Brake Bias & Trail Braking on OE Calipers

[Peterson]

Has anyone found a good setup for left foot trail braking on OE front/rear calipers?

- I’m currently running EBC USR Slotted Rotors and Yellow Stuff pads F/R.
- I run SCCA Street Prepared AutoX Class

The stock brake bias is something like 73% up front? My thought process is if I can get that a little bit more even, I could possibly brake boost through long sweepers and keep the power up through the exit. This would potentially also help lower my front tire scrub?

Can I try running something like a Blue Stuff or Orange Stuff rear pad and leave the yellows up front?

 

[zeddzik]

Has anyone found a good setup for left foot trail braking on OE front/rear calipers?

- I’m currently running EBC USR Slotted Rotors and Yellow Stuff pads F/R.
- I run SCCA Street Prepared AutoX Class

The stock brake bias is something like 73% up front? My thought process is if I can get that a little bit more even, I could possibly brake boost through long sweepers and keep the power up through the exit. This would potentially also help lower my front tire scrub?

Can I try running something like a Blue Stuff or Orange Stuff rear pad and leave the yellows up front?

Yeah you can definitely go with more aggressive pad in the rear to increase the rearward bias. I don't have any experience with the ebc pads but if you have a laser thermometer measure the rotor temps front and rear immediately after a couple runs to get a good idea of how hot your rotors are getting. I don't know if ebc has a graph showing the performance of each compound compared to temp but if it does use the graph to choose a compound that has more bite at the specific temp of the rear rotor than the yellows at the front rotor temp. You may also want to pay attention to the curves before getting to the final temps because each compound will also have different performance when getting up to temp as well.

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[Peterson]

I can definitely try and log some brake temps, but our region is BIG and I usually only get 6-8 runs an event, with as much as 10 minutes between runs in my heat.

 

[maestromaestro]

Has anyone found a good setup for left foot trail braking.

My thought process is if I can get that a little bit more even, I could possibly brake boost through long sweepers and keep the power up through the exit.

Could you elaborate on these two points? What else - besides the left foot - does one need for LFB?

And - braking more at the rear in long sweepers - what’s the end game here?

Curious.

 

[Peterson]

Could you elaborate on these two points? What else - besides the left foot - does one need for LFB?

And - braking more at the rear in long sweepers - what’s the end game here?

Curious.

Poorly worded?

I don’t need anything else to LFB, but if I can get the car to not nose dive so much in trail braking, I’m hoping I can brake boost to keep turbo spool up and boost out of the apex harder. I feel as if the car transfers too much weight to the front and upsetting the balance when I boost out and shift the weight more towards the back again.

I’m no professional, so maybe what I’m saying is totally wrong. Enlighten me 🙂

 

[rcarbajal4]

Would taking some weight off the nose and making the overall weight closer to a 50/50 distribution help achieve the desired results?

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[Peterson]

Would taking some weight off the nose and making the overall weight closer to a 50/50 distribution help achieve the desired results?

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I’ve done what I can and had the car corner balanced. A near 50/50 side to side, but that would be impossible from to back because the hatch is empty

 

[maestromaestro]

Poorly worded?

I don’t need anything else to LFB, but if I can get the car to not nose dive so much in trail braking, I’m hoping I can brake boost to keep turbo spool up and boost out of the apex harder. I feel as if the car transfers too much weight to the front and upsetting the balance when I boost out and shift the weight more towards the back again.

I’m no professional, so maybe what I’m saying is totally wrong. Enlighten me 🙂

Neither am I. With regard to the LFB technique - it is something "optional", unlike heel-toe. Trail braking, obviously is continued application of brakes late in the turn in order to assist with the rotation of the car. LFB is used - by some, but not all - to maintain the revs/boost with the right foot. No specific setup is necessary other than the driver's skill. To that end, what you're describing makes me think that maybe you are too abrupt with the pedal work - easy off/easy on is what's required. There are some professional drivers "out there" who stab their pedals, but this is not something that's taught to the amateur set like us.

The easy on/off is easier said than done in my experience; requires a conscious effort. Smooth IS fast as they say. So, I'd suggest that rather than looking for bits to bolt on to adjust braking force, the low(er) hanging fruit is in the driving technique, and if you work on that, you should see substantial improvement.

Having said this, I have difficulty rotating my FiST unless the road is mildly greasy. I have a rear trunk brace and a sway bar in the rear - and still it won't rotate. Maybe I am not carrying enough speed in turns - so, in my particular case the LFB is perhaps what the doctor ordered?

(I am still not sure what you mean when you say you want more braking in the rear in long sweepers...)

 

[PunkST]

I can get mine to step out on dry pavement. Apart from practicing technique, jumping the rear tire pressure up to make it tail happy helps. On the stock re50a tires i set rear pressure to 40 psi on wet ish pavement and 45 on dry. Putting the front at 36 allowed me to play on autocross sessions when i uses to go before the covid.

 

[Mikey456]

On the stock re50a tires i set rear pressure to 40 psi on wet ish pavement and 45 on dry. Putting the front at 36 allowed me to play on autocross sessions when i uses to go before the covid.[/QUOTE]

I’m running oem wheels with Falken tires at 32 psi in the front 36psi in the the rear. Ive never done 40 psi or more in the rear.
Does it not make the ride harsh or slide too quickly?


2017 Ford Fiesta ST, Shadow Black, Recaro seats, Mountune RMM, Swift springs, 5mm rear spacers, Falken 615+ tires

 

[jeffreylyon]

OP isn't talking about moving weight around with the brake pedal to change balance, he's talking about inducing some drag so that he can add throttle to spool the turbo up *without* moving weight and his thought is that by moving brake balance to the rear he can do so with the brake pedal.

@OP: You're running in SP, so stock turbo which spools like mad and I'm not sure that there's much to gain with a poor-man's anti-lag. Take the spring out of your e-brake ratchet and give that a try before you move brake balance. I see lots of locked rears, ruined lines, and frustration in your future. Also, you're not talking about trail braking, you're talking about brake boosting. I haven't heard about someone brake boosting outside of roll-racing since Michèle Mouton and the rally guys got ride of that with anti-lag as soon as they figured out how to stop blowing the turbo off the exhaust manifold.

 

[PunkST]

On the stock re50a tires i set rear pressure to 40 psi on wet ish pavement and 45 on dry. Putting the front at 36 allowed me to play on autocross sessions when i uses to go before the covid.

I’m running oem wheels with Falken tires at 32 psi in the front 36psi in the the rear. Ive never done 40 psi or more in the rear.
Does it not make the ride harsh or slide too quickly?


2017 Ford Fiesta ST, Shadow Black, Recaro seats, Mountune RMM, Swift springs, 5mm rear spacers, Falken 615+ tires[/QUOTE]
I really only used it on the track. It depends on how firm you press the brake pedal as you are loading up the car on corner entry. You stomp on it and its gonna rotate real fast ( i do left foot brake for this to slide) feed it in firmly while hold the throttle even will rotate it slower. Its a weird spot to brake cuz its not in a straight line so id say get plenty of practice in a safe environment. And start small to get a feel for the bavk coming around.

As for harsh ride... Well im racing, and i air the tires back down before heading home. Im sure it would be murder on my back on the street