Testing a Theory

[Fast Too]

Ok, some of you may remember I recently changed my rotors to Stoptech slotted aero-rotors. I have about 150 miles on them now since the install. I have been monitoring the rotor temps by feel since and notice that the rears are very much warmer than the fronts. Previously I had felt the stock rear rotors once after partially leaving the e-brake engaged for a short distance. I was relieved at that time to find them cool to the touch following my dumb a$$ mistake. This was before I modified my car with a Paxton / headers / high flow cats / and CORSA Track exhaust. Following the Paxton and exhaust mods I had never felt them again until now when I changed my rotors. Here is my theory for the temp increase: with the crossover gone the heat is obviously going somewhere, I assume straight out the pipes. Since I replaced my wheels with I-Forge Astras which have a four inch lip and some big 5 spokes, I think what is occurring is that my wheels are actually creating a vortex of some type and drawing the exhaust heat right through the wheels which is the cause for my rear rotors running very much warmer than the front. I have felt the pads; both main and e brake and those are cool to the touch as are the calipers. Has anyone else experienced this since changing out their exhaust? or if someone thinks of it next time you drive your car (cars with the crossover removed) can you compare rear and front rotor temps? I don't think there is a problem with the rotors or their install, rather just something I never noticed after modifying the exhaust on my car.

 

[Fast Too]

Come on, no theorists in the crowd. Oh I know, everyone is out feeling their rotors for me right now on New Years Eve

Happy New Year everyone. Are we all not blessed being Viper owners

 

[mike & juli]

Come on, no theorists in the crowd. Oh I know, everyone is out feeling their rotors for me right now on New Years Eve
Happy New Year everyone. Are we all not blessed being Viper owners

AGREED! Sorry, we are not out testing the rotor theory (tho it's a logical one)...as we are out snowblowing...Happy New Year to you also! ~juli

 

[Jsparks]

AGREED! Sorry, we are not out testing the rotor theory (tho it's a logical one)...as we are out snowblowing...Happy New Year to you also! ~juli

I gave up on snowblowing last year. My wife and I both have 4 wheel drive so we figured **** it

 

[InjectTheVenom]

I gave up on snowblowing last year. My wife and I both have 4 wheel drive so we figured **** it

Great, now I have images in my head of you and your wife with 4 legs and a traction control computer for a brain Thanks a lot

 

[jimmy6383]

my rotors are cold.....like everything else in michigan right now

 

[Warfang]

AGREED! Sorry, we are not out testing the rotor theory (tho it's a logical one)...as we are out snowblowing...Happy New Year to you also! ~juli

sn---ow---blowing.... what's that? I'll check back for your answer when I get back from driving my Viper around California Streets.

 

[Fast Too]

Proved my theory to myself today. The harder I push the car (with no braking involved) the hotter my rear rotors become. A less agressive throttle and they get cooler. Not that any of this makes a hill beans, but I thought it interesting and I also know now why the rear rotors are hotter than the fronts. I love it when I solve my own problems

 

[Nader]

Proved my theory to myself today. The harder I push the car (with no braking involved) the hotter my rear rotors become. A less agressive throttle and they get cooler. Not that any of this makes a hill beans, but I thought it interesting and I also know now why the rear rotors are hotter than the fronts. I love it when I solve my own problems

The heat from the rear end maybe traveling through the half shafts to each rear corner. I find it hard to believe that the exhaust could be causing the heat. My $0.02

 

[plumcrazy]

The harder I push the car (with no braking involved) the hotter my rear rotors become. A less agressive throttle and they get cooler.

cause the rear end is working harder causing more heat and transfering it to the rotors id assume ?

 

[Jsparks]

cause the rear end is working harder causing more heat and transfering it to the rotors id assume ?

agreed....the rear diff can pump out a lot of heat

 

[Fast Too]

The heat from the rear end maybe traveling through the half shafts to each rear corner. I find it hard to believe that the exhaust could be causing the heat. My $0.02

Nader,

Your posts always make sense and I respect them, and your thoughts makes sense here too and I'd buy that, but my stock rotors were always cold to the touch before the exhaust mods. Even following spirited driving when I was bone stock. Whatever the cause I'm not worried abut the rotors, it is either as you said heat from the half shafts or my flame thrower exhaust.

 

[Nader]

Nader,

Your posts always make sense and I respect them, and your thoughts makes sense here too and I'd buy that, but my stock rotors were always cold to the touch before the exhaust mods. Even following spirited driving when I was bone stock. Whatever the cause I'm not worried abut the rotors, it is either as you said heat from the half shafts or my flame thrower exhaust.

Interesting that it wasnt that way before the exhuast mods. Could it be that the new rotors are two piece and rotor hat can not hold heat like the stock one piece so the rotor itself is retaining it?

 

[Fast Too]

Interesting that it wasnt that way before the exhuast mods. Could it be that the new rotors are two piece and rotor hat can not hold heat like the stock one piece so the rotor itself is retaining it?

hmmmmmm could be Nader, good point. See that's why I respect your opinion. Gotta ponder that one. Your theory on the half shafts makes more sense to me, I was throwing darts as to the why for the noticeable heat difference between front and rear. Regardless I have to believe it is a normal condition now. They are not so hot that you cannot leave your hand against them, but there is a big diff between front and rear rotor temp now after this mod. I'll monitor them for a while, and for now I am not going to worry about it. I like em these brakes by the way. Pedal response is now with the SS lines, and much less dust with the EBC Red stuff pads. Life is good, and the car is running great. Cannot beat that....

 

[black mamba1]

There is nothing like data to eliminate guessing...I will say this. Car manufacturers design cars as one system, and the wheel design is incorporated into that system for both handling, sprung and unsprung weight, and the cooling effect the wheels bring to the braking system, and as well as the amount of drag the wheels make due to the vortex they produce. You have changed your wheels, which could have increased or decreased the amount of vortex created by the wheels which could decrease the cooling effect on your brakes. OR, the new rotors may simply hold heat longer (lower heat transfer coefficient), which may not necessarily mean they are running hotter, it simply could mean they stay hot longer. Or, it could be the heat transferred from the rear end. It would be interesting to see how much hotter your exhaust gases are, if you have Belanger headers (like mine) you exhaust gases will be significantly hotter than stock, several hundred degrees hotter, which could also explain the problem. This is an interesting issue as it goes to both brake life and overall braking performance. I would be surprised if no one in the forum has not already collected data on this.

 

[Fast Too]

There is nothing like data to eliminate guessing...I will say this. Car manufacturers design cars as one system, and the wheel design is incorporated into that system for both handling, sprung and unsprung weight, and the cooling effect the wheels bring to the braking system, and as well as the amount of drag the wheels make due to the vortex they produce. You have changed your wheels, which could have increased or decreased the amount of vortex created by the wheels which could decrease the cooling effect on your brakes. OR, the new rotors may simply hold heat longer (lower heat transfer coefficient), which may not necessarily mean they are running hotter, it simply could mean they stay hot longer. Or, it could be the heat transferred from the rear end. It would be interesting to see how much hotter your exhaust gases are, if you have Belanger headers (like mine) you exhaust gases will be significantly hotter than stock, several hundred degrees hotter, which could also explain the problem. This is an interesting issue as it goes to both brake life and overall braking performance. I would be surprised if no one in the forum has not already collected data on this.

Blackmamba - Good points in your comments. I'd be interested to see if this data has been collected before too.

 

[Kenneth Krieger]

Interestingly enough, today I took my 05 Comm. Edition for a spin (67 degrees today!), and just for grins I used my lazar temp gauge to check the readings on the rotors front and back. They were within 15 degrees of each other with the fronts having the highest temps on both sides. Just thought you'd like to know!

 

[Viper X]

If your new rotors are stop tech aero's with the aluminum hats, that's likely the difference.

The rear rotors don't get cool air ducted to them like the fronts do. The rears get warm and stay warm longer due to their aluminum content.

Dan