Z4 MC trackday upgrade: camber plates and Tyres

[Curtis]

Planatirion:

For a start I didn't say any of those things, please read my posts a little more carefully. I think you'll find that someone else made those comments but that's irrelevant.

The comment that " Weak brakes will weaken your performance more than anything else" is still true regardless of who said it. Your performance is virtualy zero when your sitting in the kitty litter waiting to be pulled out. The other comment " Better brakes will improve your lap time more than suspension" also holds true for the same reason and also because at tracks such as Silverstone they certainly will.


I think I've got to the bottom of the problem. The two tracks you refer to, Willow and Cal Speedway ( assuming you use the infield at Cal and not just the oval ) require very little braking especialy Willow as you yourself mentioned. At tracks such as Silversone where you slow from 145mph at the end of Hanger into Stow or even Hullavington Airstrip where you brake from 135mph to 30mph for the 180 degree u turn you will need decent brakes. You will lose much more time sitting in the sandpit at the end of the straight than you will gain with good suspension once you've been pulled back onto the circuit. On a generally swooping track like Willow Springs where brakes are seldon necessary other than the odd dab it's not surprising that suspension is more important. It also explains why your friend was only three seconds slower using standard brakes but even then, three seconds is a big difference on a track where brakes are rarely used.

The only referance you made to your BBK was midway through this thread and it was the following on your fourth post I believe:

"I ran my first Z4 MC HPDE at Horse Thief Mile, which is very hard on brakes, with my stock brakes and pads. I experienced some fade, but nothing dangerous, and I learned to adjust to it. I was very impressed by how much abuse the stock brakes could take. Even with my StopTechs I sometimes run Axxis street pads on tracks that aren't too demanding."

From this I would assume that you did one track day on standard brakes and then binned them in favour of the StopTechs. You also state that you use street pads on tracks that are not too demanding. This would indicate that on a demanding track you use a BBK with race pads. Why would you do that if the standard brakes were so good and an upgrade so unnecessary?

The fact still remains that you can't compare the use of street pads in a BBK at a track like Willow to using completely standard brakes at a track like Silverstone. At best you will get three laps of Silverstone before burying yourself in a tyrewall unless you drive like my dead Grandad as previously mentioned. Nobody pays good money to go to a track and drive like that, you can do that for free on your way to pick up your Angina prescription. That's how my Grandad died by the way. He didn't get his pills quickly enough because he lost too much time getting to the Chemist due to his crappy standard brakes.

Surely you can see that it's better to be able to slow down for corners before worrying about getting round them unless your at a track like Willow where you basicaly back off the throttle, dab the brake pedal and drop a gear or two before turning in?

 

[Blacklines]

lol!

 

[Palantirion]

Planatirion:

For a start I didn't say any of those things, please read my posts a little more carefully. I think you'll find that someone else made those comments but that's irrelevant.

-Right on both counts. But not so much on the spelling.

The comment that " Weak brakes will weaken your performance more than anything else" is still true regardless of who said it. Your performance is virtualy zero when your sitting in the kitty litter waiting to be pulled out. The other comment " Better brakes will improve your lap time more than suspension" also holds true for the same reason and also because at tracks such as Silverstone they certainly will.

-To say that brake improvements are a better mod because without them you are a sufficiently stupid driver as to overshoot your braking points and end up in "the kitty litter" is a rediculous argument. You should stay on track with ANY car, regardless of its brakes. Otherwise you are not doing your job as a driver. Learn the car, do what you can with it. THAT is learning to drive. Conversely, there is no such thing as an idiot-proof car.

I think I've got to the bottom of the problem. The two tracks you refer to, Willow and Cal Speedway ( assuming you use the infield at Cal and not just the oval ) require very little braking especialy Willow as you yourself mentioned.

-LOL, no. Willow is easy on brakes. Cal Speedway is extremely hard on brakes. That's why I brought up both tracks, as contrast. I strongly recommend track pads for demanding tracks like Cal Speedway (see every post I've made on this thread), but you could also learn to drive on it with stock brakes - or a totally stock car. Every year hundreds of stock vehicles with newb drivers track at Cal Speedway. Damage to vehicles is very rare. Again, it all comes down to learning to drive you and your car to their respective limits, and not beyond. And you will be MUCH faster around Cal Speedway with R-comps and stock brakes than with street tires and a BBK.

Perhaps you are not aware that braking is not a binary action. It is a pedal, not a button. The driver is completely in control of how much brake force is applied, and thus how much heat is generated.

On a generally swooping track like Willow Springs where brakes are seldon necessary other than the odd dab it's not surprising that suspension is more important. It also explains why your friend was only three seconds slower using standard brakes but even then, three seconds is a big difference on a track where brakes are rarely used.

