Currently I have Brembo 4 piston fixed calipers in front and larger than stock 2 piece rotors, stock rear calipers, and running with Ferodo DS 1.11. PLENTY of braking power. It seems to be as balanced as stock. Here's the question---
I am looking into fixed rear calipers. Porsche 996 rears seem to be the common solution with stock rotors and RallyRoad brackets. In doing some reading I was directed to a writeup on the Builderjournal site. The author documented the differences in brake bias. His data points to some added rear bias.
S0 ............... who has swapped to fixed rotors and what were the results (besides brake pedal feel, etc.)?
Note, I'm running stock rear calipers.
IMO, the big reason to run rear fixed calipers is to get to use a common race pad-size (which I don't believe the 996 rears are).
Also, with sticky-ish tires, bias should move forward (compared to stock), but the MK60 ABS system will hide poor bias selection unless at a high level driver ability.
Sounds awesome!
I was referring to the pad shape, a wilwood pad shape 7420 for example is an extremely common size, and any compound from any manufacturer in that size will be 70% thicker and 2/3rd's the cost of the 996 pads. It adds up over a few years.
I would CEASE AND DESIST or whatever the term is!
Sounds like you have ample braking power and balance feels good. Why oh why would you touch it any further at the risk of messing that up. Stock calipers are fine (especially on the rear) and pad prices for Pcar calipers rediculous usually.
Ferodo DS 1.11 for OEM front and rear calipers are ~$300 each end. Guess what --- the front pads for the 4 piston Brembos on the front of my car are ------ TA DA !!!!!!!!!!! ~$300 !! Not concerned with paying the same for 966 rear caliper's pads. The FEEL of the front fixed calipers is VERY different and I like it. The bonus is that the fronts now have no drag. And YES, I rebuilt the front OEM calipers with no benefit.
As for "messing it up", that is why I am asking. What I am in search of is those than may have done rear fixed calipers and what the results have been.
Sounds good. I personally have only enjoyed the downsides of fixed calipers on these cars but admittedly that's been strictly e36. Maybe the e46 has a much larger improvement in feel with limited downsides and it sounds like you are on a path regardless.
I wasn't as clear as olemiss.
For rear calipers on a street car or HPDE car, the downsides (possible incorrect bias, cost) are bigger than the upsides (any measure of performance).
That's ignoring bragging rights and esthetics, and those are fine if that's what your priority is.
My decisions are not ego based. I have had my hands on a lot of 36s and a few 46s that have seen, shall we say, low level track use. Track days, Solo, TT, TNiA, and all have improved as owners used them and we made adjustments. I sort of joke that I can build them better than I can drive them, but many say that I do well. Winning does not suck. That said, I don't try to create something new as everything has been done (either right or wrong) so I try to do what works.
To that end, I am reaching out for input. So far, few who have done what I am looking at have responded. In researching, I found RallyRoad provides the caliper mounts and has shared some good info. In pointing me to Builderjournal's site, they provided some hard number cranching about various combos of calipers on 46s.
So, the search for input continues.
Improving things is good. Rear calipers are low on the $/performance-improvement scale.
I've learned that few people understand brakes, as a system.
Most sellers of components, do not.
If you want, send me the following for front and rear and I can calculate bias for you.
Rotor Diam
Piston sizes
sliding or fixed caliper
Pad height
Master Cylinder piston size
I can also calculate pedal and line pressures with more info (vacuum boost, pedal leverage ratio, etc)
I'm pretty sure the MC f/r cylinder size is the same, so it doesn't matter for bias measurements.
on our e46 touring car, we run the wilwood SL6R calipers in front with 330mm discs (pads are usually <200 for 20mm). On the rear we have brembo 4 piston R calipers with stock 325i discs. That's a weird pad shape, but just happens to be nascar rear pads, so I get take-off on ebay for like $80/set. This setup is ridiculously good, though we also have tilton masters so can get the pressure balance perfect.
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