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      01-05-2009, 03:31 AM   #40
E92Fan
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Quote:
Originally Posted by Ant Man View Post
I understand that firmer front springs will increase understeer. Why did you change the fronts and what effect does the different bump stops provide?
The difference in spring stiffness is relatively small - the effect on increasing understeer on my car in particular is so small to be unnoticeable (at least to me - this is largely due to the uprated antiroll bars which have already altered the hanndling balance). The stiffer bump stops help prevent the front wheels deflecting too much under load - basically when the front springs were compressed and the wheels under load (in a fast corner on track for example) the standard bump stops would flex to a degree. This flex means that the front wheel geometry is not as true as it should be under load, leading to a sloppiness in hard cornering and a lack of precision. This was quite noticeable at Brands Hatch, when I found that sometimes a degree of extra mid-corner correction was needed. Now that the front suspension has been made to be a little more precise, especially true in the case of the tension struts and wishbones, I am expecting there to be much more sharpness and control during hard cornering. Certainly, the difference in high-speed straight-line stability has been improved, and driving the B-roads down in Surrey has proved a bit of revelation in terms of initial cornering bite.

Quote:
Originally Posted by Ant Man View Post
I keep reading reviews on the Alpina car set ups and how much better road testers prefer them to the M Sport package. I know Alpina do not use run flats and you sound very clued up on the subtle differences. Can you reveal more pls?
Alpina take a lot of time in fine-tuning damper/spring matching. Whilst BMW typically have 3 sets of dampers and springs to use across the whole E9x range, Alpina will go through the BMW parts bin and perhaps use a spring from a 5 series for example, or from a model not in the UK portfolio. They genrally have no restrictions on the mechanical parts they are allowed to use (except specific M parts like the diff). You will find that Alpina generally deliver a more cushioning ride, because they have spent time fine-tuning the suspension to one or two specific models only. The spec of antiroll bars differs as well, largely to compensate for the different suspension rate. The modification to the front bump stops on my car came from the Alpina engineers, who are using the 335xi stops on the B3 coupe. All this, coupled with the non-runflat tyres gives a more refined and sophisticated ride than the MSport variants.

Quote:
Originally Posted by Ant Man View Post
H&R and Eibach offer more progressive springs compared to the Msport and I've read two reviews of 335 owners that have paired up the H&R sport springs with Msport dampers and normal tyres and both said how the choppy ride over bumps at slow speeds disappeared. How do you think Eibach pro springs plus Koni FSD dampers would work together on our fabulous Queen's highway? In conjunction with H&R anti-roll bar kit of course

ACS suspensions kits - I've been told these are just rebadged Eibachs but twice as expensive??
To be honest, I can't really comment on how the FSD dampers would work as I have only ever tried one car with them on, and that was for only ten minutes. Certainly I wasn't blown away by the change, but I didn't have long enough to form a good opinion. In addition, the car that it was installed on had a few geometry issues and the like, so that would have masked a fair bit of any perceived change.

My problem with using H&Rs or Eibachs with FSD dampers (or any other cobbled-together variation) is that inherently those two products are not matched together for the application of your car. BMW specify three different spring rates and dampers, depending on the level of specification of the car in question. Koni provide ONE FSD damper specification to cover ALL 335i (and possibly other models too). That Koni damper then hasn't even been matched to a dedicated per model spring, much less those generic springs from Eibach or H&R. How can you expect to get the correct spring/damping specification??

This is why I suggest going to someone like AC Schnitzer. Yes, they use Eibach springs and Bilstein dampers, and rebadge them as ACS, but ACS will have spent time refining the suspension setup and specifying specific damper requirements and spring rates from the supplying companies. Granted, that spring/damper combination will be designed for all variations of the 335i, but at least they will have been matched. You can go to Eibach and buy springs, you can go to Bilstein and buy dampers, but I guarantee you they won't be the same spring or damping rate as a set specially made up for ACS or one of the other respected tuners.

However, unless you specifically want to lower your car for a more aggressive look, I don't understand why people feel the need to change suspension on their daily road car. Granted, if you want your car to be track-focussed, then a suspension change to a full racing coilover setup would be the answer. If you want the car to handle better, there are other ways, and in my opinion better ways, to refine the car's handling balance and to increase traction other than changing over the suspension. If you are after a more cossetting ride, ditch the runflats and go to normal tyres. And if then you still want a more cossetting ride, sell your car and buy a Lexus, or something like that, because BMWs aren't designed with a cossetting ride in mind! Not even Alpinas are... the emphasis is on sporting, and unfortunately sporting does tend to mean a firmer ride!


Quote:
Originally Posted by Ant Man View Post
Will you be looking to increase aero grip by adding the M3 lip spoiler or mechanical grip by increasing the width of the tyres in the future as you like driving the ring?
I will be adding the M3 lip spoiler in the very near future, but first I need to find a front lip that not only works, but also looks good. The problem with the standard car is that at high-speeds, and I'm talking 150mph+, there is a considerable amount of front-end lift which hinders directional stability. It's not uncontrollable at that speed by any means, but it isn't as tied down as it should be. Having driven an Alpina at those speeds, the difference in aero grip is considerable. My only issue is that the front lip from Alpina looks a little bit like a cliff-face - not the most aesthetically pleasing to me... not ugly, but not beautiful..!

I've already increased the tyre contact patch, to 235/265 front/rear, but the difference over standard is minimal. I have increased mechanical grip through the suspension refinement, uprated rollbars, and of course the LSD on the rear axle. Given that my car is actually a road car first and foremost, and not a dedicated 'Ring car, I think it is now pretty much the perfect balance of handling and comfort for me.

Last edited by E92Fan; 01-05-2009 at 03:49 AM.
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