Upgraded brakes on 128?

[Suprgnat]

Originally Posted by Blacksport

My 128 has the BMWP front BBK...the rears are stock...

According to Supernat's article, I have "increased" my stopping distance by adding larger front brakes. If anyone thinks they can outbreak my car with stock brakes, bring it by and we'll try it...we'll use my wheels/tires on both cars to make it even...

500 bucks to the winner.

No, ccording to BOTH articles you MAY have increased your stopping distances and BOTH articles are clear that braking forces and distances are not just simply based on the calipers and rotors, but are the result of many factors acting in concert.

On that note, BMW did include larger rear calipers with the PBs for some reason. As both articles point out, with your wheels and tires, your suspension, CG, pad mu, etc., etc., having 42mm rear brake pistons vs. 40mm piston my not be optimum and it's clear from the certainty of your posts that you have the scientifically objective data to prove it.

When all is said and done my intention was to point the OP in a direction where she could make an informed desicion without all the noise. I think that both TurnFast and Stoptech are great resources and, apparently, you don't. The OP can take it or leave it.

[Taskmaster]

Tires.

[bNks334]

I just did my second track day running HPDE 2. I ended up in limp mode after about 15min into 3 of 4 sessions. It was about 86* out but felt like 100 out on blacktop lol.

Did you have any issues (the OP)? I was driving very hard and several people in my, and others, run group spun out. My car went into limp mode on just about every lap that these guys started to loose grip...

I think my rear brakes were getting too hot. I would start to loose grip and I think the e-diff was roasting the rears. I am not seeing any clear way to address this. Will pads be an answer? or the 330/z4 conversion?

[3002 tii]

Originally Posted by bNks334

I just did my second track day running HPDE 2. I ended up in limp mode after about 15min into 3 of 4 sessions. It was about 86* out but felt like 100 out on blacktop lol.

Did you have any issues (the OP)? I was driving very hard and several people in my, and others, run group spun out. My car went into limp mode on just about every lap that these guys started to loose grip...

I think my rear brakes were getting too hot. I would start to loose grip and I think the e-diff was roasting the rears. I am not seeing any clear way to address this. Will pads be an answer? or the 330/z4 conversion?

Which club, which track? Limp mode for N52 is unusual. I've never hit limp mode once in the last 4 years...

[Taskmaster]

Oil temps?

[bNks334]

I might start a thread to address my situation further... seems like a lot of it wouldn't apply to the OP.

[kobeballer96]

I'm going 60 mph plus at the end and here's my stopping,

Pagid pads all around and conti tires. Note top of 2nd gear is some where around 63mph or something like that so you do the math and tell me if you stop faster then me. Tires make the stopping distance and good bite and less brake fade.

[kobeballer96]

The autocross vid was on slicks in the summer and here's how she stops in the winter/fall with the bfg rivals street tires.bsame stock 128i brakes with just pads and stoptech rotors

[KellyK]

Originally Posted by bNks334

I just did my second track day running HPDE 2. I ended up in limp mode after about 15min into 3 of 4 sessions. It was about 86* out but felt like 100 out on blacktop lol.

Did you have any issues (the OP)? I was driving very hard and several people in my, and others, run group spun out. My car went into limp mode on just about every lap that these guys started to loose grip...

I think my rear brakes were getting too hot. I would start to loose grip and I think the e-diff was roasting the rears. I am not seeing any clear way to address this. Will pads be an answer? or the 330/z4 conversion?

I did 4 runs in my car without any real issues. I sat passenger in my car with my instructor driving, and my car went into limp mode for him (as he was driving significantly harder than I was). My brakes were seeming to fade for me a lot toward the end of my day, and I was just curious what you guys have done to improve stopping power.

[chris82]

Originally Posted by KellyK

I did 4 runs in my car without any real issues. I sat passenger in my car with my instructor driving, and my car went into limp mode for him (as he was driving significantly harder than I was). My brakes were seeming to fade for me a lot toward the end of my day, and I was just curious what you guys have done to improve stopping power.

Is it an automatic transmission?

[bNks334]

I drive an N51 auto. Not sure about Kelly. I was monitoring oil and coolant temps and neither hit the 300f and 260f limits, respectively before the computer puts the car into full limp mode. I was getting hot enough to pull power though. Oil hit 141c. I cant seem to find any radiator upgrades for the auto 128i though... I know you can do an oil cooler retrofit.

There is a ton of info about various limp mode issues and the DSC cutting power at:

http://www.e90post.com/forums/showth...light=DSC+limp

Also, http://www.e90post.com/forums/showthread.php?t=1117725 talks about coding off the e-diff temperature estimation

I need to do more research on this...

[Pyrat 2]

First of all make sure that your stability and traction control are as disabled as you can set them by holding the button on the dash. This will minimize the system applying the brakes to stabilize the car while driving like a mad man.

Unfortunately, even with this I have heard of 128s going into limp mode because of brakes. I have a friend who I would meet at Road America and he ran into the same issue you are describing despite my 135 running fine under the same conditions. He never did solve the problem but did state it was a known problem. I never researched to confirm. In any event he ended up selling the car and is now driving a boxster.

[bNks334]

Originally Posted by HeelToe

First of all make sure that your stability and traction control are as disabled as you can set them by holding the button on the dash. This will minimize the system applying the brakes to stabilize the car while driving like a mad man.

Unfortunately, even with this I have heard of 128s going into limp mode because of brakes. I have a friend who I would meet at Road America and he ran into the same issue you are describing despite my 135 running fine under the same conditions. He never did solve the problem but did state it was a known problem. I never researched to confirm. In any event he ended up selling the car and is now driving a boxster.

I am willing to bet this issue can be fixed with a code change from someone experienced enough. I doubt the DME logic in the 128i is performance oriented. The thresholds on just about everything are probably much lower than the logic in say... an M car.

[PKumarM3]

Originally Posted by KellyK

I did 4 runs in my car without any real issues. I sat passenger in my car with my instructor driving, and my car went into limp mode for him (as he was driving significantly harder than I was). My brakes were seeming to fade for me a lot toward the end of my day, and I was just curious what you guys have done to improve stopping power.

brake fluid (i like castrol srf or motul 600), stainless steel brake lines (turner or bimmerworld or stoptech), and a more aggressive brake pad.

essentially learn what wet boiling temp and dry boiling temp is. dry boiling temp is the first time the fluid ever boils. wet boiling temp is the temp that the fluid boils after. obviously this degrades over time and use. the higher the dry and wet, the longer lasting the fluid will be. i had castrol srf in my former e46 m3 and running in instructor run group putting down 1:12s at NJMP Thunderbolt, I didn't flush the fluid for 2 years at a time (20-30 days per year).

stainless steel lines will keep the tightness in the pedal, since the stock lines are made out of rubber. they tend to heat up and stretch and stretch. the stainless steel lines will keep steady.

brake pad will increase bite after each application.

obviously this also works with the tires you are using. if you are using tires that don't grip very well, this will overheat the braking system.

in addition, you also have to personally manage the brakes as a driver. by this I mean that you don't drag the brakes. either on or off. and when you need them, they will be there assuming you have the previously mentioned modifications applied. in addition, brake cooling is helpful, but then you're on a slippery slippery slope.

bbk is mostly for endurance (constantly heavy braking) and makes pad changes easier. it does increase braking, but only if you have the right fluid, lines, tires, and pad in the mix.

hope that helps

[Olgeezer1]

Using the BMW Performance brakes front and rear, stock LV fluid changed yearly, EBC Redstuff pads front, stock pads rear. Great street setup - silent, almost no dust, great cold stops. Only limited track time - 20 to 30 minute stints but pleasantly surprised. Fade I experienced with the stock setup by sessions end was gone. More track oriented pads could only make it better but I'm not willing to live with the noise and dust. For me, the perfect setup and yes, they look great.

[MAMSport]

Sorry to take this off on a slight tangent, but I was under the impression that the 128i Performance brakes were the same as the OE brakes on the 135i. My car has the Performance brakes installed (yellow/gold front caliper paint, slotted and drilled front rotors), but the rear rotors look like blanks. I have seen discussions in which statements indicate the rear rotors on the 135i are dimpled and slotted.

Can anyone explain to me what the difference is/should be, and if it is possible to measure the rotor diameter/thickness to determine whether the rear rotors are of the stock 128i size or PBK size? On realoem.com, there are no specs for rotor sizes for the 'retrofit PBK', and they do illustrate a rear rotor that is neither slotted, drilled, nor dimpled.

Thank you very much!

[asbrr]

Originally Posted by MAMSport

Sorry to take this off on a slight tangent, but I was under the impression that the 128i Performance brakes were the same as the OE brakes on the 135i. My car has the Performance brakes installed (yellow/gold front caliper paint, slotted and drilled front rotors), but the rear rotors look like blanks. I have seen discussions in which statements indicate the rear rotors on the 135i are dimpled and slotted.

Can anyone explain to me what the difference is/should be, and if it is possible to measure the rotor diameter/thickness to determine whether the rear rotors are of the stock 128i size or PBK size? On realoem.com, there are no specs for rotor sizes for the 'retrofit PBK', and they do illustrate a rear rotor that is neither slotted, drilled, nor dimpled.

Thank you very much!

The fronts are the same, the rears still use a sliding caliper, albeit with a slightly larger piston than stock 128i parts. They use what I believe is the 328i rear caliper with a 42mm piston (vs 40mm stock). The rear rotors are the same size.

You could put rear 135i brakes on, but that would mean you lose your emergency brake unless you replace further parts. Also technically your master cylinder is smaller than a 135i so there are some minor negatives there. If you go with what BMW has tested, it's 135i/performance parts up front and what I listed above at the rear.

[sprp85]

I thought MCs are identical between 128 135 328 335?

[gixracer]

Master cylinders are different between 135 and 128. i currently have swapped 135i master and front brakes to my 128i. i am in the process of getting some auto axles so I can swap in the rear hubs to accommodate the rear brakes. 128 rear axles are smaller along with the ebrake diameter compared to the 135.

I was fortunate enough to have the spares from my e91 n55/manual swap. The car brakes confidently on the street, but I have yet to track it. I will be putting in an LSD and eliminating the ediff/dsc by coding.

Based on my current setup and the general internet gripe I would think that if the rear was a bit more loose that would help on turn in for a corner on the track. That would assume that the driver was experienced enough to handle it. From my experience in an E46 lift throttle over steer was wonderful and easy to manipulate. being able to trail brake and let the car rotate on the front would help turn in. So what I'm sayin is that off power and less settled rear is not necessarily a bad thing........ from my experience. my 2 cents.