Z4 3.0 Track car build

Hey all,

Its been a busy few weeks on the car so I thought i'd provide an update. The last couple of bits have arrived so the fun part of fitting could finally start.

First up was the front end - Coilovers on and 330 front brakes fitted on just fine and gave no issues. Ride height set at maximum for now, will get this adjusted and corner weighted in the next couple of weeks when the geo its done.

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The brakes look much better now behind the wheel. Will upgrade the pads shortly and paint the callipers black again also (red would clash with the colour :rofl: )

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Next were the off-set lower arm bushes to provide more camber and my goodness they make a difference (though not so clear in the second pic)

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Whilst I was at the front end the poly engine and gearbox mounts also went in along with the E46 M3 Powerflex anti-roll bar bushes
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Next up was rear end, with the powerflex poly trailing arm bushes going in, followed by the shorter differential, adjustable camber arms and rear coilovers. Its looking much better under there and i'm also going to Dinitrol it all once the set-up is doing to keep it look great for a long time to come.

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Once that was all in I took it over for a nip around the block and was stoked at how well it drove - The diff especially is amazing! The poly mounts add a bit more vibration but thanks to the BC Racing coilovers and other aspects it feels super planted but not too uncomfortable on the road - a great result in my book and means i'll be inclined to use it more often. The extra angle on the front wheels means the steering feels even more responsive and there are no creaks or rattles at-all - most excellent!

Still a few more bits to do, namely the fitting of the 4 square 17" 8.5J set-up which is currently being powder coated black for a bit of extra swagger. They are then being wrapped in a new set of 255 profile RSR's to kill what little understeer there would be left. I'm also on the hunt for a pair of racing seats and harnesses which i'll fit when I take out the interior and change the diff oil and fitting a quality HID kit.

Its moving along nicely, I just need to give it a shake-down at Oulton Park as soon as possible to ensure all is set-up right for next month's trip to the 'Ring.

Cheers guys, all comments welcome.

o
 
Finally someone else who can feel the difference with mods, so many posts say rubbish like you'll never notice it on the road etc. I too immediately noticed an improvement with offset bushes, a strut brace also improves the steering if you haven't got one.

How are you going to get 255 in the front wheel arch as it doesn't usually fit 235 with lowering? I'd suggest a 245 for the rear, there's no need for a 255 with this much power. (A C63 runs 255 rear on the smaller wheels...)
 
Cheers - Yep it does feel better!

I'll look out for the strut brace and with the new camber the tyres seems to be fitting fine at the front (famous last words!) I like them as wide as possible but will consider going down a size if they start to pub,

o :)
 
Steve84N said:
Finally someone else who can feel the difference with mods, so many posts say rubbish like you'll never notice it on the road etc. I too immediately noticed an improvement with offset bushes, a strut brace also improves the steering if you haven't got one.

How are you going to get 255 in the front wheel arch as it doesn't usually fit 235 with lowering? I'd suggest a 245 for the rear, there's no need for a 255 with this much power. (A C63 runs 255 rear on the smaller wheels...)

It's tight but possible to run 255 up front. When really pushing, I've noticed a difference having slightly more grip up front!
 
Cheers Neil,

I've tried the 255 8.5 rears on and its all-good so i'm hopeful. Won;t go too crazy with the lowering and the camber adjustment that's now possible front & rear should hopefully help.

I've just ordered a stubby aerial, high quality HID kit and various HID bulbs to get it looking fresher. Have also had the new smaller 17" wheels powder coated gloss black and an going to colour match the front grills also. Calipers will be going gloss black at some point, too.

Have ordered an air scoop and looking at a cone filter also - Does anyone know the cone filter size i'd need?

Cheers all,

o :)
 
Disaster! (Well, a little bit..)

New 17" lightweight 8.5 wide 4 square wheels (That look awesome) and RSR Tyres too wide at the front and catching on strut - Needs 5mm so looking for some 10mm spacers and longer studs. Should I fit spacers all-round or would just the fronts be ok? I'm getting the geo done as soon as the wheels are on and sorted.

Cheers for the advice all :)

o

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Front increase in track only is good to reduce understeer.

What offset are the wheels? If it would be better visually I'd space the rear too but I wouldn't say it was necessary unless you find it has too much oversteer after doing just the front.

I think you're going to need some aggressive camber to avoid the front catching the arch liner by the reflector.
 
