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Lucid Moments
08-20-2008, 07:32 PM
Okay, I've noticed something a little odd and I have a theory about it but I want to see what you guys thing.

My car is a mostly track car. I have Wilwood 12.2" rotors and 4 piston calipers. I run Wilwood's poly B pad compound on the track because I like its nice linear friction curve under heat. A very predictable pad.

I've noticed an odd pattern of wear though. The left front pads wear out first, with the outside pad on that wheel wearing significantly before the inside pad. Enough so that the outside pad will be nearly down to metal and I'll still have nearly 1/4 of the inside pad left. The right front wheel will have nearly even wear between the inside and the outside and will have much more pad material left than the left side.

My theory is that all the tracks I run are run clockwise. This puts me making more right hand turns so that the left side of the car is loaded more. More load on that side of the car means more traction there and so more brake torque. Thats the only thing I can think of anyway. If anyone else has an ideal please feel free to chime in.

oldschoolimport
08-20-2008, 08:27 PM
sounds right. could there be any play in the wheel bearing from the abuse?

Lucid Moments
08-20-2008, 08:33 PM
sounds right. could there be any play in the wheel bearing from the abuse?

We did a precautionary change of the front wheel bearings while everything was apart. There was no real indicator of wear on the bearings that came out.

oldschoolimport
08-20-2008, 08:38 PM
if you wanna see bearing wear, the hubs I put on the 86, when I bolted on the wheels, there was almost a half inch of vertical rock. looks like 2 more parts just got added to my list.:mfrown:

v1c10us
08-20-2008, 10:17 PM
Is there more wear on the top half of the outside pads than on the bottom half?
Your theory makes sense but I dont think the rotor should be wiggling inside the calipers enough to make any difference as to which pad wears more; the inside or the outside.
Puzzling scenario.
I'm not too sure how the mechanics of the brake work, do the inside and outside move towards the rotor or is the inside stationary and the outside pulled inwards?

Windchaser
08-21-2008, 12:34 AM
If you are running clockwise on every track such as making more right hand turns, the distribution will be different. You will sometimes notice this in tire wear as well. I notice that my passenger side tire @ 1/32th toe wears a lot faster than my driver side tire since I only run the course in the same direction every time I do open track @ Button Willow.

Lucid Moments
08-21-2008, 04:29 AM
Is there more wear on the top half of the outside pads than on the bottom half?
Your theory makes sense but I dont think the rotor should be wiggling inside the calipers enough to make any difference as to which pad wears more; the inside or the outside.
Puzzling scenario.
I'm not too sure how the mechanics of the brake work, do the inside and outside move towards the rotor or is the inside stationary and the outside pulled inwards?

Yes, the top of the pad does wear more than the bottom of the pad. The Wilwoods are fixed 4 pistons calipers so both sides press in to the middle. Theoretically it should be perfectly even but of course no system is going to be perfect.

mustclime
08-21-2008, 05:32 AM
my money is on the abs moving brake loads around on you.....:mangel:

talonXracer
08-21-2008, 08:12 AM
The top of the pad will wear slightly more than the bottom, the surfaces of the rotor further from the center are traveling at more inches per revolution, more speed, more friction, more wear. It isnt much but over time it does have an accumulative affect.

skep18
08-21-2008, 08:17 AM
The top of the pad will wear slightly more than the bottom, the surfaces of the rotor further from the center are traveling at more inches per revolution, more speed, more friction, more wear. It isnt much but over time it does have an accumulative affect.

That sounds like it'd make sense to me.

Are your rotors cross-drilled/slotted? This could accelerate the whole process mentioned above.

Lucid Moments
08-21-2008, 08:36 AM
The top of the pad will wear slightly more than the bottom, the surfaces of the rotor further from the center are traveling at more inches per revolution, more speed, more friction, more wear. It isnt much but over time it does have an accumulative affect.

When I refer to the top of the pad I am not referring to the outside edge. From inside edge to outside edge is fairly consistent. When I was saying the top I was actually referring to one end of the pad as it is mounted in the caliper. Although now that I think about it I have to go home and double check and see if it is the top or the bottom.


That sounds like it'd make sense to me.

Are your rotors cross-drilled/slotted? This could accelerate the whole process mentioned above.

Not drilled or slotted. Blank rotors.

adrian1281
08-21-2008, 09:13 AM
It is common for pads to wear more on one side than the other (top to bottom).

Wilwood and others sell calipers which have a different size piston bore on the top and bottom to account for this.

From Wilwood:
"The differential bore pattern balances pad loading against mechanical influences and changes in temperature over the length of the pad to help maintain even pad wear".

The "clockwise" theory you stated does hold water, but I would also look at the pistons on the outboard left front caliper to make sure they are not damaged and are freely going back into the caliper when the brakes are released.

If they are sticking any, it might be causing your pad wear problem.

mustclime
08-21-2008, 10:03 AM
I still think it is your abs moving brake load on you....In a right hand turn, the brake that will get most of the braking power is the one that has the most grip. Your left wheel has most of the cars mass on it so your brakes are going to high load there. Your right tire is being unweighted thus, you abs system is shiffting your brake load to the left when it see's lock up....

I think this is the racing gods telling you that its time for a smaller ft swaybar..:mwink:

frm_808
08-21-2008, 10:16 AM
sounds right. could there be any play in the wheel bearing from the abuse?

if u had wheel bearing play ull see the wear on a street drivin tire, but for track , the easiest way is u need to jack up the car and actually move nudge the tire to check for play, or you can put ur car on jacks remove the tire, get a dial indicator and look from there...

adrian1281
08-21-2008, 12:04 PM
I still think it is your abs moving brake load on you....In a right hand turn, the brake that will get most of the braking power is the one that has the most grip. Your left wheel has most of the cars mass on it so your brakes are going to high load there. Your right tire is being unweighted thus, you abs system is shiffting your brake load to the left when it see's lock up....

I think this is the racing gods telling you that its time for a smaller ft swaybar..:mwink:

Without this turning into an ABS thread, I am 99.9% sure this is impossible...

The EP3 is not equipped with an "Electronic Stability Control" or "Electronic Brake Distribution" system.

As per page 19-39 of the Helms manual, the only sensors which input information to the ABS module are the wheel speed sensors. There is no mention of a yaw sensor in any of the circuit diagrams. A yaw sensor would be needed in any system which provides the features you described.

Lastly, the three modes in which the ABS system can operate are (page 19-40):
1. pressure intensifying
2. pressure reducing
3. pressure retaining

No mention here either of brake distribution. :msmile:

mustclime
08-21-2008, 12:27 PM
Without this turning into an ABS thread, I am 99.9% sure this is impossible...

The EP3 is not equipped with an "Electronic Stability Control" or "Electronic Brake Distribution" system.

As per page 19-39 of the Helms manual, the only sensors which input information to the ABS module are the wheel speed sensors. There is no mention of a yaw sensor in any of the circuit diagrams. A yaw sensor would be needed in any system which provides the features you described.

Lastly, the three modes in which the ABS system can operate are (page 19-40):
1. pressure intensifying
2. pressure reducing
3. pressure retaining

No mention here either of brake distribution. :msmile:

inside wheel lift = brake lock, thus the abs kicks in and reduces pressure to the inside wheel and increases pressure to the outside wheel.

think about it....the abs system is reading wheel speed at each wheel, you brake hard on a right hand turn, the left side wheels are going to turn more revs being on the outside of the turn anyway. Add to that the car's mass is over the outside tires(left) and the weight is shifting off the inside tires( right)....The inside right rear and ft are going to be the first to lock( or almast lock), so the abs system is going to shift braking to the left side of the car to try to keep wheel speed equil. All the other crap has nothing to do with it, just think about what each wheel speed sensor would see......I use this crap all the time woth trail braking in autoX....my brakes hate me:tehehe:

adrian1281
08-21-2008, 12:38 PM
inside wheel lift = brake lock, thus the abs kicks in and reduces pressure to the inside wheel and increases pressure to the outside wheel.

think about it....the abs system is reading wheel speed at each wheel, you brake hard on a right hand turn, the left side wheels are going to turn more revs being on the outside of the turn anyway. Add to that the car's mass is over the outside tires(left) and the weight is shifting off the inside tires( right)....The inside right rear and ft are going to be the first to lock( or almast lock), so the abs system is going to shift braking to the left side of the car to try to keep wheel speed equil. All the other crap has nothing to do with it, just think about what each wheel speed sensor would see......I use this crap all the time woth trail braking in autoX....my brakes hate me:tehehe:

There's just one problem when applying that to the OP's dilemma.

