: My mod hell story - how two screws cost me $1500



jclayc
07-20-13, 01:50 PM
Thought I'd share a story and contradict something I've read almost everywhere - think those little set screws on your rotors don't matter? They do. Feel free to disagree but this is my experience.

I bought a set of fancy Coleman 2 pc rotors for the front for my 05, which I track more than I drive on the street. When they arrived, I noticed there wasn't a hole for the little torx set screw that holds the rotor against the hub. I searched for people's opinion online and even called the supplier and both responses were that, nah, those little screws don't do anything - forget about it. So I did as they suggested and just made sure my lugs were torqued to spec (100 ft lbs)... but started noticing a bad shake in the steering wheel when under heavy braking from 60+.

After a few weeks and track days and mysterious amounts of heat being generated (smoking after sessions & multiple sets of melted dust boots), I went ahead and pulled the rotors off and checked them - rings and hats are warped. Crap. About that time, I had a chance to pick up a set of Girodisc 2pc rotors as well, so I started running those. Even though they do have a spot for the set screw, by that time, I didn't have any and still didn't think it would matter. You guessed it - a few weeks later and they warped too. $900 for the Colemans and $600 for the Girodiscs shot to hell.

So I bought a cheap-ass set of iron rotors and happened to find a misc torx screw in the garage and decided to put it on one of the rotors to see if the shake was reduced. It was. Pulling the rotors back off to inspect them, here's what the (not correct) torx bolt looked like:

http://i.imgur.com/fFx3qyA.jpg

To me, this is proof that the set screw has a purpose and the kind of stress that they prevent from being telegraphed through the brakes/driveline. I now run the right set screws (GM part 11570339) with anti-seize on them and the shaking and heat problem seems like it is solved.

FuzzyLogic
07-20-13, 02:50 PM
Wouldn't over-torquing the wheel studs have the same positive effect? I'm not disputing your point--vibration between the rotor hat and the hub could certainly cause localized heating, but ARP 100-7709 (or even Raybestos 2093b) wheel studs can handle much more than 100 ft-lbs.

Also, where did you get a set of Girodiscs for $600, and do you recall where those threads were regarding the modifications necessary to run larger rotors for the 6-piston V2 calipers?

AAIIIC
07-20-13, 03:33 PM
Strange.

jclayc
07-20-13, 04:32 PM
I never torqued over the 100 ft lbs if all else because I've been having a hard time with lug nuts seizing on the studs and snapping them (still trying to find open ended ones that don't seize up - nothing from summit is immune so I'm starting to look at mucho-expensive ones now)...

I bought the girodiscs from Luke - they were probably closer to $700.

I've seen the thread on upgrading to the v2 calipers but I'm running v1 calipers at present - not sure of your question there.

I wish I could figure out that I'm just a dummy and I've been doing something wrong to cause the rotor/brake/lug nut problems and I'm definitely up for suggestions - it's probably important to note that my alignment has been good, wheel hubs are new and all wheels have been balanced during these trials

crankedupforit
07-20-13, 04:36 PM
Weird. I've run 6 weekends with those Girodiscs without the set screw.

jclayc
07-20-13, 04:51 PM
I'll be down at NjMp tomorrow and will know _for sure_ if the problem is fixed under track conditions but testing locally suggests I've solved everything with true rotors and set screws

I'm with you guys that it all doesn't make sense

FuzzyLogic
07-20-13, 05:11 PM
I never torqued over the 100 ft lbs if all else because I've been having a hard time with lug nuts seizing on the studs and snapping them (still trying to find open ended ones that don't seize up - nothing from summit is immune so I'm starting to look at mucho-expensive ones now)...

I bought the girodiscs from Luke - they were probably closer to $700.

I've seen the thread on upgrading to the v2 calipers but I'm running v1 calipers at present - not sure of your question there.