-He also didn't have any suspension work. This, and a relative lack of HP, are the primary reasons for the 3 second difference.

The only referance you made to your BBK was midway through this thread and it was the following on your fourth post I believe:

"I ran my first Z4 MC HPDE at Horse Thief Mile, which is very hard on brakes, with my stock brakes and pads. I experienced some fade, but nothing dangerous, and I learned to adjust to it. I was very impressed by how much abuse the stock brakes could take. Even with my StopTechs I sometimes run Axxis street pads on tracks that aren't too demanding."

From this I would assume that you did one track day on standard brakes and then binned them in favour of the StopTechs. You also state that you use street pads on tracks that are not too demanding. This would indicate that on a demanding track you use a BBK with race pads. Why would you do that if the standard brakes were so good and an upgrade so unnecessary?

-I've tracked at Willow with the stock brakes/pads, StopTechs with street pads, and StopTechs with track pads. All three variations with both my M5 and my Z4 MC.

I never said better brakes are an unnecessary upgrade ("necessary" is completely subjective in this context), I said that improving brakes is the least critical mod to improving lap times, relative to tires and suspension improvements.

 

[Curtis]

Your really bothered by my spelling! That's sad!

Before we get started I would like to clear something up. I have always maintained that "tyres are the most important aspect of all" however, they only work if you set up the correct geometry and pressures. This is something that Lele is not willing to do.

I have always said that "good suspension is also a high priority" however Lele has no plans to fit good suspension and even if he did he is not willing to set it up properly so it wouldn't work.

When did I ever say that brake mods are a better mod because without them you are a sufficiently stupid driver as to overshoot your braking points and end up in the kitty litter? I think it's fair to say I didn't, ever. Even clever people can end up in the kitty litter when their brakes give up.

All this arguing about what's better in a fully modified car such as your own and what some pro driver said in a book you read is completely irrelevant. This guy want's to fit useless bits of suspension in an otherwise standard vehicle and not bother setting it up ( no offence intended by the way Lele ). As I said earlier, his plans will therefore gain him nothing.

If he at least fitted a brilliant set of brakes along with good tyres he would actualy be able to do something worthwhile ie building more speed on the straights and pulling off some late braking manouvers plus he wouldn't have to worry too much about setup to be able to brake in a straight line. Don't worry, he could build up to these high speed, late braking manouvers gradually as his confidence and ability builds and before you know it he won't have to extract GT3's from his tailpipes because he started slowing half way down the straight. Do you really think a set of H&R or Bilstein "coilovers" and a set of sway bars is a superior prospect? As you quite correctly stated, a proper suspension setup will gain you 4-6mph in every bend (minimum in my experience) but bear in mind what his suspension plans are. The whole suspension arguement is therefore a moot point.

If your friend had no suspension work, standard brakes and a lack of power how is it that he was only 3 seconds slower than you? " Because suspension alone gives you an extra 4-6mph on every turn you should have left him for dead. Just curious.

If indeed Cal Speedway is a demanding circuit in your opinion I don't blame you for using uprated brakes, they will greatly decrease your lap times and reduce the chances of you being airlifted from the fifth row of the grandstand because of failure, however it doesn't look particularly demanding compared to most UK circuits. Of course as you said, you could safely drive the circuit with standard brakes but you could also drive it safely using a ride on lawnmower so I don't really see your point. This whole thread is surely about making progress on the track and reducing lap times.

 

[Palantirion]

If your friend had no suspension work, standard brakes and a lack of power how is it that he was only 3 seconds slower than you? " Because suspension alone gives you an extra 4-6mph on every turn you should have left him for dead. Just curious.

-I think he's a better driver. Also, his R888s have been through fewer heat cycles than my NT-01s.

If indeed Cal Speedway is a demanding circuit in your opinion I don't blame you for using uprated brakes, they will greatly decrease your lap times and reduce the chances of you being airlifted from the fifth row of the grandstand because of failure, however it doesn't look particularly demanding compared to most UK circuits. Of course as you said, you could safely drive the circuit with standard brakes but you could also drive it safely using a ride on lawnmower so I don't really see your point. This whole thread is surely about making progress on the track and reducing lap times.

-Like I said before, go read some books and do some basic math. Have you ever measured how much time you spend braking vs cornering or accelerating? 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.

 

[Curtis]

I notice you havn't even bothered to mention suspension anymore so I assume you've finaly realised how fruitless that arguement was.

Now were getting somewhere. You've agreed that tyres are the number one gain like I said four days ago in my second post ( bearing in mind that we're talking about tyres fitted to a car that's set up properly )and you've also mentioned the gains to be had from brakes. You have also noticed the small amount of time that has to be used braking, good. As long as you realise that this is due to HAVING GOOD BRAKES THAT SLOW YOU DOWN QUICKLY AND YOU DON'T THEREFORE HAVE TO USE THEM FOR 30% OF THE LAP.

