Z4c on track

A

Andrewthehat

Member
 Maidstone
Ok let's see... I took my z4c to brands hatch this evening. It is totally standard, and therefore what I have report is surprising... Well, I think it is. Let's see what you think.

Better then expected were throttle response even without sport mode, brakes which didn't fade or worry me, tyres (Michelin ps2 zp) which did a great job without squealing once, and torque. I was thoroughly relieved also that three 20minute sessions surfaced no problems whatsoever, and the oil indicator showed no noticeable level change.

Worse than expected was suspension. Just a wee bit too vague.

Overall impression was that as expected, this is no track cAr in standard form, but with a little fettling especially in the spring/coil over dept, it could be a lot better. Trouble is that it's a great motorway car, and it would be a shame to spoil that. What it is crying out for is a Maserati-style adjustable suspension setup. Has anyone done something like that with brilliant results? Time to go searching this forum, I think.

Brilliant track evening. Not one single yellow or red flag, and a lot of very quick hot hatches around. Also a beautifully maintained original gt40, fia-registered and readying for an imminent classic race at spa. It was an honour to be passed by it. Well.. Ok... Lapped, being honest. Hat off to club msv.
 
I'd agree the suspension needs some adjustment. I'm starting with a set of Eibachs to see how much difference that will make. The other option is, as you've suggested, a full set of coilovers but you'll be forking out a lot more for that. From what a few people have said the Eibachs improve cornering without making too much difference to ride comfort so for me that's an ideal way to go - I also use my car as a daily driver so don't want to ruin the ride. However, with coilovers you can tweak the setup, so have them nice and soft on the road and then drop it for the track. Just depends how much you want to spend.

I'm glad to hear your brakes were fine - I have the pre-facelift so my front discs are 300mm and kept overheating. I've just purchased a set of 325mm callipers and discs from the facelift which I'll be fitting soon and hopefully be seeing positive results!

Did you get any photos or videos?
 
I'm not tracking mine (not powerfull enough) but I can recommend coilovers as you can adjust the setting whenever you want. I have coilies on mine and for photohoots, I have put it at the lowest setting, for a touristic rally It's going up a few centimeters but not as high as standard. Much better than the standard set-up. Adjusting the coils is really easy, 15 minutes per wheel, including mounting and dismounting the wheels. In all a 1-hour job.

For tracking I would also recommend strut braces in the front, the back and under the car. I've heard may times on this forum that it really makes a difference. Oh and while you're at it, update the bushes :-)
 
@relic222 no photos or videos, sorry. There will be photos of the event and all cars on the motorsportvision website in a day or two... But if the photographer snapped me when he could have been filming that gt40, he needs surgery.

I will be interested to hear how your eibachs improve things.

Forgive the question (newbie) but how do I tell if I am pre or post facelift? Mine was was built in dec 07.
 
@bad Pritt - I see you are based in Belgium. Whereabouts? Are there z4 meets in Belgium occasionally? I am there most weeks (my employers hq is near Brussels)
 
Andrew, yes!

I'm the owner of the "Roadsters & Coupes Benelux" group, what started out as a Z-series group. We organise road trips about once a month, sometimes even more. For now, I only have a Facebook-group but planning to get a website if things take off:

Click here: Roadsters & Coupes Benelux

And this is the first upcoming event: a tour through Flanders, based upon the famous Round of Flanders (for the cyclist fans out there).
Click here: Ronde van Vlaanderen

Mind you, it's all in Dutch for the moment as well... When and if I have a webiste, I'll think of French and English too.
Having said that, don't hesitate to react in your own language, most of us speak English, Dutch and French anyway ;-)
 
The facelift happened in 2006 and the coupe was only introduced post-facelift :)

Adding on to Bad_Pritt, I have also heard good things about strut bars and have that on the to-do list. There was a thread about the Ultra Racing bars recently which was pretty complimentary so I think I'll go for them as a start. They offer a full setup - front, rear and underneath for the Z4. Although I'm not certain that the coupe is the same as the roadster so you may want to check the rear one.

http://www.ebay.co.uk/itm/Ultra-Racing-3-Points-Front-Strut-Brace-Bar-for-BMW-Z4-E85-2-5-02-08-TW3-1175-/321104256242?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3ABMW%7CModel%3AZ4&hash=item4ac34e1cf2

@Bad_Pritt there's no such thing as 'not powerful enough', you can have loads of fun even in a slow car, in fact you can often have more fun in a slow car because you really need to nail every corner to get the best out of the car, rather than being able to just plant your foot after a bad corner and get away with it. Give it a go!
 
relic222 said:
The facelift happened in 2006 and the coupe was only introduced post-facelift :)
@Bad_Pritt there's no such thing as 'not powerful enough', you can have loads of fun even in a slow car, in fact you can often have more fun in a slow car because you really need to nail every corner to get the best out of the car, rather than being able to just plant your foot after a bad corner and get away with it. Give it a go!
Click to expand...

