[reyoasian]

Any way to code off rear-braking on xDrive?
Don't want to cook my brakes.

[kern417]

Originally Posted by reyoasian

Any way to code off rear-braking on xDrive?
Don't want to cook my brakes.

You're asking for trouble. Rear braking stabilizes the car.

[Polo08816]

Originally Posted by kern417

You're asking for trouble. Rear braking stabilizes the car.

I haven't tried disabling the eLSD via coding yet. If you have a mechanical LSD, it might be fine.

As for brake ducts, I know that the M Sport package has air ducts for the front brakes so I view aftermarket ducts as unnecessary.

Better pads like Pagids for the M Sport/M Performance Brakes and fresh brake fluid (even OEM BMW DOT4 brake fluid) is plenty for HPDEs.

I've consistently ran F80/82 M3/M4 brake pads in my M Sport Brakes when the car is shared between my girlfriend and myself at HPDEs. Of course, my powertrain is largely stock. so I wouldn't be going nearly as fast as M3/M4s down the straights to completely overwhelm their brake pads.

[kern417]

Originally Posted by Polo08816

I haven't tried disabling the eLSD via coding yet. If you have a mechanical LSD, it might be fine.

As for brake ducts, I know that the M Sport package has air ducts for the front brakes so I view aftermarket ducts as unnecessary.

Better pads like Pagids for the M Sport/M Performance Brakes and fresh brake fluid (even OEM BMW DOT4 brake fluid) is plenty for HPDEs.

I've consistently ran F80/82 M3/M4 brake pads in my M Sport Brakes when the car is shared between my girlfriend and myself at HPDEs. Of course, my powertrain is largely stock. so I wouldn't be going nearly as fast as M3/M4s down the straights to completely overwhelm their brake pads.

Idk if you meant to respond to me, but I'm not arguing any of your points. All I'm saying is if you disable rear braking, you risk the rear end coming around on your during hard braking. You need some bias to the rear to keep the car stable.

[Polo08816]

Originally Posted by kern417

Idk if you meant to respond to me, but I'm not arguing any of your points. All I'm saying is if you disable rear braking, you risk the rear end coming around on your during hard braking. You need some bias to the rear to keep the car stable.

I think only the first part was in response to you but the rest was directed to the OP.

So I believe the M Performance LSD does have some lock during deceleration which tends to straighten out the rear of the car. If you have an open diff, I would completely agree with you. Disabling eLSD on an open diff car is asking for issues in inclement weather - snow.

[kern417]

Ah gotcha.

[Logicoeur]

Originally Posted by Polo08816

I think only the first part was in response to you but the rest was directed to the OP.

So I believe the M Performance LSD does have some lock during deceleration which tends to straighten out the rear of the car. If you have an open diff, I would completely agree with you. Disabling eLSD on an open diff car is asking for issues in inclement weather - snow.

The eLSD only comes on in DSC OFF, and it uses the rear brakes to mimic an lsd. DSC doesn't work that way as it manages power sent to the spinning wheel(s). An open diff with eLSD off would be fine in inclement weather.

[reyoasian]

Originally Posted by kern417

You're asking for trouble. Rear braking stabilizes the car.

I mean during turns, the inside-braking (fake LSD)

[kern417]

Originally Posted by Logicoeur

The eLSD only comes on in DSC OFF, and it uses the rear brakes to mimic an lsd. DSC doesn't work that way as it manages power sent to the spinning wheel(s). An open diff with eLSD off would be fine in inclement weather.

DSC and eLSD are pretty much the same things. You can't send more power to one wheel or the other without an actual LSD. All our cars do is manage the brake bias when accelerating, turning, etc. It's all ABS programming.

Originally Posted by reyoasian

I mean during turns, the inside-braking (fake LSD)

You want that. If it's cooking your brakes then turning it off just means you'll lose the rear end. Our traction control isn't that invasive that it slows you down when driving at the limit. Just prevents you from going past it.

[Logicoeur]

Originally Posted by kern417

DSC and eLSD are pretty much the same things. You can't send more power to one wheel or the other without an actual LSD. All our cars do is manage the brake bias when accelerating, turning, etc. It's all ABS programming.

You want that. If it's cooking your brakes then turning it off just means you'll lose the rear end. Our traction control isn't that invasive that it slows you down when driving at the limit. Just prevents you from going past it.

If it was the same then we'd cook the brakes all the time. Cutting the power to a wheel isn't the same as applying the brakes to said wheel. ELSD prob does both in tandem, but dsc definitely can't be applying brakes all the time. Since it's an open diff though you could be right. BMW does really weird things compared to everyone else it seems.

[kern417]

Originally Posted by Logicoeur

If it was the same then we'd cook the brakes all the time. Cutting the power to a wheel isn't the same as applying the brakes to said wheel. ELSD prob does both in tandem, but dsc definitely can't be applying brakes all the time. Since it's an open diff though you could be right. BMW does really weird things compared to everyone else it seems.

eLSD is a crappy term. It's just a form of traction control. If one wheel loses traction, it brakes the wheel with traction so that there is a load on the diff and the other wheel can continue putting down power. It's less power than an actual LSD would put down, but more power than just the Open diff. Without the eLSD controlling the brakes, no more power is being put down and you're just spinning the inside wheel. You're faster with the eLSD on. That's also why we can do a burnout and lay down two tire patches with an open diff. It's modulating the brakes so both wheels keep spinning. Without it, only one wheel would spin.

DSC controls the response time when the car begins to lose traction. So it lets you get a little sideways and put more control on the driver. But again, sliding isn't fast on tarmac so you really want to keep it on.

Both are only used when you're losing traction. When traction is good, even at the limit, no extra braking is being applied. But an open diff cannot physically in any way send more power to one tire or the other. An actual eLSD like what's in the F8x cars, where electronic actuators shift clutch plates in the diff, is what we really want to push power to the wheel with traction rather than compensating for the wheel that doesn't have traction. But it's cheaper and more economical for BMW to do it this way with controlling it using the ABS module.

[Last Gear Life]

Originally Posted by Solidjake

Received the ducts/flanges today.

Duct: 2.5" x 7'

http://www.aircraftspruce.com/catalog/appages/scat.php

Flange: 2.5" x2

http://www.aircraftspruce.com/pages/...uctflanges.php

Hose clamps:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Optional - Metal snips: (was an amazon add-on)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Optional - aluminum mesh (should have maybe gone a bit wider in spacing but this will do)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

bro, was the Duct: 2.5" x 7' large enough?

[Solidjake]

Originally Posted by Last Gear Life

bro, was the Duct: 2.5" x 7' large enough?

The length or width? The hose was too wide and it was impossible to turn the wheel all the way without hitting the hose and this was with the inner fender liner removed. I abandoned the idea due to not enough clearance.

[Last Gear Life]

ok thanks

[skier_du]

Originally Posted by Last Gear Life

ok thanks

Just wanted to post my setup. Hope it helps you or someone.
I also used 2.5 in hose and the 2.5 flange. Same one Solidjake used actually. For the way I set it up a 3in wouldn't fit. Plus the scoop flange is 2.5. Had to pull off the dust shield, hammer it somewhat flat, cut an opening and rivet the flange to it. Make sure to put the flange close to the hub so the air will go through the rotor. I'm thinking of doing a bit of a redesign with attaching a little sheet metal to the shield to block the air from coming back out and forcing more through the rotor. But it's still been helpful as is. Also mount the scoop to lower control arm. I don't remember exactly where I got it, but it's for for a Mini. So searching that you can find one. Also, if you have a 3D printer someone on one of the M boards (don't remember if it's the f80 or f82 board) had posted the model to print similar ducts. You can use clamps, but I found strong zip ties work well too. You have to have some to mount the duct to the control arm anyway.
It's not too difficult or expensive of a process. But I did find my brakes to be more fade resistant. Unfortunately I don't have temperatures to back anything up, just what the results felt like. Let me know if you have questions.
Stay healthy.

[Solidjake]

Originally Posted by skier_du

Just wanted to post my setup. Hope it helps you or someone.
I also used 2.5 in hose and the 2.5 flange. Same one Solidjake used actually. For the way I set it up a 3in wouldn't fit. Plus the scoop flange is 2.5. Had to pull off the dust shield, hammer it somewhat flat, cut an opening and rivet the flange to it. Make sure to put the flange close to the hub so the air will go through the rotor. I'm thinking of doing a bit of a redesign with attaching a little sheet metal to the shield to block the air from coming back out and forcing more through the rotor. But it's still been helpful as is. Also mount the scoop to lower control arm. I don't remember exactly where I got it, but it's for for a Mini. So searching that you can find one. Also, if you have a 3D printer someone on one of the M boards (don't remember if it's the f80 or f82 board) had posted the model to print similar ducts. You can use clamps, but I found strong zip ties work well too. You have to have some to mount the duct to the control arm anyway.
It's not too difficult or expensive of a process. But I did find my brakes to be more fade resistant. Unfortunately I don't have temperatures to back anything up, just what the results felt like. Let me know if you have questions.
Stay healthy.

Great alternate way to get the ducts in... NICE work man

[kern417]

Only thing is it's not very effective. You really need to aim the airflow at the center of the brakes so it'll direct air through the vanes. Hitting the flat part of the disk won't really cool it down.

[skier_du]

Originally Posted by kern417

Only thing is it's not very effective. You really need to aim the airflow at the center of the brakes so it'll direct air through the vanes. Hitting the flat part of the disk won't really cool it down.

It's definitely better than nothing. It was a first try at this. But like I mentioned, I'm planning on updating it a bit to try to seal it off better. There's a gap between the shield and the hub as well as the flange can be moved a little. There has to be enough space to get the duct on and off the flange, but it can move a little closer to the hub. Moving it and closing the gap down will force more air through the middle of the rotor. Thus making it more efficient.

Originally Posted by Solidjake

Great alternate way to get the ducts in... NICE work man

Thanks 👍

[Last Gear Life]

Nice work

[skier_du]

Originally Posted by Last Gear Life

Nice work

Appreciate it!

[Nordic]

,

[TheUnicorn340]

Hey! Totally reviving this thread, skier_du did you ever go back and update this setup? Thinking about attempting your set up this coming summer.

Did my first HPDE day, and had some sketchy fade on hp+'s and roasted my rubber lines on rbf600, so I'm thinking a ducting upgrade and steel lines should be the trick to getting that sweet spot.

For anyone else tracking their f30s especially the heavier's 6 cyl's any other recommendations? I already have blue calipers so I don't want or need a BBK, maybe getting DTC pads next.