Track forum general chit chat.

[CarPoor]

Originally Posted by roastbeef

ok, so i have some things to discuss. the last time i was at laguna was last march, this was also my last track day... got married and had to lay off the track days to save for a bit. that being said, i was a bit rusty. as my confidence and technique came back with seat time, i experienced a few things.

only changes to the car since my last trip were APR spats (essentially gurney flaps in front of the front wheel wells) and three trackspec hood vents.

tires are achilles endurance slicks and this was my second time out with them. they feel good, but not as grippy as nt01's. they don't seem to like a lot of slip angle and start to get pushy when you get rough. i'm probably driving these things wrong, but they were very cheap and i got them new. on my last cool down lap of the day, my front passenger tire's inner sidewall blew. it held together ok for the remaining 1/2 lap until i could get into the garage. no damage to anything.
earlier in the day, i was running them with too low of pressure. they seemed to like 34 up front and 34.5 in the rear so i left them alone at about 11am when it was about as hot as it was going to get. i think the passenger front tire blew from repeated visits to the outside curbing of turn 6. it is significant curbing where i'm dragging that particular tire over. the oem suspension doesn't care for the dip of the inside of 6 and i would get launched to the outside if i went too low. turn 6 just sucks with oem suspension.

a new thing i was trying to be conscious of was turning the steering wheel less. seems weird, but turning the wheel too much when you're trying to turn is a thing. this is especially true at turns 5, 9, and 10. turn 10 yielded the biggest improvement with this technique- i was able to get to full throttle earlier and longer before the braking zone at turn 11. i really enjoyed experimenting with this.

brakes- this was my first time trying endless re20 pads. i was running ds2500's in the rear because the rear set of re20 pads were the wrong size (ugh). i want to say i experienced pad fade for the first time... is that a thing? i haven't had to deal with brake fade since i got my brakes and i would get a longer pedal feel towards the end of a session. i didn't like that at all.
the brakes are the essex ap cp5060/5040 kit. stainless lines everywhere, and SRF fluid. nothing changed since last time but the pads.
SRF was last changed in march when my rear brakes were installed... maybe its possible i got bad fluid? but that wouldn't explain how i didn't get poor pedal feel last time.
i brought my spare raybestos st43 race pads and swapped them in between sessions. they definitely felt better, but i still had a longer pedal press that got a little longer- it just wasn't as bad.

so here is my question- is pad fade a thing? like everything else is good, but the pads are creating the longer pedal feel?
i'm thinking my fluid may have taken a dump at some point, and thats where i think i'll start.

trackspec motorsports hood vents were great. temps never got above the 3/4 mark, and came down pretty quick with a cool down lap. i'm a fan!

dparm a damn c7 grand sport was in my run group. those damn things are fast. we were almost even, but he pulled away on the straights. nice cars.

the car turned 65,000 miles on the drive home. running like a champ.

I’ve had pad fade a few times and didn’t experience the longer pedal. What I felt was almost a hard pedal with a judder. So, to me this sounds like the fluid need flushed. My $.02 fwiw, but I am nowhere near the driver most here are.

[roastbeef]

Also forgot to mention- I don't think it's knock back. My brakes have anti knockback Springs.

[Ximian]

Originally Posted by roastbeef

What did it end up being?

A small rock got stuck between the rotor and the shield. It sounded much worse than that. The NT01s pick up everything and throw it around.

A tiny bit of the rotor is chewed up but still worked well for the last session. I’ll take the rotor off to get a better look when I switch to street pads.

[dparm]

Originally Posted by roastbeef

dparm a damn c7 grand sport was in my run group. those damn things are fast. we were almost even, but he pulled away on the straights. nice cars.

Yeah man, these things are just monsters on the track...and they just have the "base" 460hp motor.

[roastbeef]

Originally Posted by dparm

Yeah man, these things are just monsters on the track...and they just have the "base" 460hp motor.

i can see those being stupid fast with just a few things. i like to find people in the paddock after we have a good chase to exchange some laughs. he had a pretty stock car using race pads. raybestos st43's, i believe.
i'm not surprised it was faster; less weight, better suspension, more power, usable brakes for an oem... with a few tweaks and some aero, i could see them being unbeatable.
i read that a few people have messed with the magnetic suspension to tune it and have been successful at making it better than oem. have you looked into that at all?

[CorruptCommie]

Running Pirellis at Mid Ohio:

[admranger]

roastbeef pad fade is most definitely a thing. I experimented with a ton of pads early in my racing career. Pads all felt different out of the box and even more so on the track. Others swear by Endless pads though, so I don't know why they felt that way for you. I mean, a quick bleed of the brakes won't hurt.

Speaking of brake pads, I had a Toyota 4Runner TRD offload version as a rental car this weekend. The pads on that thing had the most awful release characteristic I've ever felt. Never could come to a smooth stop with them as the release was so abrupt. Ugh. Whiplash...

