Z4 MC trackday upgrade: camber plates and Tyres

[Curtis]

og-m3

I havn't found the reduced shock stroke to be a limiting factor to be honest and I run them quite low, are you worried about the linear deceleration effect?

Regarding the reinforcing plates I was going to buy some from Rogue but in the end I fabricated my own and welded them in on the underside of the shock tower. The Rogue units looked good but I preferred to just reinforce the whole upper tower. I also did the same to the front subframe but I left the front towers standard because there was very little increase in force applied to them and I would just be wasting my time and adding weight.

Wondermike

LOL!!! Not really. But I know enough that I can laugh when someone says they fitted a strut brace to an otherwise standard car and now it handles like it's on rails! Thanks though!!

 

[og_m3]

og-m3

I havn't found the reduced shock stroke to be a limiting factor to be honest and I run them quite low, are you worried about the linear deceleration effect?

Thanks for th info!
in addition, im also worried about bottoming out the shock in street driving conditions. California freeways arent the greatest, especially with the expansion joints. i also commute about 40-50 miles a day, so it is a street and track car.

og-m3

Regarding the reinforcing plates I was going to buy some from Rogue but in the end I fabricated my own and welded them in on the underside of the shock tower. The Rogue units looked good but I preferred to just reinforce the whole upper tower. I also did the same to the front subframe but I left the front towers standard because there was very little increase in force applied to them and I would just be wasting my time and adding weight.

nice! thanks for the tip, i may do that as well wen i decide upon suspension. thanks!

 

[Palantirion]

Sorry to keep you waiting Curtis, had a busy few days. I don't really have a lot left to say. I think it made myself pretty clear in my earlier posts to anyone with an open and inquisitive mind that good brakes are not better at reducing lap times than good suspension - or even R-Comp tires by themselves. I don't know why you persist in trying to shift the argument to "good products and better than bad", that's obvious and was never my position. I know you enjoy dismissing my assertions because you are a "racer" and have all this "experience", and I "read books". But be aware that in dismissing what I have written in previous posts you are also dismissing the "drivel" of championship-winning drivers and team managers from F1, ALMS, Club Racing, etc. I am simply pointing out that I have tested their theories on the track and found them to be sound. Of course we know they are, or else they wouldn't have won championships.

p.s. As an alternative to reinforcement plates on the Z4 M you can use E46 xi strut bushings to reduce shock to the strut tower from camber plates. It's less work than welding in plates, but both are effective.

 

[Curtis]

og-m3

I havn't had any problems with bottoming out and the Uk roads are like the surface of the moon! As a guide, my rear suspension is at a height of approx 650mm to the wheelarch through the centre point of the wheel and the front is approx 640mm. .

Planatirion

I don't really have much left to say either. You are perfectly aware that the conversation has been centred around the fact that good brakes are better than bad suspension because of Lele's modding plans in the first place and this has always been my point. Blacklines made a comment regarding the value of brakes over suspension while bearing in mind Lele's plans and you jumped in laughing at the idea and proceded to quote completely irrelevant information that was and never will have any bearing on the situation at hand. Unfortunately Lele's plans to spend some cash on a few mods to help him on the track has become a point you constantly choose to avoid despite my constant efforts to return to it and instead you favour an argument for the attributes of a fully sorted and perfectly setup system as found on full blown racecars. That is a completely different arguement and has been irrelevant from the start. The problem is that you just can't seem to comprehent that there is a distinct difference between the two situations.

The arguement for good tyres has never been disputed by either of us. The only difference is that I stated that they would have much more value if certain settings were in place to ensure they were controlled properly and the contact angles were optimised.

Another thing you constantly fail to digest is the fact that GOOD brakes and GOOD suspension will have a varying value on different racetracks and their value will be completely dependant on how much either system has to be used on that particular circuit. This is what I was trying to convey when I talked about the reduced effectiveness of brakes on a circuit where there are fast flowing bends such as Willow but also the increased value of brakes on just about every UK and European circuit I can think of. Quoting a generalised concept from F1, ALMS etc is simply touching the surface of something that is very much more complicated than you seem to understand.

With regard to the E46 Xi strut bushings this is something I havn't heard of before, are you talking about the front or the rear? We are talking about the rear. Also are they solid or rubber? If they are solid thats good, rubber as I'm sure you know is not because it will compress and flex. I am genuinely interested by the way!

