Liam's Z4C race car project

Joycey · Post by **Joycey** » Thu Sep 05, 2019 11:34 pm

Enjoyed reading that, really capable cars these coupes. The handling really surprises a lot of bigger cars on track. Did near on 15 track days in my coupe with nothing to fault other than eating pads.

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adam1985 · Post by **adam1985** » Fri Sep 06, 2019 9:00 am

Liam22 wrote: ↑Thu Sep 05, 2019 9:54 pm Why 2 towing eyes? The MSA strongly recommend having a pair front and rear. So seems sensible to follow that advice on a new build, especially as it might become mandatory in the future.

But yeah, 650g for all 4... that hurts. Although the bonnet pins saved 1.6kg so I'm still winning.

Plus by the look of it weight saving from removing the headlight washers

Liam22 · Post by **Liam22** » Fri Sep 06, 2019 2:53 pm

Joycey wrote: ↑Thu Sep 05, 2019 11:34 pm Did near on 15 track days in my coupe with nothing to fault other than eating pads.

It does seem heavy on rear pads. Chewed through a set of Ferodo DS2500 in a couple of hundred miles. About to switch to Pagid RS29 in the hope they will last a season.

adam1985 wrote: ↑Fri Sep 06, 2019 9:00 am Plus by the look of it weight saving from removing the headlight washers

Headlamp washers: 675g (the covers will get glued back on)
Front number plate: 480g
Fog lamps: 1.5kg

The list goes on...

JamieZ4C · Post by **JamieZ4C** » Fri Sep 06, 2019 4:21 pm

Love seeing the progress of this project.

If I did something like this, I think I'd become absolutely obsessed with finding ways of losing weight! Stay away from the drill and angle grinder, Jamie

Liam22 · Post by **Liam22** » Sat Sep 07, 2019 11:07 pm

JamieZ4C wrote: ↑Fri Sep 06, 2019 4:21 pm Stay away from the drill and angle grinder, Jamie

Funny you should say that...

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Boom! 13kg

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MrPT · Post by **MrPT** » Sat Sep 07, 2019 11:26 pm

Awesome. How much did that lot weigh when it came out?!

Are you keeping that right hand portion so you can still run a 3-point belt, or was that just a work-in-progress shot?

lucasxdiniz · Post by **lucasxdiniz** » Sat Sep 07, 2019 11:26 pm

Liam22 wrote: ↑Sat Sep 07, 2019 11:07 pm
JamieZ4C wrote: ↑Fri Sep 06, 2019 4:21 pm Stay away from the drill and angle grinder, Jamie
Funny you should say that...

20190901_172554.jpg

Boom! 13kg

20190901_183530.jpg

I bet people have suggested a CFRP roof panel already for some weight saving. They claim weight ~2kg, so if the design is very similar to the stock one, it should save 4kg from the highest point of the car.

https://www.geoffsteel.co.uk/shop/bmw-e86-z4-roof-skin/

Liam22 · Post by **Liam22** » Sun Sep 08, 2019 5:48 pm

The Geoff Steel c/f roof is on the shopping list. As much as anything, to offset the roll cage up there.

The last photo is a work in progress shot. The driver's side section is trickier, with electrical cables and the fuel filler passing through it. Based on what has already come out, the weight saving should be an easy 13kg.

Vanne · Post by **Vanne** » Mon Sep 09, 2019 2:33 pm

thx for the pics Liam, car is in the shop having similar done atm. though I am keeping part of the bulkhead. the weight of the cage is really worrying me. The easiest way to make a good car even better is making it lighter, and then adding 25kgs for a cage.. kinda defeats the whole purpose of stripping it out. really has me very worried.

Newbers · Post by **Newbers** » Wed Sep 18, 2019 10:02 pm

Good work Liam - thanks for sharing!

Liam22 · Post by **Liam22** » Wed Sep 25, 2019 11:04 pm

Progress has been very slow recently but I did find the time to complete the bulkhead removal this week. The drivers side was considerably more difficult than the passenger side.

First needed to disconnect all of the rear wiring loom: lamps, tailgate gubbins, number plate lights, N/S/R ABS sensor, charcoal canister and fuel cap release (after removing wheelarch liner).

Then some careful cuts around the protection for the fuel tank breather hose.

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Altogether, it's added up to 13.1kg

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Tried my best to tidy up the cuts, minimize the raised surfaces and generally make it presentable. Once the roll cage goes in (soon, I hope!), the interior will be painted, at which point it will look a lot better.

Liam22 · Post by **Liam22** » Sun Sep 29, 2019 9:31 pm

Got a few jobs done this weekend while waiting for roll cage install.

Started by fitting cooling ducts for the front brake discs. I will run hoses to these from the front bumper so that cold air is blown into the centre of the vents.

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With the discs off I also took the opportunity to thoroughly clean the hub threads so that I could fit wheel studs. The wheel bolts are a real pain when swapping wheels frequently.

Here are the first few going in.

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Then to the rear. Changed the pads for Pagid RS29 after running one down to the metal on the way back from the 'Ring. The disc was fine - very light scoring and fine to run again, but I'm glad I looked carefully because one of the discs had a nasty crack.

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Its actually worse on the inside. This is disappointing. I've run Pagid OEM discs for racing previously but seriously considering changing for Brembo now. I think the top hat depth introduces a weakness here.

But the rears have been super hot. All of the friction material on the handbrake shoes has disintegrated! I removed it all, including the backing plates (2kg). This might help to keep the brakes cool, so I might give the Pagid discs one more shot.

Finally, I mustered the enthusiasm to remove the aircon compressor. Removed the drive belt and thermostat (which is why I've been putting it off). Three hard-to-reach aluminium bolts into later and it cleared the coolant hoses without needing anything else removing. 5.5kg though... so worth it!

Will need to measure up for a suitable length drive belt, and I'll replace the tensioner while I'm at it.

terryo · Post by **terryo** » Sun Sep 29, 2019 10:30 pm

our local FIA body has let us all know that using factory lamps as rain lamps on race cars is no longer acceptable. They have mandated a specific design and we all now have to fit a central LED lamp, with a switch option to make it flash. This may or may-not be of any interest to you but i thought i'd let you know given you have modified the car to get a 'rain-light" effect.

Liam22 · Post by **Liam22** » Sun Sep 29, 2019 10:58 pm

Thanks terryo. Motorsport UK still permit factory fogs:

5.1. A rearward facing red warning light of a minimum of 21 watts, with surface area minimum 20cm2, maximum 40cm2, or of 21 watts with a surface area minimum of 50cm2 and with lens and reflector to EU Standards, must be located within 10cm of the centre line of the vehicle and be clearly visible from the rear.

Vehicles fitted with full width bodywork may alternatively use two lights equally located about the vehicle centre line.

Mantazini · Post by **Mantazini** » Wed Oct 02, 2019 9:54 pm

Fantastic thread OP ... Keep up the good work and dont forget to share the pics

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