Liam's Z4C race car project

[Liam22]

Forgot to mention that the fuel tank needs to come out before fitting the roll cage, which was a minor pain in the arse.

 

[Vanne]

Nice progress Liam. mate noticed straight away your charcoal canister is in a way different position than mine. mine was dead center in between the rear pipes. Lovely updates, cant wait to see how custom cages get on with your install. I nearly bought their pre-fabbed cage, but found it was more than I needed for what I am doing with the car. The price is spot on though. when is it back?

(as a side note: glad to see that you removed the tank, I didn't, and nearly lost my car (not that I really care about the car), but the guy welding wouldent have been going to well after either, let alone the shop if the thing would have gone up. ) :thumbsdown:

 

[Dubbedown]

Great thread, didnt get chance to read through every page but if you haven't done so already, you should consider welding reinforcement plates by the front sway mounting studs.

Also not sure what brakes you're running but the factory e90 335i caliper bolts up directly and pairs well with the Z4M rotors. Cheap "factory" bbk option. Then just run a slightly more aggressive pad in the rear to even out the bias.

 

[Liam22]

Thanks Vanne. My roll cage guy won't touch a car with a plastic fuel tank, even though there is a decent "airgap" with the Z4. The RHS RTAB bush needs to be disconnected so that the fuel filler neck can escape.

you should consider welding reinforcement plates by the front sway mounting studs.

Can you elaborate? This is not a weakness I have come across.

Also not sure what brakes you're running but the factory e90 335i caliper bolts up directly and pairs well with the Z4M rotors. Cheap "factory" bbk option. Then just run a slightly more aggressive pad in the rear to even out the bias.

Good tip, thanks. I'm running 17" wheels so the 325mm discs are about the max. If I upgrade the calipers it will be to 4-pots but I was happy enough with the braking performance on the limited track use it has had so far.

 

[Wursle]

Hello Mate, if you dont mind me asking how much did the cage cost to buy and get fitted? im undecided on whether to go full or half cage. after seeeing the weight savings youve made i tempted to throw everything in the bin :rofl:

 

[Dubbedown]

Few of us who track regularly had this issue but its more likely scenario when running high spring rates or thicker front sway

https://www.zpost.com/forums/showthread.php?t=707425

 

[Liam22]

Thanks for the link. I have 27mm front ARB (E46 M3 cab) and 90A poly bushes. However, I fail to see how spring rates have any bearing on the load put on the ARB bush mounts. I will have a think about my options. Thanks again for the heads up.

 

[Vanne]

hey mate, just noticed your proper rear coil overs.. what springs (size and rate) are you running on the back? I had a hell of a time estimating the spring (uncompressed) length.

 

[Liam22]

If you zoom in on the last photo you will see that the rear springs are massively dislocated at full droop. Haven't got round to figuring out what length v2 will be.

 

[Vanne]

Yep, saw that. What size (uncompressed length) are the MK 1's?

 

[Vanne]

Any updates Liam, do you have an ETA for the car to be back?

 

[Liam22]

My roll cage guy can't be rushed. It'll be ready when it's ready!

It's all tacked in place. Final welding should be done in the next few days.

 

[Newbers]

No going back now....

 

[Vanne]

Looks pretty darn nice mate.
cant wait to see the cage finsihed. Looks like your whole car is coming together very nicely..
i gotta ask mate, are you staying with the oem electric steering? or swapping to the Z4m hydrolic? or complete steering box swap?

The only reason i ask mate, is cos the Oem electric is pretty rubish.

nice build mate, cant wait to see more of it. :wub:

 

[Liam22]

Yup, I'm gonna stick with the EPAS. It is s**t on the road, but since refreshing the front suspension it's actually only half bad. On track it's ok.

I was all set on replacing it but as it is the lightest option I'm gonna stick with it.

 

[NeilP]

So envious of this build! Great progress so far!

 

[Vanne]

Hows it going Liam, any headway mate?

 

[Tamir]

How's it coming along nowadays Liam?
Looking great so far even though there's no way back as it seems

 

[Liam22]

I was going to post an update today anyway, but thanks for the prompt!

Picked up the car from the roll cage fitter on Thursday. This is the basic Custom Cages 6-point weld in cage, designed for the roadster but fits the coupe just fine. Ridiculously expensive for what it is, but cheaper than a bespoke cage.

I added a few upgrades for stiffness and safety:

• Diagonal across the main hoop (behind the seats)
• Harness bar / rear strut brace (another benefit of removing the false bulkhead)
• Tie-in points on the A-pillar and upper windscreen area

The other custom work was to create a secure frame to mount the seat onto. So we have two lateral tubes welded into the body, and longitudinal mounting brackets with adjustments.



Got it home, cleaned the interior and took it straight to the paint shop. I chose a light grey from the RAL colour chart. The end result is a little lighter than I wanted, but it's OK.




It's great to have it back, but there's a ton of work to do putting everything back together.

 

[MrPT]

:wub: