Willwod, Hi spec or AP big brake kit?

[Scott Dabinett]

I am wanting to put a big brake kit on my caterham, it is just a 120bhp roadsport but I plan on doing track days and some sprints. I have always been taught big brakes, decent tyres and an LSD then worry about power!

 

I have had a look around and found 3 kits, willwood (£540), Hi Spec (£460) and AP racing (£660) just wondering which ones people would recommend?

 

Also do I have to change the master cylinder when putting one of these kits on?

 

And what size do I need to fit under 13 inch wheels? Hi spec do 232mm and 260mm

 

Edited by - Scott Dabinett on 6 Feb 2013 07:10:55

[Stationary M25 Traveller]

You will get support for all !!

 

I fitted the Hi-spec with solid 260mm dia discs. No change to master cylinder.

[Scott Dabinett]

Quoting Stationary M25 Traveller: 

You will get support for all !!

 

I fitted the Hi-spec with solid 260mm dia discs. No change to master cylinder.

 

Will 13 inch wheels fit over these or would I need the 232mm kit?

 

This is what I am looking at as it has everything needed to just bolt them on, the willwood kit doesn't come with pads and new hoses and that!

 

here

[Stationary M25 Traveller]

Will have a look at mine for you tomorrow.

[Stationary M25 Traveller]

Just looked at your link. Why not buy the kit direct from Hi-Spec ? They are just down the road from me.

[david nelson]

I am not sure its worth upgrading the calipers. Have you looked at pad materiel? What are you hoping to gain by the big brakes?

[Shad]

I'm in camp AP when it comes to brakes now. Ok you might pay a little more than for comparable kits/parts, but it all just works and for me has been 100% reliable. And it bloody works a treat too.

 

Feel free to pop over and have a look at the brakes on my car if it's useful, doesn't look like I'm far away

[TonyR]

As David says, upgrade the pad material make sure the standard discs are in A1 condition (cheap to replace) & spend rest money on other items.

 

These cars are very light and I know some very successful sprinters using the standard discs and calipers.

 

TonyR

 

Edited by - TonyR on 6 Feb 2013 09:13:21

[Stationary M25 Traveller]

For me it was the complete lack of feel with the standard brakes with M1144 pads.

 

Mountain passes with two up and luggage ... i am much happier with bigger diameter discs and 4-pot calipers. Changed rear pads to blue spot too.

[Roger Ford]

You don't need big brakes for track use. Megagrads and Supersports (both 140 - 150 hp) do fine with standard brakes for 20 to 30 minute races. If you put big brakes on the front but not the back, you'll unbalance it, and if you want to upgrade the back you'll have issues around handbrake for the MOT.

[bluenose]

The significant difference with the Hi Spec brakes is the unsprung weight saving over the standard calipers. The Hi Spec ones are 0.9Kg each. Had no issues with mine on standard solid 232mm disks. I do have the upgraded master cylinder though.

 

Nick

[Alex Wong1697456877]

On a Vx with all that (and my) weight, I kept getting soft pedal on track days no matter how I bled the system and what pads i used. AP calipers and master cylinder fixed it.

[Steve Sheldon]

I suggest you talk to Rob Morley at Ratrace Motorsport who has years of experience racing/setting up sevens. He will stop you wasting your money on unnecessary upgrades. Will also advise re spring rates etc which go hand in hand with good braking performance. You need to turn braking effort into grip not dip! My roadsport runs on standard brake discs/calipers along with Ratrace pads and uprated springs + flatfloor setup + AP M/Cyl and AP brake balance valve to the rear. Handles and stops brilliantly - even on standard tyres. Let me know if you want more info.

 

Edited by - ssheldon on 6 Feb 2013 14:04:35

[Richard Price]

Scott,

Save your money. Standard calipers stop the car just fine!

I upgraded to Hispec Ultralite 4's using standard 232mm disks early last year.

Does the car stop any better? I think that is questionable!

I run a datalogger, and I can't say that our stopping power is any greater than before.

I could lock the wheels with standard calipers, so bigger brakes are not going to stop the car any faster!

Admittedly, the car is largely used for sprints and hillclimbs rather that track days. Temperature becomes more of an issue if you're really pushing on on track days, but then you don't push quite as hard as a sprint, hillclimb or race on a track day).

A soft pedal is more often caused by boiling fluid, so replacing the fluid with an expensive race fluid (like castrol SRF) is most likely to cure that.

 

 

Why did I change calipers? Each standard caliper is almost 2KG heavier than the Hispecs.

 

 

[Stationary M25 Traveller]

And the HiSpec look might pretty .... in red

 

I have 15" wheels. With 260mm dia discs and presumably slightly longer ears on the caliper mountings the minimum clearance between caliper and wheel is 35mm. As this is a radial measurement, your 13" wheel will be around 25mm closer to the caliper so still 10mm clear. With the 232mm standard disc (reusing what you have) you will have even more clearance.

 

I also measured from the centre of the axle stub shaft to the outside edge of the caliper ... approx 150mm.

 

Blatmail if you want photos.

