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Modification ideas??

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wasupdu

Member
Minneapolis, MN
Alright, I'm kinda bummed. I was hoping to add a 3rd BMW to my garage tonight with a BMW K1200R Sport motorcycle being offered through the American Express website for $5k (USD) with an original MSRP of $17k. The damn bike was sold out even before it started if you ask me....long story, but I got my hopes up a little to high on that one.

Anyways, I'm up for a 'winter project' on the Z4. I'd like to keep it under $1k (USD) but I'm open to other suggestions as well. I have a "mod itch" in other words...lol. I'm fairly mechanically inclined, but not looking to do a turbo/supercharger quite yet. Cosmetic mods are good too. Kinda vague, but any ideas?


EDIT: I just ordered M6 wheels so those should be on within the next 2 weeks.
 
i was thinking about deleting the roundels on the side, have someone fill the hole, but i haven't found anyone that i trust with getting the lines to match!

Also i was going to get rid of the plastic rollbar covers and get some thing custom made.

Last I am trying to anodize my dash red! I have the dream red interior too.

Just some ideas, where did you get your m6 rims from? I am currenlty looking for a 18in set.
 
Active auto werke offers the software upgrade for $399 and some other interesting goodies :evil: CDV delete, stainlees steel braided brake lines
 
If it's handling your looking for then your first step should be to fit an upgraded set of suspension bushes and a good set of brake pads such as Pagid RS29's. It's not the most exciting thing to boast about to your friends but it makes the biggest diffrence for the least amount of money. The second thing is to remove the dowels on your front strut towers and push the struts inboard as far as they'll go. It takes about ten minutes to do and gives you about 1.5 degrees of negative camber. This helps a lot with front end grip when cornering. Don't be tempted to fit a strut brace unless you've done every other conceivable suspension mod. Long story but it's my pet hate! People tend to fit them as a priority for two main reasons. Firstly you can pop the hood/bonnet and dazzle your friends with your bling new bit of kit and secondly someone told them it will dramatically improve the handling of your car. The purpose of the strut brace is to slightly improve the structural regidity of the chassis and body which is great provided your suspension and drivetrain arn't flopping around under the car because you havn't addressed the real issues with the OEM parts. Rant over!

Looks wise the M6 wheels should look great. I've been considering fitting a set for a while now and it would be good to see a pic of yours once they're fitted. Aero sills are a nice mod and easy to fit. In fact the complete Aero kit might be worth considering. You can order it from your stealer pre painted and installation takes about 4 hours. Clear side indicator lights look good. Stubby antenna is another common mod.

LeatherZ do a lot of interior mods which seem to get good reviews on this forum, might be worth checking out their website.
 
Curtis said:
If it's handling your looking for then your first step should be to fit an upgraded set of suspension bushes and a good set of brake pads such as Pagid RS29's. It's not the most exciting thing to boast about to your friends but it makes the biggest diffrence for the least amount of money. The second thing is to remove the dowels on your front strut towers and push the struts inboard as far as they'll go. It takes about ten minutes to do and gives you about 1.5 degrees of negative camber. This helps a lot with front end grip when cornering. Don't be tempted to fit a strut brace unless you've done every other conceivable suspension mod. Long story but it's my pet hate! People tend to fit them as a priority for two main reasons. Firstly you can pop the hood/bonnet and dazzle your friends with your bling new bit of kit and secondly someone told them it will dramatically improve the handling of your car. The purpose of the strut brace is to slightly improve the structural regidity of the chassis and body which is great provided your suspension and drivetrain arn't flopping around under the car because you havn't addressed the real issues with the OEM parts. Rant over!

Looks wise the M6 wheels should look great. I've been considering fitting a set for a while now and it would be good to see a pic of yours once they're fitted. Aero sills are a nice mod and easy to fit. In fact the complete Aero kit might be worth considering. You can order it from your stealer pre painted and installation takes about 4 hours. Clear side indicator lights look good. Stubby antenna is another common mod.

LeatherZ do a lot of interior mods which seem to get good reviews on this forum, might be worth checking out their website.
Click to expand...

I agree with all of your post except the strut-brace part. :) In all honesty, I think aftermarket suspensions are an over-kill for most people unless one tracks/auto-x's the Z4, or unless there's 40k~50k miles on the car so one might as well start replacing parts before they're about to fail. Of course, doing it for - or at least partially for - aesthetic reasons is a whole other story. Most people don't push the Z4 to its handling limits in stock form. Adding an engine strut brace is a relatively cheap option and a good "first-step" to improve the turn-in feel a little bit and to improve the chassis rigidity (especially for the roadster). Installation is easy - almost everyone can do it in less than 10 minutes and all the tools required are a ratchet and a 13mm socket. If an engine strut brace isn't enough to satisfy one's handling needs, then of course go ahead and improve other suspension components. To me, do the simple and cheap stuff first, and if it's not enough, then open the wallet and go all out by all means.

