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discovery 1 ls3 brakes upgrade


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hi guys, I'm in the process of building my ls3 discovery 1, I'm using the vehicle for rallying and sometimes day to day,

i need help with what calliper and brake options i have or what idea you guys may have. I'm roughly running at 480 to 500hp and as you can imagine i want to stop when needed .

any help and ideas you guys have would be great, iv been looking at brembo as iv seen a defender fitted with them but no idea which ones they used, so makes options will help thank you

cheers

chris

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Only 500 Hp in a 2 ton Disco? Humm you don't need brakes, you need large testicles and a good navigator :o

its kind of a special project for me i bought the discovery when i was 15 and done everything with it, it needed a rebuild and id rather bury it in my garden than get rid so i anted to do something special with it, bespoke interior big engine , etc but just need a few ideas on braking options is all.

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Standard (genuine) brakes will stop you once no problem, if you're rallying it you may need more as I would assume heat dissipation is going to be the issue stopping 2 tons repeatedly. I'd actually wonder if the right answer is to suck it and see on a decent set of stock brakes before going wild with the credit card.

Anyone know what Overfinch did in their small-block transplants in that era?

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110 vented calipers on disco vented discs you will need to change the system to defender or possibly 300tdi disco style single line (i've done this for my ibex) or I have the complete disco system including master with vented discs up front on 45 (90) the brakes are outstanding. So as fridge says put vented discs and calipers up front and try it I think you'll be pleasantly surprised at how good they are.

Mike

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As above, I'd try the stock brakes first as long as they are the vented ones. The stock brakes are designed to stop the vehicle with that weight and are more than up to the job. In general terms a more powerful engine doesn't require bigger brakes, the braking requirement is more about the weight of the vehicle and the size of the wheels/tyres. Bear in mind also that the majority of your braking is likely to be on loose surfaces and what you need are consistent brakes with lots of feel. Over powered brakes can end up like an on/off switch which on loose surfaces can make it far more difficult to brake without locking up the fronts and understeering/under braking as a result.

If you try going for a larger disk and larger callipers you can run into problems getting the wheels over them, one of the LS1 Defenders I worked on had some Brembo callipers fitted which were beautiful (and very expensive) pieces of kit but meant that we had to use wheel spacers to fit the wheels over them and although I never tried taking it around a race track I wasn't convinced they were much better than standard and just added another component to the list of things that would be a pain to replace if they ever broke on an event.

The "normal" way for rally cars that get used for other things is simply to choose an appropriate pad grade for the desired use. A lot of road rally guys use standard brakes with EBC high temperature pads. They work really well for sustained heavy use and give very little brake fade although you'll probably want a more road biassed pad for normal use - the high temperature race ones are brilliant when they are warmed up but lack bite when they are "cold" so can feel a bit lack lustre for normal road use. Alternative brake fluids are worth looking at too to avoid boiling the fluid.

Do you have a target class/events for rallying ? A few years ago now I know but when I looked at road rallying my classic Range Rover I found there wasn't a class for them to run in due to engine size restrictions, 4x4 restrictions and so on. Our local rallying club don't have any competitive events that you can use a Discovery for in any form (production/standard/modified).

The LS3 is a bad choice for rally raid but is well suited for short course work where you can refuel regularly (single venue stage rallies, for example), you're looking at around 2-3 MPG under competition use. I have a 120 litre (26 gallon) fuel tank and have more than once ended up running on vapours. On a stage rally with limited servicing (such as the hill rallies) this can be a logistical nightmare ! Naming no names but during the days we were competing in the UK hill rallies some of the top entrants used to have "fuel drops" hidden away at the side of the road so they could run lighter with smaller fuel tanks and top up between stages.

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Leave the back discs alone to be honest 80% of braking is done by the front.

Mike

 

Not always - one of the important things on a rally-car is the ability to lock the rear wheels using the handbrake (even on 4x4 setups like the Escort RS1700t and the Metro 6R4). The standard setup was to use a hydraulic handbrake operating on the rear calipers but this was strictly not road-legal unless you had 4-pot calipers at the back so could dedicate one pair of 'pots' per wheel to the handbrake - and even then the scrutineers were not always happy!

Rule #1 of any competitive motorsport: keep the Scrutineers happy, for they can make your life a misery.

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Back in 1998 I was paid to fit a 480hp Chev rat motor into a 110 CSW with a Th400 box against a 230 transfer box. The car was very quick,mostly because it had little wheelspin on tarmac.One of the fastest cars I've ever driven,it would put you back in the seat at 95mph,changing down to second...

The brakes were the only thing that were not fully sorted.it had vented RRC brakes/axles.It would stop well from over 100mph - but only once,try it again and you just got a wooden pedal feel and little else. They stank,and smoked when you did stop,along with the burning carpet smell from inside where the 3" stainless exhaust radiated heat out up through the floor.

So I would say forget anything standard LR,go for the biggest discs,calipers and pads you can squeeze in.The Chev rat motor was heavy as it was all cast iron,but the overall weight of the car,beside the engine pushed the brakes well beyond their design limits. The door tops bowed out enough that you could stick your fingers through them at 120mph...

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TBH, having a good balanced braking (i.e. you may want to look at upgrading back, if you upgrade the stopping power at the front) is what stops the car from squirrelling around under braking, and can make for many less brown trouser moments.

Note stopping power is unaffected by the vented/non-vented nature, purely the size of the disc, pad contact area, pad material and how big a shove you can give it from the master cylinder.

I'm all for suck it and see, but I suspect you will end up wanting more than stock brakes with that amount of oomph, while you don't get paid to slow down, you do get to be alive afterwards. Problem is speeds attained will be so much higher with that engine, that you will be dissipating far more energy to get round a corner at the same speed as a slower vehicle -repeatedly doing this = too much heat for stock (probably).

If you really want to stop, might be worth having a word with one of the LR rallying firms...

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Just think whether you are likely to upgrade the axles at any point, as you will be annoyed if you spend a lot on a brake setup designed to LR axles and then decide you want different axles to be able to use the engine in anger!

Would like to see it when it's done!

Jon

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Overfinch did build a small block Disco....

If you stripped all the heavy stuff out of a Disco 200 I reckon it would be about 1700kgs

Chris, do you already rally cars?

I only ask because there is a huge variation within the world of 'Rallying'

If you wanted speed and reliability I would dump the LS3 idea and use a decent high revving lump. To be honest a T16 version of the MPI with an R380 and quick-shift, rear LSD, Eibach lowered springs, SP bushes, fiddles and something like an MX Pro-comp shock would work well. Especially with no sound proofing, side glass or trim/rear seats...

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