He never mentions he is locking up the inside tire, which he would know if he felt the ABS kicking in through the brake pedal...

Zzyzx
08-21-2008, 12:47 PM
I could see mustclime's idea being more plausable on the rear end more so then the front. I know that I pull the ABS fuse just for that reason when I compete.

Doglegging corner entry while trail brakeing = Freaked out ABS system.

mustclime
08-21-2008, 01:16 PM
Last time I saw is setup, he was running a large front bar....been there done that....but like I said, just a guess. I would need to see him drive.

Zzyzx
08-21-2008, 01:17 PM
A larger front bar would make it more likely.

and if the ABS is only acting on one of the corners the driver may not notice it.

So, Plausible, but not necessarily whats happening.

Lucid Moments
08-21-2008, 04:58 PM
I have been running the Progress 22mm rear and stock front. I've almost always had this combonation with Eibach Sportlines and Koni Yellow's.

As for my driving I've only very recently started doing any trail braking and I have never noticed being in ABS when I start my turn in. Not to say it hasn't happened of course, just that I've never noticed it.

My suspension now is different, but honestly I haven't put enough time on the new setup for it to have made any difference.

v1c10us
08-21-2008, 05:51 PM
feel free to correct me if this is wrong, which I probably am, but I dont think it has to do with the course being clockwise.
I'm having a hard time wording this properly so bear with me.
I'm using even and low numbers for maths sake, but;
if the car weighs 100KG and is traveling at 10 meters per second the momentum would be 1000.. something, I believe the units are called Momenta or something stupid.
The amount of momentum that the brakes are trying to stop wont change based on where the weight of the car is, you still have the same amount of mass and the same amount of force or momentum for the brakes to slow.
Now, while typing this I realized that is incorrect because it has to be in a straight line..

I wouldn't think the brakes would work less hard on the other 2 wheels. My reasoning for this is that if it is easier for the brakes to stop the inside wheels wouldnt the inside 2 lock up and the outside 2 not lock up?
If this does happen then that could explain your wear, the brakes are stationary on the locked up wheels and still burning on the outside?
I think a few things could be at play here.(People have probably already said these things)
If the outside wheels are making more rotations than the inside wheels but the brake pressure is even amongst all of them the wheel turning more will burn up more pad than the wheel turning less.
Also, the lack of a brake pressure redistribution system or anything like that makes me think that even if the increased load somehow made more work for the brakes even though the mass and momentum are not changing it wouldn't do anything because they will both be applying equal pressure, and any gains made by the inside wheels having an easier time will be naught because you'll just release brake pressure due to them locked up or something like that..

If any of these things are possibilities kind of depends on how you drive, if you never enter ABS or never lock up your brakes it would make for a different scenario.

edit: Is our abs system smart enough to only pump one wheel like mustclime is insinuating?
I was fairly sure that if the abs comes on it does it to all the brakes, not the only one slipping. I dont think our abs system is capable of shifting braking in the event that the inside wheels lock up in a turn. I would think it would just apply abs to all the wheels, like for instance if you were on 3 wheels while braking that rear wheel stops and appears locked up, doesn't the ABS start to pump all the brakes?

adrian1281
08-22-2008, 08:51 AM
feel free to correct me if this is wrong, which I probably am, but I dont think it has to do with the course being clockwise.
I'm having a hard time wording this properly so bear with me.
I'm using even and low numbers for maths sake, but;
if the car weighs 100KG and is traveling at 10 meters per second the momentum would be 1000.. something, I believe the units are called Momenta or something stupid.
The amount of momentum that the brakes are trying to stop wont change based on where the weight of the car is, you still have the same amount of mass and the same amount of force or momentum for the brakes to slow.
Now, while typing this I realized that is incorrect because it has to be in a straight line..

