Anyone know of front brake upgrades for the XJ-S?

Building a car for the One Lap of America race and have shedded some weight but obviously need some more stopping power up front.

I know AP can make up a kit for some serious $. Do any of the later Jag calipers fit? XKR, etc.

Cheers,
John

 

The XJS already has 4 piston front and twin piston rear. A lot of the guys here in Aus who club sprint, change the front rotors for slotted with suitable pads and cooling ducts. The rears can be upgraded with thicker slotted and vented rotors but you will need to add a spacer in the rear caliper. Unless you are doing serious track work this is all that may be needed.

 

Granted the stock brakes are very good for a 33 year old street car, but with 450hp at the wheels and much bigger shoes the brakes are the current weak point. The 11 inch rotors just don't carry enough mass to shrug off the heat. Already run slotted rotors, air ducts and ebc pads. The XK8/XKR rotors are up to 12.8 inches. Looking to get more in that range.

 

If you do not have facilities to fabricate I would look at a kit from Willwood/Brembo or the like

I would think using XK8 brakes would require the fabrication of mounting blocks for the calipers.

Most important thing in the rotor is its ability to shed heat so look for rotors with well designed vanes Alcon make excellent products although they are expensive.

One other thing you can try is water spray for the brakes. This is used by the V8 Supercars here in Australia, they run very small (376mm for the relative performance 650+HP and 1200kg) rotors.

cheers

 

John, is your car a V8 convert? Because I would love to know how to get 450 bhp out of my V12! I think my car only gets about 263 bhp.

 

450hp, not too difficult for the old V12. Stroked and bored to 6.9L with intake exhaust and aftermarket ECU should be good for 500-600hp

 

@ecbjag, yes the car is a V8 / 6 speed conversion. A safer choice for a 5000 mile cross country, multi race track event where parts might be needed at a moments notice. Also much easier to get big power and still remain smog legal in California. Warrjon is right the V12s can mash out fantastic power when massaged correctly. It is just a more expensive proposition and very rarely smog legal.

@warrjon, I will keep this post updated with what I come up with. Thanks for the suggestions. Love the V8 Supercars series. I watch it on Speed. Nascar meets European Touring Car. I understand they will be coming to the US next year. I've seen that water spray technique used before. Clever.

 

The2904 when is your event? What is the route?

 

If you are asking about the One Lap next year's current schedule is:
Saturday May 5th, start at the Tire Rack, afternoon at Autobahn Country Club.
Sunday, Mid America Motorplex, Pacific Junction, IA
Monday, Hallett Motor Racing Circuit, Hallett, OK
Tuesday, High Plains Raceway, Deer Trail, CO
Motorsports Park Hastings, Hastings, NE
Brainerd International Raceway, Brainerd, MN
Road America, Elkhart Lake, WI
Saturday May 12th, finish at the Tire Rack in South Bend, IN

You can find out more at: One Lap of America - the Official Webpage

If you are asking about The 2904 send me a PM.