Your talking about "super brakes" which give you more than 25% reduction in stopping time as if that were a strange thing. I would expect this from relatively minor braking mods alone. Do you move the cars weight over the front before applying the major breaking effort? That is critical to stopping quickly, you could probably find out about it in one of your books. As I mentioned earlier this is called "dual step variable pressure braking".

Later in this thread you made the following statement:

"Perhaps you are not aware that braking is not a binary action. It is a pedal, not a button. The driver is completely in control of how much brake force is applied, and thus how much heat is generated."

This would indicate that you didn't read my earlier statement regarding dual step braking. Which would explain why all those books you've been "reading" havn't really taught you much.

I already know about it because I've been racing competitively since I was 7. Sometimes you just have to put your calculator down, get your head out of a book and go out there and learn to race. Ask your buddy for some pointers, he seems to know what he's doing.

 

[Palantirion]

I notice you havn't even bothered to mention suspension anymore so I assume you've finaly realised how fruitless that arguement was.

Now were getting somewhere. You've agreed that tyres are the number one gain like I said four days ago in my second post ( bearing in mind that we're talking about tyres fitted to a car that's set up properly )and you've also mentioned the gains to be had from brakes. You have also noticed the small amount of time that has to be used braking, good. As long as you realise that this is due to HAVING GOOD BRAKES THAT SLOW YOU DOWN QUICKLY AND YOU DON'T THEREFORE HAVE TO USE THEM FOR 30% OF THE LAP.

-In my testing of the Z4 MC I found a comparable increase in corner speed from adding suspension to R-comps. I left off the gain from suspension specifically to overweight the possibility of your position being correct. It wasn't.

Your talking about "super brakes" which give you more than 25% reduction in stopping time as if that were a strange thing. I would expect this from relatively minor braking mods alone.

-Switching from stock brakes to 4-wheel StopTech's with track pads I would say that my stopping time, while keeping the brakes within their optimal operating temperatures, decreased by about 12-15% (a little over a 1/2 second gain in a 4 second brake zone). This is still significant in terms of car placement for passing, and it does help lap times. It just isn't remotely as significant as the lap time benefit from tires and/or suspension.

Do you move the cars weight over the front before applying the major breaking effort? That is critical to stopping quickly, you could probably find out about it in one of your books. As I mentioned earlier this is called "dual step variable pressure braking".

-Actually, braking performance improves if you use all four contact patches instead of artificially biasing the front axle. This is another thing I've proven from my own testing with stock brakes, StopTechs with equal pads on both ends, and StopTechs with more aggressive pads on the front. The balanced setup stays flatter and stops better because it has more total force of rubber on the road. This is the exact same principle as in lateral load transfer. The less lateral load transfer, the more total grip is available.

Presuming that my word isn't good enough, here is a short excerpt from Carroll Smith (race engineer for F1, Cart, and assorted other series for the last 40 years):
"In the case of braking the effects of load transfer are several - and all bad. First off, by unloading the rear wheels, the amount of braking energy that they are capable of transmitting to the road is reduced which means that the overall braking capacity of the vehicle is limited by the traction potential of the smaller front tires. Even if they are the same size - as on some sedans - load transfer between a pair of wheels reduces the capacity of the pair. At the same time, since load transfer increases the vertical loading on the front tires, it also compresses the front springs which cambers the tires in the negative direction which may help in a cornering situation but does nothing good for braking."

Also, if longitudinal load transfer was the goal to achieve ideal braking, no one would left-foot brake.

I already know about it because I've been racing competitively since I was 7.

-I'm sure you're happy that you "already know" and that you have a lot of racing experience. It is unfortunate that what you "know" isn't accurate analysis.

 

[Blacklines]

You know what if we all met up I am sure we would get on like a house on fire!

 

[Curtis]

Planatirion

It would appear to me that all that money you spent on StopTechs was wasted, perhaps you should have gone to AP's like me.