 

[Palantirion]

Another thing you constantly fail to digest is the fact that GOOD brakes and GOOD suspension will have a varying value on different racetracks and their value will be completely dependant on how much either system has to be used on that particular circuit. This is what I was trying to convey when I talked about the reduced effectiveness of brakes on a circuit where there are fast flowing bends such as Willow but also the increased value of brakes on just about every UK and European circuit I can think of. Quoting a generalised concept from F1, ALMS etc is simply touching the surface of something that is very much more complicated than you seem to understand.

-List one track, anywhere in the world, on which you spend more time braking than you spend in corners and straights.

With regard to the E46 Xi strut bushings this is something I havn't heard of before, are you talking about the front or the rear? We are talking about the rear. Also are they solid or rubber? If they are solid thats good, rubber as I'm sure you know is not because it will compress and flex. I am genuinely interested by the way!

-I thought you were talking about the front, that's why I used the term strut, not shock. The xi bushings are solid metal, and are used as a spacer on the ix. They can be used between the camber plate and shock tower to cushion the tower. The other option being reenforcement plates welded on.

It mIght be #13 here, but I'm not 100% sure. I was not around when it was installed on my car, so I didn't see it in the flesh.
http://www.realoem.com/bmw/showparts.do?model=EW53&mospid=47726&btnr=31_0408&hg=31&fg=10

 

[Curtis]

Timescale was never mentioned or part of the issue. Effectiveness at getting you round a track quickly, safely and consistantly without failure has always been the topic of conversation.

Interesting concept using the bushings. As I said earlier I have never found any form of reinforcement to be necessary on the front or the rear for that matter but it's worth looking into. The problem may be that it obstructs access to the adjusments on the camber plate so I'll probably buy one to find out.

Fair play Mr Palantirion, that might be quite usefull!

 

[Palantirion]

Timescale was never mentioned or part of the issue. Effectiveness at getting you round a track quickly, safely and consistantly without failure has always been the topic of conversation.

-Timescale was mentioned by me. It is, ultimately, the point of discussing mods for track use. Go back and read my old posts.

Interesting concept using the bushings. As I said earlier I have never found any form of reinforcement to be necessary on the front or the rear for that matter but it's worth looking into. The problem may be that it obstructs access to the adjusments on the camber plate so I'll probably buy one to find out.

-It doesn't block access to my TCK plates' adjustments. The mod stems from BMS's experience using various camber plates in their customer race cars over the years. All adjustable camber plates add some degree of stress to the strut tower compared to the struts alone. Whether cracks occur is mostly a factor of use and track conditions. In my car's case it was considered cheap insurance.

 

[Curtis]

I'm not going to read the old posts, I'll just take your word for it, so what' are you trying to say? The better the brakes the less time you have to spend using them per lap? Because you may spend less time using them they're not as important as something else? I hope we're not going over old ground again.

I'm convinced about the bushings though so I'll order a set asap. Are you sure it's item 13?

 

[Palantirion]

I'm not going to read the old posts, I'll just take your word for it, so what' are you trying to say? The better the brakes the less time you have to spend using them per lap? Because you may spend less time using them they're not as important as something else? I hope we're not going over old ground again.

-My point before was that since you spend less time braking (regardless of the brakes) than cornering or accelerating, gains made by braking are proportionately less useful to total lap time than gains made in cornering or acceleration. Additionally, if you increase your midcorner speed (decreasing time) you will correspondingly increase your exit speed AND speed down the entire length of the ensuing straight (again reducing time). So increasing the ability of your tires or suspension will pay off in lower lap times than the same (or even greater) increase in braking ability.

As examples I did the math from my in-car vids and posted in one of my previous posts:

Even on a very demanding circuit like Cal Speedway I spend just 14 of 118 seconds per lap braking. Even if you got some sort of magical braking system that decreased stopping time by 25% you would save a grand total of 3.5 seconds per lap. By increasing lateral grip by only 5% (which I've experienced with R-comp tires alone), you would shave 5.9 seconds off your lap time. At Buttonwillow (#13 CCW), which is also very hard on brakes, the previous %s would yield a 4.5 second improvement for brakes, 9.75 for tires. At Streets of Willow (CCW w/ Toilet Bowl), which unlike big Willow is pretty hard on brakes, you would again gain 3.5 seconds a lap with the +25% super brakes, and 5.2 with the +5% tires.

I'm convinced about the bushings though so I'll order a set asap. Are you sure it's item 13?

-I am NOT sure they are #13. Like I said, I never saw them in person. If you want, I can get the part number from BMS.

 

[Curtis]

The part number from BMS would be usefull. Thanks.

Right, back to business, I definately think we're going over old ground again however.

You forgot to mention the fact that as you fly out of the corner and come barrelling down the straight you then carry on through the sandpit at the end of the straight, through the tyre wall and don't stop until your upside down at the door of the AP Racing store and all because your standard brakes gave up.

