Race Build Z3 Roadster

[TheStorm]

Hi all!


I just found this forum and I feel confident that this is the place to share my build
So, I will be grateful for any tips and tricks you have for race build Z3.
The idea currently is to be street/track car for 2019 and if does good this year... will be full race mode 2020.

So, up to now:

BODY:

- BMW Z3 1996
- Fiberglass front hood
- Fiberglass fron bumper
- OEM Widebody rear fenders

Current weight : 1158kg without driver

Engine:

- BMW M52B28TU stock engine
- BMW M54B30 intake camshaft
- Sport exhaust headers
- Full custom exhaust with 2x55mm pipes
- Software delete of second lambda sensors
- software deletion of EWS
- software tuned the redline limiter
- software tuned with better vanos control
- software tuned for better DISA control


Drivetrain:

- Getrag 220 with added racing oil additives
- LSD with 3.91 ratio, custom built with racing specs and racing oil, 3 friction discs and with better acceleration ramp - 1.5Way
- Uprated front brakes with 300mm discs
- stock rear brakes due to lower weight compared to stock
- Full upgraded front suspension using BMW e46 wishbones, hubs for wide track
- full adjustable low budget coilover system
- 20mm spacers on all wheels
- wheel specs: 8,5J / 10J 17" with 245/40/17 tyres
- also set of style 66 8J / 9J with 235/40/17


Interior:

- two racing low budget seats
- two racing safety belts
- racing steering wheel
- full stock interior


Some pictures from last summer:

Here I started test fitting the widebody fenders:

Here I received the fiberglass hood and front bumper :

The big LSD and E30 big axles:

And some more progress:

And after I painted it (alone in front of the garage... dont look up closely )

I had one time attack event already. I am VERY pleased how the car drives and goes on the track... but of course .. I am looking for upgrades already

So I borrowed one wheel from a friend to test

The wheel is 18" 10.5J ЕТ25 with 270mm slick tyre. I am with 20mm spacer so effective ET is 5

BACK:

And Front:

So.. I have sold already my 17" and I am looking for wide 18" rims .. Thinking of 265 35 18 / 285 35 18 semi slicks


Feel free to any suggestions how the car could go faster
Thanks for reading the long post !

 

[TheStorm]

And some pictures from the track:

 

[Brian H]

Thanks for sharing....

Feel free to any suggestions how the car could go faster

Not being arrogant here but get yourself some instruction, the biggest improvement you will make is you.

 

[spurs fan in a coupe]

Looks like a wonderful project, looking forward to updates

Welcome to the forum

 

[TheStorm]

Thanks for sharing....



Not being arrogant here but get yourself some instruction, the biggest improvement you will make is you.

I am absolutely sure this is true .. but this will come with time! Anyway .. This is not my first track experience.. Last year I was driving my E21 around the tracks, and before that my E30

Actually from first race of the Z - I am 0.6 seconds behind a brand new M4 CS .. so I am definitely not far behind

 

[TheStorm]

Hi All,

Soo... I had small upgrades on the Z ... like .. new wheels.

18" 10J ET25 with 20mm spacers all around (effective ET 5)

265 / 35 / 18 semis

They just filled in the arches perfectly (maybe 10mm more spacer on the back)

So .. I went out for the race .. and in fact the cheap coilovers are now the main drawback of the car. Still .. was the 3rd in NA class and for better comparison - 0.4 seconds behind BMW M4CS and 0.8 seconds behind 440WHP E36 on Toyo R888

But the car felt fine on the track and did not failed on any aspect. But after a quick review afterwards .. maybe I have overheated a bit the brakes -

Thinking of getting DS2500.. any experience to share?

 

[Althulas]

A good day out and some stuff to improve all good as long as it remains fun. Look forward to the next update.

 

[spurs fan in a coupe]

Looks fantastic, I’ve used ds2500 and found them significantly better than anything ebc

Enjoy

 

[spurs fan in a coupe]

Where did you mount the seat belt harnesses?

 

[Dino D]

Looks fantastic, I’ve used ds2500 and found them significantly better than anything ebc

Enjoy

How do you find them on the road, any squealing?

 

[Dino D]

And some pictures from the track:

View attachment 103859 View attachment 103861 View attachment 103863 View attachment 103865 View attachment 103867 View attachment 103869 View attachment 103871

Loving the widened front.
Where did you get the kit from and where are you based?

What difference does the M54B30 inlet cam make?

The diff sounds very interesting (and expensive!) how do you like it?

I see you have a raised rev limiter and very low ratio diff, you must be in the redline a lot!!
Do you know about the oil pump nut that likes to come loose at high revs and kill the engine. Our @Lee went all the way to the ring to find out about it

 

[TheStorm]

I will try to answer all the questions

I am using normal ATE pads up to now .. but will get one set of DS2500 and will share experience. Anyway .. I did NOT felt any problems with the braking .. just after that when I checked the car and the view was not pleasant . I am using some Motul uprated brake fluid, so no troubles there.

Where did you mount the seat belt harnesses?

On the metal that separates the "roof space" from the trunk ... just next to where the rear shocks are bolted. With big washers and it seems like the harness has the needed 20 degree downward as the manual says, so basically I think it is good place to bolt them.

Loving the widened front.
Where did you get the kit from and where are you based?

They are fiberglass, custom built here in Bulgaria. If you want I can speak with the person who builds them for some shipping quote? He works with a lot of UK cars.

What difference does the M54B30 inlet cam make?

To be honest - I am not exactly sure, but along with the small tweaks in the ECU, the car pulls strong from 3k RPM all the way up to 6700. So I am happy because I am always with a lot of torque to pull out from the corners.

The diff sounds very interesting (and expensive!) how do you like it?

The diff was built by a person who builds all the diffs of BG drifters. He knows a lot in this. It is not very expensive .. if you give him an LSD, it costs something about 200EUR to rebuild it with custom ramps and add additional friction disc inside.
I am VERY happy with the diff. Has been performing great, not too aggressive, but locks every time I step on the pedal. I highly recommend some similar setup for performance cars ( or some powerful street cars).

I see you have a raised rev limiter and very low ratio diff, you must be in the redline a lot!!
Do you know about the oil pump nut that likes to come loose at high revs and kill the engine.

On the track - yes .. constantly between 4k and 6500. This does not seems like an issue, but I should add oil cooler as the tappets are clicking for a minute after track session. Even thou I use Motul 300V 15w50.

About the oil pump - I have read a lot. So .. the main reason is when you have faulty front damper. (Part number 1 http://bmwfans.info/parts-catalog/Z...00/browse/engine/belt_drive_vibration_damper/ ) When this damper is unbalanced - the whole vibrations go to the chains - both timing and oil chains .. and this makes the issue.
For up to 7k, you can use the OEM one, just to be sure change it with brand new one.
For anything up of 7 - you should buy aftermarket uprated one. There is JUST ONE option, for about 1000USD and it is made in USA. (https://store.vacmotorsports.com/vac-harmonic-damper-bmw-m50m52m54s50uss52us-p756.aspx)

I am currently using stock damper, I have re-tightened the nut on the oil pump and locked it with Loctite.



Feel free to ask, I will try to answer

 

[Dino D]

I will try to answer all the questions

I am using normal ATE pads up to now .. but will get one set of DS2500 and will share experience. Anyway .. I did NOT felt any problems with the braking .. just after that when I checked the car and the view was not pleasant . I am using some Motul uprated brake fluid, so no troubles there.



On the metal that separates the "roof space" from the trunk ... just next to where the rear shocks are bolted. With big washers and it seems like the harness has the needed 20 degree downward as the manual says, so basically I think it is good place to bolt them.



They are fiberglass, custom built here in Bulgaria. If you want I can speak with the person who builds them for some shipping quote? He works with a lot of UK cars.



To be honest - I am not exactly sure, but along with the small tweaks in the ECU, the car pulls strong from 3k RPM all the way up to 6700. So I am happy because I am always with a lot of torque to pull out from the corners.




The diff was built by a person who builds all the diffs of BG drifters. He knows a lot in this. It is not very expensive .. if you give him an LSD, it costs something about 200EUR to rebuild it with custom ramps and add additional friction disc inside.
I am VERY happy with the diff. Has been performing great, not too aggressive, but locks every time I step on the pedal. I highly recommend some similar setup for performance cars ( or some powerful street cars).




On the track - yes .. constantly between 4k and 6500. This does not seems like an issue, but I should add oil cooler as the tappets are clicking for a minute after track session. Even thou I use Motul 300V 15w50.

About the oil pump - I have read a lot. So .. the main reason is when you have faulty front damper. (Part number 1 http://bmwfans.info/parts-catalog/Z...00/browse/engine/belt_drive_vibration_damper/ ) When this damper is unbalanced - the whole vibrations go to the chains - both timing and oil chains .. and this makes the issue.
For up to 7k, you can use the OEM one, just to be sure change it with brand new one.
For anything up of 7 - you should buy aftermarket uprated one. There is JUST ONE option, for about 1000USD and it is made in USA. (https://store.vacmotorsports.com/vac-harmonic-damper-bmw-m50m52m54s50uss52us-p756.aspx)

I am currently using stock damper, I have re-tightened the nut on the oil pump and locked it with Loctite.



Feel free to ask, I will try to answer

Thanks for that.

Can’t believe the diff rebuild price, so much cheaper than here!

Interesting info on the damper thanks (@Lee)

 

[Lee]

Thanks for that.

Can’t believe the diff rebuild price, so much cheaper than here!

Interesting info on the damper thanks (@Lee)

Yeah its another way of addressing the Harmonics when above the redline, or you can change the oil pump nut for upgraded type using nordlock washers and caphead bolts for £240.

 

[TheStorm]

Yeah its another way of addressing the Harmonics when above the redline, or you can change the oil pump nut for upgraded type using nordlock washers and caphead bolts for £240.

View attachment 109843

Good idea about the Nord Lock!

Also - uprating the system with chain tensioner from S54 is also an option. (I think the very first E34 M50 NV have such also) .. but for RPMs up to 6500 .. just fully stock but working setup is fine.

 

[TheStorm]

As I have shared .. the cheap coilovers now seems to be the bottleneck of the car. And I am looking for all the options I can find.

Lets say I have a budget of about 1k (EUR... GBP.. not that far away..)

So the system with the most things for the value seems to be the BC Racing RM series with the inverted shocks.

I have checked the D2 kits and the K-Sport kits .. but personally I think the BC are better made.


I am open to some suggestions for some used, but fully working kits .. like Clubsport series KW or Ohlins/GAZ .. but it really depends here on the offer.


Please share with me your experience with non-cheap coilovers and what you will suggest. I need at least 1 adjustment of stiffnes, height adjustment and camberplates.

Note: because in the front I am with E46 hubs .. I am looking for kits for E46 and I will just re-locate the studs of the camber plates in the E36 location.

 

[Dino D]

@Brian H ran his Z3 3.0 on track with BC so can fill you in.
I have them but only been on road so can’t give you the feedback you looking for.

I believe the more expensive stuff like KW etc can be rebuilt- usually here labour costs means it’s expensive to do so but if you can get it rebuilt there perhaps a good way to get quality shocks cheap (by picking up a set that needs rebuilding cheap in UK?)

Also just remembered the guys that run the ZCar race series here have a specially developed set up by Gaz shocks UK. They actually race so will see if I can dig up the posts..

 

[Dino D]

Here are the contacts:

https://www.zcars.racing/

https://zroadster.org/threads/zcars-first-race-silverstone-24th-june.22078/

I believe @Julian Jeffrey is the man to speak with - when I enquired Gaz has done a proper coilover conversion for the rear for the Z3.

 

[TheStorm]

Hi All,

So .. this season was very good for the Z. I am very happy with the car. For the 2-3 month build time that I effectively had - the car performed very well.

I had 1st place in my class on the last event I attended, and I am now in the "winter break"

So - upgrades that I am planning for the winter ..

1. Brakes ...
- Front upgrade to 325x25 from e46 330 with DS2500 pads,
- Rear brakes from E39 298X20 with DS2500 pads ( the calipers are aluminum and very light)
- Servo and master cylinder from E92 (the bigger onе)
- ABS from E46, the MK60. Later I can just change the electric module from M3 without any other change.
The idea is that all the calipers and master cylinder are all the same as the E46 M3, and the ABS is very similar to m3 one... I am hoping for very very good brakes this way.


2. Transmission
- Finally going the the big ZF from 2.8/m3 ( the current G220 held up well )
- going to solid flywheel 240mm from M30
- uprated clutch and pressure plate

3. Suspension
I know that I will get strange responses here.. but this is for now.
I will use BC, ER series (external reservoirs) from Subaru STi 05-07 .. I am just limited financially and I was able to buy such one from ebay on good price. I already made some measurements and this CAN be used on the Z. Just not full coil on the back, because lack of space in the boot, but anyway. I will post pictures when I am ready with this.

4. Engine.
- Already out of the car for inspection and revision.
- I will not open it, but will change rod bearings.

- I have prepared turbo manifold, GT35, S50 oil housing, 550x230 FMIC, 630cc injectors,m54b30 intake manifold, MAF from Audi and I will convert from MS42 to MS43

Sorry for the not-great quality pictures, but more will follow.

.

 

[Lee]

Look forward to seeing more pictures. I'm interested to know more about the ASC/DSC setup this is something that's been giving me a headache with my track time.

With those extra's your zed will be in a different league.