BMW Z4 Coupe Track Toy Build

[Wursle]

Hello All,

Been meaning to do this for a while mostly for my own records (PC Hard drive recently failed and spooked me) so thought i'd post my project build here for everyone to see.

The car I have been building for the past 3.5 years has been a BMW Z4 Coupe 3.0Si.

The purchase of the car was really out of the blue, me and my dad used to go up to BCA @ Blackbush just to see what was about when we stumbled across a Z4 Coupe 3.0Si in Deep Green that I later found out was 1 of 23 in this colour. I originally thought the car was black until it rolled into the auction floor under better lighting and could see it was green. put in a bid in an empty auction hall and BOOM just bought a Z4 Coupe.

Signed all the documents etc etc and went to look at my new car!


On first inspection this was 100% a heart purchase and not a head purchase, off the top of my head i can remember there was a broken valve cover bolt, front bumper was hanging off due to the clips on either side breaking (common problem), small amount of oil around the oil filter housing (seal had gone) and just a few little niggly bits that needed attention. If i am honest I was so over joyed that I bought this car all of these things went way over my head as I was just looking at my new piece of Gucci machinery.

Taking it for its first drive everything drove straight and the car handled really well, they drive in such a nice manner you have to steer it on the throttle its hard to explain.

My initial plans for the car was to make it capable on trackdays but also be commutable in. The car later develops into basically a road legal racecar but hey we'll get there

Car back at home:







First things first I got a mechanic mate to look over the car underneath and see what really need doing in addition to the things mentioned above.

We gave the car a full service oil, plugs filters etc. my mechanic mate got the bolt out of the head without needing to helicoil (Result!) and the oil leak was fixed. one gremlin that I did not suspect to be so bad was the brake lines throughout the whole car, this thing was lethal and thank god I didnt take it on track before getting those inspected / replaced.

so with all of that sorted it was time to just enjoy the car and start ordering parts to make it a bit more suitable for track. As many have reported before the first thing this car needs above all else is an LSD, it completely transforms pretty much any car but in the Z4 Coupe it changes the car completely.

Pictures of the car without runflats and just out for a burn in the forest.



First big purchase for the car was a Quaife differential along with just about every polybush available for the car



Following this I decided to ditch the MV2's and move to some Style 108 wheels



Gave the Headlights a good clean / sand and polish. not the best but also not bad for £10
Before


After



With a ring trip incoming and very little time to spare it was time to get the LSD in an all of the bushings replaced. I also managed to source some E46 M3 front brake discs & calipers + some adapted carriers

This section will be quite picture heavy so bare with me

Brakes on and topped up with Motul600



Diff out of the subframe




Picture of the old open diff



Circlips I never want to see you again.




Loctiting the new LSD bolts in place






With all of this put back together it was time to start prepping for my first Ring trip in the Z4. I really didnt know what to expect out of it performance wise but the car was going to the ring with the follow:

Quaife differential
E46 M3 Discs with DS2500 pads
Standard suspension except polybushes
Federal 595 RSR tyres in OEM specs

all packed and ready to go the Z4 was abit of a squeeze with all the stuff



Parked up ready to head off with a group of friends all in different cars.



Arriving at the ring hungry and needing a drink we sat down at Pinoccios for a cold pint and Pizza, track time had to wait for the following day as we were knackered.



At the Hotel


I think the most amazing thing about the ring isnt just the racetrack but the scenery around the area!




Over the trip the car performed flawlessly except for the brakes, the pad were burning up after a lap so managed to pick some up locally and went for some Hawk DTC-60. once the new brakes were in I was able to achieve an 8:38 BTG



After coming back from the ring I saw the potential the car had and decided to commit to the project. i swapped back to the MV2's and sold the Style 108's as the MV2's were slightly stronger and wouldnt corrode as bad over the winter months.

I also made a horrible decision (influenced by VLN Cars) to yellow tint the headlights... please forgive me for this for I have sinned hahaha



Another purchase in the form of a TTV lightweight flywheel



The MV2's simply werent cutting it and I wanted to go down to 17's for the cheaper tyres so went ahead and picked up some Style 32's in dire need of a refurb



My Birthday was coming up and my Girlfriend only went and outdone herself! BC Coilovers 7kg/8kg with Powerflex rear camber arms!



Coilovers fitted along with camber arms, this made the car so much more planted again another brilliant change for the Z4. Every time I change something on this car i am always impressed with it. every change is noticeable in a good way. another really good modification I have not mentioned is the E46 M3 cabriolet front anti roll bar that really tightened up the front end.




Style 32's after a home refurb in Satin black along with front grills done in satin black




Also chucked on a stud conversion with the Style 32's to make them easier to mount.The style 32's were wrapped in AD08R's





With the car now driving much better and also looking quite aggressive I cam across another hurdle that I didnt really consider the price of at the time. The E46 M3 brake discs are sooooooo expensive compared with the standard ones I decided to swap back to the standard discs/calipers. The e86 3.0si comes with 325mm front discs which is the same size as the E46 M3, the only difference is the thickness of the discs and price. when going back to the original discs I managed to get a set of brand new brembo discs all round for £120 quid including some Ditchfinder3000 pads to smoke about on for my daily commute. I then proceeded to purchase so Hawk DTC-60 pads allround from the states and again was really impressed with the quality of stopping power they provided.

Picture of the E46 M3 Convertible front anti roll bar compared to the original.
|https://thumbsnap.com/BKAgvqX6[/url]

After having so much luck and endless fun in the car I was bound to trip up at some point. The car started to develop the most unusual issue where it would not stop snapping auxiliary belts. there was not pattern, no set amount of time before one would explode, replaced tensioner 3 times all for no luck. this went on for months and months and was leaving me stranded more times than I can remember. took it to multiple garages and still no luck. it was only when I took it to a local specialist that said "could give it a smoke test and see if its leaking anywhere". This was literally a fix or flog situation as I was getting fd up with missing work, missing events etc i was ready to just call it a day until hey presto small leak on the sump gasket.

BOOM! I was over the moon, i wasnt sure if it was going to fix the issue at the time due to so many let downs but low and behold it work. The specialist reckoned that due to the leak in the gasket it was causing the more resistance on the pulleys thus snapping the belt. The reduction or increase i cant remember in vacuum was cause this extra strain.


|https://thumbsnap.com/WpkBpRp3[/url]


My next modification is definitely going to split opinions for the worst as it was supposed to be black with white writing but turned up red with white writing. I went ahead with it anyway and actually really enjoyed it whilst it was on the car. definitely not for the purests though haha.

[url]

Next up was a a decent alignment to make the most of the coilovers, i first set them up conservatively then decided to go more aggresive for track.

Geo setup was
-3.2 Front
-2.2 Rear
16 clicks front
10 clicks rear



Some more pics at a friends



I decided to change it up abit and bought some Style 42 17's. Finished in Gunmetal with ploished lips I rocked these for around a year and a half.







Back out to the ring again for another trip, with the new bits and bobs added to the car and a skinnier 225/45/17 square tyre I managed to achieve an 8:19 BTG with a passenger. pretty happy with this one as it was my like 15-16th lap ever and I still felt like the car and myself had more to give, super happy with the time though



Around 6 months went by after this trip before booking on to the BTG Trackday event in April. I had lots of plans for this trip and continued with stickier Nankang AR1 rubber, a new shifter, a bucket seat and a fresh geo.





|https://thumbsnap.com/spr7mBGa[/url]
[url]


As I was in a rush the Coolerworx shifter wasn't setup properly and ended up being the Achilles heal on the trackday. the shifter kept on popping out of gear under heavy compression and braking when in 4 & 6 which is funnily enough some of the most important gears. Some arse clenching moments going under the bridge at 140mph into the compression only for the gear to pop out and have no accelerator. despite all this i managed an 8:15 BTG with a passenger A time I was happy with but also knew I had more to come.



Another successful ring trip done! saw lots of cool cars, beautiful weather and had a cracking time on track!


After coming back from the ring this time around I started to wonder what more I could want from the car and what direction I should take. The cars bodywork was dent free for the most part however the paintwork could have done with a spruce up. I started to save and plan out the new look I wanted to take with the car however some of the parts were no longer in production so a hunt was underway. I spent months scouring UK/European/US ebays, tons of forums just to acquire certain body parts. it was abit of a headache at times but also very rewarding when I found the pieces I wanted.

The funniest purchase was with a guy selling an entire Z4 for 2k and I wanted just the front aero bumper for £400. His reaction was both shock and abit weirded out especially when he found out id driven 3 hours to pick it up.

Another purchase that was made was an AC Schnitzer rear wing, these are becoming incredibly rare with some fetching over a grand on fleabay, I picked mine up for a fraction of the cost from a guy in France for £450.

this was all a stock piling exercise before the respray went ahead, I was abit apprehensive at first with fitting the Schnitzer wing as I was going to change my plans and go for more Aero with an APR wing. The Schnitzer wing was left off the car and was later fitted.

Christmas 2019 time and I decided to treat myself to a new set of wheels. I have always wanted these wheels since buying the car, I really like everything about them. They are a 17 inch 9J wheel with 235/45/17 square NS2R
|https://thumbsnap.com/bq9XDkuZ[/url]
|https://thumbsnap.com/LqP9yLTy[/url]

Next stop was taking the car to get prepped for the respray, at a friends workshop I was toying with the idea of just getting rid of everything and creating a back to basics full blown race car. It started with a small piece of trim being removed... then another... and another haha, before I knew it all of the carpets in the boot had been removed along with the plastics from the rear bulkhead section.

|https://thumbsnap.com/oC7WMP7k[/url]

I left the car with my friends body shop who asked if I wanted to keep the speakers etc to which I said "no just get rid of the lot everything thats necessary and nothing else". This turned out to be abit contradictory as I had a trackday booked at snetterton as the work was being done and put some of the trim bits back in as we ran out of time to fabricate certain things such as doorcards/handle positions.

When I returned to the car all of the media stuff had been removed and the car had a fresh new look! Absolutely in love with the way it looked. Jay at Big Jay's Speed Shop had done an amazing job on the car. forgot to mention, during this umming and arring phase about going with big aero I had purchased a Fancywide diffuser that I later remove a few months later.
|https://thumbsnap.com/5hCzV4nS[/url]



Some other bits that went on the car, Vibratechnic engine mounts and some Carbon Production DE carbon airducts along with some airduct shoots in the front bumper


|https://thumbsnap.com/d5uiPn5A[/url]




For the main thread this is how the car sat in February 2020


I will now update the thread chronologically so please continue reading if you have enjoyed things up till now.

Edited by Wursle on Sunday 21st June 19:11

[Caddyshack]

Nice project and well executed mods, I assume this is the 3.0 engine?

[Hitch]

Looks very purposeful in those last pics. Love this model.

[Wursle]

Caddyshack said:

Nice project and well executed mods, I assume this is the 3.0 engine?

Yes this is the 3.0 N52 engine. surprisingly good on fuel for a big engine 44mpg+ on the motorway with around 20mpg when used on track. couldnt afford the M and they were also triple the price when I bought mine

[Wursle]

Hitch said:

Looks very purposeful in those last pics. Love this model.

Thank you very much, the car looks so much better now than it does in the pictures here but I do still love how the 32's fit! for an OEM wheel they were ace

[okenemem]

amazing color

[(steven)]

I will follow this with interest.

I've had mine for over a decade and always struggle to think of something to replace it with. Having sold my track car recently, I was talking about getting another one of these to make it into a track car. Food for thought this thread.

[g3org3y]

Super project. The Z4 coupe really is a great looking thing, that green is quite an unusual colour.

[Wursle]

[quote=(steven)]I will follow this with interest.

I've had mine for over a decade and always struggle to think of something to replace it with. Having sold my track car recently, I was talking about getting another one of these to make it into a track car. Food for thought this thread.
[/quote]
They make amazing track cars, the car is currently undergoing a full cage throughout and being entirely stripped. So much more to come 👍

[Wursle]

g3org3y said:

Super project. The Z4 coupe really is a great looking thing, that green is quite an unusual colour.

Yeah its definitely a love hate colour but for me i wouldnt have it any other colour 😁

[Julian Thompson]

You see everyone criticises black wheels but there are sometimes when they just work. Those last photos of the car look absolutely fantastic. Good write up too thanks.

[Wursle]

Julian Thompson said:

You see everyone criticises black wheels but there are sometimes when they just work. Those last photos of the car look absolutely fantastic. Good write up too thanks.

Haha yeah i've got to admit i am probably on the fence about black wheels, this was so long ago black wheels were cool haha 😂 The car is currently on silver wheels now and more pictures of this will come. How do people normally update there threads do they tend to add to the original 1st post or do they add updates in the comments

[147lusso]

Nice car (Particularly with the Magnesium-Alloy N52 Engine of the year 2006) however that S13 is so nice! Whoever owned that had taste and is likely a wheelman

[therealsamdailly]

watching with interest. looks awesome

[5harp3y]

being a rare colour and on a YXXXXXX plate means it might have been a BMW UK car first

[200Plus Club]

Looks a nice track toy

Edited by 200Plus Club on Thursday 18th June 13:45

[SturdyHSV]

Wursle said:

How do people normally update there threads do they tend to add to the original 1st post or do they add updates in the comments

Usually just add to the comments as and when so it's chronological with the other comments etc.

Look forward to seeing what you've done

[Sf_Manta]

Watching this with interest, and from another BMW owner, good choice of car, be it mines a 330i Touring (E46) manual known as 'Oddjob' and have been to the Ring a few times now but only managed a 9.42.. though my car's a lardy thing at 1700kg!

I've been able to drive one with coilovers and they're very compitient providing you set the damping up correctly. I did have to reset the damping on a former friend's Z4 as he had it set to FULL hard all round. The car was horrid to drive and would pogo off every single bump.

If i recall from memory the coilovers were something like BC but had 30 clicks from full soft to full hard. I found the sweet spot was 14 from full soft on the front and 12 from full soft on the rear. After then the car would ride bumps, developed much more grip but kept the body roll to a mininmum. He did compliment them with H&R roll bars as well which proved to work very well

Not sure how many clicks the BC coilovers have, but would suggest you go with their recomended settings to start with then small adjustments from there.

[Wursle]

Good evening all, I have updated the main thread with some of the older images I have as there was quite abit of story telling. I will include more track pictures tomorrow and start using the thread as normal updateing cronologically once ive used up all of the old images I have stored. proper nostalgia hahaha

[Wursle]

5harp3y said:

being a rare colour and on a YXXXXXX plate means it might have been a BMW UK car first

Funny you say that this was a headoffice car owned by a lady that still works their, my friend even sits near her haha