Web www.M3Forum.net

View Full Version : Brake pedal "feel"


cardiacM3
Sun, Oct-31-2004, 02:41:11 PM
I've driven the Porsche 996 at the track have been impressed with the firmness and lack of fade in the OEM Porsche brake system. I don't get that same consistently firm brake pedal feel with the E46 M3. Is this an issue of brake fluid, stainless steel brake lines, brake pads, rotors, or calipers? What upgrade(s) would it take to give the E46 M3 that same consistently strong braking?

TCM
Sun, Oct-31-2004, 07:21:04 PM
Porsche has the best stock braking system in the world as far as I am concerned. They use a complete Brembo system with much higher quakity hardware then BMW or any of the other manufacturers IMHO. My advise to get a similair feeling would be to switch to stainless lines, higher temp fluid (Castrol SRF, Motul 600, ATE Super Blue)and get a BBK with a 4 piston setup (not an 8 piston). This should provide more instant bite and fade free braking over a perido of hot laps. Hope this helps.

cardiacM3
Sun, Oct-31-2004, 07:30:15 PM
Porsche has the best stock braking system in the world as far as I am concerned. They use a complete Brembo system with much higher quakity hardware then BMW or any of the other manufacturers IMHO. My advise to get a similair feeling would be to switch to stainless lines, higher temp fluid (Castrol SRF, Motul 600, ATE Super Blue)and get a BBK with a 4 piston setup (not an 8 piston). This should provide more instant bite and fade free braking over a perido of hot laps. Hope this helps.

I figured as much. In your opinion, which 4 piston BBK is the way to go for the E46 M3? (please, no flames about the "bling" factor :peace: )

SG_M3
Sun, Oct-31-2004, 07:48:11 PM
You can get good pedal feel out of stock m3 brakes. If you are willing to do some basic brake maintaince every couple of months then get some solid brake guides. They did wonders for my pedal feel. SS lines will help, as will a fresh brake fluid and a good bleed.

cardiacM3
Sun, Oct-31-2004, 11:36:33 PM
You can get good pedal feel out of stock m3 brakes. If you are willing to do some basic brake maintaince every couple of months then get some solid brake guides. They did wonders for my pedal feel. SS lines will help, as will a fresh brake fluid and a good bleed.

SG, pardon my ignorance but what are "brake guides"? I can see how more frequent/fresh brake fluid and bleeding will help, but it seems that some upgrade in the braking system (e.g. BBK) would give a more permanent solution equivalent to these Porsche brakes (they're pretty phenomenal out of the box without any extra maintenance!) :hmm: .

SG_M3
Mon, Nov-01-2004, 12:13:03 AM
I agree that a bbk is a nice thing to have. But it isn't a necessity, stock m3 brakes when upgraded correctly are up to the task.

www.bimmerworld.com has the brake guides.

TCM
Mon, Nov-01-2004, 03:15:15 PM
You can make the M3 brakes quite good, but again, it will never be like a bbk. You buy the bbk and there is no worry about constantly changing the fluid every coupld of months, etc.

cardiac m3:

I personally like the Brembo 380mm/4 piston setup on front and 345/4 piston on rear. It is definately costly, but weighs less, brakes more under torment, and has better pedal feel then any stock system can provide. StopTech is also a choice, but I think Brembo is of a higher quality after working on both systems in the shop. Look into it and see what kit serves your purpose and price point better, then go from there. Hope this helps.

jonam
Mon, Nov-01-2004, 03:40:01 PM
You can make the M3 brakes quite good, but again, it will never be like a bbk. You buy the bbk and there is no worry about constantly changing the fluid every coupld of months, etc.

cardiac m3:

I personally like the Brembo 380mm/4 piston setup on front and 345/4 piston on rear. It is definately costly, but weighs less, brakes more under torment, and has better pedal feel then any stock system can provide. StopTech is also a choice, but I think Brembo is of a higher quality after working on both systems in the shop. Look into it and see what kit serves your purpose and price point better, then go from there. Hope this helps.
No offense, but IMO $5000 or more is too much to get the firm pedal feel unless he wants some bling factor in the picture. Surely BBK will be better, but SS lines, high temp fluid, and right bleeding should give you pretty good feel. If you track your M3 at intermediate or higher group, brake guide will be helpful in reducing caliper flex, too.
Read this for the bleeding instruction: http://www.zeckhausen.com/bleeding_brakes.htm

cardiacM3
Mon, Nov-01-2004, 11:32:53 PM
No offense, but IMO $5000 or more is too much to get the firm pedal feel unless he wants some bling factor in the picture. Surely BBK will be better, but SS lines, high temp fluid, and right bleeding should give you pretty good feel. If you track your M3 at intermediate or higher group, brake guide will be helpful in reducing caliper flex, too.
Read this for the bleeding instruction: http://www.zeckhausen.com/bleeding_brakes.htm

I run solo in Group 2 at FATT at Summit Point (I guess that is "intermediate or higher.") Certainly, I continue to have much to learn about driving better, but I consider myself a pretty competent track driver. I am certainly NOT going for "bling." What I am trying to obtain in the M3 is more consistent (less fading) brakes, like the Porsche (if you've driven one at the track, you'll understand that those brakes seem bullet-proof). After 4 track sessions in the M3, the brake pedal is soft with long travel, etc. I did the SS brake lines/ATE Blue fluid/track pad/Euro floating rotor stuff on the E36 M3 I previously owned. Yes, braking was improved, but not in the same league.

TCM, thanks for your input. I'll look into those systems :peace: .

jonam
Tue, Nov-02-2004, 02:49:01 AM
Did I offend you somehow? :whistle: j/k
You could've mentioned that you know about ss lines, fluid and others. Don't blame me for that :D
Some of the fastest drivers in BMWCCA clubracing use OEM brake system with what you've done plus ducting and even won the races. As SG said, they are upto task even for the racers.
Still you wan to have better pedal feel, yeap, BBK makes sense. You might want to ask for smaller piston size for stiffer feel and better release in extreme condition. I've got them in my system, and love the feel.
Stiffer feel is necessarily better in performance, but if that's what you're looking for, they are available for you.

Fly'n DuthhMan
Tue, Nov-02-2004, 05:50:42 AM
Pedal feel is related to a lot of factors. Certainly doing good fluid, good pads, lines and bushing on a stock system should help. But in my experience there are two other critcal players.

One is piston area. If you have smaller overall piston area you'll get a firmer and shorter pedal. But it will require more effort. For this reason the AP system Ground Control sells should feel firmer.

Here is a link to a more detailed thread on piston area...

http://www.m3forum.net/m3forum/showthread.php?t=41798&highlight=Piston+Area

The StopTech and Brembo systems have almost identical piston areas as the stock calipers. I don't feel much difference in terms of pedal travel, effort and frimness from stock. Any improvement is a result of the 4piston caliper being stronger than the stock floating design.

The second issue, don't laugh, has to do with the actual brake pedal and the firewall it is mounted to. In some cases the pedal and the firewall flex slightly, making the pedal feel mushy or "unfirm." I have have seen some flex in these areas on several cars, I haven't really looked into the BMW setup that much.

The sad thing is that manufactures other than Porsche seem to like offering there cars with a mushier, low effort grabby brake system because to the uneducated driver it feels like the brakes work really well. Nevermind that they are difficult to modulate.

cardiacM3
Tue, Nov-02-2004, 12:24:26 PM
Did I offend you somehow? :whistle: j/k
You could've mentioned that you know about ss lines, fluid and others. Don't blame me for that :D
Some of the fastest drivers in BMWCCA clubracing use OEM brake system with what you've done plus ducting and even won the races. As SG said, they are upto task even for the racers.
Still you wan to have better pedal feel, yeap, BBK makes sense. You might want to ask for smaller piston size for stiffer feel and better release in extreme condition. I've got them in my system, and love the feel.
Stiffer feel is necessarily better in performance, but if that's what you're looking for, they are available for you.