Surely a track car should always be function over form, no need to add spacers (and therefore extra unsprung weight) to the rear axle unless absolutely required. Looks should have no bearing.

Regards to front camber, I'd expect a track dedicated car to be running a heavy front camber anyway, around -3 degrees or so, so that wouldn't be an issue.
 
If Oalloyd is using the Z4M lollipops with increased castor, this has already added more camber under steering, so adding in a load of camber without checking tyre temp spread is a seriously bad idea.

Secondly spacers are another bad idea , especially on the front, the King Pin Inclination (KPI) of the front geometry is designed to put the steering centre point of the tyre as close to the middle of the tyre as is practical, a race car with custom built uprights will be designed so the KPI intersects the centre of the tyre contact patch for the size and diameter of the tyre used, road cars tend to have a scrub radius allowance as it's quite difficult to achieve with road going geometries, so adding spacer will increase the scrub radius with negative effect.

If your going to modify suspension it's a good idea to do a lot of research first , just buying bits and bolting them on is a bad idea and can lead to dodgy handling and odd handling quirks.

For a total novice a good starting point is Alan Staniforths Race Car Suspension book.
 
Hey all, and here she is!

I think the black 17's suit it well and it will look better still with the front grill inners painted.

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Front spacers on and rear ones on order for balance - Agreed they are not strictly needed i'd like them on none-the-less as wider track means a bit more grip and it will look more balanced. Bodger I take your point ref set-up but this is the only way we could find to get arch clearance, lower it, get camber and package the 255 tyres. Its now with a well known BMW specialist to get the full geo set-up completed as well as a second-opinion spanner check on all the areas that have been enhanced for extra piece of mind. Corner weighting would also be a good shout.

Cheers all and next up is interior removal, new seats, fitting of induction aspects and the HID kit - Can't wait!

o :)
 
Just about to go and pick her up from the BMW specialist having had a spanner check and suspension set-up / alignment - Looking forward to a fun drive home but also keen to get it on the track asap to give it a proper shake-down.

Wish me luck!

o :)
 
Hi all,

Its been a busy few weeks with the car to say the least.

I got some 12mm Eibach spacers and extended studs for the front to help clearance and all is now well, even in extreme cornering. The sticky 255's also have the added benefit of looking just slightly awesome :D :thumbsup:
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Its been back in the workshop to get the interior stripped and a few other mods done.

Here it is getting its CDV deleted - This has ade changes feel much better already and should help preserve the clutch on track
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Front grills painted black and M badges removed - far cleaner now :thumbsup:
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Remap in and has made throttle response sweeter and the new panel filter has added some extra rasp. The intake duct is going in this week as are the harnesses and race seat.

Its virtually all done now, all there is to do is drive it - 'Ring departure is in 2 weeks time, can't wait!

o
 
Just ordered some soft white LED bulbs for the interior and planning on throwing out the reverse alarm module - It's huge!!!

o :)
 
I hate this thread. I track mine, and now realise how many more mods I need to make. Can someone give Westminster a call and ask them to shake the magic tree in my direction please! Ta. :thumbsup:


Seriously though, great thread!
 
A very interesting read, I also track mine.

I'm going to give the offset bushes a go first as I'm struggling with under steer mid corner!

Adam
 
Cheers guys,

Off-set bushes feel free, car feels so much more planted in corners and with the wider tyres I doubt i'll ever find out what understeer is like in a Z4....

o :)
 
Hey all,

Interior now coming out - So many pieces, its like a massive jigsaw!
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Looking good now stripped - i'm putting back in a race seat (obvs) as well as black door cards and a black centre console to house switches etc. Will post up more pics soon!

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o :)
 
Hey all,

Wheels have been sold so I have a couple of pennies to get the now-bare floor painted in Raptor for a non-slip and high wear resistance finish - Will send you pictures once it's in. In other news, today the Pagid discs and DS25000 pads went on along with some 12mm Eibach rear spacers to get it looking nice and even stance-wise - Will post up pics also.

Cheers and comments welcome,

o
 
oalloyd1 said:
Hey all,

Interior now coming out - So many pieces, its like a massive jigsaw!
IMG_4844.jpg

Looking good now stripped - i'm putting back in a race seat (obvs) as well as black door cards and a black centre console to house switches etc. Will post up more pics soon!

IMG_4845.jpg

o :)

Surely you don't need door cards in a track car?
 
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