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MG Midget and Sprite Technical - Uprated Front Calipers

Hi,
midget Mk3
I'm looking to uprate the front brakes with 4 pot calipers-any ideas what to use and where to get hold of them in the UK?
Peter King

I realise you're in Wales but wonder how you have come to the decision that you need 4 pot unless you have a different engine fitted perhaps

we're coming to the Welsh mountain passes again this year and I've just had the brake fluid changed again in readiness which along with Mintex 1144 front pads and good tyres I've found adequate even with spirited driving
Nigel Atkins

KAD do them - check their website. Nice, but not cheap. Other options include larger disc conversions with bigger and/or alloy calipers. Loads of info in the archives :)

If you feel you need them, then that's enough :) But I'm running a 1.4K and have the standard setup, albeit with better pads. Good enough for road use, but I'd want more for track use.
Rob Armstrong

A popular conversion is a triumph spitfire rotor on a special adapter to hub and MGB calipers... But those caliper are freaken heavy... So id look at KAD, wilwood, tilton, ect ect aftermarket equivants

Check with deb evans of pristist race engines she has a really nice big brake kit thats light weight and designed exclusivly for the midget

Prop
Prop and the Blackhole Midget

Kim (Magic Midget) sells the KAD ones with his excellent service included in the competitive price. Ask me how I know.. :)

And I wholeheartedly agree with Rob, wanting them can be enough to justify them :)

Besides, apart from the braking aspect, the KAD ones would seem to reduce the unsprung mass by a couple of kgs.

That's how I talked myself into it :)

OrangeSpyderMan

Good brakes are the thing that makes the car fun!

Seriously - in the modern world with cars stopping all over the place dead quick - and with the apparent increase in habits of people to just brake and THEN tell you what they are intending doing - what's the point of sticking with ancient old brake systems that were designed for a very very different world.

However, having said that, before spending vast fortunes, you need to work out what you want to do with you car - if you want to have a nice fastish road car for a bit of fun - then you just need to make sure they are effective - and the biggest upgrade you need is to a decent pad and disc. If you're going to compete it, then you can look at the KAD/Wilwood systems/bigger discs/etc etc etc. Again, if you're competing, then you'll be wanting to look at the weights - in which case, the MGB calipers/Spit stuff is not great - but if it's for a road or track days, then it's fine.

At the end of the day - everyone has different ideas for what they need - and everyone uses their cars in different ways - so, it's up to you!!!! So long as you stop when you need to, then that's good! Would recommend that the min that you do would be to fit goodridge hoses on them - even my grumpy MOT man likes them!!!!!

rachmacb

I am not sure why Nigel is asking why you need 4 pot calipers? its one of the best upgrades you can make to a car, shorter braking distance = safety in normal driving and track use.
I am in the Kad camp, expensive but good,I have found they work better with Mintex and not green stuff as seen in the picture, I would never go back to standard brakes,


Rob Newt

But don't forget it's only a shorter braking distance if you have the tyres which will transfer the extra braking onto the road. Without them you aren't any further ahead.
Paul Walbran

as Paul has put grip is from tyres plus sometimes its that the present system isn't working at its best and it can be improved by simple maintenance

my wheels lock up if I brake too hard with a standard braking system (except the 1144) that is in good condition but is worn

other elements of the car effect the braking too (but Paul would do a much better and clearer explanation than I ever could)

I can assure you I'm be the last person to stop improvements in braking I always say it's the number one important thing on a car, youngsters learnt to worry about the engine to make that a priority when it's actually one of the less important parts of the car
Nigel Atkins

Nigel,

Why I want to upgrade is that I want to be able to stop when I'm competing.
Peter King

Peter,
I didn't put unless sports use as I'm sure some others have put they use standard brakes but it depends on the sport I expect and class

I only asked in case you might be new to Spridget ownership and possibly had poor braking for some reason and thought you needed to upgrade

Rob's brakes look colourful and shiney, my mate would be glad you didn't keep the green stuff (although it's a local family concern to us here) but my mate did use to work for Pagid
Nigel Atkins

How about if all those users with non standard discs and calipers report what the MOT tester brake dyno is reading.
Daniel Thirteen-Twelve

Then they would also have to report tyre size, make/ type and pressure.
Otherwise you'd still know little
Onno K

Peter - Competition is certainly when they make the big difference - repeated severe applications which build up heat rapidly. Big brakes dump the heat, small brakes can't and fade away and as a result won;t even lock up standard tyres.

On most public roads it is hard to get even small brakes that hot unless you are dead keen to lose your licence.
If you are into nice twisty mountain roads, they won't be up to it, but for normal road driving in which you need good braking for an emergency stop the best braking upgrade is to fit better tyres.

A simple guide is that if your brakes get very smelly they are starting to heat up and you need to think about an upgrade. (If they get smoky then don't delay!) If they don't get very smelly then you aren't driving hard enough to benefit from big brakes.
Paul Walbran

my Midget brakes are just about good enough for the twisty mountain roads I go on but I've had other classics where I've had to slow, worst part of my current brake set up is the driver
Nigel Atkins

That would be interesting Daniel - but I'm not sure how many would be able to? When I take any of the "posh" cars to the MOT centre, they refuse to put them on the dynothingy coz they have LSDs, and we go for a drive in the cars with the old tester block. I also wonder what the effects of lightening them would be as well for the comparison? I guess that those who have gone to the trouble of putting on the more expensive systems, have also done alot of other work as well ....