In other words, what needs to happen to install the V2's larger front rotors on the V1?

jclayc
07-20-13, 05:16 PM
To install the larger v2 rotors, I'd just need the calipers, drill out the caliper bolt holes a bit and add larger rotors with the 6 bolt pattern either drilled in or made like the ones at racingbrake

AAIIIC
07-20-13, 08:04 PM
... do you recall where those threads were regarding the modifications necessary to run larger rotors for the 6-piston V2 calipers?
I think you're looking for this thread (http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-performance/219790-v2-rotor-caliper-retrofit-v1-cars.html). In the last couple pages of that I get into what I did to make the V2 rotors fit. Basically, redrill the bolt pattern and enlarge the center bore a bit.


I'm with you guys that it all doesn't make sense
Like I said, strange. I haven't run the little set screws (on the street or the track) since the first time I swapped rotors a few years ago. The holes on the RB center hats aren't even located right, so the set screw wouldn't fit even if I wanted to run them.

Are you running extended studs, or why do you want/need open ended lug nuts?

jclayc
07-20-13, 08:31 PM
yes, I'm running extended ARP lug studs b/c, once, I put on open-ended lugs and noticed that the factory stud was barely as tall as the lug. people even commented on it. Seeing "just enough" threads to go through a standard lug nut didn't inspire confidence - granted, it's probably academic

and it can't be that I'm such a beast of a driver that I'm exerting forces on the car that no one else is ;)

----------

I have to say I'm shocked no one has joked about ~two screws for $1500~

Junior1
07-20-13, 11:35 PM
Hmmm...
I'm running the same Coleman's on my car and I was starting to think I didn't properly bed the pads in.
I've got the warp shake on the straight at T-Bolt going from 140 into Turn 1. I thought I pushed it a little too hard too fast as the rotors now have some grooves in them.
Nothing too bad but it is noticeable under hard braking. I've run another 2-3 full track days on them since. My Giro-Disc's are still in the boxes.

Dan_Gurney
07-21-13, 08:32 PM
I don't buy that the little screw has any effect. the friction created by 6 lug nuts torqued to 100ftlb, is so large that there will be no slipping of that interface. If that interface is not slipping, then an extra screw in there will have 0 effect, once torqued that is a fixed assembly.

The only thing that screw could do it maintain the clocking during installation, but i just don't see how a slight rotation one way or another before installing the wheel would make a difference.

jclayc
07-21-13, 09:01 PM
D_G - any thoughts on the cause of bad wheel shake when under braking if it's not the rotor wobbling - and keep in mind, I'm going to near 0 from very high speed. No shakes w/o brakes on

tests w new rotors and retaining screws at NJMP seems to have eliminated the shakes/heat that I haven't been able to get rid of otherwise (even w new rotors alone) Like I say, I want to agree with everyone's opinion that it doesn't matter but I can't find any other cause and can't deny that the screws helped, if not eliminated, the problem

Only variation of the thought is that the screw isn't holding the rotor but it does hold the rotor lug holes perfectly aligned to get the lug nut conical base to seat properly... And I've just been really terrible at getting the lugs to seat without the screws...

FuzzyLogic
07-21-13, 09:39 PM
Brake pins not totally engaged? No brake shims? Caliper bolts not torqued to spec?

Andringa
07-22-13, 03:30 PM
D_G - any thoughts on the cause of bad wheel shake when under braking if it's not the rotor wobbling - and keep in mind, I'm going to near 0 from very high speed. No shakes w/o brakes on

tests w new rotors and retaining screws at NJMP seems to have eliminated the shakes/heat that I haven't been able to get rid of otherwise (even w new rotors alone) Like I say, I want to agree with everyone's opinion that it doesn't matter but I can't find any other cause and can't deny that the screws helped, if not eliminated, the problem

Only variation of the thought is that the screw isn't holding the rotor but it does hold the rotor lug holes perfectly aligned to get the lug nut conical base to seat properly... And I've just been really terrible at getting the lugs to seat without the screws...

Correlation does not always equal causation.

You changed more than one variable (You unmounted/mounted the wheels, rotors, calipers to put on rew rotors) and then assumed that the set screw was the thing that fixed it.
-If you want to test your hypothesis, take off the front wheels and remove the set screws. You should be able to get the shake to come back.
-If it comes back, then take the front wheels off and put the set screw back in. Your shake should go away.