[rj]

I've done countless trackdays with standard brakes in a 200BHP car without at any time overheating them. Only reason for upgrading was as my knee started to hurt after a few hours behind the wheel (and brake)

[Pendennis]

A lot of common sense there, although in my experience sprinting never really pushed the car anywhere near as hard as a good 20 min track/test session. But quite rightly if you can lock the wheels then bigger brakes are not initially necessary, but grippier tyres are 😬 However, this goes hand in hand with grip, more grip means more braking power and no doubt this is when you find out your brakes are not up to it

 

The AP uprated master cylinder is a better product, less prone to leak and has two circuits front and rear so does offer a significant safety benefit over the standard version.

 

Decent brake fluid like AP 551 and nice pads like Ferodo DS2500 would give you a noticeable improvement

 

But for me it's a no brainer, the vented brake disc will in the long run offer better brakes, as the solid type cannot sustain heat for long periods, thus performance reduces and failures then occur. Personally, if you can afford it I cannot see any argument for not having the best brakes available.

 

Finally, you maybe able to get the AP versions cheaper than you think, search around some distributors have different dealing status

 

Ian

[Scott Dabinett]

Thanks for all the replys, alot of mixed opinions on the subject. Do you reckon i would be better off with an LSD?

[Stationary M25 Traveller]

As well as or instead of brakes ?

 

I have just got a Quaife LSD fitted to my Ford diff. Transformed the feel of the car ... loving it already ... afteronly one days drive (150 miles)

[Cliff Richard]

Quoting Stationary M25 Traveller: 

As well as or instead of brakes ?

 

I have just got a Quaife LSD fitted to my Ford diff. Transformed the feel of the car ... loving it already ... afteronly one days drive (150 miles)

 

Would eventually be both but just one at the moment, i had an LSD in my mx5 and and notice the caterham not having one alot!

 

Think i might get an LSD first! Plan on doing 5-6 tack days this year so think i will notice an LSD more after reading the comments on here!

[Roadsport06]

LSD every time. As RP has stated, you can lock up with standard setup. I think I'll be going for an AP cylinder though as I do find the pedal travel a pain

[oldbutnotslow]

I agree with the keep your existing brake setup camp.

there is no need for the big brake setup on a car with your sort of power

 

I am also a Pagid pad fan. I run RS14 and RS 15 material but mine is purely a track car. Pagid blue should be fine for what you are planning. OK they are more expensive but "you gets what yous pay for" you use a modern idiom. PAGID link here

 

Speak to John Freeth at Performance Braking in Monmouth 01600 713 117

He worked on the Thrust project for Girling so knows a thing or two about material and will give you the benefit of his experience.

NEVER fit new pads to old rotors that have not been thoroughly cleaned by rubbing them vigorously with something like 80 grit production paper to remove the old pad material first. In fact as new rotors ar as cheap as chips at £15 each from say Rimmer Brothers and save yourself the time and elbow grease and fit some new ones.

 

My first step would be to buy a new exhaust. There are lots out there of course but many of us have Powerspeed systems This should release between 6 and 8 bhp. Get the one with the cat as this will save you all the messing about at mot time swapping back to the original system and Sports cats make no appreciable difference to performance.

 

Re master Cylinder size

This has been nicked from Tinterweb

‘What bore size master cylinders should I use? In theory, it is possible to determine the correct size of the master cylinder (piston diameter) by calculating pedal ratio, pedal travel and caliper piston diameters but it’s often easier to ‘suck it and see’ by choosing a .750" master cylinder to begin with and working from there.

Many factors will determine the optimum master cylinder size such as weight of the vehicle, tyre diameter; brake pedal length, weight distribution and servo or nonservo assistance. Brake pedal ratio is often the easiest parameter to change. Increasing the pedal length is, in effect, increasing the leverage but the pay-off is less fluid movement for a given pedal travel. If the pedal is 12" long from the fulcrum to the foot pad and the cylinder push rod is 3 inches from the fulcrum then the pedal has a 3 to 1 ratio. Increasing the ratio to say 4 to 1 will give more leverage but with longer pedal travel.

For a clutch the same rules apply to the release fork. A higher ratio will make the clutch action easier but there will be less travel of the release bearing. Determine the distance the release bearing has to travel to fully disengage the clutch (usually about 10mm) and work backwards from there.

A release fork with 2 to 1 ratio will require 20mm travel of the slave cylinder.

Brake hydraulics is really all about fluid movement so, to give you an idea of the effect of changing master cylinder sizes, A 1" cylinder will move 2 ½ times more fluid than a .625" cylinder. But the pedal will require 2 ½ times more force to get the same braking performance.

However, the pedal travel will be 2 ½ times less.

In short keep the standard M/C to start with and see how it feels.

[Roger Ford]

Spend your money on track day entries, fuel and some instruction. That will provide infinitely more benefits than tricking out the car before you've even put a wheel on the track. Unless of course you're one of those people who prefer fiddling with and admiring the car over driving it, in which case go ahead with the big brakes, LSD and flash exhaust, none of which are necessary for on-track enjoyment. An LSD just means you can dispense with any finesse when exiting corners - far more skill and satisfaction getting it right without one. All IMO, of course.

[myothercarsa2cv]

An LSD just means you can dispense with any finesse when exiting corners - far more skill and satisfaction getting it right without one.

 

You missed the only reason to get an LSD - enhanced drifting and donuting experience 😬

 

[oldbutnotslow]

Ahh. I should have read the first post more carefully. You are completely new to a 7

 

In which case I agree completely with Roger about instruction.

 

Its the best upgrade £ for £ that you can ever have.

The car is far more capable in its standard trim than most people realise and again most people never get to the edge of the cars performance.