[Ed Doe]

Ft.

(****in tight!) :lol:

But seriously bit of common sense on the back of a 1/2" ratchet should be fine

 

[jontZ4M]

Will do!

 

[Vanne]

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.

So would mine, If I didn't remind her every now and then that instead of car stuff, I could be at the pub every night pissing it up the wall instead.. Like so many guys I know do..

No thanks...

Gotta have something you like doing, your only here once..

 

[jontZ4M]

So would mine, If I didn't remind her every now and then that instead of car stuff, I could be at the pub every night pissing it up the wall instead.. Like so many guys I know do..

No thanks...

Gotta have something you like doing, your only here once..

Yup agreed.

General update:
- cat section refurbed and waiting to go back on(think I'll link it to the rest of the exhaust and then heave it all onto the car in one piece).
- bought an aftermarket used cat-back from a nice chap in London today. Already stripped it down, cleaned it up and just making it nice again.
- on Monday I'm sending the X-pipe from the new system off to another nice chap on the forum for modification.

When that comes back I'll put it all back on car and I THINK that's me done for the year!

 

[TomK]

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)

2AZ Exhaust manifold to exhaust system
S54 M10 15±2 Nm

You need to get yourself a copy of TIS...

 

[jontZ4M]

2AZ Exhaust manifold to exhaust system
S54 M10 15±2 Nm

You need to get yourself a copy of TIS...

Thanks Tom but is that a typo? The M10s on the driveshafts for instance are 100Nm. 15Nm seems too low by a huge factor?

 

[TomK]

I don't think so, TIS is rarely wrong. The correct M10 hex nut is copper there which would probably explain it?

 

[jontZ4M]

I don't think so, TIS is rarely wrong. The correct M10 hex nut is copper there which would probably explain it?

Will investigate further. I'm glad you responded as I would have tightened the hell out of these.

 

[jontZ4M]

In case anyone interested, this is what turned out to be inside the resonator in the middle of the X-pipe of our exhausts. Un-silencing mine.

 

[Mikey_Boy]

2AZ Exhaust manifold to exhaust system
S54 M10 15±2 Nm

You need to get yourself a copy of TIS...

Thanks Tom but is that a typo? The M10s on the driveshafts for instance are 100Nm. 15Nm seems too low by a huge factor?

The low torque value is because of the expansion of the joint and fixtures due to heat - too tight and it will fail. 15Nm ensures it is just snug when at room temperature.