Besides the lack of performance, I'm also chicken-sh*t :oops:
No, honestly, would love to give it a go, but the problem is that in Belgium, your insurance is invalid on the tracks (and track insurance is not cheap?). I really wouldn't want to crash my car on the tracks... That scares the hell out of me! I love touristic rally's, especially in Germany (Eifel-area) and the Belgian and French Ardennes. Great roads and indeed loads of fun in corners with the DSC off :-D And at least, I'm still properly insured.
 
Havent read through all of this yet but will later. I have done loads of suspension changes to my car. Its a weekend car so i have a very different need from my car to you. But one thing i will suggest you look into is the ARB. Maybe not even polly ARB bushes but the bar its self. Either buy an adjustable one quite pricey or do what i did get a second hand M3 bar. Cheap as chips straight swap with the M3 ARB bushes stops roll and might just make the differance you want without sacrificing the drive-ability of your car.
 
I've recently gone through the process of upgrading my suspension without going for a coilover system (yet). Starting point was the Z4MC, which comes with a stiffer setup out of the box then the non-M version.

That said, upgrading to an Eibach pro-kit improved things a lot. The suspension is less vague and more planted, but it is also bouncier under normal driving conditions. Since I'm using mine as a weekend / track car I don't mind, but for daily drives I would search for another solution (e.g., adjustable coilovers).

I'm working in Brussels and would be glad to bring the car out for you to feel my setup if you'd like.
 
Bear in mind that "adjustable" coilovers are not a complete solution. What you can adjust on coilovers is basically ride height and damper settings. The springs, which are what you "mainly" feel when driving are fixed.

The role of the dampers is to control how the spring responds. And "dampen" its tendency to bounce up and down.

Now you can usually ramp up the damper settings such that they will sort of overpower the spring and result in a stiffer suspension but this is a bit of a cheat as you are no longer properly using the spring but rather riding just on the damper itself.

In short it is pretty hard to achieve a result that is equally at home on the road as it is on the track. Adjustable coilovers definitely allow fine-tuning both from road to track and according to conditions (softer and more compliant in the wet) but you usually have to accept a compromise somewhere.
 
Lots of good advice on here. Jan- thank you very much for that offer. I will contact you next time I have an evening free and hope we can indeed compare springs.

Tertius - nicely put. My brother has a nice Maserati which has on board suspension setting controls... And it would be nice to find something like it for z4 but suspect the costs would be astronomical. I had a great adjustment setup on my now-deceased mini jcw... kW variant 2... The adjustment was invoked by a nice drive down to shoreham by sea, a short conversation with tony franks, a small bill and wallop! Suspension perfectly adjusted. I need to find the tony franks of z4, I think.better than a dashboard button any day. I suspect he is on this forum somewhere. Homework needed. Thanks again!

Mr monkey I am honoured to have your attention. You are something of a legend on this forum. I feel like I need to buy a gear stick from you just to qualify for further participation here... What do you have left?
 
So can you retrofit an E46 M3 Front ARB to a non-M Z4? Would it be advisable to replace the front and rear together, or would the front on it's own improve things? I realise a looser rear should improve rear end grip; would fitting just a stiffer front arb make it more understeery therefore?
 
Mr monkey I am honoured to have your attention. You are something of a legend on this forum. I feel like I need to buy a gear stick from you just to qualify for further participation here... What do you have left?[/quote

WOW high praise indeed thanks. No need to buy anything at all I will PM you later after work.
 
Ed Doe said:
So can you retrofit an E46 M3 Front ARB to a non-M Z4? Would it be advisable to replace the front and rear together, or would the front on it's own improve things? I realise a looser rear should improve rear end grip; would fitting just a stiffer front arb make it more understeery therefore?
Click to expand...

Yes it is i have done it. The rear one sadly dose not fit as the rear axles/diffs are completely different. I have done just the front and i think its made a big difference. Although saying that after all the upgrades i now find the car a little sketchy on wight transfer of the go and on to the slow. But only around 80 upwards (so on track!!!!)
 
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