Are you correctly bedding these rotors/pads in? Everything I've read online seems to indicate that uneven pad material distribution on the rotor causes the majority of brake pulsing or shaking.

barrok69
07-23-13, 10:20 AM
The rotor set screw is exactly that. A set screw used during assembly as an aid for line workers to not have rotors falling off the pre-assembled front and rear cradles. If you think a screw set to 11ft-lbs (finger tight) is holding on your rotor compared to the 100ft-lbs that your wheel/lugs are you are dreaming. Most companies don't use any set screws and you'd have ALOT of people complaining about wobbling rotors if that was the case.

I Don't run any on my track cars and never had any issues. Depending on how long you go out for on any track you are going to have pretty worn or chewed up rotors depending on the type of pads you are using, as each type of pad deals with heat differently.

I would suggest checking the center hole clearance of your rotors to hub. It sounds like they aren't being centered very good. Going with larger wheel bearing studs will help with this too as the holes in the rotors are generally a few mm's larger than the studs.

There was some mention of using different rotors coleman to girodisc... I assume you are using new pads for each new rotor as this will have a HUGE effect on pedal feel. Also proper pad bedding will make all the difference to the longevity of your rotors. Doing 20x 80-0mph .6 to .9G stops with time in between each to allow proper brake cooling will get you a very solid burnish and allow enough pad material to transfer for consistent stopping thereafter.

How often do you check the torque on your lugs after running the car?

Are you overheating the brakes and getting uneven pad wear which is causing your vibrations?

There are way too many factors to consider here. Just don't fool yourself that a finger tight screw solved your problems.

-ATS-
07-25-13, 02:01 AM
Well for starters if the screws are there why aren't you installing them to begin with? And how were you able to bend the screws like that? I don't think the rotors are meant to shift on the hub like that.

CTSV_Rob
07-26-13, 11:19 PM
Strange.
Well put.

thebigjimsho
07-27-13, 02:58 AM
Correlation does not always equal causation.

You changed more than one variable (You unmounted/mounted the wheels, rotors, calipers to put on rew rotors) and then assumed that the set screw was the thing that fixed it.
-If you want to test your hypothesis, take off the front wheels and remove the set screws. You should be able to get the shake to come back.
-If it comes back, then take the front wheels off and put the set screw back in. Your shake should go away.

Are you correctly bedding these rotors/pads in? Everything I've read online seems to indicate that uneven pad material distribution on the rotor causes the majority of brake pulsing or shaking.

Yep. You have no constant throughout any of this...

jclayc
07-27-13, 06:04 PM
*L* one constant - the shake

i think the answer is somewhere in between all the posts - the set screw itself isn't preventing the wobble, but perhaps having the set screw makes sure the studs are centered in the lug holes, allowing the lug nuts to securely/properly seat.

Nate37AZ
07-30-13, 02:39 AM
Your original post isn't clear... or I'm just dumb. Which rotors did you put back on with the set screw? More OEM-style rotors or more two-piece rotors? If you went back to the OEM rotors and set screw, why aren't you suspecting the rotors?

jclayc
07-30-13, 01:29 PM
Your original post isn't clear... or I'm just dumb. Which rotors did you put back on with the set screw? More OEM-style rotors or more two-piece rotors? If you went back to the OEM rotors and set screw, why aren't you suspecting the rotors?

After failing to solve things with 2 piece rotors and an OEM set of rotors and no set screw, I put another set of new OEM style rotors back on with the set screws - bedded them - and the problem seemed to be significantly reduced.

At this point, all of this seems like beating a tiny dead horse but I think it's a combo of the set screw centering the lug holes over the lugs, allowing the lug nuts to hold things together with no play + some contribution of either incomplete bedding and/or beating the crud out of the pads/rotors to the point where I'm leaving some pad on the rotors, eventually causing shakes

thebigjimsho
08-01-13, 08:42 PM
OEM is guaranteed to fit and perform perfectly. Aftermarket brings on a little of the mod hell. If you left off the set screw on a set of OEMs, then you'd have a valid claim...

yooper
08-09-13, 12:50 AM
A few thoughts.

