Liam's Z4C race car project

2003 - 2009, roadster, coupe, facelift
Post Reply
User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Fri Mar 01, 2019 7:23 pm

Forgot to mention... new control arm bushes have saved 100g

Winning!

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Sat Mar 09, 2019 10:30 pm

Got a few more hours on the car today.

Removed the bracing at the rear of the car, heat shields, exhaust, and propshaft. Then set about the rear-left corner: brakes, damper, ARB, inboard wishbone bolts, and driveshaft. Unlike the rear-right wishbones, the inboard bolts cannot be removed with the diff in-situ.
20190309_160917_HDR.jpg
20190309_160917_HDR.jpg (247.84 KiB) Viewed 566 times
The handbrake system is a complete pain in the arse. Is it possible to disconnect the handbrake from inside the car? I'm very tempted to delete the whole thing, but still planning to drive it to the Nurburgring, so that may be unwise.

With the handbrake cables finally detached, the subframe came away surprisingly easily. I kept the diff attached, lowered the whole thing on a jack, and separated the diff once on the floor.
20190309_180647_HDR.jpg
20190309_180647_HDR.jpg (270.35 KiB) Viewed 565 times
So now I've just got the job of replacing all of the rear bushes before putting it back together again!

User avatar
Jembo
Lifer
Lifer
Posts: 5296
Joined: Sat Jun 25, 2011 11:59 pm
Location: Kent

Liam's Z4C race car project

Post by Jembo » Sun Mar 10, 2019 12:23 am

Keep going fella, don’t forget the GoPro mount(s)
The dark side with a ///M Hell Bronze Sepang Coupe :happyclap:
Ex Aug 2005 Maldives Blue 3 litre cruizer, lots of toyz,

Lifer 54
Image

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Sun Mar 10, 2019 11:30 pm

Got started on bush extraction this afternoon. Quickly realised that my hydraulic press won't be much use.

This is my technique. Cut out the rubber centre, then cut 2 slots in the outer shell with a hacksaw. Drift out the slot and the rest falls out wirhout much effort.

Rear trailing arm front bush:
20190310_170728_HDR.jpg
20190310_170728_HDR.jpg (200.55 KiB) Viewed 523 times
Upper wishbbone inboard bush:
20190310_180755_HDR.jpg
20190310_180755_HDR.jpg (207.62 KiB) Viewed 523 times

User avatar
Davz
Member
Member
Posts: 315
Joined: Mon Jul 10, 2017 8:35 pm
Location: Wellington, Shropshire

Liam's Z4C race car project

Post by Davz » Tue Mar 12, 2019 12:24 am

Liam22 wrote:
Tue Feb 26, 2019 10:37 pm
I won't make any friends saying this, but the suspension design is disappointingly archaic. It's only half a step forwards from my 1989 E30. Especially when compared to the RX8, which has double, unequal length wishbones up front, and proper 5 link setup at the rear. All fully adjustable from the factory. Looks like it's going to be difficult to adjust the rear wheel alignment at home (without a ramp).
You will also miss the torque sensing LSD and light Carbon propshaft of the RX8.
I will be amazed if you get a Zed to handle as well as an RX8, the ride and handling is the most disappointing element of a Zed. Couldn't you have upped the power of the RX8 or was that not allowed in the race series?

Interested to know when you lower it on coilovers, how low you are taking it and what effect this has on the ARB's and if you will need to fit shortened ARB links.

Keep adding pics, this is most interesting.
2006 2.5, orange led footwell lights, Blue led boot lights, 20/15mm wheel spacers, Buckley06 stainless gear knob, Aux, MV2's, M-sport pedals, Eibachs, Bilstein B4's, Whiteline arb's. Roof motor relocated.

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Tue Mar 12, 2019 10:07 am

Good points Davz. In reality the BMW thin aluminium tube propshaft doesn't feel much heavier than the Mazda carbon fibre resin item. I'm going to see how I get on with the open diff but plan to put a Kaaz 1.5-way LSD in the case sooner rather than later.

I'll keep an eye on the front control arm angle as I lower the car and try to stay close to parallel with the road. I'll only buy new drop links when it's all fitted up.

Just bought a set of pullers for removing the rear subframe/diff bushes. The subframe is in decent condition but it'll get a couple of coats of POR15 before going back on the car.

What I could really do with is a guide on assembling the handbrake shoes. I used to be a master on the E30 drum brakes but these little handbrake shoes are fiddly!

JDavis21
Member
Member
Posts: 81
Joined: Tue Jan 15, 2019 1:45 pm
Location: Cambridge

Liam's Z4C race car project

Post by JDavis21 » Tue Mar 12, 2019 10:24 am

Liam22 wrote:
Tue Mar 12, 2019 10:07 am
I'm going to see how I get on with the open diff but plan to put a Kaaz 1.5-way LSD in the case sooner rather than later.
I was already getting frustrated by the open diff after the one track day in mine! Have you looked at the option of getting an E36 LSD built for it with a shorter final drive? From my experience, that or a Gripper will be the most available and serviceable option :thumbsup:
Image

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Tue Mar 12, 2019 10:58 am

Kaaz DBW3020 should drop straight in with the 3.46 FD. That seems reasonably short and should see 145mph at the redline in 5th. Are shorter FDs available?

