My 2004 Z4 3.0i Modifications

[jonathancaddick1]

Hello all,

I thought I'd make a new thread to detail the changes I've made to my 2004 BMW Z4 3.0i (and future mods) to inspire anyone looking to make yours a little more original (better!).

So far I have done the following:

1) Painted brake calipers red
2) Installed Gaptech RHC+ (remote hood control)
3) Had the secondary cats removed and replaced with straight pipes
4) Wrapped the wing mirrors in carbon fibre vinyl (soon to be hydro-dipped instead)
5) Replaced standard air box with universal cone filter (attached to MAF with 3.5"-3" silicone reducer)

Future modifications:

1) Custom backbox (being installed 26-03-2016)
2) Custom re-map

I will attached some pictures of the work I've done so far. If anyone has any suggestions or questions just let me know!

 

[mr.tourette]

top work so far

 

[nfbr]

That intake needs sorting straight away, it's simply not big enough and could be severely restricting your engines breathing capabilities.
You shouldn't have to sleeve up in size between the airbox and the air mass meter. The opposite however would be perfectly acceptable.

Otherwise the car looks great!

 

[Flyingfifer]

That intake needs sorting straight away, it's simply not big enough and could be severely restricting your engines breathing capabilities.

+1

Could you possibly do a wee video of how the car sounds with the straight pipe replacement?
I am searching for the best configuration for the best sound!
Car's looking great

 

[jonathancaddick1]

That intake needs sorting straight away, it's simply not big enough and could be severely restricting your engines breathing capabilities.

+1

Could you possibly do a wee video of how the car sounds with the straight pipe replacement?
I am searching for the best configuration for the best sound!
Car's looking great

Thanks all for the comments so far. In terms of the decat, to be honest I slightly regret it only because it cost £200 at a local custom shop and the sound isn't actually that different to stock. I have linked a video I made a while ago of the sound from inside the cabin, I havent got any external shots yet!

The reason I regret it is because I would have rather put the money towards a custom back box for a more exciting sound. But I've decided to bite the bullet and go for a back box now anyway! Should be a good combination, I will post a video on the weekend.

https://www.youtube.com/watch?v=-yULBQm4IFI

 

[Flyingfifer]

That intake needs sorting straight away, it's simply not big enough and could be severely restricting your engines breathing capabilities.

+1

Could you possibly do a wee video of how the car sounds with the straight pipe replacement?
I am searching for the best configuration for the best sound!
Car's looking great

Thanks all for the comments so far. In terms of the decat, to be honest I slightly regret it only because it cost £200 at a local custom shop and the sound isn't actually that different to stock. I have linked a video I made a while ago of the sound from inside the cabin, I havent got any external shots yet!

The reason I regret it is because I would have rather put the money towards a custom back box for a more exciting sound. But I've decided to bite the bullet and go for a back box now anyway! Should be a good combination, I will post a video on the weekend.

https://www.youtube.com/watch?v=-yULBQm4IFI

Thanks for that, strangely enough I have already watched this while researching the different options! lol

If you're looking for something like that dude I would hold off, nfbr has his car at Scorpion this week for them to design a straight replacement cat back system for the car. Worth holding out to see what they come up with
LINK

 

[jonathancaddick1]

I have actually been watching that thread for a few months now and I'm sure it will be a great system, it looks very tempting, but for me I think it will be out of my budget. I've been quoted £245 for a custom backbox incl. fitting so I will try that out first!

 

[jonathancaddick1]

Update 27-03-2016

So yesterday I had the custom back box installed by MIJ Exhaust in Walsall. Unfortunately it is far too loud for my liking, I imagine having removed the secondary cats and have a sports back box which is practically a box with a perforated pipe running from front to back, makes it as loud as it is.

What's next?

I plan on installing a Magnaflow muffler in place of the secondary cats and keeping the new back box on the back. Hopefully this will lower the volume of the system but keep the crackles etc. Any thoughts/suggestions?

Here's the magnaflow muffler that is meant to fit:

http://www.ebay.co.uk/itm/261823128264?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Here's what it should sound like with the Magnaflow muffler:

https://www.youtube.com/watch?v=7lSJwp_Wb9I

 

[nfbr]

Pipe work diameter on that mangaflow silencer is too big.
From memory, the original pipe work before/after the secondary cats is 50mm/2inch.

You would need to step up before and step down after to run that silencer, which means 8 joins instead of 4 and also messing wi the Venturi effect decreasing the exhaust gas velocity as it enters the silencer then creasing a slight bottleneck after the exhaust silencer.

 

[rossonr]

I'm liking that. Especially the crackles

 

[jonathancaddick1]

Pipe work diameter on that mangaflow silencer is too big.
From memory, the original pipe work before/after the secondary cats is 50mm/2inch.

You would need to step up before and step down after to run that silencer, which means 8 joins instead of 4 and also messing wi the Venturi effect decreasing the exhaust gas velocity as it enters the silencer then creasing a slight bottleneck after the exhaust silencer.

Cheers for the advice, definitely don't want to go ahead if it's a different diameter, I'm sure I've read in a couple of places that its 2.25". I will try and borrow a jack to check them out for myself. Unless anyone has a 2004 Z4 3.0 that knows the exactly pipe diameter around the secondary cats?

Thanks.

 

[nfbr]

well worth double checking. I know the silencer bypass pipes I made for the 3.0si were a 50.5mm internal diameter and slipped over the existing pipe.

See here: http://www.z4-forum.com/forum/viewtopic.php?f=6&t=72036&start=167

From all the research I've done I've never seen anything mentioned about the 3.0i using a larger diameter pipe.

 

[jonathancaddick1]

Thanks for that nfbr.

Update 28-03-2016

So the latest update is replacing the chrome kidney grill trims with carbon fibre ones. Instead of spending £40+ on a new set of black ones, I simply removed my ones (to do this just slide them upwards and pull the lower half out first), removed the outer chrome trim and wrapped them in carbon fibre vinyl. I think they've turned out really well and compliment the wing mirrors!

 

[nb67]

Do the fins come away from the surround then Jon?

If so, how, as I may look at pasti-dipping my grey fins in black if I can take of the chrome surround.

 

[jonathancaddick1]

Do the fins come away from the surround then Jon?

If so, how, as I may look at pasti-dipping my grey fins in black if I can take of the chrome surround.

Yes the fins and the surround are 2 pieces, held together with 8 or so plastic clips. Just be careful when you bend the clips back as they are prone to snapping (I found out by snapping 1). Easy enough job though!

 

[jonathancaddick1]

Update 02-04-2016

Quick update on the exhaust project, today I took my Z4 to My Tyre, Leicester to have a Magnaflow 11385 centre oval muffler installed but unfortunately it would not fit in the tunnel where the secondary cats are located. This modification has been done on other Z4s but please note, I believe that earlier Z4s 3.0i such as my one must have less space in that tunnel!

My next step is going to be modifying the OEM backbox/rear muffler to remove the walls in between each cavity and install 2 2" perforated pipes (either mild or stainless steel) and then put all the wadding/sound insulation back in around these new pipes. My thoughts are the straight pipes will give me the sound and pops/bangs that I love on my current set up but hopefully get rid of the drone and 'boy racer-ness'!

If anyone has any suggestions or ideas on this or an alternative for me to try, I'm all ears! Here's a rough diagram of what I hope to achieve:

(PS: Also keeping an eye on the Scorpion system that is being developed but fear it will be out of my budget)

 

[Worcester_spoon]

(PS: Also keeping an eye on the Scorpion system that is being developed but fear it will be out of my budget)

It's also, I believe, for facelift 3.0Si onwards as the pre facelift 3.0 (like mine) has a different set up so this project won't fit.

I like the perforated idea and will likely so something similar on mine, but within the wadding put back