wstar's Journal

wstar · 09-10-2011, 09:06 AM

Yeah, I also start braking earlier and more gradually than I need to most of the time. I could say it's to save brake wear, but really it's because I'm not confident in exactly when it's "too late" to aggressively brake at the last minute and still shed enough speed for the corner. Same thing with staying on them too long and not using the accel to plant the car down instead. I understand how that works in theory, but confidently doing it in practice is another matter entirely

I'm sure it will all become clearer after I get a couple days in with a good instructor pointing me around.

travisjb · 09-10-2011, 09:38 AM

Your instructor should wear a headset so they can provide direction/commands as you go around... that will que you to make the correct pedal input at the right time

Equinox · 09-11-2011, 06:53 AM

Quote:

Originally Posted by wstar

Also, I had two fuel cuts on my last run of the day, around 2/3 of a tank this time. Both were exiting the same fast right corner onto a straight, in the exact same spot on the track as last time. Seems like an ECU limiter kicks in temporarily at 6K RPM. I'm guessing the ECU sees the loss of fuel pressure/volume/something and sets up that temporary limit automatically to protect itself or something.

I had a power cut out a second time - which is one of the reasons I left early, as well as me suspecting my diff cooler programmer unit was possible going off and on - turns out it was fine. Pretty sure the second power loss was just fuel starvation since it came back up to full power in less than a minute. Was worried I was breaking the car too much for one day.

Quote:

Your instructor should wear a headset so they can provide direction/commands as you go around... that will que you to make the correct pedal input at the right time

Travis, at the training sessions, they do wear headsets and give you one.

travisjb · 09-11-2011, 08:55 AM

headsets are generally personal property of the instructors... in the clubs I run with, most do but not required that I know of

wstar · 09-19-2011, 10:10 PM

Got my brake rotor kit in from Relentless finally. Looks nice, around 21 lbs per rear and 19 lbs per front. Need to sort out the rear caliper work, etc. Probably do it tomorrow and/or wednesday, assuming a last minute trip out of town doesn't come up by then.

Equinox · 09-20-2011, 08:36 AM

you most likely will need a brake piston retracting tool. Cheap little cube that you can get at auto parts stores; because you of course are going to put on new pads with new rotors.......

wstar · 09-20-2011, 08:38 AM

Hmm I've seen those cubes before, I thought that was for removing or re-installing the actual pistons? I usually just use small c-clamps to push the pistons back in to fit new pads.

Equinox · 09-20-2011, 08:56 AM

rear brakes usually screw in because of the parking brake (in my experience). Go ahead and try the c clamp method, but if it isn't going any where, your best bet is to screw that sucker back in.

ChrisSlicks · 09-20-2011, 09:04 AM

Quote:

Originally Posted by Equinox

rear brakes usually screw in because of the parking brake (in my experience). Go ahead and try the c clamp method, but if it isn't going any where, your best bet is to screw that sucker back in.

No screwing on these. Straight up pistons with separate e-brake shoes built into hub assembly. With fixed calipers it is tough to use a c-clamp, usually I just use an old pad to gently lever the piston back. Of course as you push one back another one wants to come out so it is like a game of wackamole.

wstar · 09-20-2011, 09:19 AM

Yeah I've swapped pads on these brakes twice before so far (oem -> hps, and hps -> hps), and I've managed with the C-clamps. I also use boards to help too, which I guess is similar to your "old pad" idea. e.g. I put a section of 3/4-inch think board I have laying around inside the caliper and then c-clamp that to the outside of the caliper until I get them both pushed in.

Equinox · 09-20-2011, 09:45 AM

good to know, thanks guys.

wstar · 09-25-2011, 11:53 PM

Just got done with my big weekend of brakes work:

1) Put the Relentless 2-piece rotors on all 4 corners (along with their rear caliper expansion kit for the thicker rear rotors, which means taking the rear rotors completely apart and introducing lots of air into the system in the process).

2) A very thorough bleed of all the fluid: ran 2L of cheap Prestone stuff from autozone through just to clean out air bubbles and old fluid/moisture, around the 4 corners 2x over. Then flushed that with fresh RBF600 to past the obvious color change at all 4 corners.

3) Installed Carbotech XP8 pads all around.

4) Bedded it all in together.

The Carbotechs seem to bed in fine, and no real noise so far, so I may just keep using them as street pads, at least until they start getting noisy on me.

The Relentless kit seem to function fine so far. Both the rotors and the caliper expansion kit seem quite high quality. The rears are considerably thicker than stock, and at all 4 corners it's obvious they've got a better cooling vane setup in the interior (that and they're slotted to boot).

The only technical gripe I have is about the weights. The fronts are as advertised and talked about elsewhere on the board: ~19lbs per rotor, vs 29lbs for the stock ones I took off, so there's 20 lbs of unsprung rotating weight gone from the front of the car.

However, at least in my personal case, the "lightweight" 2-piece rear rotors are actually heavier than the stock ones I took off, by 1.8lbs per rotor. I checked and double-checked and triple-checked. Relentless claims roughly 3-4 lbs lighter on the rear rotors, and other installers seem to have confirmed this. Scott@RA claims I'm the first person to report having lighter stock rotors than his 2-piece ones. It's not an insignificant difference though, or just some minor measurement error. "3-4 lbs lighter" vs 1.8 lbs heavier is a net of ~5-6 lbs difference from expectations, which is in the ballpark of ~25% of the weight of the objects we're talking about. I repeatedly measured both of my RA ones and both of my stockers. The stockers are 19.2 lbs each, and the RA's are 21 lbs flat. It's hard to imagine some Nissan variance (as in, maybe on some 2009 cars they sourced different rear sport-package rotor part numbers) accounting for such a large weight discrepancy.

I'll have to check and see if anyone else kept the actual weight numbers from their stock and RA rear rotors for comparison sometime to delve deeper into this mystery.

wstar · 09-27-2011, 03:39 PM

Brakes update after 2 full days on the street. Minor squeals during light braking at low speeds are starting to creep in. It's not all that bad though so far, not enough to make me want to swap in a street pad for regular use anyways.

I imagine it will be a while before I fully understand the squeal, but so far the evidence seems to point to the idea that it's very dependent on how you treat the brakes. Basically if you're light on them on the street like a normal driver, it seems to de-bed them a little (remove some of the good xfer layer) and make them noisy. Doing a light rebedding seems to quiet them down for a while (and by light, I mean really just 4-5 good hard stops from ~50-55mph down to 10mph, fairly closely spaced together).

As I've always done, I'm careful to time it out so that I can let off the brakes and roll the last foot or two to a stop without them, to avoid burning them into one spot on the rotor (with a little parking brake help when necc). That alone probably avoids a lot of rotor and pad problems for me.

Time will tell if I can sustain a pattern of occasional partial re-bedding to keep them relatively quiet on the street between track days, or if I'll eventually give up and use a street pad to avoid noise.

The braking performance is awesome though, they're very grabby

wstar · 09-27-2011, 03:47 PM

Oh one other totally random technical note on our cars, maybe someone will Google this in a time of need someday:

Idle Air Volume Learning

The service manual details the pre-requisites for this, as well as the steps to accomplish it without any special tools (e.g. Consult-III), on pages EC-18 through EC-20. It's a good thing to do when you've made significant breathing changes (intake/exhaust work, etc), after changing the idle speeds via UpRev, or just anytime after a full ECU reset as well. I assume we all already know this. I've done it several times in the past without issue.

Yesterday after having my battery disconnected for an extended period, and fixing a minor intake problem (I had a leak between my filters and throttle plates, someone didn't fully hook up one of my PCV intake hoses properly last time they were in there...

), I tried to do Idle Air Volume Learning again like before.

For the life of me, I couldn't get it to work. I kept repeating the Service Manual's sequence over and over (the gas pedal timing, etc), but never got the blinking SES light that indicates you've done it all right.

I finally figured out the problem after a while, randomly: Having my PLX Kiwi Bluetooth adapter hooked up to the OBD-II port was preventing it. I wasn't even running any diagnostic software, I just had the adapter hooked up and powered on. Disconnected it and the procedure worked on the very next try.

My wild guess is that if it senses a CAN-capable device hooked to the OBD-II port, the "manual" procedures for things like Idle Air Volume Learning are disabled because it assumes you've got Consult-III available or something. Who knows. Bottom line: disconnect your OBD-II adapters before doing this procedure or it will never work.

Equinox · 09-27-2011, 06:49 PM

nice gremlin find.

09-10-2011, 09:06 AM	#406 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Yeah, I also start braking earlier and more gradually than I need to most of the time. I could say it's to save brake wear, but really it's because I'm not confident in exactly when it's "too late" to aggressively brake at the last minute and still shed enough speed for the corner. Same thing with staying on them too long and not using the accel to plant the car down instead. I understand how that works in theory, but confidently doing it in practice is another matter entirely I'm sure it will all become clearer after I get a couple days in with a good instructor pointing me around. __________________ 7AT Track Car! Journal thread / Car setup details

09-10-2011, 09:38 AM	#407 (permalink)
travisjb A True Z Fanatic Join Date: Jan 2009 Location: GSO Posts: 2,803 Drives: VIR Rep Power: 188	Your instructor should wear a headset so they can provide direction/commands as you go around... that will que you to make the correct pedal input at the right time __________________ 2009 370Z #104 For Sale

09-11-2011, 08:55 AM	#409 (permalink)
travisjb A True Z Fanatic Join Date: Jan 2009 Location: GSO Posts: 2,803 Drives: VIR Rep Power: 188	headsets are generally personal property of the instructors... in the clubs I run with, most do but not required that I know of __________________ 2009 370Z #104 For Sale

09-19-2011, 10:10 PM	#410 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Got my brake rotor kit in from Relentless finally. Looks nice, around 21 lbs per rear and 19 lbs per front. Need to sort out the rear caliper work, etc. Probably do it tomorrow and/or wednesday, assuming a last minute trip out of town doesn't come up by then. __________________ 7AT Track Car! Journal thread / Car setup details

09-20-2011, 08:36 AM	#411 (permalink)
Equinox Track Member Join Date: Jul 2009 Location: Beaumont, TX Posts: 685 Drives: 06 Porsche Carrera S Rep Power: 18	you most likely will need a brake piston retracting tool. Cheap little cube that you can get at auto parts stores; because you of course are going to put on new pads with new rotors....... __________________ Check out my Albums '13 Subaru WRX STi \| '06 Porsche 911 Carrera S (SOLD) \| '96 Mazda RX-7 6.0L V8 RHD (SOLD) \| '09 Nissan Nismo #0058 (SOLD)

09-20-2011, 08:38 AM	#412 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Hmm I've seen those cubes before, I thought that was for removing or re-installing the actual pistons? I usually just use small c-clamps to push the pistons back in to fit new pads. __________________ 7AT Track Car! Journal thread / Car setup details

09-20-2011, 08:56 AM	#413 (permalink)
Equinox Track Member Join Date: Jul 2009 Location: Beaumont, TX Posts: 685 Drives: 06 Porsche Carrera S Rep Power: 18	rear brakes usually screw in because of the parking brake (in my experience). Go ahead and try the c clamp method, but if it isn't going any where, your best bet is to screw that sucker back in. __________________ Check out my Albums '13 Subaru WRX STi \| '06 Porsche 911 Carrera S (SOLD) \| '96 Mazda RX-7 6.0L V8 RHD (SOLD) \| '09 Nissan Nismo #0058 (SOLD) Last edited by Equinox; 09-20-2011 at 08:58 AM.

09-20-2011, 09:19 AM	#415 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Yeah I've swapped pads on these brakes twice before so far (oem -> hps, and hps -> hps), and I've managed with the C-clamps. I also use boards to help too, which I guess is similar to your "old pad" idea. e.g. I put a section of 3/4-inch think board I have laying around inside the caliper and then c-clamp that to the outside of the caliper until I get them both pushed in. __________________ 7AT Track Car! Journal thread / Car setup details

09-20-2011, 09:45 AM	#416 (permalink)
Equinox Track Member Join Date: Jul 2009 Location: Beaumont, TX Posts: 685 Drives: 06 Porsche Carrera S Rep Power: 18	good to know, thanks guys. __________________ Check out my Albums '13 Subaru WRX STi \| '06 Porsche 911 Carrera S (SOLD) \| '96 Mazda RX-7 6.0L V8 RHD (SOLD) \| '09 Nissan Nismo #0058 (SOLD)

09-25-2011, 11:53 PM	#417 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Just got done with my big weekend of brakes work: 1) Put the Relentless 2-piece rotors on all 4 corners (along with their rear caliper expansion kit for the thicker rear rotors, which means taking the rear rotors completely apart and introducing lots of air into the system in the process). 2) A very thorough bleed of all the fluid: ran 2L of cheap Prestone stuff from autozone through just to clean out air bubbles and old fluid/moisture, around the 4 corners 2x over. Then flushed that with fresh RBF600 to past the obvious color change at all 4 corners. 3) Installed Carbotech XP8 pads all around. 4) Bedded it all in together. The Carbotechs seem to bed in fine, and no real noise so far, so I may just keep using them as street pads, at least until they start getting noisy on me. The Relentless kit seem to function fine so far. Both the rotors and the caliper expansion kit seem quite high quality. The rears are considerably thicker than stock, and at all 4 corners it's obvious they've got a better cooling vane setup in the interior (that and they're slotted to boot). The only technical gripe I have is about the weights. The fronts are as advertised and talked about elsewhere on the board: ~19lbs per rotor, vs 29lbs for the stock ones I took off, so there's 20 lbs of unsprung rotating weight gone from the front of the car. However, at least in my personal case, the "lightweight" 2-piece rear rotors are actually heavier than the stock ones I took off, by 1.8lbs per rotor. I checked and double-checked and triple-checked. Relentless claims roughly 3-4 lbs lighter on the rear rotors, and other installers seem to have confirmed this. Scott@RA claims I'm the first person to report having lighter stock rotors than his 2-piece ones. It's not an insignificant difference though, or just some minor measurement error. "3-4 lbs lighter" vs 1.8 lbs heavier is a net of ~5-6 lbs difference from expectations, which is in the ballpark of ~25% of the weight of the objects we're talking about. I repeatedly measured both of my RA ones and both of my stockers. The stockers are 19.2 lbs each, and the RA's are 21 lbs flat. It's hard to imagine some Nissan variance (as in, maybe on some 2009 cars they sourced different rear sport-package rotor part numbers) accounting for such a large weight discrepancy. I'll have to check and see if anyone else kept the actual weight numbers from their stock and RA rear rotors for comparison sometime to delve deeper into this mystery. __________________ 7AT Track Car! Journal thread / Car setup details

09-27-2011, 03:39 PM	#418 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Brakes update after 2 full days on the street. Minor squeals during light braking at low speeds are starting to creep in. It's not all that bad though so far, not enough to make me want to swap in a street pad for regular use anyways. I imagine it will be a while before I fully understand the squeal, but so far the evidence seems to point to the idea that it's very dependent on how you treat the brakes. Basically if you're light on them on the street like a normal driver, it seems to de-bed them a little (remove some of the good xfer layer) and make them noisy. Doing a light rebedding seems to quiet them down for a while (and by light, I mean really just 4-5 good hard stops from ~50-55mph down to 10mph, fairly closely spaced together). As I've always done, I'm careful to time it out so that I can let off the brakes and roll the last foot or two to a stop without them, to avoid burning them into one spot on the rotor (with a little parking brake help when necc). That alone probably avoids a lot of rotor and pad problems for me. Time will tell if I can sustain a pattern of occasional partial re-bedding to keep them relatively quiet on the street between track days, or if I'll eventually give up and use a street pad to avoid noise. The braking performance is awesome though, they're very grabby __________________ 7AT Track Car! Journal thread / Car setup details

09-27-2011, 03:47 PM	#419 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Oh one other totally random technical note on our cars, maybe someone will Google this in a time of need someday: Idle Air Volume Learning The service manual details the pre-requisites for this, as well as the steps to accomplish it without any special tools (e.g. Consult-III), on pages EC-18 through EC-20. It's a good thing to do when you've made significant breathing changes (intake/exhaust work, etc), after changing the idle speeds via UpRev, or just anytime after a full ECU reset as well. I assume we all already know this. I've done it several times in the past without issue. Yesterday after having my battery disconnected for an extended period, and fixing a minor intake problem (I had a leak between my filters and throttle plates, someone didn't fully hook up one of my PCV intake hoses properly last time they were in there... ), I tried to do Idle Air Volume Learning again like before. For the life of me, I couldn't get it to work. I kept repeating the Service Manual's sequence over and over (the gas pedal timing, etc), but never got the blinking SES light that indicates you've done it all right. I finally figured out the problem after a while, randomly: Having my PLX Kiwi Bluetooth adapter hooked up to the OBD-II port was preventing it. I wasn't even running any diagnostic software, I just had the adapter hooked up and powered on. Disconnected it and the procedure worked on the very next try. My wild guess is that if it senses a CAN-capable device hooked to the OBD-II port, the "manual" procedures for things like Idle Air Volume Learning are disabled because it assumes you've got Consult-III available or something. Who knows. Bottom line: disconnect your OBD-II adapters before doing this procedure or it will never work. __________________ 7AT Track Car! Journal thread / Car setup details

09-27-2011, 06:49 PM	#420 (permalink)
Equinox Track Member Join Date: Jul 2009 Location: Beaumont, TX Posts: 685 Drives: 06 Porsche Carrera S Rep Power: 18	nice gremlin find. __________________ Check out my Albums '13 Subaru WRX STi \| '06 Porsche 911 Carrera S (SOLD) \| '96 Mazda RX-7 6.0L V8 RHD (SOLD) \| '09 Nissan Nismo #0058 (SOLD)

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