I wouldn't think the brakes would work less hard on the other 2 wheels. My reasoning for this is that if it is easier for the brakes to stop the inside wheels wouldnt the inside 2 lock up and the outside 2 not lock up?
If this does happen then that could explain your wear, the brakes are stationary on the locked up wheels and still burning on the outside?
I think a few things could be at play here.(People have probably already said these things)
If the outside wheels are making more rotations than the inside wheels but the brake pressure is even amongst all of them the wheel turning more will burn up more pad than the wheel turning less.
Also, the lack of a brake pressure redistribution system or anything like that makes me think that even if the increased load somehow made more work for the brakes even though the mass and momentum are not changing it wouldn't do anything because they will both be applying equal pressure, and any gains made by the inside wheels having an easier time will be naught because you'll just release brake pressure due to them locked up or something like that..

If any of these things are possibilities kind of depends on how you drive, if you never enter ABS or never lock up your brakes it would make for a different scenario.

edit: Is our abs system smart enough to only pump one wheel like mustclime is insinuating?
I was fairly sure that if the abs comes on it does it to all the brakes, not the only one slipping. I dont think our abs system is capable of shifting braking in the event that the inside wheels lock up in a turn. I would think it would just apply abs to all the wheels, like for instance if you were on 3 wheels while braking that rear wheel stops and appears locked up, doesn't the ABS start to pump all the brakes?

I'm not even going to comment on the rest of your post since it gave me a headache reading it...

I said it before and I'll say it again, you NEED to read some books or even the Helms manual which is specific to the EP3. It has alot of great information in it.

If you don't want to spend the money to have it in hard copy (which you should), there are alot of places to download it from.

The short answer to your question is no. The ABS system (in any car for that matter) has the ability to "pump" any of the tires independently.

edit: So you don't think I'm an a-hole that likes picking on you, I've uploaded the helms manual for you (or anyone else really). I did not make it, only found it a while ago. I do recommend you buy the paper version since the quality of the images is obviously better and easier to read through.

http://netload.in/dateid3511d2311633acb1c05bdad9c5a0144/Honda_Civic_EP3_02_03_Service_Manual.pdf.htm

Zzyzx
08-22-2008, 10:15 AM
There are currently 2 main versions of ABS in use today. 3 channel, and 4 Channel. The difference being in a 3 channel ABS system both front tires have their own ABS Solinoid, and the two rear tires share one. meaning if one of the two rear tires start to slip, the ABS system kicks in for both where as on the nose the two tires are adjusted independantly.

In a 4 channel ABS system, every corner has its own solinoid, so the system can control each tires ABS independantly.

Honda pretty much uses 4 channel ABS systems for thier cars at this point.

v1c10us
08-22-2008, 04:23 PM
I'm not even going to comment on the rest of your post since it gave me a headache reading it...

I said it before and I'll say it again, you NEED to read some books or even the Helms manual which is specific to the EP3. It has alot of great information in it.

If you don't want to spend the money to have it in hard copy (which you should), there are alot of places to download it from.

The short answer to your question is no. The ABS system (in any car for that matter) has the ability to "pump" any of the tires independently.

edit: So you don't think I'm an a-hole that likes picking on you, I've uploaded the helms manual for you (or anyone else really). I did not make it, only found it a while ago. I do recommend you buy the paper version since the quality of the images is obviously better and easier to read through.

http://netload.in/dateid3511d2311633acb1c05bdad9c5a0144/Honda_Civic_EP3_02_03_Service_Manual.pdf.htm

I do have the manual, I just wasn't sure if our ABS systems were sophisticated enough to do that and I guess I misunderstood a post and reply that were in here earlier about our ABS systems not being able to redirect something or other.
Thanks anyway though

drjd888
08-22-2008, 05:30 PM
edit: So you don't think I'm an a-hole that likes picking on you, I've uploaded the helms manual for you (or anyone else really). I did not make it, only found it a while ago. I do recommend you buy the paper version since the quality of the images is obviously better and easier to read through.

http://netload.in/dateid3511d2311633acb1c05bdad9c5a0144/Honda_Civic_EP3_02_03_Service_Manual.pdf.htm

You rock! Downloading now...