Drilled slotted rotors worth trouble?

Looking to stop my 35s better.. Are drilled and slotted rotors worth the money? What brand and pad would you use??

 

I have had drilled and slotted rotors on my daily driven tacoma for 8 or 9 years and around 120,000 miles. I couldnt notice the difference between the stock and slotted even with high quality pads like EBC. A better caliper might make a bigger difference.

 

That is such an opened ended question it's really hard to answer............you haven't told us much about your Jeep other than it has 35's and it doesn't stop well.

So:

• Power Boosted?
• What size rotors?
• 15" tire?
• Drums or Disc's in the rear?
• If vacuum boosted how many inches of vacuum at the booster?
• Two piston caliper or single?
• vented or solid rotor?
• Have you checked your pedal ratio? Should be about 5:1 for power and 7:1 for manual
• What size is the piston in the Master Cylinder?

This is just a few of the many questions to analyse your braking issues.
Drilled holes in rotors used to be something that folks looked to in order to improve braking..............mostly to reduce heat and allow water to dissipate more quickly but the biggest reason was to allow gas trapped between the friction materials and rotor's that was created by the braking and friction process.........the gas created a barrier that reduced the friction process that also reduced the ability for the vehicle to stop..........as better friction materials came along the holes went away in rotors..........most High Performance rotors now have a semi circled grove cut in the rotor and most are now vented................
Big tires equals a bunch more rolling weight , so if you have a brake system on there originally designed for a passenger car...........it will never do a very good job! But go through the checklist and perhaps there is a few things that might help.

 

I still have the original brakes on my 73 CJ5 but I added a power booster and it stops on a dime. Vast change for the better. Light pressure on the peddle will stop it quickly and easily. Best mod I've done on my jeep. I haven't done it but I expect drilling will keep the rotors cooler for sure. Couldn't hurt.

 

Uhh, '73 didn't have disc brakes stock.

 

Definitely this.
More information on your Jeep would be helpful.
Tarry99 nailed it though without knowing what the op has.

 

Pretty simple.. I have a CJ2a with a narrow track d30 single piston disks up front and a mid 50s Tapered 2 pc D44 in the rear with drums.. Herm the Overdrive Guys Master Cylinder upgrade...manual brakes.

 

Make sure the master cylinder has the right bore size for the brakes you have. Also if the brakes were changed or modified after the mc upgrade that changes the needs of the system. Also, are you using organic pads on the disc brakes? Semi-metallics are meant for power booster applications. What size drum brakes on the rear? This can make a big difference also.

 

What Nick said above....................and

Pedal Ratio is one of the most overlooked parts of a brake system. One of the main reasons and causes of a hard brake pedal is simply due to incorrect pedal ratio. When a brake pedal gets modified to “fit” in a vehicle or a booster/master cylinder gets installed where it “fits” in the car, the pedal ratio is rarely taken into consideration. Proper pedal ratio is a must when installing and operating a brake system. Below is a diagram to show how to properly figure pedal ratio:

Pedal Ratio = X divided by Y



In a manual brake system, the pedal ratio will be between 5:1 and 7:1 and a power system will be between 4:1 and 5:1. In the above illustration of the hanging pedal on the left, let’s assume the overall length of “X” is 12” and the “Y” measures 3”. That puts the pedal ratio at 4:1 which is perfect for a power system. To make this function as a manual system, the “Y” measurement would need to change to 2” giving a 6:1 ratio.
If the correct pedal ratio is not achieved, the pedal will be extremely sensitive due to too much pressure being applied too quickly.
As you can see, if you don’t take pedal ratio into account, you are not getting the most from your brakes.

Master Cylinder Piston size / volume is also a large factor in calculating the needs of a brake system......small bore equals more pressure but less volume.........while a larger bore equals more volume but less pressure.........Your front Single piston calipers and if they came with the D-30 as factory item they are normally a rather large 3" bore piston...........Disc brakes require more fluid volume to move the large piston as opposed to a drum brake wheel cylinder. A proper proportioning valve is necessary along with the proper residual valves in line. Due to the increase in the fluid volume needed most Master Cylinders of that era have a split reservoir , with the larger 1/2 going to the Disc side..........Some masters along with some proportioning valves may already have the proper 2 & 10 lb valves in line...............Not sure what version you got from Herm , but you may want to check that out.
Confusing Yes ..............but easy to solve if you pay attention to all the basics.

 

I have slotted rotors on my 2001 Cherokee running 31's, I couldn't tell any difference. Waste of money and switching back to stock rotors next brake job.

 

Like Tarry99 said above, drilled rotors are meant to allow gases that build up between the pad and rotor to escape to minimize fade. The slots are for gases to escape but also to microscopically scrape off the glazed surface of the friction pad to maintain braking performance. Drilled and slotted rotors are primarily to maintain
Braking performance under adverse conditions, not really to improve it. Some can, if used with certain pads, the rotor is made from certain types of materials, and they are matched to the vehicle's braking system. Most don't though.
I plan on putting them on my '04 Silverado but that's because I tow with it and it likes to warp rotors. In this case it should help. It would be a waste of money to put them on my CJ's.

 

Lots of useful information guys.. I'll have to do some measuring to see what my ratio is on the pedal to start..

 

Everyone tries to make this way more difficult then it has to be.
This is one reason why I have preached for people to use the entire system out of a certain donor.
A 84-92 Jeep Cherokee is an excellent donor to use the pedal assembly, brake light switch, booster, master cylinder, and proportion valve. ALL engineered by people who know what they are doing. TOTAL bolt-in assembly in a CJ5 with nothing but a backing plate bolted to the fire wall to stiffen it up where the stock heater holes live.
The most common setup on an old Jeep for optimum performance and economical work is a disk brake Dana 30 up front and 11" drums rear.
This is almost exactly what the Cherokee has.
No guessing, no internet trolls telling you what you can and can't do.
Not to mention that a replacement master cylinder is only $25 and in stock at almost every auto parts store on the planet.
It really doesn't have to be so difficult to figure this out as it really has been done before.
On a side note, a properly functioning system with 11" drum brakes on all 4 corners should stand a 3000 pound Jeep on it's nose with moderate pedal pressure. Add a set or all 4 discs if you run in wet conditions and you can stop these things with minimal effort.

 

my '00 Tundra stopped horribly from the factory , it's a super reliable truck but seriously underpowered and under braked .I have to flat tow because the truck could never handle the jeep AND a trailer (dangerous stuff)
I have Power Slot rotors on it but the biggest difference was using Hawk LTS pads ......