Looking for high performance brake pads for a XJR or XKR?
Discussion
What problems are you having with the current brakes? What are you trying to achieve? If you are driving it on the road and having brake fade, I would suggest you get your standard pads/discs looked at and maybe even swap them out unless you know they are the correct type. Standard brakes should be fine for any kind of road use (well, unless you are driving down the alps or something)
If you want to improve feel you might want to change your brake fluid and check your flexi-hoses as a first step, I assume it doesn't use any fluid?
As for performance friction pads; I have them and standard discs on my track car (bog standard BMW 328i) and they are superb. Solid pedal, very consistent and no fade whatsoever however they do not work too well from cold, and generally give worse bite and feel the the standard pads at light loads (i.e. on the road)
As suggested above if I was looking into upgrading the brakes on my XJR I would look into getting the brembo brake package.
Probably worth talking to Paul, he races XJS's and will probably be able to help:
http://www.hyper-transformations.com/
If you want to improve feel you might want to change your brake fluid and check your flexi-hoses as a first step, I assume it doesn't use any fluid?
As for performance friction pads; I have them and standard discs on my track car (bog standard BMW 328i) and they are superb. Solid pedal, very consistent and no fade whatsoever however they do not work too well from cold, and generally give worse bite and feel the the standard pads at light loads (i.e. on the road)
As suggested above if I was looking into upgrading the brakes on my XJR I would look into getting the brembo brake package.
Probably worth talking to Paul, he races XJS's and will probably be able to help:
http://www.hyper-transformations.com/
Changing pads alone is more likley to give you a change in braking characteristics as well compromising pad and disc life rather than give an increase in overall performance. It's the ability of the braking system to convert the kenetic energy of a moving car into heat and then effectively dissipate that heat into the atmosphere as quickly as possible that counts.
JS Baby has done several laps of the 'ring this year on two seperate visits. The first was done on standard pads and the second was on Greenstuff ones. Making allowances for the fact he was getting more familiar with the 'ring and bringing his times down a bit on the second visit he didn't really find much overall difference between the two. Initial braking on the Greenstuff pads was better but he experienced more rapid onset of brake fade on these ones and warped both rear discs through overheating as well so I'm not sure uprating pads on their own was really a good idea. He did the 'ring trips on semi trackday tyres which give more grip then standard road ones in the dry and therefore allow you to brake much harder, placing even more stress on the braking components.
I found more or less the same when as a spotty yoof I fitted softer pads to a suicidally fast Escort. Initial improvement in braking on the first few hard applications - meaning in the real world you just locked up earlier - followed by rapid fade and cooked discs. Eventually I went back to standard spec ones.
I'd suggest you try some and see what you think, but I'm not convinced just different spec. pads are really the answer for a big improvement in overall braking performance.
JS Baby has done several laps of the 'ring this year on two seperate visits. The first was done on standard pads and the second was on Greenstuff ones. Making allowances for the fact he was getting more familiar with the 'ring and bringing his times down a bit on the second visit he didn't really find much overall difference between the two. Initial braking on the Greenstuff pads was better but he experienced more rapid onset of brake fade on these ones and warped both rear discs through overheating as well so I'm not sure uprating pads on their own was really a good idea. He did the 'ring trips on semi trackday tyres which give more grip then standard road ones in the dry and therefore allow you to brake much harder, placing even more stress on the braking components.
I found more or less the same when as a spotty yoof I fitted softer pads to a suicidally fast Escort. Initial improvement in braking on the first few hard applications - meaning in the real world you just locked up earlier - followed by rapid fade and cooked discs. Eventually I went back to standard spec ones.
I'd suggest you try some and see what you think, but I'm not convinced just different spec. pads are really the answer for a big improvement in overall braking performance.
I have had bad experiences with greenstuff pads, they overheated and smeared themselves all over the disc.
As for not matching discs to pads...well it's a compromise. Harder pads will result in increased disc wear, but pads that are too soft will just break up or overheat. As I said I have got on well with standard discs and PF pads on my BMW (and am willing to put up with the compromises I mentioned, and increased disc wear, for good performance on track), I dare say it's not perfect but i'm happy with them, the standard BMW pads just weren't up too track work.
I'm quite surprised standard XJR brakes are up to track work, that's quite impressive.
Just to re-iterate, it's all a compromise. You need to choose the correct brake pads/discs for what you are doing; which is why I asked the OP what he's hoping to achieve. As steve's post points out better isn't always better.
Jaguar steve said:
I found more or less the same when as a spotty yoof I fitted softer pads to a suicidally fast Escort.
You wouldn't usually put softer pads on for track/fast road use, I'm not surprised they overheated, usually 'uprated' brake pads means 'harder'.As for not matching discs to pads...well it's a compromise. Harder pads will result in increased disc wear, but pads that are too soft will just break up or overheat. As I said I have got on well with standard discs and PF pads on my BMW (and am willing to put up with the compromises I mentioned, and increased disc wear, for good performance on track), I dare say it's not perfect but i'm happy with them, the standard BMW pads just weren't up too track work.
I'm quite surprised standard XJR brakes are up to track work, that's quite impressive.
Just to re-iterate, it's all a compromise. You need to choose the correct brake pads/discs for what you are doing; which is why I asked the OP what he's hoping to achieve. As steve's post points out better isn't always better.
