Tem120

iTrader: (5)

I was pretty sure the FD had good brakes , but i proved myself wrong .

I did an Auto-x on my FD , now I've noticed that the car really wasn't stopping like I wished it to , but I thought it was my imagination since I've been driving the car for only a week..

but I noticed I'm lockign the front brakes way to easily , the car is not really making an effort to stop before the front tires give way . now My ABS is not working obviously the cars locking its tires LOL

and I know the RX7 has alot of forward bias ..


now in my miata which had similar issues , fixed the bias issues by putting grippier pads in the rear . is this a common thing to do for hte rx7? ( even with working abs )

I plan to try and diagnose my abs issues this weekend . but I'm just trying to learn as much about whats going on

also the tires are absolute crap no grip at all they are old and material is all season hard tires .

so I know one of the biggest issues is the lack of grip from those tires . but I just cant see this little braking as safe at the track or DD .

Brekyrself

iTrader: (30)

Need details...

Tire type, size, and psi
Brake pads front and rear
What was the outside temp? IE did braking improve once the tires warmed up?

Tem120

iTrader: (5)

it improved only marginally temp was in the upper 70's lower 80's

in my miata ofcourse I had summer tires on that car , but I would get seat belt bruises from braking ,

on the rx7 it feels like i'm trying to stop at a red light in normal DD driving that seems to be the limit of grip ,

tires are offset 255/50/16's in the front , 275 's in the back .

thats how the car came the front tires are 2 different brands , sumitomo , and bridgestone . I dont know the kind unfortunatly off the top of my head and I cant check right now , brake pads , again what hte car came with but its locking the front tires atleast . its just

could the fact that my abs is broken be the cause of my terrible braking , not enough braking force going to the rears when the fronts are in ABS mode ?

or could it be the very cheap old front tires?

as for PSI they were at 30 PSI .

jgrewe

iTrader: (1)

I would guess tires first. Brakes are only as good as the contact patch on the ground.

Tem120

iTrader: (5)

I know , but brake bias can make a big difference , and I have no rear pads .. they are a thin sliver of life . on them . and i'm just trying to figure out a few things since I'm going to be restoring my brake system .

the fact that my front tires lock up like nothing . is it because the car's brakes were designed to ONLY work with abs ? and thats why the brake bias is so forward ,

how do people fix this ? I dont need abs , as I've driven cars w/o abs all my life I know how to threshhold brake . BUT if the car was designed to work with abs and abs working will improve my brakes period I'll fix my none working abs system ,


ALSO pads .. I'm going to upgrade to performance pads and I need to know if I should go with grippier pads in the rear to offset the brake bias issue , or if I should get same pads , and the ABS working will fix the bias issue ...


And then we go into the abs itself .

I have friend with an ABS computer for the FD , that he just got he has no working ABS either , and he has no idea how to use it

My car's a 93 I read that the 94+ were the ones with the diagnosis port is this true??

and how do you work that abs diagnostic tool anyways LOL



as for tires .. I'm going to upgrade my wheels / tires to some hankook rs-3's in a month or two but I want to get some other things working first .

Rxmfn7

iTrader: (4)

You have a car that is not in good functioning condition. Mis-matched tires, worn brake pads, and a possibly faulty abs system. Why are you trying to autox it in this condition anyway? I'd say spend a few bucks, get some decent tires on it all the way around, replace pads/rotors, bleed the system and fresh fluid, and then you can troubleshoot any issues from there.

Tem120

iTrader: (5)

it was a shake down .. but well liek I've said ten times I know the tires are a big deal this still has Not yet answered my questions ..



brake pads offset bite or uniform bite ? no abs .. is abs really needed ? how much is it needed I dont need abs as I thresh holld braked at hte auto-x but i was just dissapointed with stopping power , which can be becauseo f the tires . BUt can also be due to tomuch of the stopping force being directed only onto the front tires instead of all 4 .

if i hadn't auto-x'd it I'd never of found out how bad the brakes were without dangerously hitting another car , I wouldn't have found out that my car was understeering , maybe due to the front shocks set to stiff , wouldn't have found out alot about the car .it wasn't me trying to get FTD in the car . that Ik now was flawed it was having a safe enviornment in whcih to test the car .

Rxmfn7

iTrader: (4)

Fair enough. Im by no means as track experience as some of the guys, but Ill try and answer a few of your questions. As far as pads, yes most people who track their FD use a different compound front and rear. As far as your question if ABS is needed, thats a bit of a personal question, but it is very helpful. In serious track situations, most guys remove it as well as the factory master cyclinder and booster for a dual master setup. For most other street and light track applications, ABS is helpful and the FDs usually isnt very intrusive. An FD is not by any means a brake challenged car. The rotors dont have much mass and can overheat on fast tracks after a few laps, but just for autoX, street and light track duty, with even decent pads and good street tires it should be able to about put you through the windshield. As I suggested before, if you havent already at the very least bleed the brakes, get new fluid in there, and get some decent pads on it. Then go from there.

Tem120

iTrader: (5)

the brakes have been bled , and replaced with superblue , the whole system was drained , but I see thanks I guess I'll look into having grippier pads in the rear .

Brekyrself

iTrader: (30)

Looks like you have identified the problem, mismatched tires and unknown brake pads. Get these sorted out first before jumping to any conclusions.

When going for new tires, keep the overall diameter near stock not to throw off the ABS logic.

Regarding brake pads, I have been happy running the same compound front and rear while some others do prefer split compounds. DTC60's all around stop like none other with 285 r comps in front

ArmenMAxx

iTrader: (21)

I used to experience the same issue. I had ok pads, (axxis ultimates on all 4 corners) and still I felt my front was engaging abs way to early. I know you dont have abs but its essentially the same as locking up the tires. I remember once I had to do a panic stop and the car felt like it was on ice the last few feet before stop.

I remember researching about newer abs unites because I thought my ABS was the issue.
Luckily, the first thing I changed were my tires. I bought sticky tires (225's) and even with the exact same brake pads my braking became MUCH better. Later on when I switched to 275 toyo r888's I began having a hard time engaging abs, thats how much they gripped and how good the car braked.

I switched brake pads eventually, EBC yellows front, ultimates back and now im running EBC yellows all around. The main difference with these pads was just the fade resistance. Brake bias barely changed since they are good pads. (RUN EBC yellow if ur car is a track warrior and street driven) I would not worry about bias until you start upgrading to BBK's as then you may want to add bias to the rear w/ a huge front caliper.

To sum things up: Tires are MOST important for stopping distance. For track use, you need good pads on all 4 corners that wont fade and good tires. Thats it.

Juan

iTrader: (28)

I run Hawk HP+ all around with ATE Super Blue fluid and have no problems stopping the car on the track. I also have 265/35/18 Hankook R-S3 tires all around and havent had an issue with my tires locking up after a long straight on the strack. It literally feels like you're going to fly through the windshield when braking from a long 5th gear straight away into a slow 90 degree turn. I've had very low rear pads before and still didnt experience the issues you're having with braking. Your problem could very well be your old hard tires and not your ABS system.

Tem120

iTrader: (5)

I was planning on running hawk hp's.

Miata_mx5

Need good tires, Need good pads. Depending on brand and quality you can run same pads front and rear or you might need a split friction setup.

Make sure the caliper seals are good as that can affect the "feel" of the brakes.