Try a quick test and remember we're not talking about full race cars like your book guy is relating to and incidently, if you read a hundred books you would get a hundred different opinions. Fortunately I can talk from experience. Drive down the road at a set speed, say 50mph. Apply the brakes aggressively and note when the tyres break traction and the ABS kicks in. Do the same thing again but this time apply 50% braking to shift the cars weight over the front before fully applying the pedal. You will stop a lot quicker and you shouldn't be able to activate the ABS. It makes sense. When you slow down, the cars weight automatically shifts to the front anyway and the more force you can use to press the front of the car into the ground the more brake pressure you can apply before breaking traction. It's an unavoidable law of physics. The car is preset to have the vast majority of the braking effort operating the front brakes just as any other road car for exacty the reason explained above.
It's the same principle that causes the rear of your car to squat down on acceleration and the front to lift because the opposite is happening under acceleration and the weight transfer has moved over the rear axle which of course helps traction under acceleration. Thats why front wheel drive cars can struggle to get good traction off the line, because the front wheels are trying to grip but the acceleration has transferred the weight to the rear.
That again is basic physics and you don't need to troll through your library of F1 engineers findings to know that. Why we're even comparing the two I have no idea. Most pro race cars have adjustable brake bias so you can vary the pressure to the front and rear brakes but in a simple Z4 you don't so you have to fall back on the basics for anything to be applicable. That I suspect is the root of the problem, the F1 or Cart engineers findings in your beloved books can in no way be related to a common BMW Z4. For a start the Z4 has no downforce pushing the tyres into the ground and creating extreme levels of traction, nor are they rear engined, nor are they so light weight, nor do they have ceramic or carbon brakes etc etc.

Any camber changes in the suspension caused by travel are negligable in the Z4's geometry setup and you should have setup your suspension properly before going on the track anyway to take all these factors into account.

Again we get back to the original point. Will a useless set of "coilovers" and a set of swaybars ( why swaybars I don't know but that's a different matter ) with absolutely no adjustment or setup give you better gains than a properly setup full set of uprated brakes. The answer is an obvious NO. Tyres are a given by the way, a decent set of tyres is always a good thing I'm sure we agree even though the benefits will be minimal without suspension adjustments.

This lack of setup is a major contributing factor to this discussion. The example I gave earlier about fitting a superb hunting scope and not bothering to zero it is very relevant. Sticky tyres have a great benefit when your travelling in a straight line and the contact patch is virtualy flat on the ground, that would give you major gains in straight line accelerating and braking. As soon as you turn a corner though your suddenly running on the edge of your tyre and you have terrible grip. The purpose of setup is to make sure you have the best possible grip under all circumstances. Unfortunately most people can't be bothered to do this so we end up with the following.

We can compare the two options like this:

1. Top class brakes and track tyres with no geometry setup = Superb stopping power and straight line acceleration but minimal improvements in cornering.

2. Really terrible aftermarket suspension mods and track tyres with no geometry setup = minimal improvement in braking, minimal improvements in handling, a massive feeling of disappointment, the wife divorces you for being a d**k and wasting the holiday fund and two weeks later you die in a ball of flames because your brakes gave up.

I know what the sensible option is and I suspect you do too.

Go on then, read some books and get your calculator fired up then try to tell me I'm wrong just so you can nurse your damaged ego. In the mean time I'll be off racing and winning even with my useless grasp of how some guy in a book says I should be doing it.

By the way, you probably won't find the above comparison in some F1 engineers book because he probably credited everyone with enough common sense to realise it's correct in first place.

 

[Palantirion]

You know what if we all met up I am sure we would get on like a house on fire!

-Some pints would probably help put out the fire

Try a quick test and remember we're not talking about full race cars like your book guy is relating to and incidently, if you read a hundred books you would get a hundred different opinions. Fortunately I can talk from experience. Drive down the road at a set speed, say 50mph. Apply the brakes aggressively and note when the tyres break traction and the ABS kicks in. Do the same thing again but this time apply 50% braking to shift the cars weight over the front before fully applying the pedal. You will stop a lot quicker and you shouldn't be able to activate the ABS. It makes sense. When you slow down, the cars weight automatically shifts to the front anyway and the more force you can use to press the front of the car into the ground the more brake pressure you can apply before breaking traction.

-It's amusing that you have just unproven your own point. If what you are saying about load transfer (It's "load transfer", not "weight transfer" btw. The weight in the car pretty much stays put.) is true, and increasing load on the front axle is the best way to stop a car, then stomping the brake pedal would produce quicker stops. Obviously if you stomp on the brake pedal you will create the highest amount of load transfer because you are creating the most abrupt application of G force and increasing compression the front suspension. By progressively braking (your 50% example) you are keeping the car flatter, reducing longitudinal load transfer by allowing the suspension to work over a greater period of time, and increasing available traction - as I had described in my last post. You would stop even quicker if you left-foot braked and slightly overlapped brake application with your release of the throttle pedal.

Again we get back to the original point.

Yes, let's...

Blacklines wrote:Weak brakes will weaken your performance more than anything else.

Better brakes will improve your lap time more than suspension.

-LOL, WRONG!

For the Z4 M the first thing you want is R-comp tires. After that, you will want suspension and track pads.

-I have mathematically demonstrated that lap time improvements due to an increase in braking ability are less than improvements due to switching to R-Comp tires or readily available suspension. This disproves Blacklines' original statement. I have yet to see any argument from Blacklines or yourself that shifts the burden of proof back to me.