[Ximian]

I beat up my PFC 08s with stock rotors all day with threshold braking and they haven't disappointed me yet. The sample size of people supporting how good Endless brake pads perform is much smaller than that of PFC pads so perhaps there are some weak points that haven't been identified.

After just one track day of regular Rowe 10W-60, I'm ready to change it out. It was at 250F on a warm up lap. It was about 270F after a few hot laps and 72-78F ambient temp.

Pushing hard with Liqui Moly didn't go past 230F on a warmer day just weeks before.

[roastbeef]

Originally Posted by admranger

roastbeef pad fade is most definitely a thing. I experimented with a ton of pads early in my racing career. Pads all felt different out of the box and even more so on the track. Others swear by Endless pads though, so I don't know why they felt that way for you. I mean, a quick bleed of the brakes won't hurt.

Speaking of brake pads, I had a Toyota 4Runner TRD offload version as a rental car this weekend. The pads on that thing had the most awful release characteristic I've ever felt. Never could come to a smooth stop with them as the release was so abrupt. Ugh. Whiplash...

ok ok, i didn't know if i was making up new problems in my head or not. the wear seemed to be good. i had them in for three sessions. first session wasn't bad, but i wasn't really pushing it... getting in the mindset, knocking the dust off my helmet, warming up the car, bedding in the new pads, you know.
second session, i started to get a longer pedal feel. maybe they weren't bedded in all the way? i'm starting to get distracted by the pedal management. did a double tap to see if it was maybe knockback and i got a little more pressure, but still not ideal. it was most prominent at the braking zone for turn 8, so i was thinking maybe the big suckdown and sideways throwing of the car at 7 was causing some knockback, but it started happening in the longer braking zones as well.

like i was saying, this srf got flushed in last march and i this is my second day on it. i have been daily driving the car since july, but i doubt that is the problem.

it was a lot less pronounced with the raybestos st43's, but it was still there. the st43's don't quite have the torque i crave, but they had a better pedal feel and i used them the rest of the day.
i'm probably still going to do a fluid flush, just in case a bubble got in there or something.

the conditions at laguna on friday were fantastic. no morning fog, enough sun to warm up the track, ambient temp was 69*, and we got that cool constant breeze through the garage to cool the car between sessions. sadly, i didn't pb with these tires this time around... i got them to feel good with the pressures, but i didn't feel fast. then there were the brakes.

so what is happening if it is just "pad fade?" is it a pad/rotor pairing problem, or just a pad problem for the application? how is the heat getting to be too much for the pad and not the rotor? is the rotor not getting up to temp? sounds silly, but when the ambient air is cool and the track surface is warmish- i can't help but ponder that.

[Ximian]

It could be a bedding/burnishing issue if a different pad had better feel. This Endless compound might be more sensitive and requires a burnishing procedure that you can't do easily during a session.

Taking the burnishing best practices from all the different manufactures and what you end up is this procedure - 10 constant braking force stops from three different initial speeds of 40 MPH, 70 MPH, 100 MPH to about 10 MPH, 20 MPH, 40 MPH respectively. The first set is low braking force, the second is medium force, and the third is high force. The cool down is especially important for the transfer layer to stay intact which means 20 or so minutes on the highway and then parking it until the rotors and pads reach the ambient temperature.

I have never been able to follow this procedure fully, but the PFC 08 compound isn't particularly sensitive to OEM pad layer on the rotors.

[dogbone]

Originally Posted by roastbeef

brakes- this was my first time trying endless re20 pads. i was running ds2500's in the rear because the rear set of re20 pads were the wrong size (ugh). i want to say i experienced pad fade for the first time... is that a thing? .

I don't think Endless RE20 is a thing. Was it ME20 pads? I know a few people that have used ME20's successfully on track. (I've never run them.)

I would guess that you boiled the fluid at some point. It's possible that you actually boiled the fluid at your last event with the previous pad setup, whatever that was. And then the fluid just sat quietly doing ok while you drove on the streets for the last few months. Then, at this event, when you pushed the fluid hard again, the previously boiled fluid reared it's ugly head.

Any fluid can be boiled. If your last pads were on the thin side and you pushed hard at Laguna, it's possible enough heat transferred into the fluid to boil it. I boiled my fluid years ago at Thermal club without realizing it. The fluid held up fine that day. But then, at the next track at Buttonwillow, my pedal travel was long.

Anyway, I recommend bleeding the brake fluid.

[inTgr8r]

^whs
I would agree to check fluids first.

[Mantii]

Do you guys have any recommendations for rear rotors on the e46? Currently have the OEM cross drilled ZCP ones but want to replace and keep these as spares. Was looking at the Stoptech Slotted ones, not sure if any good for the track.

Thanks fellas

[Chris_PDX]

Originally Posted by Mantii

Do you guys have any recommendations for rear rotors on the e46? Currently have the OEM cross drilled ZCP ones but want to replace and keep these as spares. Was looking at the Stoptech Slotted ones, not sure if any good for the track.

