# Z4 track prep.. any thoughts?



## Ares2600 (Mar 7, 2007)

Hey everyone,

I'm taking my Z4 to the track for the first time here in April and I'm starting the process of waking her up from winter hibernation and getting things ready. It's an '03 3.0i. Here's what I'm planning on right now:

New Rubber to replace the run-flats - BFGoodrich KDW2's
225/40ZR18 up front and 255/35ZR18 --- that's on the '03 18" wheels from BMW. Anyone have any experience with different size tires that might fit those wheels?

CDV delete (just haven't gotten around to that one)

Hawk HP-Plus pads and frozen rotors

Not looking to 'upgrade' the car now as I want to get a feel for what needs the most tuning with a few lapping weekends this spring and then move on from there.

Any other thoughts on 'must have' preparations? (Besides normal Brake/clutch fluid change/bleed and other maintenance items)

I've got a strong base of knowledge in my friends over at trackpedia, but I'm the only late-model BMW owner to date over there and thought I might solicit some insider info.


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## elbert (Mar 28, 2002)

I used to be bullish about KDW2, but now I have mixed feelings about them. I used them for track use before I switched to r-comps.

They're durable, have big tread blocks that won't squirm under hard cornering, and have stiff sidewalls that IMO gives good turn-in response and feel. Pretty cheap too.

The one downside is when track conditions are cold and wet, the tires aren't very good at all. But since this is your first track event, it probably won't make much of a difference.

Can't really make a size recommendation without knowing the wheel width. The "widest tire possible" isn't always best.


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## cwsqbm (Aug 4, 2004)

On the stock rims, I'd stay with the stock size tires for now. With the short side walls, there shouldn't be much squirm, and wide isn't necessarily better. By the time you are thinking wider, you'll also be thinging R-compound and suspension mods.


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## Nick325xiT 5spd (Dec 24, 2001)

Stay with the stock tires. There's no real reason to waste money on tires that you're going to destroy anyway.

The CDV isn't really relevant on track - it's more of a street smoothness issue.

And the HP+ pads are NOT ACCEPTABLE for track work. Use real track pads or stick with OEM.


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## Ares2600 (Mar 7, 2007)

My current tires need to be replaced anyways, so this isn't a replacement just for the track. I would've picked the KDW2's either way.

I'm interested in your assessment of the HP+ for the track. I've gotten great recommendations about them as a pad that can work on and off the track. Specifically a heavily tracked Ferrari 348 as well as a 996 C4. You think the HP+ is actually worse than OEM? That's surprising. Could you elaborate?


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## mikea128 (Jul 20, 2004)

the issue i've frequently heard about HP+ is that they work great until they hit MOT (max operating temp), but then the coefficient of friction falls off very rapidly, potentially making for a very unsafe scenario due to very little warning of pad fade. Some people have been able to get away with them on track, but once you exceed their capability, the results are potentially disastrous. This has primarily been advocated by Dave Zeckhausen of Zeckhausen racing and reportedly comes from Hawk themselves. The same goes for Hawk HPS and Performance Ceramic. HP+ is also not a very good street pad - noisy, dusty, and hard on rotors. Some people use it in a hybrid street/track application, and you'd probably be ok on a light car, but not a late model BMW. 

I highly recommend a dedicated set of track pads if you get serious. If it's your first time, you'll be fine on OE pads, which have a more progressive fade. If you get "warped rotors" (which are really due to pad deposits), then you can safely say you've exceeded the capability of OE pads and start looking into track pads. Make sure you take a cool down lap and go easy on the brakes to try and let them cool. Don't come to a complete stop in the paddock either with your brakes and don't park with the parking brake on. This will help avoid pad deposits on the rotors as well.

I'd skip the frozen/slotted/drilled/whatever rotors too and stick with OE blanks - there's no real world benefit IMO, but this is hotly debate. 

Unfortunately, there's really not a good compromise pad - believe me, I've looked hard. All the options out there are either crappy street pads, crappy track pads, or both. The best compromise I've heard of is the Ferodo DS2500, which can be a bit noisy on the street, but otherwise not too obnoxious. Probably next best is the Performance Friction Z-rated are supposed to be similar to the HP+, but better on the street (not noisy, less dust, not aggressive on rotors). If you go with the PFC Z, get them from Bimmerworld to ensure that you get the updated compound.


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## AzNMpower32 (Oct 23, 2005)

Ares2600 said:


> My current tires need to be replaced anyways, so this isn't a replacement just for the track. I would've picked the KDW2's either way.


I think there's a "break-in" period for new tires, where for like the first 300mi or so they don't achieve their optimum grip. Something about the manufacturing process that leaves a residue on the tires' surface.

For a first timer, I agree with those that say stick with the OEM pads. The hardcore racers who do this often sometimes get their own aftermarket pads, but from what I've gathered, the OEM pads will work very well on the track.


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