Loss of traction on off camber corners

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Trise30rally
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Post Thu Jun 19, 2008 12:49 pm

In my hill climb 325i sport i have gaz coilovers which ofcourse couse tripoding on off camber corners, the standard zx lsd does not cope with this and the car just spins up the one wheel causing me to lose atleast a second...

Rather than replace the diff with a better one, would it be a good idea to try removing the rear ARB so i get better traction on the rear???
handpaper
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Post Thu Jun 19, 2008 1:36 pm

It sounds like your LSD is worn out and is now effectively open. Rebuilding or replacement are your only real options.
Removing the rear ARB will help, but not much.
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mikekean
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Post Thu Jun 19, 2008 1:55 pm

the inside wheel will allways spin no mater what lsd you have. but unlike an open diff the other wheel will still drive so foward momentum is not lost. i was taught that if you have a 50% lock up diff then when traction is lost on one wheel the wheel with grip can turn 50% of what the input shaft is turning. hence the higher you go on the lock up the more sideways you will go as its gets more and more like a welded diff. thats what i was taught anyway. so you probably need to soften the rear end up. so try the ARB if thats not soft enought try different spring rates on the rear. or you could just get a diff with more lock up. my choice would be to soften the rear as id rather not have the back end stepping out all the time.
Trise30rally
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Post Thu Jun 19, 2008 2:16 pm

Am i likely to lose a lot of handling if i remove the rear ARB?
JimmyC
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Post Thu Jun 19, 2008 2:55 pm

what spring rates are you running?
Trise30rally
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Post Thu Jun 19, 2008 3:41 pm

ummmmm 250 on the rear and 500 on the front i think! :mad:
JimmyC
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Post Thu Jun 19, 2008 4:39 pm

I was on 500lbs and 275lbs and was lifting a wheel all over the show, upped my springs to 600lbs and 325lbs and it has massively improved the problem and handling

its the diagonal roll that was causing me issues, still does it for example at Graham Hill at Brands, but previously was doing it there, druids and surtees

Maybe worth a look?
shorty73
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Post Thu Jun 19, 2008 8:06 pm

I'm running 650 f and 300 r on a 325i. Softened the rear arb right off as well. Seems to have worked.
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Post Fri Jun 20, 2008 12:22 am

i have heard this with e30's.. harder springs softer roll bars to improve the handling, particularly in the rear
Got cable ties? Get diffin..

Arch roller for hire.

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Trise30rally
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Post Fri Jun 20, 2008 10:09 am

Cool,


Has anyone tried these diffs out??

http://cgi.ebay.com/ebaymotors/OBX-Heli ... 0061218028

I have heard they are meant to be a quaife copy.....
billgatese30
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Post Fri Jun 20, 2008 2:22 pm

same method of torque balancing as the Quaife diffs by the sounds of reading the ad. Not sure how well they perfrom in e30's though
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kimbo
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Post Sat Jun 21, 2008 5:24 pm

Torque biasing diffs only work when both wheels are on the floor and would therefore not help in the situation outlined above. If the inside wheel lifts, they act just like an open diff. Stick with the plate diff but get it upped to 50% lockup (std is 25% IIRC)
As Jimmy C says, the problem sounds like front end too soft, although going softer / disconnecting the rear arb to increase rear wheel droop would help.

Kim.