Very very impressive - Z4M BtG under 7'40"
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Wow…that's wide at the frontkrisa9977 said:
My best time at the ring is 8.30min (with some traffic). You know the track really well and your car has great grip! I have a Z4M roadster with lighter CSL-wheels, Michelin Supersport tyres, Eibach spring (oem M-dampers), BMW stutbrace and a full AP racing BBK with Pagid pads.
Brakes and horsepower are absolutely great on my car… But the only thing I would like is a some more grip in the corners and I think the suspension moves to much.
Question to the guys who drive on track and upgraded their car...
From what upgrade would my car benefit the most for my purpose…if I need to chose between "a" or "b"?
a) Fitting better suspension; in my case I would go for the easy adjustable Bilstein PSS10 (KW V3 does not fit without spacer in combination with CSL wheels and I don't want spacers)
b) Buying an extra set of 18" wheels with semislick "track only" tyres like Kumho, Toyo...
My Z4M is my dual purpose sun & fun car for street and track… It's not my daily car, but my girlfriend still drives it daily on the street for a distance of 20 min (in sun and rain and also in snow with 18" winter wheels). In the dry months, the car comes every month on the ring…and I drive it on my free days. With the Bilstein PSS10 it's a 2 min job to turn the little knobs and set the suspension softer (street) and harder (track).
For me personally I would like to avoid buying an extra set of alloy wheels with semislick track tyres. There are also some little downsides on driving with certain semislick tyres (they have to get warm enough, wear, costs, more wear on some suspension components, different grip characteristics at the limit, etc)… Also there is the issue that I have to change the wheels every time I'm going or coming from the ring (every month). And I then have 3 set of wheels for the car (summer, winter, track)…and that takes a lot of place in my garage. Also; I actually really like the Michelin Supersport tyres, the wear and tear with these tyres is awesome and IMO they are a great dual purpose tyre!!! They perform great on wet and dry roads and are also good on trackdays (with the right pressure) with some really unbelievable wear (I can use them for 2 years on street and track). Okay; Michelin Cup + and semislick tyres are better on track, but is the difference really that big?
http://www.tyrereviews.co.uk/Article/Michelin-Pilot-Performance-from-track-to-street.htm
http://www.motormorph.com/?p=3523
neither of this will benefit the most.
First what you need:
1. Poly bushings (Powerflex)
2. Track alignment (as much camber as you can dial)
3. Proper suspension setup(balance front and rear spring rates)
4. Better suspension (PSS10 will help)
There is not so much difference between PSS and Kumho semiscliks. I even not sure which tire is faster, so I recommend to stay with PSS.
First what you need:
1. Poly bushings (Powerflex)
2. Track alignment (as much camber as you can dial)
3. Proper suspension setup(balance front and rear spring rates)
4. Better suspension (PSS10 will help)
There is not so much difference between PSS and Kumho semiscliks. I even not sure which tire is faster, so I recommend to stay with PSS.
This is something that can not be done in our country. These bushings will make me fail the MOT. Spacers and Powerflex bushings are not allowedkrisa9977 said:
I have to look into this… When there is a lot of camber, does this not translate into more and uneven tyre wear?krisa9977 said:
I presume this can only be done with an aftermarket suspension like the PSS10krisa9977 said:
Is on the future mod list...krisa9977 said:
What was custom tuned about the suspension? I presume you have a different then standard alignment, doe have any numbers of this? Does Powerflex bushings make such a big difference?krisa9977 said:
I did not know the Dunlop Direzza's… What kind of tyre are the exactly? They don't look as a full semi-slick. I thought the most sporty street-track tyre Dunlop makes is the Sport Max Race… This is more the equivalent of the Michelin Cup then a full on semislick tyre.
If you'd like bushes but don't want the obviously aftermarket blue/yellow/orange etc then you could always try these.
http://www.powerflex.co.uk/black-series/
Nice and stealthy :wink:
Saying that, i think they'll be even harder than the regular ones so it depends on what your priorities are for the car.
http://www.powerflex.co.uk/black-series/
Nice and stealthy :wink:
Saying that, i think they'll be even harder than the regular ones so it depends on what your priorities are for the car.
With standard RTAB bushes your toe can go up to 20mm in and out in hard corners. Car becomes very unstable and loose a lots of grip. If you replace those bushes to black Powerflex, only experienced BMW mechanic can see the difference. They are not metal, and I'm sure they are legal in all countries (regular replacement part).
