redpriest HPDE journal

[roastbeef]

more pad taper like uneven wear from the inside pads are wearing faster than the outside pads, or more pad taper like they are being pressed against the rotor unevenly?

[ayao]

Originally Posted by roastbeef

more pad taper like uneven wear from the inside pads are wearing faster than the outside pads, or more pad taper like they are being pressed against the rotor unevenly?

Taper from the leading edge of the pad vs the trailing edge (leading edge gets thinner than the trailing edge.) Even though the caliper is designed with a smaller piston bore on the leading edge to mitigate this, it's still pronounced. Ritter says its normal and to just flip the pads. I just found it disconerting because the phenomenon was minimal on the stock setup.

[roastbeef]

Originally Posted by ayao

Taper from the leading edge of the pad vs the trailing edge (leading edge gets thinner than the trailing edge.) Even though the caliper is designed with a smaller piston bore on the leading edge to mitigate this, it's still pronounced. Ritter says its normal and to just flip the pads. I just found it disconerting because the phenomenon was minimal on the stock setup.

Which kit do you have?

[redpriest]

Originally Posted by ayao

Taper from the leading edge of the pad vs the trailing edge (leading edge gets thinner than the trailing edge.) Even though the caliper is designed with a smaller piston bore on the leading edge to mitigate this, it's still pronounced. Ritter says its normal and to just flip the pads. I just found it disconerting because the phenomenon was minimal on the stock setup.

I made a note of this tapering phenomenon and follow this rule when I swap pads now:

"Bottom part of rotor wears more than top
Put beefy part of pad at bottom"

Literally copy pasted note from my phone haha. You can basically counteract the impact by doing this.

I dunno, I vastly prefer my AP racing rotor + ferodo pads to pfc08 on stock caliper on stock rotor. Yeah, I had plenty of pad left after 8 track days but my rotors were destroyed.

[roastbeef]

i have zero tapering going on with my essex 5060 kit. my insides wear a little more than the outsides, but i think thats just because they may get more wind. depending on the track, one complete side wears a bit more because of mdm...

[ayao]

Originally Posted by roastbeef

Which kit do you have?

Essex/AP CP5060. After two days at TH there's a difference of ~2mm in pad from top to bottom on the right side (CCW track) Now that I've realized this is happening I'll be flipping the pads to even out the wear.

The BBK only has those two days on it, though, so I don't have a great feel yet for how it will behave over the longterm or what pad wear patterns will look like. The rotors look a little more heat-checked than I would have expected, but again we'll see how it goes this year.

[roastbeef]

can you notice the 2mm by eyeballing it? because just eyeballing my pads, i'm not getting tapered wear. however, i haven't taken a micrometer to them yet.

i'll be giving 1.11's a try next and i plan on keeping a journal and measuring the pads to keep track of about how much each track takes out of the pads. just a more organized way of managing stock.

[redpriest]

When it happens, it's very noticeable - you don't need any tools to measure it

[redpriest]

Day 1 at Chuckwalla Valley Raceway over.

Improved my time tremendously over my last visit in this configuration almost a year ago - 2:07.42 to 2:04.547, thanks to the JRZ RS Pro suspension.

Won't be able to set any heroics on day 2 though; I corded my RC1s so have to take it easy on streets. I will probably run a couple sessions, then drive the 502 miles back to my house, lol.

Spent some time tweaking the suspension, because I couldn't get the feel exactly how I wanted it. I had some vicious understeer that I tried to dial out in various ways, and then towards the end of the day the tires, the track, or my settings made things very greasy.

Got some advice to soften the suspension, since for tracks that have lots of sweeping turns (like this one) soft is better.

[roastbeef]

do you have more understeer now then you did with the oem suspension? obviously your times are better, but what do you think the problem is?

[bigjae1976]

If the throttle/brake indicators are right,I see a couple of things...

I'd try and clean up your braking. It looks like your on/off/on/off the brakes a lot of times where you are fighting the car through the turn. That will cause understeer.

And the throttle is going up and down. I drive my E46 and E90 in comfort mode because the throttle sport setting in both a way too sensitive. Really needs to be a more progressive application without coming off the throttle.

I see some times where you're coasting into a turn trying which looks like you're trying to scrub speed. That's an indicator that you either need to brake more to kill the understeer or commit to the throttle and steer it with your right foot.

Again, if those indicators are accurate, I'd clean that up before making more suspension changes. You'll be constantly chasing handling problems.

[ayao]

Originally Posted by roastbeef

can you notice the 2mm by eyeballing it? because just eyeballing my pads, i'm not getting tapered wear. however, i haven't taken a micrometer to them yet.

i'll be giving 1.11's a try next and i plan on keeping a journal and measuring the pads to keep track of about how much each track takes out of the pads. just a more organized way of managing stock.

Yeah like redpriest indicated, it's noticeable. Not like "OMG it's shaped like a wedge!" noticeable but more like "uhhh are my eyes playing tricks on me -- I ought to measure this..."

How many track days did you guys have on the rotors before they developed noticeable heat-checking?

[roastbeef]

Originally Posted by ayao

How many track days did you guys have on the rotors before they developed noticeable heat-checking?

probably 10-12ish, but thats including two days of double run groups at laguna, and a completely open day (no run groups) at auto club. your hats will turn a dark purplish color, too.
red got a lot more days out of his, but he's running the bigger kit, so his rotors probably stay cooler and last longer as a result.

[macdude357]

Originally Posted by redpriest

Day 1 at Chuckwalla Valley Raceway over.