No offense taken :thumbsup: . All of this input has been helpful. Yes, I guess a consistent stiffer feel is what I'm looking for. So, a BBK with smaller piston size achieves this? Which BBK did you go with?

jonam
Tue, Nov-02-2004, 01:43:43 PM
No offense taken :thumbsup: . All of this input has been helpful. Yes, I guess a consistent stiffer feel is what I'm looking for. So, a BBK with smaller piston size achieves this? Which BBK did you go with?
I've got Stoptech front kit with piston size of 36/40. Regular ones are 38/42.
It might be too stiff for street driven cars..but I think you would like it.:thumbsup:
Talk to Dan Law for good price and service (suppot forum sponsor) :thumbsup:

cardiacM3
Tue, Nov-02-2004, 10:25:37 PM
I've got Stoptech front kit with piston size of 36/40. Regular ones are 38/42.
It might be too stiff for street driven cars..but I think you would like it.:thumbsup:
Talk to Dan Law for good price and service (suppot forum sponsor) :thumbsup:

Front kit alone; rear brakes are stock? This doesn't mess up the braking balance F/R?

jonam
Tue, Nov-02-2004, 10:43:49 PM
Front kit alone; rear brakes are stock? This doesn't mess up the braking balance F/R?
so far I have only one track day with them..Stoptech is known for balanced system and it seemed fine to me other than the fact that the rear brakes worked harder(more wear in the pads than before). It's popular setup among the clubracers(budget minded). If you got $, 4wheel kit is better option, though.

SG_M3
Tue, Nov-02-2004, 10:57:32 PM
Front kit alone; rear brakes are stock? This doesn't mess up the braking balance F/R?

Bias can be basically adjusted by using the correct rear pad compound.

jonam
Tue, Nov-02-2004, 11:46:56 PM
Bias can be basically adjusted by using the correct rear pad compound.
True!
but most likey it would not be necessary if going with stoptech front.
I was recommended by stoptech to use slightly less torqued front pads than what I have in the rear..that is with smaller pistons than usual kit.
I will find out more in couple of weeks..

Dan Law
Wed, Nov-03-2004, 08:35:47 PM
JonAm:

Other than Stock classes, who are these guys winning on stock systems?


Cardiac M3:

Anyway, You'll notice a huge improvement in brake feel with just a front kit upgrade. Rears are nice to have but the fronts make the difference. I would suggest StopTech unless buying the trueblue Brembo racing stuff - $10.000 calipres. In fact StopTech is used widely in WSC Touring cars.

EMail me for a good price then go ahead and check Flying Dutchman's sources.

Dan Law
DERMotorSports@gmail.com

jonam
Wed, Nov-03-2004, 09:12:03 PM
JonAm:

Other than Stock classes, who are these guys winning on stock systems?

Mike Gilbert IP,
Scott Smith(with hint hint ;) Motorsport ABS Controller) CM,
Sean Tillinghast IP

These are the racers who actually won something..and there must be other racers with stock brakes who's slow like me :D

Dan Law
Wed, Nov-03-2004, 10:34:56 PM
Jon:

I can definitively state that I have not encountered anybody using them in Prepared and above - albeit we don't encounter the folks you cite too often down here and it has been a full year since I've raced - anybody got some money to throw my way? Or better yet, a job!

Dan Law

Fly'n DuthhMan
Thu, Nov-04-2004, 01:33:43 AM
so far I have only one track day with them..Stoptech is known for balanced system and it seemed fine to me other than the fact that the rear brakes worked harder(more wear in the pads than before). It's popular setup among the clubracers(budget minded). If you got $, 4wheel kit is better option, though.

Jonam...if your only doing a front kit, then the 36/40 pistons are better, after I adjust for the larger rotor, the brake torque is 97% of stock according to my calculations...Thus pedal effort is about the same maybe slightly higher, but travel is shorter. Correct? This set up probably feels the best, but there might be an issue with rear.

The smaller pistons offset the brake torque from the larger rotors maintaining a balance system with the stock rears. These smaller pistons should not be used with StopTech standard rear, you'll need a smaller than stander rear piston size also.