Your argument referring to "Really terrible aftermarket suspension mods" is as irrelevant as it is obvious. I could make the same point about "Really terrible aftermarket brakes" or "Really terrible aftermarket tires", but I wouldn't waste our collective time with something so silly. Yes, Lele originally suggested he might buy some less-than-perfect coilovers. But in conversation he seemed open to considering other products. I think it would be wisest to hear what his thoughts are now, with all the new information we've given him to consider, before one goes on to assume what he would purchase.

 

[Curtis]

I have to agree with Blacklines too, a few pints and we'll probably be best buddy's!

I don't see how I've disproven my point from what I've read you've just backed up what I said. Whether you call it weight transfer of load transfer doesn't really matter. Left foot braking is a completely different thing and I've intentionally avoided the subject under the circumstances because we're talking about a guy who has just done his first track day. Maybe I'm not giving him enough credit but hey, I thought I'd keep it simple.

Going back to basics again we both now agree that the quickest way to stop is to transfer the weight, load, banana's, whatever terminology you want to use over the front axle before fully applying the brakes. If you were to cornerweight the car at the point where the brakes are fully applied the vast majority of the WEIGHT would have transferred to the front, it's the load that causes the WEIGHT to transfer so as far as I'm concerned it's WEIGHT transfer.

I have consistantly made the point throughout this thread that a good set of brakes will give better gains than a poorly planned suspension mod with no setup. I can't see how it could possibly be disputed.

Obviously fitting crap brakes will be just as bad as fitting crap suspension but that has never been mentioned as a possibility. What I have repeatedly said is that rather than bodge up the suspension spend the same money on a properly sorted set of brakes and you will gain more. I better emphasise the fact that I mean roughly the same amount of money, I don't want you running off to get your price books and calculator then getting all excited because the brakes are $5 more.

Naturaly if he is willing to rethink his plans and spend a lot of time, money and testing on his suspension he will reap the rewards but to be honest I doubt that is likely and I think we've probably put him off the idea of even touching his suspension forever. Both you and I know it takes a lot more than he has suggested to gain any improvements from his suspension and that's how this debate and Blacklines comments arose in the first place. On another subject, if you hadn't laughed at the Blacklines as if he were some kind of moron then this discussion could have been more civilised. Have some respect.

Another difference is the fact that you don't have to use brakes much at all on on MOST North American circuits and I'm not just meaning the tracks where you go round in a circle all day ( better make that oval just in case you get the books out again, actually I better say oval with the potential or posibility of the odd deviation from a perfect oval ) therefore you won't appreciate the benifits of good brakes as much as someone who has to use them. That would explain why you were of the opinion that standard brakes were fine for track use while everyone over here knew they were useless.

So in short you have "mathematically demonstrated" how YOUR suspension on the tracks YOU go to have been more benificial than YOUR brakes ( which you don't have to use much ). We however are looking into things a lot deeper than that, things that even a state of the art calculator wouldn't know and yes, all these theories would change if you drove around like a pansy being very careful not to wake up your brakes but that's hardly the philosophy on a race track.

As a conclusion, as you suggested, Lele should either reconsider his suspension plans and be prepared to take out a second mortgage or address the main issues with his suspension rather than coilovers and sway bars or forget about suspension all together and fit a good set of brakes or compromise and do something to both. That's exactly what I did for Memo, front and rear bushes, a limiter kit, front and rear pads, braided hoses and synthetic fluid ( because Turkish tracks are demanding on brakes too ). A compromise yes, but the overall gains much more than coilovers and sway bars for a fraction of the cost. The other thing I gave him was probably the most important of all, a complete setup sheet and instructions on how to get 1.5 degrees negative front camber without fitting camber plates. Like I said earlier, all the shiney parts in the world are worth nothing ( or very little so you don't quote me something Juan Fangio said about the limited benifits of shiney bits back in 1954 ) without setting them up properly.

 

[Palantirion]

I don't see how I've disproven my point from what I've read you've just backed up what I said.

-You stated your preferred theory is that braking improves with increased load transfer, then described your preferred braking technique which actually decreases load transfer. That is a direct contradiction.

Whether you call it weight transfer of load transfer doesn't really matter.

-Actually it does, but only if you care about technical details. For your benefit: Weight is mass. Mass does not move about the car unless something is broken. Load is a directional force imparted from a change in G force relative to geometry, resistance, and inertia (mass * velocity). So weight and load correlate to a certain extent, but they are not interchangeable terms any more than horsepower and torque are interchangeable.

Going back to basics again we both now agree that the quickest way to stop is to transfer the weight, load, banana's, whatever terminology you want to use over the front axle before fully applying the brakes. If you were to cornerweight the car at the point where the brakes are fully applied the vast majority of the WEIGHT would have transferred to the front, it's the load that causes the WEIGHT to transfer so as far as I'm concerned it's WEIGHT transfer.

