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rear disc conversion

Posted: Tue Sep 20, 2016 3:21 pm
by Nikos.sami
hello
i just want to ask if it is a good idea to do a rear disc brake conversion to my :BS:ami or it wont have a big difference?
Also will handbrake turns :rhinohump: with the clutch down be a problem for the diffs?

Re: rear disc conversion

Posted: Tue Sep 20, 2016 4:15 pm
by Anton
Disc brakes make a huge difference but only under certain circumstances - basically if you're in mud.

Brake drums fill up with mud and then become useless until you clean them out.

Although, the fact that you talk about handbrake turns makes me wonder if you're going to rally your SJ? If so, discs also have another benefit - cooling. Drums can heat up under hard braking, and there's no easy way for the heat to get out of the drum, which heats up from the inside out - little to no airflow means *terrible* cooling. Matters not on a slow road car, but on something quick - it's a problem. A big one.

If you're going to race your SJ in some way, then discs are going to help stop brake fade. I would think about getting vented brakes from a Vitara front and rear, and using a dual brake bias valve to get the F/R balance correct. Vented brakes are much less likely to fade than solid rotors. If you spend a lot of time in gloopy mud, however, they'll just fill up with mud and your extra cooling will be zeroed out.

As for handbrake turns - forcing the diff to stop turning then dumping the clutch is hard on any diff, but SJ diffs are pretty strong. If you're worried, though, Vitara's have bigger, stronger diffs.

Also, if you're rallycrossing, 4wd will be useless to you, as the tarmac sections will need to be in 2wd, while the dirt sections be ok - but you can't exactly stop to switch from 2wd to 4wd. Although you might be able to replace the transfer case with a centre diff. Maybe.

If you're rallycrossing, then I'd say find a 2wd X90 and start with that. Vitara rear diff, no 4wd, no transfer case should mean a little more usable HP. If you're going to be on dirt or loose surfaces, then your SJ should be good.

Re: rear disc conversion

Posted: Tue Sep 20, 2016 4:22 pm
by zook123
Do you offroad a lot? If so, a rear conversion would be good as it won't get filled with muck.

Handbrake turns probably aren't good in an SJ, ask Dan.. except he didn't use a handbrake.

Re: rear disc conversion

Posted: Tue Sep 20, 2016 5:46 pm
by Nikos.sami
Anton wrote:Disc brakes make a huge difference but only under certain circumstances - basically if you're in mud.

Brake drums fill up with mud and then become useless until you clean them out.

Although, the fact that you talk about handbrake turns makes me wonder if you're going to rally your SJ? If so, discs also have another benefit - cooling. Drums can heat up under hard braking, and there's no easy way for the heat to get out of the drum, which heats up from the inside out - little to no airflow means *terrible* cooling. Matters not on a slow road car, but on something quick - it's a problem. A big one.

If you're going to race your SJ in some way, then discs are going to help stop brake fade. I would think about getting vented brakes from a Vitara front and rear, and using a dual brake bias valve to get the F/R balance correct. Vented brakes are much less likely to fade than solid rotors. If you spend a lot of time in gloopy mud, however, they'll just fill up with mud and your extra cooling will be zeroed out.

As for handbrake turns - forcing the diff to stop turning then dumping the clutch is hard on any diff, but SJ diffs are pretty strong. If you're worried, though, Vitara's have bigger, stronger diffs.

Also, if you're rallycrossing, 4wd will be useless to you, as the tarmac sections will need to be in 2wd, while the dirt sections be ok - but you can't exactly stop to switch from 2wd to 4wd. Although you might be able to replace the transfer case with a centre diff. Maybe.

If you're rallycrossing, then I'd say find a 2wd X90 and start with that. Vitara rear diff, no 4wd, no transfer case should mean a little more usable HP. If you're going to be on dirt or loose surfaces, then your SJ should be good.
thnx for your answer
my sami is my daily car it have kybs i have change all bushings 3mm wheel spacers and some toyo at bucket seats and a rollbar
i use it for offroad but i dont want to lift it so i can go fast in the mountain roads and also have some drifting fun on gravel :guns:
so its an all around car

Re: rear disc conversion

Posted: Tue Sep 20, 2016 5:53 pm
by Nikos.sami
zook123 wrote:Do you offroad a lot? If so, a rear conversion would be good as it won't get filled with muck.

Handbrake turns probably aren't good in an SJ, ask Dan.. except he didn't use a handbrake.
i offroad a lot and also i drive fast on gravel roads
i ask for handbrake turns because when i have to U turn the most times i just pull the handbrake up :smokin:

Re: rear disc conversion

Posted: Tue Sep 20, 2016 6:02 pm
by twiss
I absolutely love my disc conversion... pretty much zero maintenance. Had no problems since putting it on and the pads last a lot longer than the shoes when you're driving in mud.
Im using an sj410/early sj413 transfer box handbrake though, so no handbrake turns for me. Im using front caliper all round.
I know muddyzook used to do a kit for rover 600 calipers, which had a handbrake, but I'm not sure if they are making them any more? Worth a look

Re: rear disc conversion

Posted: Wed Sep 21, 2016 2:08 pm
by Nikos.sami
twiss wrote:I absolutely love my disc conversion... pretty much zero maintenance. Had no problems since putting it on and the pads last a lot longer than the shoes when you're driving in mud.
Im using an sj410/early sj413 transfer box handbrake though, so no handbrake turns for me. Im using front caliper all round.
I know muddyzook used to do a kit for rover 600 calipers, which had a handbrake, but I'm not sure if they are making them any more? Worth a look
Thank you for your answer
so you are using front sami discs all around?
isnt a litle bit dangerous 50/50 brake balance?
so latest samurais have the handbrake directly to rear brakes?

Re: rear disc conversion

Posted: Wed Sep 21, 2016 4:08 pm
by ScottieJ
If your sj has a transfer box/ propshaft handbrake then I would really advise against handbrake turns, you will break something eventually.

Re: rear disc conversion

Posted: Wed Sep 21, 2016 4:10 pm
by twiss
Mine was originally 1993 spanish built "Samurai Sport" and they have the handbrake in the rear drums, with twin handbrake cables.
Im using front discs and calipers all around, but using 2 different types of calipers. I think the fronts are lucas and the rears are girling?
Basically some from japanese and some from spanish. The front ones have larger pistons so you get more brake force.
Also, there is a stock brake bias valve, its just not very good. With the stronger piston calipers up front I can lock up the rear wheels if I brake really, really hard...
But it has never been a problem for me....

Re: rear disc conversion

Posted: Thu Sep 22, 2016 12:35 pm
by ScottieJ
twiss wrote: Basically some from japanese and some from spanish. The front ones have larger pistons so you get more brake force.
You have this backwards......the larger the piston in the caliper the more brake force. (edit: you did have it backwards and now you have edited both posts :hahaha: )

Some reading for you :tongue:
http://www.pirate4x4.com/tech/billavista/Brakes/