Thanks fellas

OEM size? I have some of the StopTech slotted on the rears, paired with Cobalt XR2 race pads. They last a fairly long time but the brake balance is biased front, so they wear less.

I've been running OEM spec rotors up front (with the same XR2 pads) and they aren't holding up well at all. I'm going to an AP Racing BBK up front over the winter.

[M3 Number 86]

roastbeef you need to go with Endless N05U, it's a step above ME20. ME20 are for some reason considered a street pad even though pro series run these (lighter cars albeit).

I've done Buttonwillow twice, Laguna, and ACS, and drive these on the street and there's still way more than half the pad left lol.

[ThunderMoose]

Originally Posted by Mantii

Do you guys have any recommendations for rear rotors on the e46? Currently have the OEM cross drilled ZCP ones but want to replace and keep these as spares. Was looking at the Stoptech Slotted ones, not sure if any good for the track.

Thanks fellas

I use centric slotted.

[Mantii]

Originally Posted by Chris_PDX

OEM size? I have some of the StopTech slotted on the rears, paired with Cobalt XR2 race pads. They last a fairly long time but the brake balance is biased front, so they wear less.

I've been running OEM spec rotors up front (with the same XR2 pads) and they aren't holding up well at all. I'm going to an AP Racing BBK up front over the winter.

Originally Posted by ThunderMoose

I use centric slotted.

Thanks. Yeah it would be OEM size for the rear. I heard the Stoptech slotted rotors are basically rebranded Centric? Not sure if this is true.

Might pick up a set and see how it goes. I run the AP Radical Kit up front with the J Hook rotors. Those things are beautiful. I wish they had a rear kit available with the new calipers.

If anyone has any other suggestions or experience for the rear, please share. Thanks

[kyippee]

Great weekend. Starting at 3:41 mark, had 2 fun laps with a track vehicle. Horsepower vs. grip was fun and the differences are entertaining.

Had my friend who happens to be an HOD instructor give me some tips later in the day, so I've got my homework already cut out - you'll see some mistakes I made. Crazy how in my PB lap I made up for lost time by doing turns 14/15 way faster

[roastbeef]

Originally Posted by M3 Number 86

roastbeef you need to go with Endless N05U, it's a step above ME20. ME20 are for some reason considered a street pad even though pro series run these (lighter cars albeit).

I've done Buttonwillow twice, Laguna, and ACS, and drive these on the street and there's still way more than half the pad left lol.

Hmmmm... bummer

[scotty_miller]

Originally Posted by Mantii

Thanks. Yeah it would be OEM size for the rear. I heard the Stoptech slotted rotors are basically rebranded Centric? Not sure if this is true.

Might pick up a set and see how it goes. I run the AP Radical Kit up front with the J Hook rotors. Those things are beautiful. I wish they had a rear kit available with the new calipers.

If anyone has any other suggestions or experience for the rear, please share. Thanks

Centric owns stop tech. Just get a set of centric rear blanks and call it a day. Absolutely no benefit to their slotted rotor vs a blank other than for "looks"

Just my .02

[ThunderMoose]

Originally Posted by scotty_miller

Centric owns stop tech. Just get a set of centric rear blanks and call it a day. Absolutely no benefit to their slotted rotor vs a blank other than for "looks"

Just my .02

You gotta look good!

[NoCarrier]

Originally Posted by roastbeef

so what is happening if it is just "pad fade?" is it a pad/rotor pairing problem, or just a pad problem for the application? how is the heat getting to be too much for the pad and not the rotor? is the rotor not getting up to temp? sounds silly, but when the ambient air is cool and the track surface is warmish- i can't help but ponder that.

It's not actually "pad fade," so to speak. You can experience gas buildup between the pad and rotor, but in that case the pedal would be as firm as ever but the car wouldn't be slowing down. If you have a long or spongy pedal that is usually from boiling the fluid. In your case it sounds like the cause of that could be one of two things, or a combination of the two.

First, wrong pads. I don't know anything about the Endless pads, but based on what M3 Number 86 is saying, it sounds like the ones you ran were not full-on track pads.

Second, lack of bedding. Not just bedding period, but bedding of the current pad compound that you're using. Perfect bedding involves first scraping all of the old pad material off and then doing the series of stops and cool-downs to transfer a layer of new matching pad material to the disc. Without that adherent friction your brakes are working a lot harder and getting a lot hotter in order to slow the car down.

For what it's worth, Laguna is the only place I've ever had brake fade with my PFC-08s (the only track pad I've run on my e90). It happened once coming down the hill into turn 10, but luckily went away for the rest of the day.

I've gotten it a few times on the e36 Lemons car on Hawk DTC-60s in hot weather at the end of a long straight when following another car, I guess from the brakes getting less cooling.