Improved my time tremendously over my last visit in this configuration almost a year ago - 2:07.42 to 2:04.547, thanks to the JRZ RS Pro suspension.

Won't be able to set any heroics on day 2 though; I corded my RC1s so have to take it easy on streets. I will probably run a couple sessions, then drive the 502 miles back to my house, lol.

Spent some time tweaking the suspension, because I couldn't get the feel exactly how I wanted it. I had some vicious understeer that I tried to dial out in various ways, and then towards the end of the day the tires, the track, or my settings made things very greasy.

Got some advice to soften the suspension, since for tracks that have lots of sweeping turns (like this one) soft is better.

Holy Sh*t. You weren't kidding about the popcorn sound. I thought I was at a movie theatre.

And how the heck do you get away with what you do in turn 7; turn in at the 1 marker, *then* brake, all the way past turn 8. Looks like you have some serious understeer there too.

[redpriest]

Originally Posted by macdude357

Holy Sh*t. You weren't kidding about the popcorn sound. I thought I was at a movie theatre.

And how the heck do you get away with what you do in turn 7; turn in at the 1 marker, *then* brake, all the way past turn 8. Looks like you have some serious understeer there too.

Brakes give me amazing confidence, plus bail out via trail brake. I still think I could have carried more speed through there if I had trail braked it properly; I kinda screwed it up on that lap, as you can see by the fact that the car is not turning in.

[redpriest]

Back home from the 2nd day at Chuckwalla, all in all, a 1,258 mile trip (500 miles to and from, + track miles + trips to gas station/hotel).

Had to run street tires since I basically corded the crap out of my Maxxis RC1 tires yesterday afternoon:



Last time at Thunderhill, I had a lot of understeer with the JRZ RS Pro settings I use on my R-comp tires - 16 rebound/9 comp front, 14 rebound/8 comp rear. I decided to try softening it to start - 12 rebound/8 comp front, 10 rebound/6 rear.

First session on street tires proved to be the fastest. I went out a little later after the session started, and had a good clean run, which is always PB. Add on having the track session fresh in mind, that was good for setting a 2:04.9 lap on street tires, only .5 off my best lap from yesterday, haha.

I definitely seem to be a street tire hero - these Kumho Ecsta PS91s have treated me pretty good in an emergency situation:

[bigjae1976]

Is that the outer edge corded? If you run stickier tires...you need more negative camber.

[redpriest]

Originally Posted by bigjae1976

Is that the outer edge corded? If you run stickier tires...you need more negative camber.

That's actually the front tire inner part - I run -3.5 camber.

[macdude357]

Originally Posted by redpriest

That's actually the front tire inner part - I run -3.5 camber.

Maybe too much camber then? I have a contact pyrometer that you can check your tire temps with at BW next month if you want to see if the insides are getting too hot.

[PrimeBMW]

Dinan front sway bar: I haven't read your whole thread so don't know where you have yours set. I originally installed because I had high speed instability and hoped to cure some understeer. I have softer springs than i would like to keep comfortable on the street. I set the bar on medium which cured instability but had to increase front camber to -3.2. My laptimes did not decrease. So I just reset the bar at the softest setting. It feels better on the street but have yet to try it on track. My theory (in my case and maybe not yours or others) is that the front bar did not allow faster lap time. It might have felt better but in fact been slower. I wish i have data to support.

PS Your handling looks really wonky during your T-hill 3 mile video.

[redpriest]

Originally Posted by bigjae1976

If the throttle/brake indicators are right,I see a couple of things...

I'd try and clean up your braking. It looks like your on/off/on/off the brakes a lot of times where you are fighting the car through the turn. That will cause understeer.

And the throttle is going up and down. I drive my E46 and E90 in comfort mode because the throttle sport setting in both a way too sensitive. Really needs to be a more progressive application without coming off the throttle.

I see some times where you're coasting into a turn trying which looks like you're trying to scrub speed. That's an indicator that you either need to brake more to kill the understeer or commit to the throttle and steer it with your right foot.

Again, if those indicators are accurate, I'd clean that up before making more suspension changes. You'll be constantly chasing handling problems.

If it's a clean lap, I will always either be on throttle or brake - I've noticed that even sometimes with maintenance throttle it won't register until you're actually deep into the pedal, which is kind of weird.

I'll pull the brake pressure data from AIM, but also don't think I'm pumping the brakes intentionally - I generally try to brake, and then ease out on brake pressure as I turn in.

Throttle setting is Sport - when I feather the throttle in turns basically I will try to get as much throttle as I can, feel the back end step out, then back off until it stops slipping, etc.

[redpriest]

Originally Posted by PrimeBMW

Dinan front sway bar: I haven't read your whole thread so don't know where you have yours set. I originally installed because I had high speed instability and hoped to cure some understeer. I have softer springs than i would like to keep comfortable on the street. I set the bar on medium which cured instability but had to increase front camber to -3.2. My laptimes did not decrease. So I just reset the bar at the softest setting. It feels better on the street but have yet to try it on track. My theory (in my case and maybe not yours or others) is that the front bar did not allow faster lap time. It might have felt better but in fact been slower. I wish i have data to support.

PS Your handling looks really wonky during your T-hill 3 mile video.

That's a good point actually. Before I had my JRZs put on, I put my sway bar in the understeer setting, since I was sliding all over the place if I came anywhere near the throttle. Might be time to revisit that setting.

Which lap has the wonky handling? I have two 3-mile videos, one with street tire where I was understeering quite severely (suspension set up was the same as with the R-comp tires, which I felt was too stiff for the tire).