-No, we don't agree.
1) You claim that maximum braking performance increases with load transfer. I disagree, maximum braking performance is achieved with minimal load transfer.
2) You claim that increasing braking performance reduces lap times more than a similar upgrade in suspension. I disagree, and have demonstrated that advantages gained by better suspension are greater than those gained by better brakes.
3) You claim that load and weight are interchangeable terms. I disagree, it is simply not true.

I have consistantly made the point throughout this thread that a good set of brakes will give better gains than a poorly planned suspension mod with no setup. I can't see how it could possibly be disputed.

-It is disputed because you have in fact never "made the point". You have offered an opinion, repeatedly, belligerently, and ignorantly. At no time have you contributed any factual data to substantiate your opinion.

Naturaly if he is willing to rethink his plans and spend a lot of time, money and testing on his suspension he will reap the rewards but to be honest I doubt that is likely and I think we've probably put him off the idea of even touching his suspension forever.

-No testing is required. If he simply buys what I have bought, and set them to the settings I recommend, he can leave it that way for the rest of his life and have a MUCH quicker car than if he bolted on a 4-wheel BBK. It won't be as perfect a setup as if he did test and modify the settings, but it will be a good 90% towards perfect.

Another difference is the fact that you don't have to use brakes much at all on on MOST North American circuits ... you won't appreciate the benifits of good brakes as much as someone who has to use them. That would explain why you were of the opinion that standard brakes were fine for track use while everyone over here knew they were useless.

-This comment only demonstrates your ignorance of US tracks. Or possibly also of braking physics. You do know that there is a difference between braking hard on a circuit and the circuit being hard on brakes, right? The former is most relative to brake torque, tire traction and heat capacity, the latter to frequency of use, duration of use and efficiency of cooling.

So in short you have "mathematically demonstrated" how YOUR suspension on the tracks YOU go to have been more benificial than YOUR brakes ( which you don't have to use much ). We however are looking into things a lot deeper than that, things that even a state of the art calculator wouldn't know and yes, all these theories would change if you drove around like a pansy being very careful not to wake up your brakes but that's hardly the philosophy on a race track.

As a conclusion, as you suggested, Lele should either reconsider his suspension plans and be prepared to take out a second mortgage or address the main issues with his suspension rather than coilovers and sway bars or forget about suspension all together and fit a good set of brakes or compromise and do something to both. That's exactly what I did for Memo, front and rear bushes, a limiter kit, front and rear pads, braided hoses and synthetic fluid ( because Turkish tracks are demanding on brakes too ). A compromise yes, but the overall gains much more than coilovers and sway bars for a fraction of the cost. The other thing I gave him was probably the most important of all, a complete setup sheet and instructions on how to get 1.5 degrees negative front camber without fitting camber plates.

-I'll simplify this for you. How is gaining 3.5 seconds a lap better than gaining 5.9 seconds a lap? Or 4.5 seconds better than 9.75 seconds? It's not.

p.s. You can get over -3.0 degrees front camber without camber plates by using shims. -1.5 is easily achieved simply by knocking out the strut tower pin and moving the top of the strut over. I hope you told him to get his car aligned afterwards, as his front toe will have changed a little during the movement.

 

[Curtis]

I don't have much time to respond to this naive and unsubstantiated bo****ks just now. I have to head off racing and I'm sure you could do with a break so you can return all those books to the library. If anyones interested in paying a visit I'm at Brands Hatch with the white M3 GTR for the GT Cup until Saturday night.

One quick point though. You will never be aware of your own ignorance and we will never resolve this issue because you constantly fail to read and fully comprehend what is being discussed. You are more concerned that the terminology used in conversation is not the same as yours. I'm sure everyone else understands or can perceive what weight transfer is and couldn't give a fudge whether strictly speaking it should be called load. It reminds me of how you couldn't wait to tell me I'd misspelled something. How petty. This would never happen to you because you simply copy things from a book. I suspect your used to everyone else simply taking your word as gospel because you can quote things that sound technical and pretend they're your own findings. Now you've found that your way too deep into a conversation of which you show very little grasp and you can't afford to back down or see sense because of your ego.

Let me give you a quick example of what I'm up against.

I said " The other thing I gave him was probably the most important of all, a complete setup sheet and instructions on how to get 1.5 degrees negative front camber without fitting camber plates."

You then said "I hope you told him to get his car aligned afterwards "

Do you not understand what a complete setup is?

Another problem I'm up against is the constant attempts at showboating. Of course we all ( or most of us know ) that you can get 3 degrees plus of negative camber using shims but it was in no way relevant to the conversation or the situation so what's the point in mentioning it? Was it an attempt to show that you knew something that I didn't?

The person in question who I gave the parts and setting to wanted a compromise, something he could comfortably drive to work with and track occationaly. He has no mechanical experience or knowledge and he certainly wasn't willing to change settings or parts before and after every event. Therefore as I said in the previous post everything was a compromise, 3 degrees neg on the track is great but not on the road. The fact that you feel it's necessary to jump in with a comment like " p.s. You can get over -3.0 degrees front camber without camber plates by using shims " shows your inability to look at the bigger picture and backs up my theory that your simply showboating. In short, Yes we already know that. Yawn. I specifically told him how to get 1.5 degrees neg. Not 1 degree or 2 degrees but 1.5. That's because it's ( in my experience ) the best compromise and not because I don't know how to get any other amount. I shouldn't have to waste my time explaining all this to you. I have looked at your comments and made the assumption that you are aware of other options but have settled on whatever you've chosen for a reason. Maybe I shouldn't.



Anyway, I'll be back on Sunday to reply to whatever drivel you've come up with or taken from a book. In the mean time, here's the basics you need to dispute.

Good brakes are a good thing.
Bad suspension is a bad thing.
Good brakes are more benificial than bad suspension.

Try to focus on that. Don't try to distort it, deviate from it or mask it behind a load of technical crap you obviously don't understand yourself ( but hey, it looked good in a book somebody else wrote.)

Have fun at the library.

 

[og_m3]

hi curtis,
just wondering if you can elaborate on your suspension setup. i think i read that you were using intrax 1k2 coilovers.

are they tru-coilovers in the rear? what are your rates that your running?

if you want to discuss over pm, please let me know as i dont want to clutter up this thread.
thanks

 

[Curtis]

Hi og-m3,

I hope you'll understand if I'm a bit suspicious. The bookworm seems to have run out of quotes and all of a sudden a Newbie appears who's only post is on this thread asking about my suspension. If your genuine then please accept my appology but it does look very dodgy.

Anyway, I'm willing to give you the benifit of the doubt just now!

Yes I use Intrax 1k2 coilovers and yes they are true coilovers front and rear. I've tried a few spring rates but if I remember rightly I've settled on 80Nm front and 30Nm rear springs. I will double check that later because the original spring rates were in Kg/cm. The Intrax has 50 damper settings which is a bit excessive but I use about 40 "clicks" from minimum on the track and about 25 on the road. The main reasons I like the Intrax is that they are rebuildable and serviceable, have a choice of spring rates, they come complete with camber/castor plates, the build quality is excellent ( titanium and INOX body etc )and they are very easy to cornerweight. I was going to go to the next level before I bought them so I could get seperate bounce and rebound adjustment etc but this was deemed unnecessary. The Intrax 1k2 kit has internal valving that allows for true seperation of bounce and rebound functions but using the same adjuster so it was hard to justify the expense. The 1k2 kit wasn't cheap at around £2100 plus 17.5% tax but they are worth it in my opinion. That price included fitting, cornerweighting and full setup.

To quote Simpson Motorsport who designed the kit in conjunction with Intrax:

" Intrax dampers are the most sophisticated suspension you can fit to your BMW. This is in a completely different league to Bilstein, KW, Koni etc. The performance is comparable to Moton and Ohlins, and in our opinion is better than both."

Hope you found this helpfull.

 

[chariszzzz]

 

[og_m3]

Hi og-m3,

I hope you'll understand if I'm a bit suspicious. The bookworm seems to have run out of quotes and all of a sudden a Newbie appears who's only post is on this thread asking about my suspension. If your genuine then please accept my appology but it does look very dodgy.

Anyway, I'm willing to give you the benifit of the doubt just now!

Yes I use Intrax 1k2 coilovers and yes they are true coilovers front and rear. I've tried a few spring rates but if I remember rightly I've settled on 80Nm front and 30Nm rear springs. I will double check that later because the original spring rates were in Kg/cm. The Intrax has 50 damper settings which is a bit excessive but I use about 40 "clicks" from minimum on the track and about 25 on the road. The main reasons I like the Intrax is that they are rebuildable and serviceable, have a choice of spring rates, they come complete with camber/castor plates, the build quality is excellent ( titanium and INOX body etc )and they are very easy to cornerweight. I was going to go to the next level before I bought them so I could get seperate bounce and rebound adjustment etc but this was deemed unnecessary. The Intrax 1k2 kit has internal valving that allows for true seperation of bounce and rebound functions but using the same adjuster so it was hard to justify the expense. The 1k2 kit wasn't cheap at around £2100 plus 17.5% tax but they are worth it in my opinion. That price included fitting, cornerweighting and full setup.

To quote Simpson Motorsport who designed the kit in conjunction with Intrax:

" Intrax dampers are the most sophisticated suspension you can fit to your BMW. This is in a completely different league to Bilstein, KW, Koni etc. The performance is comparable to Moton and Ohlins, and in our opinion is better than both."

