x2 on the no reason to be rude.

 

well then sure your trying to stop to fast to short a decent rotor, not advanced auto... and decent pads.. not low noise bs at advanced auto.. you shouldnt have those problems.. its the pads that is the reason your feeling that.. hate to tell ya but u need to upgrade those... drilled and slotted rotors are used for repeated high temp HARD breaking in close repetition.. not slowing from 80-0.. they are designed to allow the rotor to cool faster in between so not to heatsoak and render them useless. go take your jeep out and try stopping from 80-0 5 -7 times in a row then you will feel heat soaked.. when you CANT stop.. thats what they are designed for.. not petty daily driving repetition...lol your problem can be solved with pads as i said..

anyone wants good pads
here they are
http://www.quadratec.com/products/56214_0200.htm
http://www.quadratec.com/products/56214_100.htm

i run these pads on my evo for SCCA events and they are outstanding.. you cant go wrong with most hawk pads
http://www.extremepsi.com/store/cust...cat=455&page=1

 

http://theorientacademy.top-forum.ne...iscs-t1208.htm

 

my first post I'm sure I'll catch some heat for it.....

I put Power Stop drilled rotors on our XJ about ten years ago when I went to 31.5's. They have not cracked.

Our XJ also has 11" rear drums that came on the chrysler 8 3/4 I put under it.

Slotted rotors are designed to clean and drilled rotors to cool.

"When you apply the brakes you convert the kinetic {moving} energy of the car to heat. A moving vehicle has a lot of energy so it is not uncommon to see temperatures over 1000 degrees F. On the street, about 25% of the heat is removed by conduction, 25% by convection and 50% by radiation. At high speeds, the ratios shift to about 15% conduction, 40% convection, and 45% radiation. Therefore, during high speed stops, convection heat transfer [i.e. how air flows over the rotor] plays a very important role. This is where drilled rotors significantly improve convection heat transfer to lower the brake temperature up to 200 degrees. During panic stops on the highway, this can help stop your car 6 to 20 feet shorter." http://www.powerstop.com/content.wws...edslotted.html

Something no one has really mentioned here is the addition of large tires to a brake system that was not designed for it equates to decreased braking efficiency, so anything that helps is a positive move.

I liked them enough that I put them on my two Dodge turbo diesels along with exhaust brakes. The trucks tow 18K trailers and we have noticed an immediate difference we never noticed with pad only upgrades. They haven't cracked either....

Now about that WJ conversion? Tell me more!

 

Just to add $0.02..

all of my vehicles run OEM spec Rotors, with Hawk HPS pads. I love this combo, my braking distance improved dramaticly on the 5.9

Cant say much for my XJ right now.. found out i have a leaky brake line connection. so that "taints" any review. when its back on the road in 3 months we will see.

 

Finally, some sense in this thread.

 

efficiency is such a mis-used word

if you are talking heat-loss efficiency, then yes slotted/cross drilled rotors will do the job

but as far as stopping shorter, no
if you really look at it, the only way to stop shorter, is to increase clamping force of the rotor, increase friction between the pad and rotor, increase the surface area of the rotor and pad, improve the way the suspension react to a hard stop, increase the traction of the tire or increase its contact patch

fancy rotors will do none of that

slotted and cross drilled rotors will ONLY help reduce brake fade when the brakes are being heavily used, and remove gases produced by the heating of the frictional material

 

I will chim in on all this non sense.

Yes slotted and drilled will help braking distance. If you have the extra coin then by all means, go for it.

Quick link for the "brake experts" http://www.autoaccessorystore.com/re...kes/rotors.asp

Quick quote: "Slotted rotors improve the braking distance by 40% then a regular OEM (Original Equipment Manufactures) rotor."

Also you can see the Brembo brake FAQ.

Quick quote: "Drilling or slotting discs aids the disc in several ways:
The edges of the slots or holes continuously clean and refresh the pad surface as well as providing increased brake "bite". Additionally, they prevent gasses from collecting between the pad and disc interface.
The disc is lightened, thereby decreasing its rotational inertia.
Improved ventilation increases the disc's ability to shed heat, resulting in cooler operating temperature."

 

LIke an 80 to zero stop with tall tires after you've come off the "hill" from Donner Pass in the Sierras?

Your point is well taken if we only stopped once however heat soak occurs over multiple braking events and the faster the rotor can cool between them the more "efficient" the system and the more reliable the subsequent braking events.

 

You contradict yourself. Thats exactly what a "fancy" rotor does.

 

Guys, guys... here is a link to a forum where they discuss EXACTLY that topic. Not some merchant, but actual users. Of course, the merchant will try to sell you his x-drilled or slotted rotors and tell you how much better they are than stock. The general consensus is, Porsche's x-drilled rotors crack just like any other, they do not significantly decrease stopping distance, they help fading a little, but boy, they look good. Here, have fun with this discussion.
http://www.nissanclub.com/forums/arc...cussion-4.html

There's also a discussion about that on corner-carvers.com, where a lot of professional racers hang out. They despise those things...

 

For the record I never run cheap brakes... brakes and tires, never ever mess with quality in those departments. My XJ currently runs with Wagnor rotors and Raybestos Brute Stop pads (extra dust and noise). Did that combo on all my vehicles and was rather happy until I tried quality made slotted/drilled rotors and same pads.

I guess this whole thread boils down to 2 types of deals;
1. folks who have made the change and know there is a difference
2. folks who have not made the change and are adamant there is no difference.


With posted speed limits of 75mph, it’s pretty easy to get caught up with traffic running 80mph… and whomever said I was braking too hard… ummm… ok, next time I’ll simply slam into stopped traffic to keep from overheating/fading the brakes.

 

one other thing... if they suck so bad, why do the WRC cars run 'em? You can't tell me the sporting reg's make them run slotted/"drilled" rotors.

 

i think there's a big misunderstanding. i don't think people are saying that drilled, slotted rotors are simply junk. the main point is that, you can't really see the benefit of those on XJ's. regular rotors will stop you quick enough until they overheat, but why would they overheat? you're not taking off at the light shooting for a 10 second 1/4 mile and you are not going into a curve @ 100 mph. if you are in a stop and go traffic, just don't stomp the "GO" pedal when you see the "GO" light and you won't have to stomp your brakes when you see a red light.