3.0si custom exhaust fitted on friday

Cool - I'll be there before you go.

As an aside do you seriously expect them to go buy a new OEM system and fit it back on, or somehow weld up the bits of your old one and refit it?

Nargh - just let them do their work and if the result is no good then and only then consider a return to OEM.
 
Bugger.

This is the problem with mods, everyone is a guinea pig, and chances are this company have no 3.0Si development car to try these things out on, so you are the piggy :)

Output differences are hard to gauge, a quieter exhaust can make a car 'feel' slower, or faster, or a bit of both... a performance gauge like a g-tech or vBox before/after is usually a good way to make you realise there is no real difference despite you thinking so.

Tough one now is that you didn't take a reference measurement as standard before modding, so no matter what they do now you may still end up down on power or torque etc and not realise :(


Good luck with it though! This is yet more proof BMW have a good damn idea already, and to improve it takes time and testing, not just sticking on new boxes and pipes and calling it a job well done :(

Dave
 
If you look at the system fitted to the 'M' cars by BMW it looks restricted. Squared off pipes from the cats, a tiny resonator box then two heavy restricted back boxes. BMW have to fit a system that is 'civilised' and yet has a 'sporty' exhaust note under acceleration. They don't have maximum power as their main criteria for design.

Some of us want more noise and accept that there will be more drone at certain revs. My through flow system was fitted by Longlife Exhausts in Leeds and at the time I was thinking of using MIJ who are a similar set up. The exhaust seems to give the car a little more power especially when the sport button is engaged. It certainly has made 'sport' mode very usable and much better than as stock. But in the end I wouldn't be surprised if I'd lost a few BHP by fitting it. I like the more sporty sound and it weighs a lot less than the stock set up.
 
I agree that BMW exhaust systems are very heavy - an aftermarket one could be 30kg lighter than the BMW one. Although I guess the aftermarket one won't be double-skinned. I'd have no problem going to an aftermarket exhaust (preferably in titanium) when my BMW exhaust fails as I don't fancy paying BMW prices for a new system.

I did have an aftermarket one on the M5 at one time and it probably saved more than 30kg as it had no cats and no silencers - but it sounded like it had 1000bhp and I couldn't do a track day with it unless it was a rare unsilenced event :P
 
Met Chilz4 in the shop and he's being sorted out right now. They admitted to a screw up over the weekend, but seem to be on the case for him

Left mine for the day as it's a 5 hour job all-in. Seem to be very confident in their work and what they will be able to do with the prep I've done.
Interestingly they actually wanted to run single pipe for a section as removing the kidney balancer it really needs a balancer, but they'll work around that.

One option they are considering is to remove the cats, leaving just the precats. Thye say it won't fail MOT's as the pre cat can take care of that if the engine is warm and no lambda /engine lights as they are all precat.

OK so it will make more BHP I guess but will it make more noise?? What do we think??

Back on line later once I get changed through B'ham station :thumbsup:
 
If you're taking away one of the cats, it'll be louder, no doubt. Doesn't the Z4 have foam in part of the standard exhaust to make it quieter?
 
Quick change of train and here we are online already?

OK so makes sense that it will make more noise, which is not what I want really.
Never heard of foam in an exhaust, but I' open to learning? Some foam in the sound generator on the intake side of things?
 
As long as you've got a resonated exhaust, then it'll be as quiet as you're going to get it.

And yes, you've got it; it's a bit of foam in the sound generator, from what I've read. I'm by no means an expert though, since I currently drive an Astra VXR! :lol:
 
IK. said:
And yes, you've got it; it's a bit of foam in the sound generator, from what I've read. I'm by no means an expert though, since I currently drive an Astra VXR! :lol:
Click to expand...
Foam plugs are present in the sound generator tube which runs into the passenger compartment through the firewall. Purpose is to increase the intake/engine sound to heighten the "ultimate driving experience." Sound generator tube usually comes with two foam plugs which can be removed in all or part to adjust sound level to driver's preference.
 
Incompatible said:
IK. said:
And yes, you've got it; it's a bit of foam in the sound generator, from what I've read. I'm by no means an expert though, since I currently drive an Astra VXR! :lol:
Click to expand...
Foam plugs are present in the sound generator tube which runs into the passenger compartment through the firewall. Purpose is to increase the intake/engine sound to heighten the "ultimate driving experience." Sound generator tube usually comes with two foam plugs which can be removed in all or part to adjust sound level to driver's preference.
Click to expand...

Well aware of this :) I have it already as standard on the 3.0i. When talking about noise, cats, etc. IK suddenly referenced foam in the exhaust :?
 
The exhaust has been completly overhauled and now I am alot happier, its sounds amazing and pops and crackles when you lift off. Only issue is its to droney when cruising so will get that looked at this saturday. Despite the innitial setback I am very happy with MIJ!
 
ChillZ4 said:
The exhaust has been completly overhauled and now I am alot happier, its sounds amazing and pops and crackles when you lift off. Only issue is its to droney when cruising so will get that looked at this saturday. Despite the innitial setback I am very happy with MIJ!
Click to expand...

That's great. The boss ran me to the station after I left and had given a bit of grief to the person who built your first system as he knew even from a phone call that it could not work. Reckoned it would strangle it. Said he knew exactly what was needed to fix it, so sounds like he did :thumbsup:

Hopefully mine wil be finished this afternoon and will see and collect it in the morning :)
 
Yeah, the exhaust will start to sound different after a while, basically the inside of the backbox / pipe start to fill with the soot if you like...
 
t20lau said:
Yeah, the exhaust will start to sound different after a while, basically the inside of the backbox / pipe start to fill with the soot if you like...
Click to expand...

It's basically a seasoning effect like you get when you cook with a wok. if you rap a metal spoon against a new wok it will make a ting, if you do that to a wok that's seen plenty of action you'll get a dull dunk.

However, the drone may simply appear to be diminished as you get used to it.
 
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