Peter - you don't say what sort of competition you are going to enter - you'd best check the regulations before making any changes, that's normally the limiting factor on any upgrades :(

One thing that my MOT tester has said regarding the two cars that I've had MOT'd recently with Goodridge hoses fitted is that, compared with the other Midgets and BGTs that he's tested, there's an increase in braking efficiency of up to 15%, however, again, one would have to know total like-for-like - tyres/weight/daily use etc - as these all have bearing.
rachmacb

Green stuff pads & standard discs, 175/70 R13 Continental Eco-contact with 4mm left on rear, same size Avon CR322 with 6mm left on front.

FL FR
119 123

RL RR
68 71


(in kgf)

Handbrake L Handbrake R
35 37

(% of veh weight)

Wrote them down at the last MOT after a previous mention by daniel about brake numbers.
Rob Armstrong

Thanks - any of the 4pot brigade like to declare anything higher?
Daniel Thirteen-Twelve

While more brake dyno info is pending, here's amother intersting comparison I was reminded of tonight while driving along a bit of road where my tester (see below) checks modified brakes:

In NZ, any modifications have to be individually certified (one of the siller ideas we got from our mates in West Island, and which you in the UK should be thankful hasn't caught up with you yet.)

The test for braking is 5 stops in quick succession from 100km/h (opern road speed limt) to zero, at a minimum average retardation rate over the whole stop of 0.6g and without any wheels locking. This tests both front/rear balance and fade, and while 0.6g is at the light end of things for the track, in terms of repeated applications its the more vigorous end of the spectrum on the road (as I found when I was driving my car for the test).

When I went to do the test on my B, my tester commented that the best car he'd ever checked was a BGT tarmac rally car which I know well. Well enough to know that the owner never fitted anything more than uprated pads & linings on otherwise standard brakes. The figure he achieved with that consistently over the 5 stops was well over 0.9g. Though the brakes were almost standard, the car was shod with Dunlop Formula R's.
Paul Walbran

OK, so the brake dyno records brake torque which isn't quite the same thing as stopping distances. For example a Spridget may stop in a shorter distance with one make of brake pad compared to another (not sure about if 'g' meter will see that) but the brake dyno doesn't see this, it just sees the absolute torque.
Daniel Thirteen-Twelve

4 pot Wilwood aluminium calipers on Capri 2.8i vented discs on my Spridget Challenge class E car using Hawk carbon metallic pads - all the stopping power you'll ever need on a Spridget...

Rally Design is the place to look for Wilwood calipers

http://www.rallydesign.co.uk/index.php?manufacturers_id=45&sort=&filter_id=588
James B

Really James... wow!

Mine has standard calipers as per Fisc regs.

Looks like I better start spending some more pennies and developing the car a bit further then.

Or maybe when you think I'm being really really brave and outbraking you into that corner, I may just have run out of brakes instead ;-)

A
Andrew McGee

I rather became fed up with constantly replacing pads and shoes every meeting after my FISC seasons, with the Wilwoods I use a set of pads every 2 seasons and a set of shoes every season, I have also never been troubled with fade since I fitted them.

The reduction in braking distance and time is also a useful factor on a race car... Don't worry Andrew, on standard Midget brakes you won't be outbraking me... ;o)
James B

...unless you're a demon in the rain and Yoko 48Rs prove significantly better than ACB10s in the wet of course... :o)
James B

Daniel

If it's stopping in a shorter distance the g's are higher and the torque achieved is also higher. They are all related - you can't get one without the other.
However, a key part of this equation is the friction between tyre and road. (This would also be a limiting factor on a brake dyno if it's rollers the car sits on like we have.)

Unless a pad was really rubbish or tyres extremely sticky, I can't see a change of pad would make any difference at all to a single stop at normal speeds as standard brakes can get most tyres to limiting friction (point of lock-up) anyway. But doing it twice or several times in a row or from very high speed is another story of course as fade starts to set in.
Paul Walbran

James... I meant sailing past you as you anchor up nice and safely and my brakes do beggar all and only leave me with a greater velocity so I have no choice but to career past you with terror!!! :D
Andrew McGee

Just had my brake readings after a pass with Mr mot man, thought folks might be interested in readings.
Kad calipers,
Standard discs(but crossdrilled)
Yokohama A048 tyres,
On the rollers.
FL..180
FR..220
The big difference between the two probably comes down to lack of use (300 miles in 12 months)

Wolseley drums on the rear
RL..110
RR..90


Rob Newt

Daniel, good suggestion!

My car is up for its 2year mot somewhere end june begin july.
Would be intresting to see the outcome as I presently have greenstuf pads and might go for mintex in the future.
4 pot Willwood on 10 inch vented disc and braided hoses at front and 8inch disc with audi/volkwagen calipers and pads on the rear.

With regards to tyres Ive just fitted new "Michelin energy" tyres as theyve been very good in rain(atleast until now...).
Very importand as sh*t usualy happens in the wet.
Proper roadtyres insted of specialised sticky "track" tyres.
Arie de Best

This thread was discussed between 16/04/2012 and 31/05/2012

MG Midget and Sprite Technical index

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