[esoulliard]

I just recently got my car ready for track season this year. My car spends most of its time on the street, but it does see some HPDE action. I made the following changes this year:

PSS staggered to P4S square (245s on 8" wide wheels all around)
Motul DOT 5.1 brake fluid
Hawk street/race pads

The setup feels really great on the street. The front end of the car feels much tighter (almost like the switch from comfort to sport mode). The pads have really good initial bite. They shrieked like nails on a chalkboard until they were bedded though! I ran Motul 600 in the past, but the shop that I worked with this time suggested that the DOT fluid would be best for street and track duties.

I'm really happy with the setup so far. I think the biggest change is the new tires with the square setup. I thought I'd post this in case anyone is looking to do something similar. I haven't had it to a track yet this year, but I'll post impressions after I do. Happy motoring.

[Maynard]

I did almost the same to start into HPDE - pads and fluid, and new Conti's. I considered going to square, if I step up to new wheels - what are the specifics on your setup? any rubbing in front w/ the 245s, spacers?

[buster-riley]

you are on 18 inch wheels right? or did you downsize to 17s?

[esoulliard]

I am not getting any rubbing at all. I am on the stock suspension with 18" Ultraleggeras. From what I've read here, it seems like 17" wheels might be the way to go, but I kind of made a concession to style by staying with 18s. I highly recommend the square setup.

[dradernh]

This is good info - thanks.

Which aspect ratio did you go with: 35 or 40?

[Anthony235]

The 5.1 fluid has a lower boiling point so it's considered more of a street fluid.

But I've ran RBF600 in all my cars and with the m2335i I've experienced inconsistent pedal feel with it at the limit. I've posted that I think it might have to do with the high viscosity of RBF600 not working well with the BMW brake system.

I believe 5.1 is lower viscosity so it might actually be a better fluid for this car.

[harkes]

Originally Posted by Anthony235

The 5.1 fluid has a lower boiling point so it's considered more of a street fluid.

But I've ran RBF600 in all my cars and with the m2335i I've experienced inconsistent pedal feel with it at the limit. I've posted that I think it might have to do with the high viscosity of RBF600 not working well with the BMW brake system.

I believe 5.1 is lower viscosity so it might actually be a better fluid for this car.

Very interesting note on the Motul RBF600. I also had the pedal going soft running it last time. No real brake fading - just a soft pedal that I had to pump once or twice every lap.

[capt_and]

Originally Posted by Anthony235

The 5.1 fluid has a lower boiling point so it's considered more of a street fluid.

But I've ran RBF600 in all my cars and with the m2335i I've experienced inconsistent pedal feel with it at the limit. I've posted that I think it might have to do with the high viscosity of RBF600 not working well with the BMW brake system.

I believe 5.1 is lower viscosity so it might actually be a better fluid for this car.

The inconsistent feel is from the hydraulic brake assist. Under various conditions, the car will prime the brakes, add additional boost, or hold onto abs. I coded all of that out and did notice a huge difference. Whenever I boiled the Motul 600, the pedal went straight to the floor whereas before the coding, it would go soft but would still be firm enough to use. You can code out the inconsistent feel if you hate it enough like I did.

[dradernh]

Originally Posted by capt_and

Under various conditions, the car will prime the brakes, add additional boost, or hold onto abs. I coded all of that out and did notice a huge difference.

I think I read somewhere in BMW's literature that the car will prime the brakes when the driver comes off the throttle especially quickly. The car reasonably assumes the driver will next be getting on his brakes. That's probably fine on the street, but not on the track.

How did you code-out these brake assist features, which have no place on a race track?

[Anthony235]

Originally Posted by capt_and

The inconsistent feel is from the hydraulic brake assist. Under various conditions, the car will prime the brakes, add additional boost, or hold onto abs. I coded all of that out and did notice a huge difference. Whenever I boiled the Motul 600, the pedal went straight to the floor whereas before the coding, it would go soft but would still be firm enough to use. You can code out the inconsistent feel if you hate it enough like I did.

Yes, I remember reading about this a few years ago. I think it was actually a X3 driver who was driving One Lap that was the first.

I'll look into if I ever get back on the track with the BMW.

[dradernh]

Originally Posted by Anthony235

Yes, I remember reading about this a few years ago. I think it was actually a X3 driver who was driving One Lap that was the first.

http://www.onelapx1.com/

[Nugget]

Originally Posted by capt_and

The inconsistent feel is from the hydraulic brake assist. Under various conditions, the car will prime the brakes, add additional boost, or hold onto abs. I coded all of that out and did notice a huge difference. Whenever I boiled the Motul 600, the pedal went straight to the floor whereas before the coding, it would go soft but would still be firm enough to use. You can code out the inconsistent feel if you hate it enough like I did.

