Eric said: disadvantages: (the front brake pressure will not reduce until master cylinder (and rear) pressure is lower than front pressure)
This is an interesting point, and with a regulator type device is likely accurate. Fortunately, I have SS lines all around, and the pressure drop is near instant. Any lag will no doubt caused by the calipers' clamps stretching, and the time and pedal travel it takes for them to relax. I haven't noticed any loss in the ability to modulate the fronts once locked. (I still have it set to significant front bias) I can lock the fronts from initial brake application, or mid brake event, and even after all the weight is transferred, and just as easily back off enough to unlock. So far no ill effects, except a fear that the person behind me has no chance of matching my braking performance. Regards CB ----- Original Message ----- From: "Eric Schieb" <[email protected]> To: "Miatapower" <[email protected]> Sent: Monday, March 16, 2009 8:13 PM Subject: Re: Big brake upgrade, installed front porporing valves > CB:>OK....... should have said > DON'T TRY THIS AT HOME > ONLY FOR TRACK USE > > I'll buy this. One of the potential advantages of a front proportioning > valve set up is that the inside front will drag during trail braking > instead of the inside rear (kind of like a formula car ;-) ). > Unfortunately you really need to keep after the adjustment as track > conditions change. > > Eric Schieb > Electron Speed > > Charles Brown wrote: >> While I am aware that it is an imperfect solution, the only other >> solution I am aware of is "carbotech panther + (6 years old compound) >> on rear. >> Stock 2001 pads front "= *excellent braking* >> >> Problem is, not well balanced when cold, and the front pad will fade >> before the carbotecs, if you can push them that hard. You are >> essentially >> in the same boat, of unknown grip balance during warm-up, and failure >> mode would be extreme rear bias with little warning.. >> >> The best solution is smaller front caliper pistons, the rear calipers >> are already the largest available. >> >> OK....... should have said >> DON'T TRY THIS AT HOME >> ONLY FOR TRACK USE >> >> Regards >> CB&Stoker >> >> ----- Original Message ----- From: "Eric Schieb" <[email protected]> >> Cc: "Miata Power List (Miata Power List)" <[email protected]> >> Sent: Monday, March 16, 2009 2:57 PM >> Subject: Re: Big brake upgrade, installed front porporing valves >> >> >>> While front proportioning valves have been done before (including by >>> Lotus once) and can have some advantages if you know what you are >>> looking for, the disadvantages are significant enough that I would try >>> to come up with a brake package that does not need the brake pressure >>> reduction in the front. >>> >>> disadvantages: >>> >>> -significant modulation challenges (the front brake pressure will not >>> reduce until master cylinder (and rear) pressure is lower than front >>> pressure) >>> >>> -theoretically incorrect slopes of pressure rise (if you have correct >>> bias on one surface and then find a grippier one, you will become rear >>> biased at a rate faster than normal)(if have correct bias on one surface >>> and then it rains, you will become front biased at a rate faster than >>> normal). >>> >>> Sorry to play a bit of a downer, but brakes are a potentially serious >>> safety matter and the positives of a front proportioning valve should be >>> balanced with some of the negatives before anyone tries it at home. >>> >>> Eric Schieb >>> Electron Speed >>> >>> CB wrote: >>>> Well I finally did it. >>>> I have been living with a 2001 big brake upgrade on my 90 with way >>>> too much front bias. >>>> So I put in two adjustable brake purporting valves in the front! >>>> lines, with no rear valve of any kind. >>>> It took 7.5 turns out to get great brake bias. The fronts can still >>>> be locked at will, it just takes a lot more will. >>>> >>>> The braking is stellar, and the rears so far have never locked using >>>> porterfield R4-S all around. >>>> I hope that the stock 2001 12" vented fronts don't fade before the >>>> ~12.5 solid rear rotor setup, and all will be good. >>>> Does anybody have the fade mode on sport rotor setup? Thinking about >>>> direct ducting from the front spoiler to prevent it. >>>> >>>> I sure is nice to have great brakes again, hopefully the front bias >>>> remains greater in all circumstances. >>>> >>>> Odd that the 02 sport brakes are so out of balance on a 1990 with a >>>> very tight suspension setup. !???! >>>> >>>> >>>> CB&Stoker >>>> >>>> ------------------------------------------------------------------------ >>>> >>>> >>>> _______________________________________________ >>>> Miatapower mailing list >>>> [email protected] >>>> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >>>> >>> >>> _______________________________________________ >>> Miatapower mailing list >>> [email protected] >>> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >> >> > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