Edited by varsas on Thursday 9th July 10:05
varsas said:
I'm quite surprised standard XJR brakes are up to track work, that's quite impressive.
I strongly disagree with that statement. After my first "spirited drive" in my XJR I thought there must be something wrong with my brakes! The brembo option is a necessary upgrade for hard driving in my opinion. Certainly in my X308. I wouldn't even consider anything but OEM pads/discs until I'd switched to them.
The cars are so heavy I think any additional performance offered by "performance pads and discs" would almost be unnoticeable. When you factor in the different characteristics of the pads it simply isn't worth doing on a standard set up in this layman's opinion.
It appears more knowledgeable people than me agree with this.
GT, I agree.
My comment was in response to this:
I actually now wonder if the OP was just an advert, still this has been an interesting discussion. I'd like to take my XJS on track but just don't think the brakes will cope (not that the suspension or auto box would be too happy either)
My comment was in response to this:
Jaguar steve said:
JS Baby has done several laps of the 'ring this year on two seperate visits. The first was done on standard pads
I have not driven my XJR on track so don't know if they are OK or not but, as I meant to convey, I would be surprised if they were. I probably should have made that clearer.I actually now wonder if the OP was just an advert, still this has been an interesting discussion. I'd like to take my XJS on track but just don't think the brakes will cope (not that the suspension or auto box would be too happy either)
Edited by varsas on Thursday 9th July 12:05
I played around with a few different compounds on the 'Scorch as it was used for fast road, not track use and found that although softer pads wore out very quickly it did give a better pedal feel and improved braking - but as you might expect also more succeptable to early fade. But this was on an ancient technology car with crude suspension and no ABS. It was also very high maintainence and got through tyres and brake components - not to mention engines and gearboxes - like there was no tomorrow.
It's important to make sure everything on the suspension and brakes is working as effecively as possible before you start modifying IMO. Soggy springs, shocks and bushes, worn discs and pads are less thermally efficient (they overheat quicker) and contaminated fluid with a much lower BP will also have a big influence on braking performance too.
Most cars will mangage one or two really good high speed stops regardless of what pads or disc combination is fitted, with ABS, braking performance is down to the amount of grip that's ultimately available from the tyres. Problems usually occur with repeated hard braking putting so much heat into the pads and discs they start to loose their efficency and this is where bigger brakes or different pad/disc compounds cope better than the standard ones.
Suspension geometry must remain spot on for maximum braking perfomance too. A car may read OK when stationary on a alignment rig but may not be able to maintain the correct geometry when braking hard from 130 MPH if the bushes are starting to fail.
I'd suggest the OP tries some different pad compounds and see how he gets on. Baby JS likes his Greenstuff ones for fast road use but was dissapointed with them on the track, but the proof of the pudding is to try some - just don't expect a transformation.
I guess the final test is that if you have the ability to either repeatedly lock up or trigger the ABS no matter how hard or often you brake then you don't need bigger brakes, you need more grip from the tyres first. If you can lock up or trigger the ABS at first, then with repeated hard braking you then loose the ability to do so, that's when brakes should come up for attention.
EFA
It's important to make sure everything on the suspension and brakes is working as effecively as possible before you start modifying IMO. Soggy springs, shocks and bushes, worn discs and pads are less thermally efficient (they overheat quicker) and contaminated fluid with a much lower BP will also have a big influence on braking performance too.
Most cars will mangage one or two really good high speed stops regardless of what pads or disc combination is fitted, with ABS, braking performance is down to the amount of grip that's ultimately available from the tyres. Problems usually occur with repeated hard braking putting so much heat into the pads and discs they start to loose their efficency and this is where bigger brakes or different pad/disc compounds cope better than the standard ones.
Suspension geometry must remain spot on for maximum braking perfomance too. A car may read OK when stationary on a alignment rig but may not be able to maintain the correct geometry when braking hard from 130 MPH if the bushes are starting to fail.
I'd suggest the OP tries some different pad compounds and see how he gets on. Baby JS likes his Greenstuff ones for fast road use but was dissapointed with them on the track, but the proof of the pudding is to try some - just don't expect a transformation.
I guess the final test is that if you have the ability to either repeatedly lock up or trigger the ABS no matter how hard or often you brake then you don't need bigger brakes, you need more grip from the tyres first. If you can lock up or trigger the ABS at first, then with repeated hard braking you then loose the ability to do so, that's when brakes should come up for attention.
EFA
Edited by Jaguar steve on Thursday 9th July 18:45
Jaguar steve said:
I guess the final test is that if you have the ability to either repeatedly lock up or trigger the ABS no matter how hard or often you brake then you don't need bigger brakes, you need more grip from the tyres first. If you can lock up or trigger the ABS at first, then with repeated hard braking you then loose the ability to do so, that's when brakes should come up for attention.
rarely got to ABS on last track day at Odiham (quite fast!), so guess i'm little way from the limit yet... grip is fine with R888 295s/335s on the front/back.Item relisted at lower price
nb. this second set i'm selling, with the 1st set currently fitted to the fronts along with brake ducts and Motul rbf600 fluid
Edited by zs on Saturday 11th July 17:09
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