Even with bone stock car with stock alignment with PSS it is possible to brake 8 minutes BTG. To go under 7:40 with semislick and no engine mods or weight reduction it is more complicated. You need to fine tune suspension (low speed, high speed rebound and compression), aggressive spring rates and more then 3 degrees of camber(front and rear). Obviously you forget about street tire wear and comfort to be able to go that quick
Even with bone stock car with stock alignment with PSS it is possible to brake 8 minutes BTG. To go under 7:40 with semislick and no engine mods or weight reduction it is more complicated. You need to fine tune suspension (low speed, high speed rebound and compression), aggressive spring rates and more then 3 degrees of camber(front and rear). Obviously you forget about street tire wear and comfort to be able to go that quick
Are there any big downsides on fitting these Powerflex bushes and what is the difference between the purple and black ones. The black ones would indeed not be visible. Are the black ones not race only? My car is still a street car, that also comes on track. Which bushes would you advise to change and are the most important?krisa9977 said:
http://www.powerflex.co.uk/black-series/products/Z4+%28E85%29-1203/1.html
I don't need to go under 7:40min or something like that…that's not the goal. I will not modify my Z4M to that extend to try and achieve this. It just want to make my Z4M perform a bit better on the ring without going to extreme and kill the street drivability. If the fastest time would be my concern, then I should have bought some other car then a roadster :wink: . I'm not that focused on the laptime… Still; I time most of my laps, because it's fun to know how you are doing and how the progress is in learning the ring. Under 7:40min with a Z4M is still really, really fast. A friend of mine who is an ex racecar driver does BTG under 7.40min with a modified e92 M3 (stock interior, stock weight, ECU tuning, KW clubsport, Michelin Cup, AP racing, Acrapovic) and he knows the track really well… So under 7.40min with this Z4M is utterly fast and there is good knowledge of the track by the driver!krisa9977 said:
For me personally; it's all about the driving experience and how much fun it is when driving fast at the ring. A this time a good and fast lap for me is around 8.30min. This is with the set-up my car now has and most importantly with the knowledge I now have of the track (this is my second year of driving a lot on the Nurburgring). The main thing to go fast at the ring is the knowledge of the track. If I would one day have the knowledge, experience and the right car set-up to go under 8.30min and get close to 8min, then it would be nice and absolutely great. But I'm not haunting these times and it's not something that needs to be done… In the end there will always be someone faster and it's not a real race with prizes and stuff… It's only fun
Thanks for the info!krisa9977 said:
So you mean these bushes: http://www.powerflex.co.uk/black-series/product-details/Rear+Trailing+Arm+Bush/10113.html
Which bushes did you change on your car? All of them or only these two..? Did you experience a big difference from only the bushes?
Side question; you are living in Russia; how do you manage it to get so much time at the ring?
How great is that! That explains some of you track knowledge… But I can't complain also; I live 2 hours from the ring and 1 hour from Spa…can be a lot worsekrisa9977 said:I live 15 minutes away from the Ring.I changed 4 bushes 2 front and 2 rear
So at the rear you changed the two bushings of the rear trailing arm bush. And which one at the front?
http://bmwfans.info/parts-catalog/E85/Europe/Z4_M3.2-S54/L-N/2006/browse/front_axle/front_axle_support_wishbone
Franzino said:How great is that! That explains some of you track knowledge… But I can't complain also; I live 2 hours from the ring and 1 hour from Spa…can be a lot worsekrisa9977 said:I live 15 minutes away from the Ring.
So at the rear you changed the two bushings of the rear trailing arm bush. And which one at the front?
http://bmwfans.info/parts-catalog/E85/Europe/Z4_M3.2-S54/L-N/2006/browse/front_axle/front_axle_support_wishbone
Front number 9. You need to buy one with the hole in a middle, so your wheel goes back(less caster) and you have more space in wheel housing to put bigger wheel or to drop the car more with no rubbing issues
krisa9977 said:Franzino said:How great is that! That explains some of you track knowledge… But I can't complain also; I live 2 hours from the ring and 1 hour from Spa…can be a lot worsekrisa9977 said:I live 15 minutes away from the Ring.
So at the rear you changed the two bushings of the rear trailing arm bush. And which one at the front?
http://bmwfans.info/parts-catalog/E85/Europe/Z4_M3.2-S54/L-N/2006/browse/front_axle/front_axle_support_wishbone
Front number 9. You need to buy one with the hole in a middle, so your wheel goes back(less caster) and you have more space in wheel housing to put bigger wheel or to drop the car more with no rubbing issues
I have talked to the guy who does all my modifications… Chancing the rubber of the rear trailing arm bush is good idea and a lot of people do this. In the front he would stay OEM. I don't want my car lower than now (it's now 1,5cm lower then OEM) and I have no rubbing issues. I will do my suspension modifications at the same time when I fit a PSS-10 in the future (this year or next year)….