JDavis21
Member
Member
Posts: 81
Joined: Tue Jan 15, 2019 1:45 pm
Location: Cambridge

Liam's Z4C race car project

Post by JDavis21 » Tue Mar 12, 2019 1:44 pm

Liam22 wrote:
Tue Mar 12, 2019 10:58 am
Kaaz DBW3020 should drop straight in with the 3.46 FD. That seems reasonably short and should see 145mph at the redline in 5th. Are shorter FDs available?
There's quite a range available, 3.64, 3.85, 3.91 and 4.10 all seem quite common. Lots of E46 M3's run them built by JC Racing, with varying numbers of friction plates built to the specific use. All 188 sized (E36 EVO) so they fit in our diff casings too.

I'll be at Snetterton on 30th March with two M3's, one with a 4 plate 3.91, the other with a 6 plate 3.85, feel free to pop along for a few passenger laps so you can feel how they behave if you want! The guys I'm with know a thing or two about setting up BMW's, so may be worthwhile your time even for a chat :thumbsup:

A 3.85 would take you to 156 at 7000rpm in 6th, which even at Spa you may struggle to hit. The E46 M3's can get away with 4.10's due to the extra RPM's available.

Would you not also be stung with import tax on the Kaaz? I'd personally rather have something that I know spares are available in the country for etc.
Image

User avatar
MrPT
Lifer
Lifer
Posts: 4037
Joined: Sun Oct 21, 2012 7:44 pm
Location: Bucks/Oxon

Liam's Z4C race car project

Post by MrPT » Tue Mar 12, 2019 2:24 pm

Please keep disassembling stuff and taking photos. Enjoying this. :) :popcorn:

What's the thinking behind improved braking feel and the eccentric lollipops? Or did you mean that switching to poly will give you less deflection under braking?
2008 Z4MC: SG/Imola|+OEM CSLs|+KWv3|+TMS RTABLs|+VT mounts|+Eventuri|+OEM strut brace|+DB9 front BBK|+cruise
2006 Z4 2.5si: gone

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Tue Mar 12, 2019 2:47 pm

JDavis21 wrote:
Tue Mar 12, 2019 1:44 pm
I'll be at Snetterton on 30th March with two M3's, one with a 4 plate 3.91, the other with a 6 plate 3.85, feel free to pop along for a few passenger laps so you can feel how they behave if you want! The guys I'm with know a thing or two about setting up BMW's, so may be worthwhile your time even for a chat :thumbsup:
Cool. If I can get the car back on its wheels, and Javelin get a cancellation, then I will try to get along.

Regarding FD ratios, 3.46 looks pretty good to me. That's partly why I want to try the open diff before making big decisions about LSD. Let's see what it's pulling at the end of the Bentley straight. And I know the UK Kaaz importer, so it's the most cost effective way into an LSD for me.

JDavis21
Member
Member
Posts: 81
Joined: Tue Jan 15, 2019 1:45 pm
Location: Cambridge

Liam's Z4C race car project

Post by JDavis21 » Tue Mar 12, 2019 3:18 pm

Liam22 wrote:
Tue Mar 12, 2019 2:47 pm
Cool. If I can get the car back on its wheels, and Javelin get a cancellation, then I will try to get along.

Regarding FD ratios, 3.46 looks pretty good to me. That's partly why I want to try the open diff before making big decisions about LSD. Let's see what it's pulling at the end of the Bentley straight. And I know the UK Kaaz importer, so it's the most cost effective way into an LSD for me.
That's a quick turnaround if you do!

And that explains the push towards a Kaaz then, handy to know.

What tyres and suspension are you looking at running?
Image

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Wed Mar 13, 2019 3:17 pm

I'll be running Gaz monotube dampers. Same spec as on the 330 Challenge cars with spring rates from the ZCars series to get me started.

Tyres Federal 595RSR to start with, as again, I know them well from the RX8 which will give me a good baseline.

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Wed Mar 13, 2019 3:20 pm

The only thing better than receiving new parts is receiving new tools!

Looks like this kit will make light work of the subframe/diff bushes. I gave it a quick test on the upper wishbone inboard ball joint.
20190313_133058_HDR.jpg
20190313_133058_HDR.jpg (259 KiB) Viewed 392 times
20190313_133251_HDR.jpg
20190313_133251_HDR.jpg (178.78 KiB) Viewed 392 times
20190313_133503_HDR.jpg
20190313_133503_HDR.jpg (197.03 KiB) Viewed 392 times

User avatar
Liam22
Member
Member
Posts: 136
Joined: Thu Dec 06, 2018 2:28 pm
Location: Herts/Cambs

Liam's Z4C race car project

Post by Liam22 » Fri Mar 15, 2019 1:08 pm

It's amazing how quickly you can go with the right tools. I think I'm at the point of maximum disassembly now.

Only when I got to the last subframe bush had I perfected the spacing of the sleeve and how long to heat the rubber for.
20190315_114347_HDR.jpg
20190315_114347_HDR.jpg (222.82 KiB) Viewed 353 times
20190315_114656_HDR.jpg
20190315_114656_HDR.jpg (221.42 KiB) Viewed 353 times
In general the old bushes were in good shape.
20190315_115446_HDR.jpg
20190315_115446_HDR.jpg (267.51 KiB) Viewed 353 times
Subframe is now empty and has been attacked with a sanding wheel. I'll put a wire wheel over it now the bushes are out and then paint.
20190315_115553_HDR.jpg
20190315_115553_HDR.jpg (232.79 KiB) Viewed 353 times

Post Reply