Do you have more info on that coding?

I dislike the inconsistent pedal on track.

[Anthony235]

Originally Posted by Nugget

Do you have more info on that coding?

I dislike the inconsistent pedal on track.

Originally Posted by dradernh

http://www.onelapx1.com/

[capt_and]

Originally Posted by dradernh

http://www.onelapx1.com/

Yes, I used this as a guide to do coding, however, our cars have different nomenclature as the ones listed on that site.

Originally Posted by Nugget

Do you have more info on that coding?

I dislike the inconsistent pedal on track.

Yes, but, I am not sure you'll really want to do that. The stock system doesn't intervene too often, but when it did, I didn't like it. I wouldn't necessarily do it if I had stock brakes. I am going to keep the assisted coded off because I am ordering a BBK and won't really need the assists but they are actually not bad to have. As a matter of fact, I wish I had them this last weekend when I boiled my fluid and the pedal dropped to the floor. The assist would've provided some boost to give the car some stopping power whereas with everything coded out, I was on my own. This is an extreme example since my brake calipers did catch on fire several times due to over heating, destroyed seals, and possibly piston scoring. Needless to say, the stock brakes are more than adequate for tracking. But once you decide to track very often as I have, the front calipers simply aren't enough. Mine are black now...

[Maynard]

I think this post has some info too, but I'm just going from what is left of my memory, and doing a quick search at work: http://www.2addicts.com/forums/showt...ghlight=assist

[dradernh]

Originally Posted by Maynard

I think this post has some info too, but I'm just going from what is left of my memory, and doing a quick search at work: http://www.2addicts.com/forums/showt...ghlight=assist

That blog was pretty exciting, wasn't it!

I was very disappointed when the vehicle was totaled on the street by an errant driver, and the story came to an abrupt halt.

[Anthony235]

Originally Posted by capt_and

Needless to say, the stock brakes are more than adequate for tracking. But once you decide to track very often as I have, the front calipers simply aren't enough. Mine are black now...

When I had my EvoX we called them Brownbo instead of Brembo.

[harkes]

So what do you recommend to try instead of Motul RBF600?

My last session from Ningbo Racetrack (China) - hotlap @ 9:40

[Dylan86]

Originally Posted by harkes

So what do you recommend to try instead of Motul RBF600?

My last session from Ningbo Racetrack (China) - hotlap @ 9:40

Nice lap! I'm using Motul RBF 660, and it's great! No issues with pedal feel, if anything it's better than stock.

[harkes]

Originally Posted by Dylan86

Nice lap! I'm using Motul RBF 660, and it's great! No issues with pedal feel, if anything it's better than stock.

Didn't know there was a 660. They description and boiling point is practically the same.

RBF 600
Extreme high performance polyglycol brake fluid. Far exceeds the standards of DOT 4. Each bottle is filled with Nitrogen, increasing shelf life and eliminating contamination while factory sealed. Extremely high dry boiling point 594F(312C) helps prevent vapor lock and brake fade during hard use, with excellent recovery time. Wet boiling point 399F(204C).

RBF 660
Very high dry boiling point of 622F (328C) and a wet boiling point of 399F (204C). For all types of hydraulic brake and clutch actuators requiring non-silicone synthetic fluid. Specially designed to resist extreme temperature generated by racing brakes (carbon and ceramic) only allowing a minimal air entrance for brake cooling.

[Dylan86]

Originally Posted by harkes

Didn't know there was a 660. They description and boiling point is practically the same.

RBF 600
Extreme high performance polyglycol brake fluid. Far exceeds the standards of DOT 4. Each bottle is filled with Nitrogen, increasing shelf life and eliminating contamination while factory sealed. Extremely high dry boiling point 594F(312C) helps prevent vapor lock and brake fade during hard use, with excellent recovery time. Wet boiling point 399F(204C).

RBF 660
Very high dry boiling point of 622F (328C) and a wet boiling point of 399F (204C). For all types of hydraulic brake and clutch actuators requiring non-silicone synthetic fluid. Specially designed to resist extreme temperature generated by racing brakes (carbon and ceramic) only allowing a minimal air entrance for brake cooling.

Yea I didn't know either, until my local race shop put me on the 660 when I ordered the 600. They said they don't use the 600 anymore.. No apparent reason, but I have read several complaints from German car owners, regarding the 600, who struggle at getting a good pedal feel. I can tell you without question, my pedal is very firm, right at the top 3/4 stroke position and I have yet to require a re-bleed or feel any sponginess when things are at temperature.

[MarcoZandrini]

New LiquiMoly 5W-30, fresh Motul RBF600 and Performance Friction pads. No issues, no fade.