Shaking Z4 on Track Day - Brakes need upgrading

[k31ron]

Went to Oulton Park for a very cheap "novice" track day on Friday...the criteria for being "novice" was apparently only having attended a max of 3 previous trackday's...it quickly became apparent that very few people fitted this Critieria, with some very rapid cars and drivers in attendance and the few legit novices quickly blitzed and overwhelmed.

Anyway I didn't really get chance to test my "ego" as after 2 laps the car started shaking violently, immediately came in to inspect expecting to find my wheels hanging off...no visible issues and after a quick and enthusiastic drive round the local roads no problems evident...odd...so back onto the next session and same occurrence 2 laps and car starts shaking but realise this time only on the brakes...

came in again and had a chat with some of the helpful racers! (couldn't find a novice) and they thought it was warped disks (or material on disks) on the road they don't get hot enough to be an issue but on the track (even in the rain) they get a lot hotter.

I stuck it out for a bit (trying to not use the brakes much and minimize the vibes) but it wasn't much fun and left early, all fine on the way back.

So it sounds like I probably need new front disks and pads if I'm to do a track day again, if your going to replace may as well upgrade any recommendations on pads and disks? (2004 3.0 E85) always been a fan of Mintex and Pagids on past cars. Also is it an easy change to upgrade from 300mm to SI standard 325mm disks? (searched but didn't find definitive answer) do you just need a different calliper hanger?

 

[mmm-five]

You've probably got some pad transfer which may take 500 miles of A/B road driving/braking to smooth out.

It sounds like you've been braking late and then harder & harder to slow you down for a corner. It's what I'd expect as a novice, and did it myself!

It's not really bad until you realise that there's nothing left in the pedal to slow you down anymore once you've pressed it as hard as you can.

I prefer to get the big/heavy braking out of the way early on in the braking phase (when the air will have the most cooling effect), and then lift off the pedal to gain more control & take the car off it's nose. With this method you can always use the brake again if you're

Bigger brakes will not help with your braking technique and you'll just 'damage' more expensive discs. Some instruction really helped me, and made my cornering much smoother & faster.

 

[wilbo]

Can't offer advice unfortunately, but just wondered were you running OEM pads?

 

[Toe-side]

325mm's need caliper and carriers + new discs of course. Bolt on mods very easy. Sourcing the 330 calipers is the worst bit. There is loads of info in the How to brake guide.
Rear discs are difficult to increase in size without some engineering.

mmm-five is right... bit more time on the track and your braking technique will improve dramatically.
Change to a Dot 5.1 fluid with higher boil temp. Helps a little also.

 

[Stug]

I have a pair of almost new 3 .0si front discs that I removed from my coupe when I did an upgrade going cheap. If you need them?

 

[k31ron]

You've probably got some pad transfer which may take 500 miles of A/B road driving/braking to smooth out.

It sounds like you've been braking late and then harder & harder to slow you down for a corner. It's what I'd expect as a novice, and did it myself!

It's not really bad until you realise that there's nothing left in the pedal to slow you down anymore once you've pressed it as hard as you can.

I prefer to get the big/heavy braking out of the way early on in the braking phase (when the air will have the most cooling effect), and then lift off the pedal to gain more control & take the car off it's nose. With this method you can always use the brake again if you're

Bigger brakes will not help with your braking technique and you'll just 'damage' more expensive discs. Some instruction really helped me, and made my cornering much smoother & faster.

Thanks for the tips, Probably should have said I'm not exactly unfamiliar with trackdays either ;-), my issue with this day was that I used to run my own “novice orientated” track evenings at Donnington with the VX220 forum and I wouldn't have allowed this disparity of people on my sessions, I just think its intimidating to people who've never been before and just want the “experience”.

I freely admit I've plenty to learn if I wanted to be faster, my focus and advice to people has always been just have fun and stay right side up I sadly don't have the requisite natural skill or training to offer much more, I always leave that to the professional ARDS trainers, who unlike me know what they are talking about.

As I understand it it’s unlikely a couple of gentle laps on a wet track will have caused the problem even with my relative ineptness, I suspect its pre-existing condition (either from defective materials, previous owner or the fact its been left standing for a few months) that only started to become evident when started to give my brakes a bit of proper stick something you don't really get to do on the road unless you’re doing a twisty alpine descent or similar.

My interest in upgrading is that there's often plenty of scope to make things better, I upgraded my old VX220 to Mintex 1144 all round and it transformed the braking feel from somewhat wooden to very progressive and capable of sustaining a full track session without fade… because of the vibration I issue I didn’t really get chance to explore out what my Z4 braking was like and until I get it resolved I’m not likely to find out if it’s a limiting factor, but always interested in a an easy upgrade.

325mm's need caliper and carriers + new discs of course. Bolt on mods very easy. Sourcing the 330 calipers is the worst bit. There is loads of info in the How to brake guide. Rear discs are difficult to increase in size without some engineering.

Thanks for that, not sure I want to get into trying to find some 330 calipers, think I will probably just look at some performance pads and decent disks.

 

[Toe-side]

"325mm's need caliper and carriers + new discs of course. Bolt on mods very easy. Sourcing the 330 calipers is the worst bit. There is loads of info in the How to brake guide. Rear discs are difficult to increase in size without some engineering".

Its not that time consuming all the data you need is here http://www.z4-forum.com/forum/viewtopic.php?f=24&t=8399

Phone a couple of breakers, breaking a E46 330 model (any) and hey presto. £60-80 quid should get a set and the extra 25 mm does help. :wink:

 

[k31ron]

"325mm's need caliper and carriers + new discs of course. Bolt on mods very easy. Sourcing the 330 calipers is the worst bit. There is loads of info in the How to brake guide. Rear discs are difficult to increase in size without some engineering".

Its not that time consuming all the data you need is here http://www.z4-forum.com/forum/viewtopic.php?f=24&t=8399

Phone a couple of breakers, breaking a E46 330 model (any) and hey presto. £60-80 quid should get a set and the extra 25 mm does help. :wink:

Dammit you've got me tempted a couple of calls to breakers and I get the callipers for £40! (I also noted on Ebay that you can buy brand new "pattern" calipers for about £70 not sure how good they are) and my brake fluid probably does need changing...

so its literally remove old callipers and hanger, put new one's on, bleed and your ready to go? no additional parts required?

alternatively I could get these

http://www.ebay.co.uk/itm//221350331577

cant believe there is a market for them.

 

[Stug]

OEM brakes on all engine sizes are poor for track days, only the M brakes are fine, mine are utter turd and a new BBK is on cards soon

My 3.0si brakes did a fine job. Drive smoother and use less brakes maybe Jonny? :wink:

 

[aquazi]

For a track i quite like ebc yellow stuff... Although wouldnt want it for road use.


Sent from my iPhone 5s using Tapatalk

 

[Toe-side]

"so its literally remove old callipers and hanger, put new one's on, bleed and your ready to go? no additional parts required?"
Other than 325mm discs ........nope!