Is it possible to make the z4 a proper drivers car?

[Ewazix]

Ok, so having lived with my 3.0 SE for a while now I've been thinking.

It's not really the kind of car that makes me just want to go for a drive. It's not really a proper sports car in my opinion, more of a GT.

Having recently put proper non run flats on that has helped but I can't stop thinking that all the component parts seem to be there (RWD, decent engine and box, good brakes, wheel at each corner, reasonably light etc) but it doesn't feel exciting in the same way a similar age boxster S or Elise (probably unfair comparison) does. Haven't had an MX5 but I bet if feels more exciting / involving than the Z.

I'm really not looking to have a go at it or change it, but I'm really interested in what options there are to improve what is a good car into a decent sports car.

Initial thoughts -

I came from an Elise prior to the zed & while the 3litre has much more engine it's the extra weight that blunts it's edge (series 2 Elise-860kg Z4-1300+kg) however, it's a more suitable day to day car that still retains some fun & that's why I made the change.
Trust me, unless you are a masochist you would not enjoy an Elise as your daily driver!
Regards

I'm sure the Z4 could take being stiffened up a bit but the weight will always be the issue and it's different tools for different jobs as you say. I actually wanted a VX220 T but went for the Z4 after turning up with the money to buy the VX and was gutted to find that as at 6'3" tall I couldn't physically fit with the roof on

 

[Machine monkey]

I have a M rear ARB waiting to go on. But the front made a big difference one of the best things I have done.

That will only fit if you use the m3 rear axle (with the really short ratio diff) (I presume you mean a m3 (or z4m) rear arb). Also use spacers or rims with different ET because the m3/z4m rear axle has a narrower track width as the standard rear axle.

Yeah I know it dose not fit. It's why it's not on already but I have a cunning plan. Don't want to say to much I case it dose not work!

 

[GuidoK]

Don't want to say to much I case it dose not work!

I'm very curious :roll:
It must involve in making a different back cover for the diff and a different subframe.
The single rear diff bushing/mounting etc. is in the way. that's why the rear arb has that bend in the middle.
The m3 rear diff mounting has 2 higher mounting points so the straight bar can run underneath.

 

[Smartbear]

Ok, so having lived with my 3.0 SE for a while now I've been thinking.

It's not really the kind of car that makes me just want to go for a drive. It's not really a proper sports car in my opinion, more of a GT.

Having recently put proper non run flats on that has helped but I can't stop thinking that all the component parts seem to be there (RWD, decent engine and box, good brakes, wheel at each corner, reasonably light etc) but it doesn't feel exciting in the same way a similar age boxster S or Elise (probably unfair comparison) does. Haven't had an MX5 but I bet if feels more exciting / involving than the Z.

I'm really not looking to have a go at it or change it, but I'm really interested in what options there are to improve what is a good car into a decent sports car.

Initial thoughts -

I came from an Elise prior to the zed & while the 3litre has much more engine it's the extra weight that blunts it's edge (series 2 Elise-860kg Z4-1300+kg) however, it's a more suitable day to day car that still retains some fun & that's why I made the change.
Trust me, unless you are a masochist you would not enjoy an Elise as your daily driver!
Regards

I'm sure the Z4 could take being stiffened up a bit but the weight will always be the issue and it's different tools for different jobs as you say. I actually wanted a VX220 T but went for the Z4 after turning up with the money to buy the VX and was gutted to find that as at 6'3" tall I couldn't physically fit with the roof on

Were you aware there is a seat lowering kit? Well it's not strictly a lowering kit as you can't even get your fingers under the seats anyway but it tilts the seat to give more headroom.
Regards

 

[NeilP]

I would say a decent suspension kit would put you in the right direction.

After swapping my oem sports suspension (had covered approx 34k miles) for a set of KW V2's, the difference was incredible.

 

[Machine monkey]

I haven't had a good look but I am hopping I can do something! I have a LSD to go in and I am stripping the hole rear end new bushes. And a good tidy up. I had a quick look befor when I tried to fit it. And it looked like I could do something?!?!?

Fingers crossed I will take pictures.

 

[alekos911]

Here is a quick list of things you can do to spice things up a bit:
1. More aggressive geo settings (zero toe or slight toe in up front, maximised front camber (pull out strut tower camber pins), reduce rear camber (this will make the car a bit more balanced) and slight toe in at rear)
2.Change front lower control arm bushings with either meyle HD or polybushes
3.Install a rear trailing arm limiting bushing kit.
4.use non runflat tires.

These mods are not extensive and can certainly make the car a bit more live! :driving:

 

[itguy]

Here is a quick list of things you can do to spice things up a bit:
1. More aggressive geo settings (zero toe or slight toe in up front, maximised front camber (pull out strut tower camber pins), reduce rear camber (this will make the car a bit more balanced) and slight toe in at rear)
2.Change front lower control arm bushings with either meyle HD or polybushes
3.Install a rear trailing arm bushing kit.
4.use non runflat tires.

These mods are not extensive and can certainly make the car a bit more live! :driving:

Thanks for these

Well I've just done (4) above and it has made a noticeable difference.

Ref (1) - where are the strut tower camber pins? I've not had the suspension apart, but can't see any adjustment on here anywhere? http://www.realoem.com/bmw/showparts.do?model=BT52&mospid=47797&btnr=31_0646&hg=31&fg=10

Do you have a copy of the setup sheet you're running (geo) for your car now then and how extreme is the tyre wear on the fronts with the camber pins removed?

Anyone have the factory geo settings?

 

[GuidoK]

Ref (1) - where are the strut tower camber pins? I've not had the suspension apart, but can't see any adjustment on here anywhere?

They're located on the top bearing of the strut tower:

the odd one with the hex fitting
If you remove that one you can wiggle the strut tower 1-2mm in the mounting holes. (mounting holes are oval):

 

[itguy]

Awesome, thanks

 

[alekos911]

Just to make a clarification, in (3) I meant a trailing arm bush limiter kit like the one Turner Motorsport makes.
I dont have my last alignment spec sheet with me right now, but if I recall correctly my settings were (almost 1 degree of negative camber at front and a little less than 1.5 degrees at the rear. My toe settings were 0.02mm front and 0.05mm rear, both are toe in but I am not sure about these values. In general this setting offers good traction during acceleration (due to the decreased rear camber) and good balance between understeer and oversteer. I havent noticed any uneven tire wear.

I believe that the Z4 platform is a good platform and offers great potential BUT you have to trim the handling to your own requirements. You can create a spreadsheet of what you want from your car and then try to identify what needs changing to meet your goals.

For example my top priorities where predictability and balance. So far I have done all 4 mods I mentioned in my previous post. In addition, I have installed a quaife lsd and a custom made bilstein suspension(custom valved for my own car and my own needs). My car has 17in (square setup) wheels. They dont look well but I can safely bet that my car behaves better than a zed with 18in or greater wheels in real world roads. Right now my car feels great to me. It is well balanced and gives you great confidence in all conditions.

You can also experiment with tire pressures. The recommended pressures for my car were 2.3 bar (F) and 2.6 bar (Rear). These are the recommended pressures for a full tank and 2 passengers. Since I usually drive alone I experimented with the pressures and ended up using 2.15 bar (Front) and 2.45 bar (rear). To define these pressures, I kept tire profile temperature data and notes on subjective feel for several combinations of pressures. The pressures I ended up with offer reasonable ride, good balance, nice steering wheel weight (https://www.tut.fi/ms/muo/vert/11_tyre_as_car_component/handling_cornering_pneumatic.htm) and plenty of information regarding the available levels of grip. The only downside is that they take longer to warm up.

That's all for now. Enjoy driving and be safe :driving:

 

[Brasseye]

Coming from sub 1000 kg cars,Id say no. Just too heavy. But a great GT style car.

 

[LeeZ4MR]

Coming from sub 1000 kg cars,Id say no. Just too heavy. But a great GT style car.

This

With BMW`s you have to adjust your expectation of them if you have experienced lighter or more powerful cars because they aren't really built as drivers cars in the first place in terms of sound or driver involvement...they are very nice to drive and I have liked all six of the BMW`s I have owned but I haven`t loved any of them and that tells its own story I think and for proper driving thrills you have to look elsewhere but as a tool to do a good job they tick the box for sure.

