Brake Bias Question (4-Piston vs. 6 Piston Brembos)

[TheAverageJoe93]

Does anyone know what the brake bias is for the 4-piston GT Calipers, versus the 6-Piston Brembos? I hear people complaining about how the brake bias is severely skewed (high front brake bias) with the 6-piston Brembos. Alluding towards people opting for lesser brakes up front to balance out the bias. Anyone have experience at the track with both brakes?

Thanks!

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[EFI]

I went with the GT350 brakes up front and I can say that I have not noticed any bias issues on track vs. the base GT calipers. I'm not the fastest driver to really push the brakes, but going 7/10ths is not an issue. Maybe if you're an IMSA driver you might have issues.

 

[TheAverageJoe93]

I went with the GT350 brakes up front and I can say that I have not noticed any bias issues on track vs. the base GT calipers. I'm not the fastest driver to really push the brakes, but going 7/10ths is not an issue. Maybe if you're an IMSA driver you might have issues.

I identify as an IMSA driver. Lol.

So, pros still outweigh the cons, correct?

 

[VisceralSyn]

Track dayed the 4-piston brakes, the master cylinder failed twice, warped all rotors the 3rd time. 20 minute sessions ever hour. Had the PP1 Brembo's and master cylinder installed, 4 track day events, nothing has broke, same format 20 minute sessions every hour.

Sidenote... the stopping power of the Brembo's vs the 4pots, is day and night better.

 

[EFI]

So, pros still outweigh the cons, correct?

Very much so. The 4 piston brakes are absolute garbage on track if you're anything more than a novice. The inherent inverted cooling design just brings it all down and I don't know of any good way to cool them.

I wouldn't even consider tracking the 4 piston brakes again.

 

[angermgmt14]

Track dayed the 4-piston brakes, the master cylinder failed twice, warped all rotors the 3rd time. 20 minute sessions ever hour. Had the PP1 Brembo's and master cylinder installed, 4 track day events, nothing has broke, same format 20 minute sessions every hour.

Sidenote... the stopping power of the Brembo's vs the 4pots, is day and night better.

I upgraded my GT 4 pistons to the 6 pistons ~6 yrs ago and I am just hearing about possibly needing to upgrade the master cylinder. If you aren't tracking the car and are just driving normally 95% of the time, is there a need to still upgrade the master cylinder? When I purchased these from FRP they mentioned nothing about this.

 

[VisceralSyn]

I upgraded my GT 4 pistons to the 6 pistons ~6 yrs ago and I am just hearing about possibly needing to upgrade the master cylinder. If you aren't tracking the car and are just driving normally 95% of the time, is there a need to still upgrade the master cylinder? When I purchased these from FRP they mentioned nothing about this.

In my opinion, and since I was on my 4th master cylinder, I recommend upgrading. Most particularly if you are tracking. Also agree, there is no mentioning that the PP Master Cylinder is needed. The plain-jane one just kept on failing for me.

 

[EFI]

If you aren't tracking the car and are just driving normally 95% of the time, is there a need to still upgrade the master cylinder?

I don't think it's needed even if you track the car, at least moderately. An advanced+ driver might notice a downfall, but intermediate and below probably not. For street it's 100% not necessary.

 

[TeeLew]

In my opinion, and since I was on my 4th master cylinder, I recommend upgrading. Most particularly if you are tracking. Also agree, there is no mentioning that the PP Master Cylinder is needed. The plain-jane one just kept on failing for me.

How exactly are you failing the master cylinder. That's a strange failure.

The piston area of the 4 piston calipers and 6 piston calipers is essentially the same. The larger front discs which accompany the 6 piston calipers will give a lot more braking torque just due to leverage. It's not an issue of the hydraulic ratios. Those are similar on all the Mustang brake packages. The bias is all managed electronically in the ABS distribution block, so it's not like a caliper change is really going to do that much to the actual mechanical system.

The heat management is a different deal. 14" discs are pretty decent in size if they had the cooling on the correct side of the disc, but not with a reverse hat. That makes running these discs a lost cause on track. The 15" disc has the cooling vanes on the correct side of the bell, so they actually cool. The good news here is that for 2022, Ford has changed the 14" disc cooling vanes to the conventional side of the bell, so they will now response to cooling and they may be track-worthy in this form.

 

[VisceralSyn]

How exactly are you failing the master cylinder. That's a strange failure.

I'm not failing anything, non-performance pack brake master cylinders have failed on me. By the end of my 2nd or end of the 3rd session in all cases, brake pedal has gone to the floor. Was also using whichever brake fluid came with the car. Upgraded to Brembo's DOT 5.1, when I had the Brembo's installed. Stuff kept braking with the stock parts, notsomuch with performance pack parts.

 

[Mike Pfeifer]

The good news here is that for 2022, Ford has changed the 14" disc cooling vanes to the conventional side of the bell, so they will now response to cooling and they may be track-worthy in this form.

This is interesting. Is there any other change beside that? Is the brake rotor a supersession for the old part?

 

[Angrey]

There seems to be a lot of misunderstanding about how brakes actually work here.

Firstly, MOST cars nowadays have enough initial bite to activate the ABS. That means there's more brake than traction. From that point on, you could add GINORMOUS brakes and it won't help the car stop any faster, it just provides additional heat reservoir for repeated hard braking (aka track brakes).

Ford Engineers discovered on the 350 that the rear brakes were underutilized and so they went down a bit in the 500 (which also increased the front). Granted, the 500 added some bulk to the front of the car, but the point is, at the limits of traction, the brake initial stopping capability and bias are what they are. Unless there's more traction than brake (almost unheard of in modern cars) increasing or decreasing the calipers or rotors isn't going to change their contribution, they can only contribute up to the point of activating the ABS (to prevent lockup/skid).

Now, for less than max braking and daily driving you would see a difference in bias (I guess you could call it partial bias and wear) where now ginormous brakes in the front do more of the work and the rears just take the week off. But at max pedal, front and rear can only contribute as much as the tires will allow. Anything beyond that is either wasteful size and weight (for a drag car) OR beneficial to a track car for fade resistance and temp control.

 

[TeeLew]

There seems to be a lot of misunderstanding about how brakes actually work here.

Indeed, maybe more than you might suspect.

 

[shogun32]

By the end of my 2nd or end of the 3rd session in all cases, brake pedal has gone to the floor

that's not failure - ie fluid integrity compromise aka seals letting fluid past the piston. you simply boiled your brakes and in so doing got giant air (well water vapor) bubbles in your lines such that hydralic pressure was no longer being applied correctly.

NEVER go to track with factory fluid. NEVER go to the track without FRESH fluid.

The 'revised' 14" look otherwise identical to their previous counterparts except for the obvious.
WTF was Ford smoking that it took 7 FREAKING YEARS to pull their head out of their ass?

 

[VisceralSyn]

NEVER go to track with factory fluid. NEVER go to the track without FRESH fluid.

Lesson learnt with the brembos installed, thanks tho !!!

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