Hope you found this helpfull.

thanks for offering the benefit! glad you did and i assure you im not plantirion

I am actally picking up a z4m soon and am upgrading from a 350z.

what is the conversion rate from nm to kg/mm? i know this isnt worth much, buit i used to run 18kg mm front and 16kg mm rear on my 350z, i would have to test the car itself since i know the dynamics are different as well as design and weight balance.

I have extensively modded the brakes and suspension aspect of my z and have noticed that the rear suspensions, of the z4 and 350z, have a similar design as far as using a separate shock and spring. i have also converted my 350z to a true-coilover rear and noticed that you did that to your Z4. i was just under the impression that there should be some reinforcement added to the rear shock towers if this was indeed done. i faced this controversy over on the 350z forums about converting to a true coilover rear. what are you opinions on this? also, one of the major things i have noticed on alot if not all coilovers for the z4, is the lack of ability to change ride height without affecting spring pre-tension, do the intrax coilover let you adjust the ride height separate from just adjusting the spring?

with my time in the drifting, auto-x, and time attack here, i was actually planning to run a custom setup from Zeal. ( http://www.endlessusa.com ) i know they arent well known in the euro market, but their racing experience in japan as well as their R&D impressed me. if that doesnt go through, i will plan on importing a set of intrax coilovers here.



Thanks for all the info!

 

[Curtis]

Glad to hear your not Planatirion, that would be a bit pathetic, friend or family perhaps?!!!!

All I can offer you on the conersion factor is that 1N per sq meter is 0.102 kg per sq meter. I'll let you take it from there! I double checked my spring rates and I have 90NM fronts and 40Nm rears fitted at the moment not 80Nm/30NM as I thought. I'm quite happy with it but of course it's personal preference at the end of the day.

Unfortunately the Intrax units use spring seat adjustment to change ride height and cornerweighting, I havn't come across anything different for the Z4 yet either assuming you mean a unit where the overall length of the assembly can be adjusted as well as the spring seat height.

As far as reinforcing the original rear shock mounts goes, all I can say is that I did over 10k miles using the standard mounting before I reinforced the mounting points. During that mileage there was no distortion or cracking of the upper mounts at all but I decided to fit plates to it anyway when I was rebuilding the back axle just to be on the safe side. As far as I'm aware there are not many Z4's or indeed E46's out there that have had the upper mounts reinforced to help cope with the extra pressure but I have never heard of an instance where the upper mount has failed so it's probably overkill. Simpsons do a lot of Intrax conversions for road and race use on a wide range of BMW's and they have never had an upper mount failure YET! I suppose it depends on the intended use, rallying would be an obvious example of when it should definately be done!

The Zeal units look like a fine job but I don't know much about them so I can't really judge.

 

[og_m3]

All I can offer you on the conersion factor is that 1N per sq meter is 0.102 kg per sq meter. I'll let you take it from there! I double checked my spring rates and I have 90NM fronts and 40Nm rears fitted at the moment not 80Nm/30NM as I thought. I'm quite happy with it but of course it's personal preference at the end of the day.

thanks, i'll look into it!

Unfortunately the Intrax units use spring seat adjustment to change ride height and cornerweighting, I havn't come across anything different for the Z4 yet either assuming you mean a unit where the overall length of the assembly can be adjusted as well as the spring seat height.

yup, you nailed it on the head as what i was refering to. maybe when i get my car, i'll look into developing it if its needed. only reason i asked is that shock stroke is sacrificed if someone wanted to lower the car.

As far as reinforcing the original rear shock mounts goes, all I can say is that I did over 10k miles using the standard mounting before I reinforced the mounting points. During that mileage there was no distortion or cracking of the upper mounts at all but I decided to fit plates to it anyway when I was rebuilding the back axle just to be on the safe side. As far as I'm aware there are not many Z4's or indeed E46's out there that have had the upper mounts reinforced to help cope with the extra pressure but I have never heard of an instance where the upper mount has failed so it's probably overkill. Simpsons do a lot of Intrax conversions for road and race use on a wide range of BMW's and they have never had an upper mount failure YET! I suppose it depends on the intended use, rallying would be an obvious example of when it should definately be done!

The Zeal units look like a fine job but I don't know much about them so I can't really judge.

thats good to hear. i assume when you said you fiited plates, you mean the plates like the rogue engineering or ground control bits that go on top of the mounts and secure the shock that way.

yeah, rally would definatly kill those...haha

in my experience with the zeals, i have no complaints, they are very quiet, and have very ease of serviceability. again, i have had no experience with intrax, but i will for sure go ahead and look into it.


thanks for all your help!

 

[Wondermike]

What a thread, I was lost after the third post but never mind

Curtis, you are a 'professor of suspension' :smart: