K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

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AndyBeech
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K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

Post by AndyBeech » Tue Apr 13, 2021 6:55 pm

Just a mini review thread for those that may be interested in the above parts / places! Previously done a suspension refresh and a few other bits that can be found in previous thread I've done. The (sort of) aim overall with this car is to keep a decent road going car without too many compromises that can also be used on track reasonably well from time to time, not for chasing lap times and ultimate speed at all but to enjoy a good day out while keeping things safe and going home at the end of the day in the car, rather than using trailers....or worse on a recovery truck! In essence a road going car first and foremost that can do a few track days a year as well.

Decided to use this winter to gather some more parts for the M having done a few track days last year and some general driving and found a few areas that were, in my opinion, lacking.

Brakes

Firstly, and most importantly! While the standard setup is certainly not bad at all, I did find that they fade relatively quickly when pushing on which is probably the most unnerving (and potentially dangerous) part of doing track days. Good brakes give you so much more confidence to push on a bit and once the pedal starts getting longer it also makes it more difficult to heel and toe and it all starts getting a bit hairy. At least for a bit of a novice such as myself! On the road the standard setup I feel is less of an issue, but then I don't drive like a lunatic on the roads.

So in respect of keeping one eye on still being useable on the road (albeit not a daily driver) I decided to go for the K Sport front brake kit and Pagid RSL-29 pads all round keeping the standard rear calipers and discs. Obviously there are better kits available, AP, Alcon etc. However with the usage my car gets I struggled to do the man maths on those. No doubt better kits, and if I was doing more track work than road usage the maths would have made more sense. The RSL-29 pads however are not cheap whichever way you cut it but for me they made sense in that (from what I've read) they wear well, are relatively kind to the discs and you won't have to worry about stopping power or fade so that made my mind up. I was apprehensive about potential noise, performance from cold etc. I'll come to that in a bit.

I used RBM in Hook to fit all these parts by the way, good stuff from Ross and happy with his work and well priced as well so would certainly recommend him in future and to anyone else in the area.

I had concerns initially that the K Sports wouldn't clear the 18" track wheels I have, luckily no problems though and fitted without needing spacers or any other work, bonus! Obviously no issues clearing the 19" wheels. (Yes I have new wheel nuts to replace the old shabby looking ones :lol: )
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Not a fan of the K Sport branding as such but.....I'm also not going to peel the sticker bits off and pretend they're AP's either using suitable stickers, much as I'd like to, that would be far worse!

Ross said there were no issues when coming to fitment of the kit. Nice and easy, just a trim of the RSL pads backing plate to get them to fit all the way in the calipers. The pads aren't made specifically for the K Sports, they use the AP caliper fitment hence the slight trim of the backing plates needed. Obviously rears are no issue. When I get a chance I'll weigh the OEM calipers to see the weight difference to the K Sports. I know the K Sports calipers weigh 3.1kg each and the discs 10kg each so I'm expecting a reasonable saving there, possibly offset by the bigger disc though. Discs are floating by the way and grooved rather than drilled. I believe grooved are better if you intend to go on track due to drilled discs potentially cracking around the holes when hot, remember TomK demonstrating this nicely on a previous thread I believe! It does mean I have drilled at the rear and grooved at the front, not great for the OCD but function over form! Fresh RBF600 brake fluid as well.

On the road.....wow, very impressed. The initial bite...even from cold (and it has been cold the last few days!) is insane. It's hard to not chuck yourself through the windscreen the first few stops, it really bites...and like I say that's from relatively cold. Pedal feel is excellent and you don't get that massively loud groaning on heavy stops you get with drilled discs either, at least not the same extent. My only slight concern is that they bite so well near the top of the pedal my heel and toe technique might have to be adjusted but I think once they bed in and the pads wear down a bit it'll be a bit better in that respect. In short, the difference really is night and day, it's almost a bit of a shock initially. I can't comment on fade yet until I get on track and really try them in anger, hopefully next week at Bedford. I'm really not expecting many problems in that area anymore, given reasonable stints and breaks in-between, it's still a heavy car of course regardless so still have to bear that in mind.

Niggles, well none really. Initially the fronts do bind slightly but I put this down to bedding both the calipers and the pads in. I think I could have taken a couple of mm off the pads to alleviate the issue as I think there is just a fraction too much material from new for the calipers. I'll keep an eye on it but I'm not expecting any issues after a few hundred miles and certainly after a track day, imagine it will be fine before then though.

On the noise front, way better than I was expecting. Haven't heard the pads rattling around at all and any squeal on stopping is very very minor and often none at all so both are none issues for me. I'll update if this changes. I have heard some people have mixed results with the RSL's in this respect so maybe I just got lucky but I wouldn't let it put you off them if your considering it.
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Camber Plates

I don't think these are necessary for most to be honest as there are other ways to get camber which are a lot cheaper. I got a good deal on them though from the good old US of A and the 'man maths' again worked out for me. I did have this rather misguided idea though that you could easily chop and change the camber between a road setting and track setting myself with just a jack and a spanner, in short it's not that simple and if that's your goal for camber plates then I wouldn't bother. In short, because of the slotted nature of the original top mount holes it's more faff and possibility of getting it wrong even if you mark the plates with separate road and track setting. So yeah, I won't be doing that (plus I believe it messes with the toe when you change camber also).

However! The plus side is you can get a nice range of camber adjustment on them which is really the point, stupid as it sounds. I went for the Ground Control 'street' versions and they are a lovely bit of kit and can probably be adjusted to around -2.7 though I haven't maxed it out that far yet.....road car first, track work second!
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Ross again said no issues fitting them. Just had to wait until a trip to Center Gravity to get a proper geo done. Not much else to say on them for now, they seem well built, look good and no noises.....yet. However, I've been warned they will almost certainly get a bit noisy once they wear in a bit. Something I'll have to report back on in future. At worst, they'll likely knock a bit at low speed over heavier bumps, at regular speed's this shouldn't be an issue, or at least won't hear it anyway! Either way, all good so far, and if your thinking about them, go for it in my opinion.
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Visit to Center Gravity for Chassis tune / Geo

I suspect a few people have heard of these chaps. Based up near Birmingham and do a lot of work on Porsche's and high end machinery. A very nice Ferrari was there while I was, as an example! Was the only picture I got while my car was out getting tested, forgot to get any others amongst the chatting and coffee drinking :roll: Really need to get on top of my photo taking efforts.
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They've got an excellent rep, and having been there now I can say rightly so in my opinion. Elephant in the room, they are not cheap. If your expecting a sub £100 set up and go while the mechanic tries to tell you that 'the camber (or any other setting for that matter) can't be adjusted on these mate' :roll: ,it's not for you. Think £400 as a baseline.....

Having said that, I feel it was worth every penny. They book you on for a whole day as a worst case scenario so you know your not just getting a quick adjustment. Pete talked me through the process on arrival, talking about the car's previous behaviour handling wise and what I now wanted out of it. I would say suspension / geo is probably my weakest knowledge area when it comes to cars so to have him talk me through loads of different settings, the effect one area can have on another etc. was incredibly useful, I learnt a lot.

Anyway he took the car for a drive to get a baseline feeling then the work was underway. It's very much a whole chassis evaluation, any parts that are worn, not fitted correctly, improvements that can be made etc. Biggest one for me...the suspension was lowered far too much, so much so it was basically riding on the bump stops. Not good. I thought it felt a bit 'crashy' :lol: . So ride height was sorted, raised up a bit front and back. Various other tweaks also, the brake cooling, greasing tie rods, checking for rubbing of wheels / suspension etc.

Corner weighting, my weight simulated in the drivers seat (85kg, it's been a tough lockdown! :lol: ) and a roughly full to 3/4 tank of fuel as that's mostly how I drive, and turn up to tracks with an almost full tank. So it's a bit on the tubby side certainly, though not so bad bearing in mind the above.....
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I'm not stripping out any parts for weight saving so sadly that'll be pretty much it as good as it gets but I can live with it, don't want to sacrifice road going equipment comforts! As far as the actual Geo goes, I would say it's a relatively safe set up and a good compromise between road and track. More camber was possible but for now I'll see how I go as it is. What I can say is it felt absolutely fine on the road, in hindsight maybe could have pushed the camber a bit more but that's easily doable in the future if I want to. Cup 2 tyres don't work great with any less than -2 camber so it should be a bit of a beast around corners, talent notwithstanding!
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In short, the car feels brilliant on the road now, on track it should be even better. That's when we discussed a 'road' setting and a 'track' setup on the plates and it just wasn't worth the hassle.

The guys are very friendly here and we chatted at length about various things, more than happy to share their knowledge and answer my questions all things suspension and geo. Nice place to relax also, get a full view of your car being worked on and also often go into the workshop to ask any questions or go through anything at all / see what's being done. You are very much part of the process, very very far from your usual setup shops. Having said that, I'm sure there are other places equally as good, I felt more comfortable going with tried and tested on this occasion though and glad I did. I would highly recommend them especially if you've had new suspension fitted and you want to go through set up and how to get the best out of it. It's the first time I think I've had a geo setup where I wasn't a bit sceptical afterwards or didn't feel like I really knew what was being adjusted and why. Say's it all that I was running around on the bump stops for the best part of 6 months..... :headbang:

Anyway, yes be aware it's not a cheap day out, but well worth it in my opinion.

Hope that helps someone! Will probably add to this in future as I get more experience with how everything's working. So far though, so good!
Also did a few other bits that get an honourable mention, M3 strut brace, new front arch liners....on these if you do replace them, get normal Z4 ones and they just require a tiny bit of trimming to fit. A LOT cheaper than M one's and they're exactly the same otherwise, thanks to someone on here for that tip, can't remember who now! Strut brace also fits fine and plenty of M3 one's about so easy to get a bargain, such as I did, Z4M one's are rocking horse poo and have the price to go with it.
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Last edited by AndyBeech on Tue Apr 13, 2021 10:47 pm, edited 1 time in total.
Z4MR - Gruppe M, Bilstein PSS10, CSL's + 18" CSL reps with Cup2's, RTAB Limiters, Powerflex’d, PF Camber Arms, K-Sport BBK / RSL-29, GC Camber Plates, Strut Brace, Exhaust valves, custom brake cooling, complete underside refresh!

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K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

Post by TomK » Tue Apr 13, 2021 8:02 pm

Nice update Andy! Looks like a great selection of mods :thumbsup:
I've sent a friend of mine to CoG with 4 P cars based on all the good things I've heard, never been myself mind, maybe one day. Glad to hear you too felt the money was worth it. I've learnt over the years that geo/ride height damping is so crucial, it's very easy to ruin a car.
AndyBeech wrote: Tue Apr 13, 2021 6:55 pmI believe grooved are better if you intend to go on track due to drilled discs potentially cracking around the holes when hot, remember TomK demonstrating this nicely on a previous thread I believe! It does mean I have drilled at the rear and grooved at the front, not great for the OCD but function over form!
Sadly that's not been my experience, I've cracked (now) many sets of slotted discs both by AP and Performance Friction at unpleasant expense. You have andre's cooling kit though right? Hopefully that should help.
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How are the PSS10 going? I've been thoroughly disappointed with my KW CS, terrible build quality and they don't feel a patch on the intrax I used to run on the m3. The flipping internal nut holding the piston on backed out recently :( Luckily no damage and rebuilt fine, but I'll be keen to get shot of them when I can justify the cost of some decent shockers. KW customer service must be the worst I've ever experienced to top things off!

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K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

Post by AndyBeech » Tue Apr 13, 2021 9:06 pm

TomK wrote: Tue Apr 13, 2021 8:02 pm Nice update Andy! Looks like a great selection of mods :thumbsup:
Cheers Tom! I found there's not that much information on some of this stuff for our cars so always useful to throw experiences in the pool for future reference for others, even if it is relatively niche.
I've sent a friend of mine to CoG with 4 P cars based on all the good things I've heard, never been myself mind, maybe one day. Glad to hear you too felt the money was worth it. I've learnt over the years that geo/ride height damping is so crucial, it's very easy to ruin a car.
Yep likewise, I've been burnt many times by various places not doing what I hoped, giving excuses for not adjusting stuff or just plain doing a duff setup so thought I'd splash the cash this time and get it right. The advice and chat I had was worth a lot of the money alone. To be honest it seems like you have a good handle on geo type stuff, remember you saying you do some of it yourself these days? They're not wizards as such and I doubt they do anything that someone else couldn't do, it was more the whole experience for me. But yes, would recommend them. He also said he'd more than happy to respond to any emails for advice in the future with any questions so that was also a nice touch. :thumbsup:
Sadly that's not been my experience, I've cracked (now) many sets of slotted discs both by AP and Performance Friction at unpleasant expense. You have andre's cooling kit though right? Hopefully that should help.
Ah ok, apologies I just remembered a thread about drilled discs and micro cracking around the holes and thought it might have been yourself. I do remember you mentioning that about slotted discs come to think of it. Well I'll see how I go on them, didn't have much choice to be honest at the time of purchase but when the time comes I'll no doubt be looking elsewhere for discs. I do have the cooling kit so hopefully might prolong the life of them a bit....maybe! Those discs must've been glowing before they cracked, blimey :cry:
How are the PSS10 going? I've been thoroughly disappointed with my KW CS, terrible build quality and they don't feel a patch on the intrax I used to run on the m3. The flipping internal nut holding the piston on backed out recently :( Luckily no damage and rebuilt fine, but I'll be keen to get shot of them when I can justify the cost of some decent shockers. KW customer service must be the worst I've ever experienced to top things off!
The Bilstein's are pretty good so far, can't complain at all. No issues yet though I haven't really done that much mileage on them yet to give a completely fair assessment. Glad I went with them over the V3's for now, saved me enough pennies to spend elsewhere which was useful. Obviously Clubsports are a different league, and to be fair designed for a different kind of usage!

Very surprised to hear about your experience with KW! Don't hear that often! Sorry to hear about the issues though, I do find myself getting annoyed with the niggly stuff the more bits get modded but guess it's part of the territory to an extent. Either way sounds like a bit of a nightmare all told, I presume Intrax is yet another step up again? (And in terms of price!).

Out of interest, and slightly off topic, do you ever wonder about ditching the M and going elsewhere? As in you're kind of reaching the limitations of the chassis or getting a bit tired with it for want of a better word? I guess cost is a factor but I guess a 911 or similar would be a next step up from an M...
Only reason I ask is I look at the amount I've spent (roughly anyway, the exact total would be too painful!) and think I could probably be in something like a Porsche quite easily by now...not that its necessarily better....but I do wonder why I'm ploughing so much money in to a 15 year old car sometimes! I suppose one plus is I own this outright rather than having to get finance on something newer...
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K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

Post by TomK » Tue Apr 13, 2021 9:57 pm

AndyBeech wrote: Tue Apr 13, 2021 9:06 pm The Bilstein's are pretty good so far, can't complain at all. No issues yet though I haven't really done that much mileage on them yet to give a completely fair assessment. Glad I went with them over the V3's for now, saved me enough pennies to spend elsewhere which was useful. Obviously Clubsports are a different league, and to be fair designed for a different kind of usage!

