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Thread: Which MC for Massive Brake Booster Delete?

  1. #126
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    Quote Originally Posted by Massive Lee View Post
    I have just written a lengthy and detailed reply with precise pedal ratio calculations. I saved it and it disappeared. WTF. Admins, your interface sucks gorilla dongs. ;-)
    And oddly, it got sent out to subscribers...at least to me. Here the version I received:

    ***************
    Arghhh. It hurts using this interface...
    The lever in the twin MC booster delete kit (pedal box) has two positions. The mounting point closer to the 1" balance bar multiplies the original pedal ratio by 1.52 while the mounting point further away has a multiplier of 1.73

    On an e30 with the original pedal ratio being 4:1, it translates into either 6.1 :1 or 6.9:1
    On an e36 with the original pedal ratio being 4.3:1, it translates into either 6.4 :1 or 7.2:1

    Most racing pedal boxes you get from AP, Tilton, Wilwood etc have a pedal ratio of around 6:1

    The higher the ratio, the easiest it is to push on the brake pedal, with the adverse effect of longer pedal travel. In the ideal world, the brake pedal should not move (or barely) and it is the pressure applied that makes for the braking. Tis is in an ideal situation as we know that calipers move, pads have a slight knockback, wheels bearings have play allowing rotors to move sideways, brakelines absorb some of the energy, etc.
    ***************

  2. #127
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    Thanks for resuscitating it... ;-)

    BTW On an e46 with the original pedal ratio being 3.8:1, it translates into either 5.7 :1 or 6.5:1

  3. #128
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    Quote Originally Posted by Massive Lee View Post
    Thanks for resuscitating it... ;-)

    BTW On an e46 with the original pedal ratio being 3.8:1, it translates into either 5.7 :1 or 6.5:1
    Lee thanks for the info. I'm going to go back to stock for now and see if maybe I've caused some other problem.

    I'll have a report on Monday or so. Second race this weekend.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  4. #129
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    This past weekend, I went back to the stock master and booster - which was quite a challenge to put back on the car... I had to fab some lines, T fittings to replace the ABS, and install a hydraulic rear limiter.

    Anyway, the brakes are just fantastic and I'm going to stick with the stock 23mm master and booster for now. I'll try the 25mm M3 master if it fits the booster I have, at some point.

    Sorry I couldn't make the dual master stuff work. I may go back to it sometime next year - the feel was great, well, with .750 masters - but the car just wouldn't stop. The .625 masters were better but the feel was horrible.

    Hope others have better luck than I did. *If* I try the setup again, I'm going to change the pedal ratio drastically and see if that helps. FWIW I didn't find the bias adjuster to be very friendly anyway.
    Last edited by CoMZ302; 05-30-2017 at 09:58 AM.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  5. #130
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    discouraging to hear you could not get it resolved since we are running near identical setups with the exception of brake pad compounds. Agreed the bias adjuster needs the addition of the in car dial to get it correctly tuned. My only issue at the moment is with the firmer brake pedal and less travel my geometry for heel toe is screwed up.

  6. #131
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    Are you (Relatively) easily able to lock up the brakes? I just couldn't without a tremendous amount of pedal effort. That's the only reason I gave up.

    I was convinced I had some other problem - til I went back to the stock stuff. It's great and I can threshold brake effortlessly. Lee thinks I have frog legs.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  7. #132
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    Quote Originally Posted by CoMZ302 View Post
    Are you (Relatively) easily able to lock up the brakes? I just couldn't without a tremendous amount of pedal effort. That's the only reason I gave up.

    I was convinced I had some other problem - til I went back to the stock stuff. It's great and I can threshold brake effortlessly. Lee thinks I have frog legs.
    Some people just like the easy pedal feel, and are used to it. Without ABS, this is absolutely horrible for us, and the rock hard pedal, where you literally have to stand on it to lock up is perfect. I never want to lockup, unless I REALLY want to lock up. In the e36 we run a stock 95 M3 MC, and no booster. Front brakes are e36 M3, rear is e46 328. Setup is perfect. In the e46 cars, it's all dual MCs, but all the brake stuff is different (brembo, wilwood, etc). In all cases, pedal is very hard, and braking starts as soon as we touch it ... moves maybe 2" total.