Alternatively you could come flying out of the corner, hit the straight and instantly start appying the brakes in a cautious and non aggresive manor because

A. You know they won't slow you down quickly at the end of the straight and
B. You know that if you try to push them they will die and subsequently so will you.

As a consequence, all that time you spend accelerating like a bat out of hell down the straight in theory has now reduced dramatically in reality because you have to start braking gently half way down it.

What happens next is this:

1. You head back to the pits and get out of your car in a perplexed state of mind because some guy in a Daewoo with a BBK has done two laps to your one.
2. You make some lame excuse about being on Cup tyres and the track was slightly soggy.
3. You take a look at your telemetry and realise that while everyone was blasting down the straight you were gently applying your crappy standard brakes.
4. You realise that you were on your brakes more than you were accelerating.
5. You then have an an epiphany and you think to yourself " f**k me sideways, that Curtis guy has a point."

Eventually you will get to a corner though and filled with confidence at your amazing H&R "coilover" kit complete with a set of swaybars you decide you can probably stay on the tail of the Daewoo and you do for about a tenth of a second before flying off sideways into the scenery.

Back at the pits again you contemplate the situation and your thoughts go like this.

1. Those crappy go faster bits didn't improve anything in fact it's worse than standard.
2. Maybe I should spend an absolute fortune on the suspension and do the job properly.
3. I don't have a small fortune to spend and even if I did it was never my intention in the first place to do so, I just want to go a bit faster.
4. Maybe I should have spent the money on something that would actually make an improvement.
5. A BBK would come in at around the same price and I could still afford to do the suspension and steering geometry and replace those crappy bushes.
6. You then have an an epiphany and you think to yourself " f**k me sideways, that Curtis guy has a point."
7. You wonder what the hell that Palantirion guy was babbling about because this makes a lot of sense.

When you arrive back home on the back of a recovery truck you decide to go onto your favourite forum and convey your experiences and concluisions to your fellow members.

You explain to them the above situation and the whole world agrees it makes a lot of sense not to botch up your suspension but to go for a nice usefull BBK. Unfortunately some ill informed member ( who will remain nameless ) laughs at your findings and declares.

" According to some Formula One guy and a guy who used to race in the Le Mans series your suspension is much more important "

To this you reply.

" Yes but I have a Z4 and it's not the same as an F1 car or even a Le Mans car because they are at the pinnacle of racing technology and have the best of everything, all I have is these crappy H&R parts and I've just discovered that the suspension mods that I could afford made the car handle worse, shouldn't I have spend the money on something constructive like good brakes? "

Nameless guy then replies

" Hell no because according to some Formula One guy and a guy that used to race in the Le Mans series your suspension is much more important "

And so the conversation continues on the same theme for many many days because nameless guy refuses to see sense and admit he's wrong. Which finally brings us back to your standard response which no doubt will ignore everything of any relevance to the above situation and will go something like this..............

 

[zee42]

I'm going to have to try that f***ing sideways thing......see if i can make up some time

 

[flimper]

That was one serious thread, hope it gets a few more reads now after a gap of a few months. Took me all night to read, but I think I've learned a bit from the experience. Palantirion vs. Curtis - definitely went the distance, I'd have to give it to Curtis on a split decision Good stuff fellas

 

[jhbuining]

Very informative thread guys! It's nice to get some well-spoken opinions, reasoning, experiences and background info - thx for the input!

 

[Darren M]

Very informative thread guys! It's nice to get some well-spoken opinions, reasoning, experiences and background info - thx for the input!

Agree even though I haven`t read it thoroughly. As these cars get older and cheaper I suspect more enthusiasts will join the forum and there will be lots of such threads regarding car setup etc as people track them more.

ONe thing I don`t think I have read in this thread is any mention of driver tuition. My recommendation to the original poster is to get some driving tuition first to learn how to get the best out of the BMW package before then deciding what bits you want to improve (assuming you are realativeky new to trackdays). For example, someone who thinks the CSL brakes are no good after a few laps might find out they aren`t braking correctlly (brake too lightly and they may heat too much and less time to cool before the next corner).

As with all aftermarket stuff, there is a lot of crap out there I`m sure. Not every component will make your car faster.

PS it`s okay to have differnt opinions . Me, although it is not the cheapest option, learning to drive the BMW package to get the best out of it is probably the best place to start. What`s great about tyres that make you faster by 2 seconds a lap when your lack of drving skills is costing you 15? People don`t usually look at the option of upgrading the driver as it`s not as exciting or interesting as spending loads on some new shiney bits.