When it comes to selling the car, simply spend another 10 minutes to uninstall the strut brace and re-sale value is usually pretty good (seems to be at least 50% or more).

Just my 2 pennies. :thumbsup:
 
I think your missing the point. The structural rigidity of the Roadster is actualy quite good. Making it slightly stiffer will have no effect whatsoever on handling because the system beneath the body is fundamentally flawed. When you turn in sharply a lot of forces are exerted on the suspension and steering components. The geometry settings which dictate the handling characteristics of your car change dramatically because the parts are all mounted using soft rubber bushes. These flex massively even under braking and acceleration. The main culprits are the large bushes on the front wishbones and rear trailing arms. These are huge blocks of soft rubber which you can easily move with a screwdriver never mind huge cornering forces. They are designed primarily for ride comfort while sacrificing handling. All those precious camber, castor and toe settings mean nothing when the systems are free to shift around freely.

Think of it this way. The front end of your car between the inner wings is already braced by two diagonal strut braces, a bulkhead/firewall, the front crossmember, the radiator panels and an engine. How much movement do you think there actually is in the body? Compare this to the main suspension components at the front that are held to the chassis by a 66mm block of soft rubber. Under any degree of force which do you think will flex most?

Even if you could completely illiminate body flex it would have a minimal effect on the handling characteristics of the components below it as long as they're flawed. I have nothing against strut braces, I have one myself. The difference is that I've sorted all the problem areas with the suspension. Once you've got everything as it should be there's no harm fitting a strut brace in an attempt to help lock those precious geometry setting into place but why try to preserve something thats useless in the first place?

A full set of upgraded bushes is cheaper than most strut braces and if your even slightly mechanically minded fitting is simple and free.
 
Curtis said:
The structural rigidity of the Roadster is actualy quite good.
Click to expand...


It might be good, but still far from the rigidity of the M-coupe. Not that adding a strut brace is going to make a world of difference or bring the roadster's rigidity close to the M-coupe's; it's simply not. But any little bit helps. As soon as I installed the strut brace on my roadster, I noticed that the interior rattles decreased some when going over rough pavements (the same roads that I drive on everyday). For that reason alone the strut brace is worth it for me and I wouldn't call it useless.

Also when BMW first started selling the Z4 strut brace, they also showed a (short) report of the strut brace adding X % of ridigity to the roadster's chassis. I can't remember what the number was and will need to do some digging. Perhaps Ron Stygar on bimmerfest already knows this stat.
 
All I'm saying is that it's a case of priority's. Start with the major flaws before tackling minor details. If your bonnet/hood is being crushed between the wings under cornrering then fit a strut brace. I have a 2mm gap between these parts in some areas yet even before fitting the strut brace there was no sign of them coming in contact due to body flex and I drive hard! In comparison I could move the wishbone in it original rubber bush by at least 10mm using a screwdriver as a lever. This pressure was minor relative to the forces exerted under driving conditions so I dread to think how much movement there is in day to day situations. If your strut brace helped with rattles then fine. Mine increased the rattles because the inlet manifold kept hitting it! I now use some washers as spacers.

I remember reading the stats for structural rigidity on Zforum and although I can't remember the exact figures I do remember that the Z4 Roadster was approximately four times as rigid as the Z3. Although the Z3 had issues I still think this is quite an acheivement and I won't be losing any sleep worrying about it.

By all means fit a strut brace but don't expect the results ( other than potentially helping with a rattle ) to be remotely near the results you could achive by tackling a real issue.
 
the rigidity of the Z4 is one of the reasons that I bought one it the first place - Its the only softtop that I have driven that the chassis is stiff enough to feel like a normal car.

The worst car I drove was a TT which felt like it was bending - I could feel the scuttle shake all the time

IMO if I had the money I would do the brakes 1st

mitch
 
I drive my '05 525 in the winter. The 525 is fitted with Michelin Pilot Alpin tires (mounted on the stock 17" wheels) that are an absolute dream in the winter. The Z4 is sleeping in the garage with Sta-bil in the tank, covered, oil changed, windows cracked, tires slightly overinflated, and battery inside on a battery tender.

I'll check out the Leather Z website again, but last time I checked a few months ago nothing really caught my eye. So far I'm leaning towards the aero kit and perhaps a dual exhaust....but that'll be quite a bit out of my price range. I suppose I could put my tax return check towards it come February.

Good suggestions so far. Thanks again. I'll post up pics as soon as I get the 19" M6 wheels with tires, but I probably won't be mounting them on the car until winter is over in March to avoid unnecessary flat spots.
 
I went for aero side skirts on my Z4M. They look especially good in black. They cost $194 per side unpainted. Got them painted for $340 and installed them myself.
 