 

[craig3.2]

I would say the current e89 is more of a relaxed cruiser/gt car.
The e85/6 3.0i is a definite drivers car, more raw than the boxster, but more fun, imho....I found the boxsters/caymans to be a bit too well polished and too esay to drive quickly, with little skill required on the drivers part, as you get with a 911 turbo.
A 3.0i z4 is a car that you can drive on/near the limit out the box, once ditching the runflats, and gives you plenty enjoyment....loved going for a blast in mine just for the fun of it, as well as plenty spirited runs and meets.

The only thing that I added other than non-rft's was a strut-brace on my Roadster, which helped, though stiffer bushes(powerflex) added a slightly sharper feel, not something I would do again.

 

[Luke the spark]

Great thread guys, really interesting reading you guys know your stuff

 

[Beedub]

e85/e86 is as above a definite drivers car, and can be taken into proper sport car league with some tweaks, but theirs fine balance between going to far and actually creating a more enjoyable car, with some dropping the stock seats for something very light is a massive chunk of weight gone, weight is what id like to tackle next, imagine if we could get the car to low 1300kg mark.

 

[Brasseye]

Coming from sub 1000 kg cars,Id say no. Just too heavy. But a great GT style car.

Don't get me wrong. Driving the Z can be very rewarding,but the high weight loses a lot of agility compared with "driver" cars.

The extra weight gives more comfort giving the car a better ride.Just a bit of a handful on the corners (bit like a well sorted TVR !)

I know my Z4 E89 35i is maybe the heaviest Z at 1600kg. If this could be halved to 800 - 1000kg it would be the best all rounder car EVER.

The only car that comes close to the Z with a folding hardtop is the Mazda MX5 but the engine and gearbox are so far behind BMW,s offerings.

 

[Ed Doe]

As above, as far as I and many are concerned, the E86 is most certainly a drivers car.

Obviously by comparison to a sub-1000kg Lotus or similar it will feel numb and heavy, but by the same token the Lotus/alternative would most likely be tiresome to live with as a daily.

I wont pretend I've owned any super-powerful, uncompromised road racers in my time, but I did embark on a similar quest for 'improving the manufacturers recipe for a drivers car' with hot hatches a few years ago (I had amongst others two Peugeot 306 GTi6s. Yes I can hear the sighs already!)

In my opinion, the result ruined what had been an accomplished road car. It had stiffer arbs, torsion bars at the rear, bump and rebound adjustable coilovers with custom spring rates, adjustable caster and camber pillow-bearing top-mounts, braces, upgraded brakes with trackday pads and fluid, braided brake lines, light wheels with sticky rubber, bucket seats, 4-point harnesses, removal of the rear seats and sound deadening, and a load of engine work I wont bore you with. So yes on paper it was lighter, and cornered flatter, and had loads more grip. But no amount of mucking about with damping and rebound settings on the coilovers would give it the same road compliance as the OEM suspension. Unless the tarmac was completely flat, it skipped over bumps under braking and in cornering, and sacrificed grip. I still maintain today that an identical car with at most the Bilstein & Eibach equivalents of OEM suspension would have shown the car a clean pair of heels on all but a smooth track where that reduction in roll and additional grip would pay dividends.

I guess what I'm trying to say is beware of trying to make a car into something you think it should be. Increasing some characteristics of how a car drives will inevitably reduce its breadth of ability, and more often than not result in disappointment!

That being said, the M-diff, and having a play with geo following a discussion with a specialist who really can set the car up with the characteristics you want would probably give you a far more rewarding driver experience.


And I can't resist but leave a link to the Evo review of the Coupe here;
http://www.evo.co.uk/carreviews/evocarreviews/202574/bmw_z4_30si_coupe.html

 

[itguy]

I think this is the key reason for the thread - what can be improved, not what can I turn it into.

Clearly it will never be sub 1000kg and it would be too compromised if it were, but turn in could be sharper, it could corner flatter etc etc.

As per my first post, I know a decent geo can transform a car, my previous exige was super sensitive to minor adjustments.

I think camber and toe all round first, then take it from there.

 

[Ed Doe]

Sorry, I think I've waded in a bit there in retrospect :roll:

In my experience I felt that particularly coilovers on a road car just don't work in the way we all want them to!