If you are utilizing the full potential of the V1 brakes with R6, A6, or road racing slicks and the appropriate temp range pads the rims will move on the wheel studs and bend the little "set screws". Yes even when properly torqued to 100 lb ft. The OEM V1 brakes are very good, IMO they are far superior to even the C6 ZO6 Corvette brakes.

Most OEM brakes have limititations when put into the extreme application of aggressive track days or road racing.

While tracking my V1 I did a number of enhancements to reduce some of the consumable costs.

First enhancement was the SKF racing hubs (bearings) because of their lateral stiffness. See attached cut-away.

The ARP wheel studs have a somewhat larger diameter than OEM studs. but the GM Racing studs have the largest diameter therefore tightening up the tolerance between the stud and rotor. When working with PerformanceAFX on the V1 2pc rotors I asked them to tighten up the tolerance (drill holes just large enough for the actual diameter of the ARP studs. Unfortunately this did not happen as they told me not to worry because they didn't have problems with the many rotors they supplied to the corvette track day guys. Well the vette is lighter than the V and the vette brakes are not in the same league as the V1 brakes. The stud holes in the rotors should be sized so tight that they are a pain in the butt to install and will eliminate the movement of the wheel on the studs. I suggest GM had the T27 head set screws thru rotors so the rotors didn't fall off during installation and injure the service technicians foot.

A properly designed "full" floating 2pc rotor is required. The rotor should be capable of handling high torsional stress and severe temperature fluctuations.

Full on race pads matched to the temperature range encountered in your application are a must as is brake cooling ducts which direct the air to the center of the directional rotor and not on the braking surface of the rotor. IMO the OEM rotors are the best bang for the buck. As driving skill and confidence advance (when you move into slicks) you may want to skip the Coleman and Racing Brake rotors and go right to a true race set up. See attached photo.

On my C5 track car I replaced all four spindles (uprights) with the ZR1 spindles because of the torsional strength in the area where the calipers mount. See photo.

The V2 calipers/rotors equiped with Cobalt Racing XR1 pads and cooling ducts are friggin fantastic on the V1. I had to machine the rotor hub diameter to fit the SKF hubs.

yooper
08-09-13, 01:01 AM
Seat time is the best mod
Safety equipment is the smartest mod
Brake system is a mandatory mod before any power enhancements

Bill

mberisha
08-09-13, 07:19 AM
^^^well said.....

Twin Turbine
08-09-13, 05:49 PM
The rotor set screw is exactly that. A set screw used during assembly as an aid for line workers to not have rotors falling off the pre-assembled front and rear cradles. If you think a screw set to 11ft-lbs (finger tight) is holding on your rotor compared to the 100ft-lbs that your wheel/lugs are you are dreaming. Most companies don't use any set screws and you'd have ALOT of people complaining about wobbling rotors if that was the case.

I Don't run any on my track cars and never had any issues. Depending on how long you go out for on any track you are going to have pretty worn or chewed up rotors depending on the type of pads you are using, as each type of pad deals with heat differently.

I would suggest checking the center hole clearance of your rotors to hub. It sounds like they aren't being centered very good. Going with larger wheel bearing studs will help with this too as the holes in the rotors are generally a few mm's larger than the studs.

There was some mention of using different rotors coleman to girodisc... I assume you are using new pads for each new rotor as this will have a HUGE effect on pedal feel. Also proper pad bedding will make all the difference to the longevity of your rotors. Doing 20x 80-0mph .6 to .9G stops with time in between each to allow proper brake cooling will get you a very solid burnish and allow enough pad material to transfer for consistent stopping thereafter.

How often do you check the torque on your lugs after running the car?

Are you overheating the brakes and getting uneven pad wear which is causing your vibrations?

There are way too many factors to consider here. Just don't fool yourself that a finger tight screw solved your problems.

