drilled?

Slotted?

solid?

any advice? I'm about to order rotors and i was wondering what some people had used and how they performed?

 

Im sure some people are going to dispute this but the more the better.

Some of the differences aren't that noticeable if you are just driving to work, but slamming on the brakes and slowing down from the highway is very noticeable with drilled and slotted. They are a great DD upgrade.

Drilled or slotted cost pretty much the same as both, so get both, they do two different things.

 

I recommend Brembo OE blanks. I have used them on all my cars (when available) for the last 10 years or so and could not be happier.

The other features serve specific purposes. I think the primary purpose of the slotted rotors is that it constantly resurfaces your pads. Unfortunately, it really accelerates pad wear. If you're dead set on getting a rotor with a special feature, I'd definitely go with slotted.

The primary purpose of the drilled rotors is to dissipate heat. Often times people say it's to vent "gas" - I think that was true when pads used organic compounds. If your pads still create ventable gas when braking, you need to buy better pads. On the downside, the drilled rotors have less mass, and therefore do not tolerate changes in temperature as well as solid rotors and are prone to crack. I've seen it recently myself on late model Mercedes and Porsche rotors. Google Images has plenty of pics on this. Drilled rotors also have less braking surface area than regular flat rotors.

Get the Brembo OE blanks!

 

Willwood 4 pot, with aluminum hot rotors. Rotors are 1.25 inches thick and 12.25 round. Thats about 1 inch bigger than the Jag rotors and .25" thicker. This makes a world of difference in brake performance yet they weigh slightly less the EO Jag rotor. The calipers are about 15 lbs lighter each. I use this setup on my hi-power 1976 XJC. I also have vented rear rotors, outboard from a 1994 XJS. My car stops awesome and brake feel is great too. Rotors and calipers are off the shelf. Hats and caliper mounts are custom. This was way cheaper than DB7 sport calipers and rotors if you can find them. If you're interested I could help you make up a set for your car in this size or bigger. Once you go bigger than 12.25 inches on the rotor the price basically doubles. Wilwood does have the rotors I used in drilled and slotted and just slotted. Next time I change them I'm going to try the slotted.

 

I just put on a new set of rotors and pads for the front of my car a couple of weeks ago.

I went with solid Centric rotors and EBC Greenstuff pads. I'm very happy with this set-up so far. Install was very easy and braking distance and brake feel is much better than stock.

I decided against going with slotted because they tend to be a bit noisy.

Allan

 

I'm going to need to get the specs for the back, as I am going to switch to outboard brakes with vented rotors as well as custom brackets and 14in z06 rotor for the front, because I can get a good deal on thoes.

 

I am not a brake expert, but have modified road car brakes for track days.
I have an Aussie Ford Falcon 4 litre straight 6, 240bhp, weighs about 1800 kg (same as XJS, less power)

I went for slotted front rotors and 'track day' type pads, plus the high boiling point fluid. I built my own ducts to the front. I could not get brake fade on the tight and twisty Taupo track here in NZ (where they held A1 GP a few years ago) after 10 or more laps - 'normal' road car brakes are usually fading after 3 or 4 laps of Taupo.
These same brakes saved my bacon one day in the rain on the motorway - prevented me rear-ending the car in front.
I have replaced them with the same combination again, so been this way 7 years now. No squeal, just great stopping power

My understanding of slots is they vent any thin layer of gas between pad and disc, which can come from vapourised glue when braking hard. They 'scrpae clean' any residue on pads.
Drilled holes lead to major heat variations in the hot disc/rotor, and crazing/cracks. However you do see them on cars such as Astons, Porsches etc - I am not sure why - looks? Probably overkill for fast road car driving.

my 2 cents..

 

I have the stock vented discs with EBC red stuff. Very little brake dust and excellent stopping distance. I am going to replace my rotors with Brembo or EBC stock vented style, again with red stuff pads. Our 1999XJ8L will also get new front rotors and red stuff pads.

 

The cracking issue with drilled and slotted isn't something the average drive will encounter probably, it is mostly from very high heat coming on quick and being cooled off quickly, this is why drilled aren't used much in racing. In ever day driving this isn't going to happen. Because gases don't build up and the rotor doesn't overheat you end up with more grip.
Pads do wear out more quickly, but when you are talking about a 60 dollar item that usually takes 30k to replace..well I'm not really going to complain for the advantages.

 

iscamerica -> Which wilwood calipers did you end up using for the front? do you have any drawings for the adapters?

Thanks!

 

I need thoes too!

 

Wilwood caliper 120-11136 which is a forged super lite internal that supports a 1.25 inch rotor with a 1.75 inch piston area. The Jag pistons are 1.69. That's very close and when you factor in the additional leverage, feel and initial bite are identical to stock despite the slightly larger piston area. When I stand on the brakes they really bite hard. This works out well because modern tires have more grip. There are other calipers in that line that can use a 1.1 inch rotor or .81 inch rotor which are closer to the OEM jag size so one could choose the thinner rotor and have a large reduction in weight.

My first install used a bracket which was not ideal. The bracket flexed enough to diminish brake feel greatly. Over all stopping power was much better but I wanted the stock feel too. In order to get rid of the flex I cut off the stock caliper ears from the spindles and welded on new ones in the right location. That fixed the feel issue.

 

Great info about Wilwood upgrade - thanks for sharing!

 

have you looked into 6 piston calipers? I was thinkin about doing that

 

Another alternative I have been looking at are AP racing brakes, they do a kit for the XJS.
Here is a link for the kit http://www.apracing.com/product_deta...5200-1026.aspx

 

The only issue I have with the ap racing brakes is the price...~$2000 last time I checked. I know these kits were the brake upgrades TWR sold, so they should be well engineered.

 

I've thought about keeping the stock calipers and making a spacer to go in between the halves of the caliper - somewhere around 1/4", so it would accommodate a wider rotor. Then, I would run a rotor that was 1/4" wider on an aluminum hat. The result would be rotors with more mass to more effectively take the heat and reduce fade.

What I like best about this idea is that it would not further bias the front brakes. When I slam on the brakes, the front wheels already lock up. There's no point in locking them up sooner with taller front rotors - I want the rear brakes to help slow the car down, too! The sooner the front brakes lock up, the less the rear brakes are contributing to stopping the car, which leads to longer stopping distances in an emergency stop situation.

Running a thicker front brake rotor with more mass will help fight brake fade. I'll also be able to run a fancy rotor - maybe one with directional vanes for better cooling. I'll also be able to reuse the stock calipers. Although they're heavy, they seem to be extremely stiff and of good design. The only thing I'm not sure about is whether there's an extra 1/4" between the caliper and the inside face of the wheel to accommodate the spacer.

 

You guys must be seriously fast drivers !


Cheers
DD

 

Details, please??

 

My favorites are EBS Slotted rotors and RED STUFF pads. I got em on every car I own (especially the 95 XJS 4.0 conv...) NO noise and NO dust. Quicker stopping too. Good pedal feel. Can't beat em. IMHO

BTW: I used to use drilled & slotted, but had a cracking episode so I never went that route again. Slotted is fine for our application anyway. Unless you're running it on a track!