Very surprised to hear about your experience with KW! Don't hear that often! Sorry to hear about the issues though, I do find myself getting annoyed with the niggly stuff the more bits get modded but guess it's part of the territory to an extent. Either way sounds like a bit of a nightmare all told, I presume Intrax is yet another step up again? (And in terms of price!).
Glad to hear, I hear many good things about them/
There's not much difference between V3 and clubsport in terms of the shocker, the spring and top mount is though. From what I have read I'm certainly not the only one with issues (the design fundamentally in certain parts is a bit crap) and definitely with requesting support from KW uk. That said there seems to be no perfect company and you'll hear of bad experiences across the board inevitably.
The intrax set I want come in around 4k so yes a step up, and they have their own issues too. The damping is otherworldy though in comparison ime.
AndyBeech wrote: Tue Apr 13, 2021 9:06 pm Out of interest, and slightly off topic, do you ever wonder about ditching the M and going elsewhere? As in you're kind of reaching the limitations of the chassis or getting a bit tired with it for want of a better word? I guess cost is a factor but I guess a 911 or similar would be a next step up from an M...
Only reason I ask is I look at the amount I've spent (roughly anyway, the exact total would be too painful!) and think I could probably be in something like a Porsche quite easily by now...not that its necessarily better....but I do wonder why I'm ploughing so much money in to a 15 year old car sometimes! I suppose one plus is I own this outright rather than having to get finance on something newer...
Hah, not really to be honest. I've kind of resigned myself to getting the best out of this car. I have had some good seat time in a 997.1 gtr3rs which is probably all I would swap for, or a gt4. Both great cars no doubt, but a tricked up z4m is close to if not far on a par at far less cost. I can afford (ish) to lose 30k worth of car if it all went terribly wrong, but 100k I would have a bit of an issue, that would dull my enjoyment of either I've concluded (yes I know there is track insurance but the excess etc and general expense...). I love driving the z4 for all it's foibles and would miss the S54 greatly also :wub:
MC IB, CSL box, Schrick 288/280 cams, SS race cat back, AP Racing BTCC brakes, Apex ARC-8 with AR-1, KW ClubSport, Turner arms & RTAB limiters, Vibratec mounts, Rogue pulleys & RSMs, Tillett B6, UUC ssk, custom half cage

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Post by AndyBeech » Tue Apr 13, 2021 10:30 pm

TomK wrote: Tue Apr 13, 2021 9:57 pm
Hah, not really to be honest. I've kind of resigned myself to getting the best out of this car. I have had some good seat time in a 997.1 gtr3rs which is probably all I would swap for, or a gt4. Both great cars no doubt, but a tricked up z4m is close to if not far on a par at far less cost. I can afford (ish) to lose 30k worth of car if it all went terribly wrong, but 100k I would have a bit of an issue, that would dull my enjoyment of either I've concluded (yes I know there is track insurance but the excess etc and general expense...). I love driving the z4 for all it's foibles and would miss the S54 greatly also :wub:
Fair one, and don't get me wrong, certainly not looking at replacing it, just makes me wonder sometimes! I feel the road / track hybrid I'm going for, albeit both compromised to a degree, will keep me interested for quite a long time to come. Like you say the S54.....though you've just reminded me about your carbon airbox....can see another few k's going down the pan sometime soon! :lol: I see Turner are doing what looks like a reasonable copy these days, might have to investigate soon....
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Post by RedUn » Wed Apr 14, 2021 8:04 pm

Great review Andy, I've been using Chris and Pete for geo since 2005, they are spot on everytime, I wouldn't go anywhere else.

Tom surprised at the CS issues mine have been great although less track time than yours!

Courtesy pic at CG :thumbsup:
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K Sport BBK - RSL-29 / GC Camber Plates / Center Gravity Geo - Mini Review

Post by TomK » Thu Apr 15, 2021 7:56 am

RedUn wrote: Wed Apr 14, 2021 8:04 pm Tom surprised at the CS issues mine have been great
To be fair, cornering force, who I sent them to in the end have seen this issue on other brands so it's not just a kw thing.
MC IB, CSL box, Schrick 288/280 cams, SS race cat back, AP Racing BTCC brakes, Apex ARC-8 with AR-1, KW ClubSport, Turner arms & RTAB limiters, Vibratec mounts, Rogue pulleys & RSMs, Tillett B6, UUC ssk, custom half cage

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