I fully agree with barrok69. But, something has caught my interest. Correct me if i'm wrong. You say you are running ARP wheel studs and you do not torque beyond 100ft lbs. However, you have a set screw that shows considerable share load applied to it when you ran it. You also have problems with the nuts binding and braking off, not sure if you mean stripping nuts or perhaps twisting off the ARP studs. This causes me to think that the nuts that you are using, begin to go thru a heat cycle which it cannot hold the torque applied to the wheel studs.

So say you have torqued your wheels, you do your track session, and all your front end components also heat up. Somewhere along the line, the nuts you are using became the week link in your setup. The studs can take the heat no problem, but i question the nuts you are using. Sure you may come in the pits and the car has cooled down and everything shrinks, and seems it has torque still applied to it. However, on the track during sessions its damn hot and now running loose.

Do a few hot laps come into the garage quick and have someone with an infrared temp gun, and someone else with a torque wrench, recheck wheel torque and record temp as you do it. You might find they are a bit loose. Same as heating a nut to get it to come loose when taking something apart. Upside... you may have found your problem, downside.... when cold after doing this, good luck getting the nut back off. But, you will have found the nuts are not up to the task.

This has happened to many track teams, and rally teams resulting in just what you described with your rotors. That set screw is messing with your head!!

jclayc
08-09-13, 06:57 PM
good feedback, thanks. and perhaps by saying "mod hell" I mean that I'm constantly fiddling with the brakes, trying to get them more and more "perfect" rather than putting on new heads or a maggie

yooper, I am running r6s and try to push hard on the track (1:17s on NMJP Lightning) - what rotors would you call true race, as opposed to Coleman and/or Racing Brake? Your picture's "J" slots look like those at MAPerformance (http://www.maperformance.com/maperformance-cadillac-cts-v-rotors-full-set-map-rotors-cts-v.html) - I've thought about calling about those...

Eventually, I'll likely upgrade to the v2 6 pistons. I see there's an AP Racing kit ?truly available? (http://www.maperformance.com/ap-racing-front-big-brake-kit-cadillac-cts-v-04-07-ap7200-ap7200.html) and 8 piston kits like http://thmotorsports.com/ksport/ksport_procomp_big_brake_kit/bkca010841ss/i-1704114.aspx, although I've never heard anyone running these and don't know that they'd increase pad area like the v2 calipers.

Upgrading the knuckles might have to happen too - these look like the right ones - http://www.newgmparts.com/parts/2012/CHEVROLET/CORVETTE/ZR1/?siteid=213815&vehicleid=1501821&section=FRONT%20SUSPENSION&group=FRONT%20SUSPENSION&subgroup=SUSPENSION%20COMPONENTS&component=Knuckle

although I do torque my lug nuts between sessions, I agree that my nuts *ahem* need to be upgraded. I'm considering http://store.pfadtracing.com/c6-racing-wheel-lugnuts/ since I need open ended ones to run with the longer ARP studs I'm using. I have a feeling the warp in the colemans and girdiscs are more from not having the lug nuts seated perfectly + beating the ever loving heck out of them on the track + some factor of imperfect pad selection and bedding

final question about your ducts - I've hesitated to put on aluminum backing plates to hold the ducts up to the back of the rotors b/c I don't want to put aluminum between the knuckle and the hub that's softer and thicker than the thin steel piece that's there right now. am I worried about nothing? seems like putting aluminum there is asking for trouble.

FuzzyLogic
08-09-13, 11:13 PM
Can someone explain why the Corvette knuckle is meaningfully better than ours?

yooper
08-10-13, 12:03 AM
Can someone explain why the Corvette knuckle is meaningfully better than ours?
Not applicable. The corvette uprights,spindles, or knuckles will not work on the V. My previous post and pictures regarding these was to point out the benefit of torsional rigidity and I did state the V1 brakes are superior to the C6 ZO6 brakes.

----------


good feedback, thanks. and perhaps by saying "mod hell" I mean that I'm constantly fiddling with the brakes, trying to get them more and more "perfect" rather than putting on new heads or a maggie

yooper, I am running r6s and try to push hard on the track (1:17s on NMJP Lightning) - what rotors would you call true race, as opposed to Coleman and/or Racing Brake? Your picture's "J" slots look like those at MAPerformance (http://www.maperformance.com/maperformance-cadillac-cts-v-rotors-full-set-map-rotors-cts-v.html) - I've thought about calling about those...

Eventually, I'll likely upgrade to the v2 6 pistons. I see there's an AP Racing kit ?truly available? (http://www.maperformance.com/ap-racing-front-big-brake-kit-cadillac-cts-v-04-07-ap7200-ap7200.html) and 8 piston kits like http://thmotorsports.com/ksport/ksport_procomp_big_brake_kit/bkca010841ss/i-1704114.aspx, although I've never heard anyone running these and don't know that they'd increase pad area like the v2 calipers.

Upgrading the knuckles might have to happen too - these look like the right ones - http://www.newgmparts.com/parts/2012/CHEVROLET/CORVETTE/ZR1/?siteid=213815&vehicleid=1501821žion=FRONT%20SUSPENSION&group=FRONT%20SUSPENSION&subgroup=SUSPENSION%20COMPONENTS&component=Knuckle

although I do torque my lug nuts between sessions, I agree that my nuts *ahem* need to be upgraded. I'm considering http://store.pfadtracing.com/c6-racing-wheel-lugnuts/ since I need open ended ones to run with the longer ARP studs I'm using. I have a feeling the warp in the colemans and girdiscs are more from not having the lug nuts seated perfectly + beating the ever loving heck out of them on the track + some factor of imperfect pad selection and bedding

final question about your ducts - I've hesitated to put on aluminum backing plates to hold the ducts up to the back of the rotors b/c I don't want to put aluminum between the knuckle and the hub that's softer and thicker than the thin steel piece that's there right now. am I worried about nothing? seems like putting aluminum there is asking for trouble.

CCW reccomends 80 lb ft torque on their aluminum race wheels.
http://www.essexparts.com/shop/complete-brake-systems/competition-brake-systems.html
I use acorn style basic Dorman lug nut from local parts store. Do not check or torque your lug nuts when hot! Do you use a good click style calibrated torque wrench.
On the cooling ducts, I used mid grade .063 aluminum and made spacers from same material for the caliper mounts to keep the rotors centered.
I like the GM Racing wheel stud p/n 22551491
pm me as to what pads you are using

jfreezn
08-10-13, 02:48 AM
I suspect your studs are one silly fraction of a milimeter longer than your thread depth in the blind lug nuts. When you reach your torque of 100 pounds the stud is bottoming in the hole, not quite clamping the rotor, just giving the appearance of doing so.

jclayc
08-10-13, 02:02 PM
good thought jfreezn, but I'm using open-ended lugs.

this AM, I upgraded both front hubs to SKFs. I need to take it in for alignment (steering wheel now points slightly left) so I can't make a true judgment but the shake when getting on the brakes from 60+ is as bad as ever. I'll check all my torque values, get it re-aligned, rig up my cooling ducts/hoses again and re-bed the pads/rotors and see where that gets me. If/when that doesn't solve the brake shake, I'll be really frustrated - I really don't want to throw yet another set of rotors and pads at this thing but that's where I'll be

I'm running Raybestos st43 pads

I know there are differing opinions about allowing ABS to stay on when on the track but I'm thinking about disconnecting a hub sensor to turn ABS off and seeing where that gets me as well.

BSR-1
08-11-13, 09:43 PM
I suspect your studs are one silly fraction of a milimeter longer than your thread depth in the blind lug nuts. When you reach your torque of 100 pounds the stud is bottoming in the hole, not quite clamping the rotor, just giving the appearance of doing so.

+1, Exactly what I was thinking!

----------

Guess I posted too soon, I didn't see that you'd switched to open ended lugs.
I just pull the relay/fuse to disable ABS.

11s42k
08-11-13, 10:38 PM
Just a casual observer here. Another constant is your wheel studs. Is the shoulder length on those the same as stock? If shorter, they may be missing engagement on the rotor. The threaded portion of the stud cannot be relied upon to locate anything - it'll chew through the hat like a saw. Good luck!
Erik

kzx03p
08-12-13, 08:30 AM
I can tell you with certainty that the small torx screw has only one purpose: As an assembly aid for the factory to keep the rotor in place during caliper installation and runnout measurement. That's it.

jclayc
08-12-13, 04:21 PM
11s42k - I'm not sure what the ARP shoulder height is compared to stock, but the ARP stud threads go all the way down to the hub where the knurled shoulder starts. I think that's just how it should be.

I took everything apart again, cleaned up the rotors (scotchbrite & brake cleaner), noted that the new GM set screws were bent a little, noted that one of my Raybestos pads looked like crap (some chipping), so I put in my Hawk+ 70s, re-bedded the brakes and things are still juddery when braking from 60+.

I did find a really good article by searching for "brake judder" - http://www.powerbrake.co.za/downloads/tech_01_judder.pdf. Given this article's info, plus a number of factors (constantly-fried caliper rubber + cracking around the center of the braking surface all the way around on powerslot rotors with 1 track day) and comments in this thread, I think the problem is that I only track the car and do so very aggressively, overheating the brakes and rotors every time. That's why I didn't have judder the first half of my last track day - new rotors and I hadn't fried them until later in the day. Although I've been using Raybestos st43 pads, they and the rotors I've been using just aren't up to the task in combination, I think.

Yesterday, I set up more aggressive 3" cooling ducts running from scoops in place of my fogs/drls and will see if I can find a good combination of pure race pads, rotors and calipers or else I think I'm going to be buying new rotors every track day. If/when I come up with the cash, it's likely I'll either see if yooper's source (http://www.essexparts.com/shop/compl...e-systems.html) can put something together for me or see if MAP has the AP Racing setup I can run with something like the Cobalt Friction XR1s

thanks for your continued feedback on this thread, which is probably of interest to like 6 people...

Junior1
08-12-13, 04:43 PM
I've got the same Raybestos pads and the same Coleman 2pc rotors and mine does the same warp shake.
It happened right after the first time out.
I've had a pro-driver shake it down and never complain about it. Its at the shop now getting prepped for Lightning on Wednesday and they didn't see concern for rotors or pads.
Maybe its just the nature of the beast with this setup...

Let me know if you decide to go with an AP setup etc, I'd look into it with you and the other 5 people :)

GizmoQ
08-12-13, 11:20 PM
thanks for your continued feedback on this thread, which is probably of interest to like 6 people...

Make that 7 :thumbsup:

OneFast V
08-13-13, 11:11 AM
also interested in good brake ducting.

jclayc
08-13-13, 01:07 PM
I have a few cruddy pics but can take more. As I say, I took out the fog/drls and put in these: http://www.summitracing.com/parts/aaf-all42140?seid=srese1&gclid=CL2ol6Dz-rgCFdBcMgodHjsAbQ plus bought some spindle ducts for a mustang and cut them way down (mounted to one of the hub bolts). That was before I saw the 'vette ones made by LGmotorsports, which I may still try (http://www.lgmotorsports.com/product_info.php?products_id=1752).

A few of the "secrets" are that you have to take out the fender liners and run the ducts under the headlights for the forward part to fit... even then, though, I had to kind of squish the 3" ducting flat where it goes along the body and near the shocks to prevent rubbing... and it's still veeeery tight - will probably rub when I run 275/35s

http://i.imgur.com/YRyhiZO.jpg

http://i.imgur.com/nzZW9GP.jpg

jclayc
09-30-13, 11:47 AM
Closing the loop on this post - I upgraded to v2 brakes and 2 pc rotors from RacingBrake. (I like that the RB rotors support the use of the little rotor screw :)) I changed to Hawk DTC-70s at the same time. I also replaced my front ball joints, tie rod ends, all front bushings and changed my power steering fluid (figuring some juddering could just be failure of the tie rods and steering to dampen natural movement) then had everything aligned. I can't trace the solution back to any one of these items because they were all changed at the same time but, after two full days at Pocano North and a few days on the road, I can say the problem seems to be solved and that's even with what I think are uneven brake pad deposits I can see on the rotors.