Curtis said:
If it's handling your looking for then your first step should be to fit an upgraded set of suspension bushes and a good set of brake pads such as Pagid RS29's. It's not the most exciting thing to boast about to your friends but it makes the biggest diffrence for the least amount of money. The second thing is to remove the dowels on your front strut towers and push the struts inboard as far as they'll go. It takes about ten minutes to do and gives you about 1.5 degrees of negative camber. This helps a lot with front end grip when cornering. Don't be tempted to fit a strut brace unless you've done every other conceivable suspension mod. Long story but it's my pet hate! People tend to fit them as a priority for two main reasons. Firstly you can pop the hood/bonnet and dazzle your friends with your bling new bit of kit and secondly someone told them it will dramatically improve the handling of your car. The purpose of the strut brace is to slightly improve the structural regidity of the chassis and body which is great provided your suspension and drivetrain arn't flopping around under the car because you havn't addressed the real issues with the OEM parts. Rant over!

Looks wise the M6 wheels should look great. I've been considering fitting a set for a while now and it would be good to see a pic of yours once they're fitted. Aero sills are a nice mod and easy to fit. In fact the complete Aero kit might be worth considering. You can order it from your stealer pre painted and installation takes about 4 hours. Clear side indicator lights look good. Stubby antenna is another common mod.

LeatherZ do a lot of interior mods which seem to get good reviews on this forum, might be worth checking out their website.
Click to expand...

Ok I'm sold where do i get these bushing and is there a good write up on the removing the dowels?
 
Curtis

Perhaps we should all get off this tread and have a dedicated suspension set up thread/sticky and let wasupdu have his post back...lol

I've read your comments before on bushings, locking in suspension settings etc. and consider it all makes enormous sense. My question is a simple one in that if I replaced all the bushes from soft flexible OEM to presumably poly bushes, how much harsher and rattly would it make an everyday drive. I'm all for making it tight and precise on corners but not at the expense of making a bone rattling track car out of a great all rounder that the Z is.

wasupdu

I've done a lot of mods in a few months but real cheap ones to add to the thought process:
Replaced the aerial with a 3" flexible rubber (from USA)
Fitted a set of alloy pedals - gives the cockpit and much better look
Clear repeaters and rear third brake lights
Different style rear light cluster
High quality/low dust brake pads
 
I cannot comment on bimmers but the feel of poly bushings on my camaro was great. She did not become excessively stiff to tell the truth. Then again my z is already fells harsher and rattly thanks to the RFTs.
 
The thread was kinda hijacked!

You can usualy choose how stiff you want the bushes to be from OEM to solid alloy. The stiffness of the front wishbone bushes won't have any effect on ride comfort because they simply work as a pivot for the rear of the wishbone, any irregularities in the road surface are absorbed by the struts in a vertical motion rather than the wishbone bushes. The same can be said for the rear trailing arm bushes. There may be a slight increase in transfer of vibration though firmer bushes but none that I've noticed. Turner Motorsport supply all the necessary goodies and you can order all the parts through Simpson Motorsport in the UK. Another option for the rear trailing arms is to fit the limiter kit which retains the OEM bushes but prevents them flexing beyond a sensible point. I tried these before moving to solid bushes and they were very effective. If your worried about vibration/ride comfort then polybushes may be the best option. They're not as firm as the nylon/alloy bushes I fitted but they still make a dramatic difference. Check out the E46 section on Turners website, many suspension parts are interchangeable with the Z4.



http://www.turnermotorsport.com/html/sh ... aramCat=Z4

http://www.simpsonmotorsport.com/defaul ... &name=Home
 
Defy:

If you look at the top of your stut tower you'll see the three nuts which secure the top strut mount to the tower. You'll also notice a dowel with an allen key fitting. The three nut's hold the strut in place through elongated holes. The dowel positions the strut tops in a fairly central position which is preset at the factory. If you jack the car up, remove the dowel completely then slacken off the three nuts you can move the strut top along the elongated holes. If you hold the strut at the most inboard position and tighten up the nuts you now have 1.5 degrees negative camber!
 
but if you do that you will have uneven wear on your tyres and they will last substantially less to what they normally would though wouldnt they?
 
Curtis said:
Defy:

If you look at the top of your stut tower you'll see the three nuts which secure the top strut mount to the tower. You'll also notice a dowel with an allen key fitting. The three nut's hold the strut in place through elongated holes. The dowel positions the strut tops in a fairly central position which is preset at the factory. If you jack the car up, remove the dowel completely then slacken off the three nuts you can move the strut top along the elongated holes. If you hold the strut at the most inboard position and tighten up the nuts you now have 1.5 degrees negative camber!
Click to expand...
^I highly recommend this...
It makes a HUGE change in the handling.

I recommend doing a full alignment when doing this though.
If you just crank the camber over you also affect the other settings.
 
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