    When I was setting it all up, I used the Excel brake force calculators to get the MC sizing right, and found that the calculator was pretty bang on. We do have in-car bais adjustors for the dual MCs, and those help for sure. The e36 has no additional adjusters ... just a stock setup with booster removed.
    Check out the 8legs Racing page: https://www.facebook.com/8legsRacing/


  8. #133
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    Very interesting.

    Not sure why my setup is so much different than everyone else. The car simply didn't slow down at all until I used 0.625 masters- and then it really didn't slow down fast enough, and the pedal travel was way longer than stock.

    All I know is, stock (23?) master with stock booster is really awesome, both feel and how fast the car slows.

    Clearly something is different!
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  9. #134
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    Agreed with ScotcH, you want a balanced system that allows you to aggressively brake and then easily modulate without a over tendency to easily lock up. So I approached the setup as a well balanced system, ability to lock up but only if I am very aggressive. It is a completely different feel and had never driven a car without boosted brakes its taken me some time to learn and gain confidence to tighten up my zones- but getting there. Note sure why you would have longer travel- I have maybe 2". As far as what is different- perhaps going back to Lee's comment on pad type, may try going to a much more aggressive compound.

  10. #135
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    Quote Originally Posted by jettero View Post
    Agreed with ScotcH, you want a balanced system that allows you to aggressively brake and then easily modulate without a over tendency to easily lock up. So I approached the setup as a well balanced system, ability to lock up but only if I am very aggressive. It is a completely different feel and had never driven a car without boosted brakes its taken me some time to learn and gain confidence to tighten up my zones- but getting there. Note sure why you would have longer travel- I have maybe 2". As far as what is different- perhaps going back to Lee's comment on pad type, may try going to a much more aggressive compound.
    Maybe the 328 caliper bores are the culprit, not sure. I can say for sure the stock system is great. Very controllable lockup. Not overboosted. Way *less* travel and more brake than any thing I tried on the dual-master setup. That had at least 6" of travel if not more, and still wouldn't stop.

    Yes I could change masters and make the travel shorter, but the car simply wouldn't stop. It was flat dangerous.

    Is anyone running stock 328 calipers with the system?
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  11. #136
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    Quote Originally Posted by jettero View Post
    Agreed with ScotcH, you want a balanced system that allows you to aggressively brake and then easily modulate without a over tendency to easily lock up. So I approached the setup as a well balanced system, ability to lock up but only if I am very aggressive. It is a completely different feel and had never driven a car without boosted brakes its taken me some time to learn and gain confidence to tighten up my zones- but getting there. Note sure why you would have longer travel- I have maybe 2". As far as what is different- perhaps going back to Lee's comment on pad type, may try going to a much more aggressive compound.
    Pads 100% make a difference. We run PF01 or PF11 pads mostly.
    Check out the 8legs Racing page: https://www.facebook.com/8legsRacing/


  12. #137
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    Quote Originally Posted by ScotcH View Post
    Pads 100% make a difference. We run PF01 or PF11 pads mostly.
    I usually run Carbotech XP12s - Lee also suggested more pad, so I jumped up to XP20s, which is the second most aggressive pad they have.

    So, tried that.

    The caliper bores are much smaller on the 328 and I'm going to assume that's the problem. I'm glad you guys are having success with the setup; it did not work for me. I can generate way more G-Forces braking with the stock stuff - it is much easier to threshold brake - and the pedal feels much better too. Sorry my experience isn't the same as yours.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  13. #138
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    The goal is to getting better braking performance- if you are able to achieve that with getting the oem boosted setup dialed in Awesome!

  14. #139
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    Quote Originally Posted by CoMZ302 View Post
    I usually run Carbotech XP12s - Lee also suggested more pad, so I jumped up to XP20s, which is the second most aggressive pad they have.

    So, tried that.

    The caliper bores are smaller on the 328 and I'm going to assume that's the problem. I'm glad you guys are having success with the setup; it did not work for me. I can generate way more G-Forces braking with the stock stuff - it is much easier to threshold brake - and the pedal feels much better too. Sorry my experience isn't the same as yours.
    Yeah, it's 54 front 36 rear. I ran stock E30 M3 brake parts with 54 front 38 rear caliper bores, and it wasn't that easy to lock the brakes up / get sufficient brake torque.

    I moved up to 57 / 40 with dual .625s and it feels reasonably good, but yes, it could certainly feel better, as according to data I can decelerate as quickly as E36s with boosted brakes, but the modulation still isn't there for me. If I could reduce the pedal effort by another 10% I think I'd feel pretty good, but there is no easy and inexpensive solution out there for me at the moment.

  15. #140
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    I had a chance to test the 23mm master with booster delete this weekend... I absolutely LOVE it. It is EXACTLY what I wanted out of the brake pedal. I haven't looked at the data yet, but I am 99.9% confident I am braking much deeper into turns and not over braking like I was with the OEM setup.

    Highly, highly, highly, recommend.

    Only thing I want now is brake pads with slightly more initial torque than my Hawk DTC-70's.

  16. #141
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    I am sometimes puzzled. Two identical set-ups. Different drivers. One is very happy and it fills all his/her expectations. The other, it is the total opposite. ;-) Oh well. Live and learn. But still. Thanks everyone for helping the community with your feedbacks.

  17. #142
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    Quote Originally Posted by Massive Lee View Post
    I am sometimes puzzled. Two identical set-ups. Different drivers. One is very happy and it fills all his/her expectations. The other, it is the total opposite. ;-) Oh well. Live and learn. But still. Thanks everyone for helping the community with your feedbacks.
    No not the same setups.

    I have 328 calipers.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  18. #143
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    ^^ Correct, I am on Porsche 911 Brakes front and rear.

    I looked at data yesterday, I am carrying more speed into corners, braking later and sustaining a higher braking G's than with the booster setup. With some more fine tuning and getting more acquainted with the pedal, I feel I can brake even deeper.

  19. #144
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    Quote Originally Posted by Inflame View Post
    ^^ Correct, I am on Porsche 911 Brakes front and rear.

    I looked at data yesterday, I am carrying more speed into corners, braking later and sustaining a higher braking G's than with the booster setup. With some more fine tuning and getting more acquainted with the pedal, I feel I can brake even deeper.
    Lee would like you to try the 328 stock brakes so you can confirm I have frog legs

    Seriously, great for you. I am going to try the stock M3 master to see if less travel and more effort is better.
    2002 BMW M Roaster.
    1998 BMW 328is SCCA E Production road racer.

  20. #145
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    Hey gents,

    So I too am chasing some issues with my stock brakes and suspect it's a bad MC. Before I just buy a replacement MC and call it done, I wanted to look into replacing the booster thanks to BMW discontinuing the brake booster with the sensor.

    For me to move forward, I need to figure out what MC I can use. I've seen Lee mention the 1987 Porsche 944 non-ABS in other threads as it's 19/19.

    I just don't know what's the right MC to get since it needs to mate up to my stock M10 lines and work with my stock 60mm/40mm OEM pistons. I also have G-loc R14/R12 (my next pads will be symmetrical compounds all around) pads if that helps.

    Does anyone have a proven set-up for a moderately stock system before I give up and just get a Centric OEM MC?

  21. #146
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    19/19mm from a VW Dasher
    http://www.ebay.ca/itm/Audi-Fox-VW-D...9Z0rE6&vxp=mtr

    Also available in 20/20mm

    Also, there's not one single MC size to fit everybody. Some people go to a much bigger 25/25mm. But in all cases I strongly suggest to fit brake pads with a higher coefficient of friction. Racecars don't use street pads... ;-)
    1969 2002 racecar + 1989 e30 M3 racecar


  22. #147
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    I have a 19mm Dasher mc if someone wants to buy it. Pedal was just a little too soft for my particular setup.

  23. #148
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    I have a 19mm Dasher mc if someone wants to buy it. Pedal was just a little too soft for my particular setup.
    How much shipped to 22923?

  24. #149
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    Anyone try the dual MC booster delete with the new center valve master cylinders from AP Racing? They are designed specifically to work with ABS. I continue to worry that marrying my booster delete with a Bosch M4 ABS setup ultimately will lead to an issue.

    https://www.apracing.com/product_det...nge_mount.aspx

    --Peter

  25. #150
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    Tilton says that the 74 series (long body) is compatible with ABS.

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