Let's assume I wanted to go sprinting with a Z4MC

[carl]

What (cheap) mods would I have to do to make it perform best on the track -- bearing in mind the tracks vary from the tight and bumpy like bits of North Weald to the open tarmac of Rockingham and Hethel. I'll be driving the car to and from the track and it will be my occasional daily driver too, so I don't want to go down the competition seats route. Nor do I want to spend a fortune on big brakes and aftermarket suspension -- might as well get a cheap Caterham instead.

So I was thinking:
Geometry -- what's a good setting to start with? I've heard max neg camber on the front.
Brake pads -- EBC yellows? Mintex 1155 (I used them years ago and they covered the sides of the car in rusty crud, stopped well though)
Tyres -- currently got AD08, AD08R supposed to be better. R888 probably a step too far without a second set of rims.
Stainless brake hoses
Replace brake fluid, clutch fluid, PAS fluid with something decent (my dad managed to boil the PAS fluid on our Saxo when we did an Autosolo...)

Anything else? Strut brace? RTAB limiter (I don't really know what this does)? Polybushes?

Finally does anyone know somewhere in East Herts/West Essex/South Cambs that would be able to do the geometry changes and general work on the car? There's a place in Newport but I don't know if they look after ///Ms.

 

[mmm-five]

If you're going for BED pads, then the Bluestuff NDX are better than the Yellowstuff. Pagid RS are better pads but probably 3 times the price.

I don't do sprinting (see Beedub for that), but other than brake pads & fluid and Pilot SuperSports, I've not (yet) upgraded anything on mine for general usage of 25k per annum commuting, hooning, track days & Ring trips.

I take mine to Darjac in Halstead, Essex (between Braintree & Colchester). My only complaint is that he can get very busy sand you can have a month's wait to get your car in.

 

[carl]

Won't Bluestuff NDX be too hard for road use? The issue with sprints is that it's more like a fast road then a circuit as you start from a standstill and don't go that far in one stint (usually somewhere between 60 and 120 seconds on most course layouts). So tyres and pads that do nothing when they're cold just won't cut it.

 

[BMWZ4MC]

I use EBC Bluestuff with Motul RBF 600 fluid and they work well from cold and extremely well when very hot on the track. I don't do sprints, but I do prefer short technical tracks to long fast ones. For several years I ran Eibachs with a strut brace and front maximum negative camber (by pulling the camber pins) but otherwise standard suspension and geo. I was able up keep up with 996 GT3s and easily beat E46 M3s with this set up (I was comparable with an ESS stage I supercharged M3 with coilovers and a BBK). You'll still experience understeer though. This can be reduced further with better tyres and spacers up front. Overall, I found sticky tyres and trail braking were the most effective means of reducing understeer with the car in that guise.
I'm now running a very different set up and the handling is sublime. Interestingly my braking distances have significantly shortened with improved consistency too and I'm certain it has little to do with my brake cooling mods or braided lines.
Have you considered just buying a Westfield? It will give you everything you want in a track car for really not much money.

 

[carl]

Kit car class is a bit more complex due to the capacity split (up to 1700cc and over 1700cc, plus all bike engined stuff in the over 1700cc class). Last year someone turned up in an SBD Motorsport Caterfield purporting to put out 350bhp. I know it looked like a missile going down the back straight at Hethel.

Plus I can't really justify the spend on something that I will only do sprints in. Can't go down the shops in it, can't get the missus to drive it, etc.

 

[ga41]

RTAB limiters reduce toe change in the rear under certain conditions, (an extreme example here: https://www.youtube.com/watch?v=X9HhqLhxKc4).

I think you couldn't go wrong with some upgraded brake pads and fluid, the aforementioned Bluestuff might be good but i've no personal experience with them, Motul RBF660 is my current fluid and am very happy with its performance, the RTAB limiters and the Turner camber bolt kit for added front negative camber for not really much money at all http://www.turnermotorsport.com/p-424-front-camber-bolt-kit-e36-z3-z4-m-turner-motorsport.aspx. Throw some decent tires and you'd be sorted for the time being.

 

[carl]

Thanks for this. I will have to check the regs to make sure the RTAB limiters and the camber bolt kit are allowed, but since it will be in Roadgoing rather than Standard Production I think it should be OK.

 

[ga41]

No worries, i've bought the bolts myself too but sadly lost the package somewhere when moving house before i had a chance to install.... :?

 

[Stevie.w]

What (cheap) mods would I have to do to make it perform best on the track -- bearing in mind the tracks vary from the tight and bumpy like bits of North Weald to the open tarmac of Rockingham and Hethel. I'll be driving the car to and from the track and it will be my occasional daily driver too, so I don't want to go down the competition seats route. Nor do I want to spend a fortune on big brakes and aftermarket suspension -- might as well get a cheap Caterham instead.

So I was thinking:
Geometry -- what's a good setting to start with? I've heard max neg camber on the front.
Brake pads -- EBC yellows? Mintex 1155 (I used them years ago and they covered the sides of the car in rusty crud, stopped well though)
Tyres -- currently got AD08, AD08R supposed to be better. R888 probably a step too far without a second set of rims.
Stainless brake hoses
Replace brake fluid, clutch fluid, PAS fluid with something decent (my dad managed to boil the PAS fluid on our Saxo when we did an Autosolo...)

Anything else? Strut brace? RTAB limiter (I don't really know what this does)? Polybushes?

Finally does anyone know somewhere in East Herts/West Essex/South Cambs that would be able to do the geometry changes and general work on the car? There's a place in Newport but I don't know if they look after ///Ms.

Go for it, track/sprints are a very good way of getting the best feed back from your car and learning how it works. Lost count as to how many competing cars I've built, but what you need to look at is keep it simple and remember this is your road car. Seen way to many vehicles taken too far and end up fit for neither.
Stay away from EBC, Padgid only for the best feed back and longevity, don't scrimp on pads. Poly bush as much as you can suspension wise. As for tyres the AD08R's are just a little bit better than previous version. AO48R's are a very good track tyre, but once seen numerous heat cycles go of fairly quickly. Brake fluid use racing blue used by Porsche cup series, being blue in colour you know old fluid flushed out.
I've always said to my customers keep it as simple as possible and if you start to find the cars limits then look at addressing them.

 

[carl]

Lost count as to how many competing cars I've built, but what you need to look at is keep it simple and remember this is your road car. Seen way to many vehicles taken too far and end up fit for neither.

Agreed, and this is absolutely what I want to avoid.

 

[carl]

If you're going for BED pads, then the Bluestuff NDX are better than the Yellowstuff. Pagid RS are better pads but probably 3 times the price.

Which Pagids would you recommend? I had RS4-2 (Blue) on my Impreza many years back and they were excellent, but would I be better off with RS29 bearing in mind the mixed road and track use?

 

[mmm-five]

If you're going for BED pads, then the Bluestuff NDX are better than the Yellowstuff. Pagid RS are better pads but probably 3 times the price.

Which Pagids would you recommend? I had RS4-2 (Blue) on my Impreza many years back and they were excellent, but would I be better off with RS29 bearing in mind the mixed road and track use?

Yes, the RS29s should be perfect for the combined use. Your wheels will need cleaning regularly though :wink:

 

[carl]

Yes, the RS29s should be perfect for the combined use. Your wheels will need cleaning regularly though :wink:

£6 at my local hand car wash should sort that -- as long as they don't weld bits of friction material to the sides of the car, like the Mintex 1155s did on my Impreza