280zNHChris Posted November 2, 2009 Share Posted November 2, 2009 I recently got a 73 240 with a 74 260 motor with dual webers and was messing with the carbs and trying to get it to idle and drive without pumping the gas and did a couple drops in my garage and laid these 2 patches. When I jacked up the rear and spun each tire the other tire didn't move on either side, unlike my 2 other Z's which each tire turns opposite. Any chance there's an LSD in there or is it open and will go single real quick? Thanks Chris Quote Link to comment Share on other sites More sharing options...
hoov100 Posted November 2, 2009 Share Posted November 2, 2009 jack it up, have someone hold one tire, while you spin the other and watch the driveshaft, if it spins and the other tire isnt moving, then you have an open diff. doing a burnout isnt a good way to identify if you have an LSD. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 2, 2009 Share Posted November 2, 2009 Clutch LSD tries to lock the wheels together. If you spin one side the opposite side moves in the same direction and you'd have to hold one side still and exceed the breakaway pressure of the LSD to spin them at different rates or in different directions. Unfortunately this doesn't apply to gear driven LSDs. The best test is to take it out and look, but barring that do some donuts and see what happens. If it spins the inside tire, then you need a (better) LSD. IRS tends to spin both tires, unlike a solid axle, so the fact that you got two stripes doesn't mean a thing. Quote Link to comment Share on other sites More sharing options...
zgeezer Posted November 3, 2009 Share Posted November 3, 2009 Clutch LSD tries to lock the wheels together. If you spin one side the opposite side moves in the same direction and you'd have to hold one side still and exceed the breakaway pressure of the LSD to spin them at different rates or in different directions. Unfortunately this doesn't apply to gear driven LSDs. The best test is to take it out and look, but barring that do some donuts and see what happens. If it spins the inside tire, then you need a (better) LSD. IRS tends to spin both tires, unlike a solid axle, so the fact that you got two stripes doesn't mean a thing. If your only concern is getting power to both tires for straight line drag racing: a little attention to tire pressure may put off for a while the time in which you will have to go to LSD. g Quote Link to comment Share on other sites More sharing options...
zgeezer Posted November 3, 2009 Share Posted November 3, 2009 Clutch LSD tries to lock the wheels together. If you spin one side the opposite side moves in the same direction and you'd have to hold one side still and exceed the breakaway pressure of the LSD to spin them at different rates or in different directions. Unfortunately this doesn't apply to gear driven LSDs. The best test is to take it out and look, but barring that do some donuts and see what happens. If it spins the inside tire, then you need a (better) LSD. IRS tends to spin both tires, unlike a solid axle, so the fact that you got two stripes doesn't mean a thing. Quite right, but if his only concern is getting power to both tires for straight line drag racing: a little attention to tire pressure may put off for a while the time in which he will have to go to LSD. g Quote Link to comment Share on other sites More sharing options...
Racer Z Posted November 3, 2009 Share Posted November 3, 2009 The nature of the IRS (Independent Rear Suspension) that is in the 240Z is that it can maintain equal traction during hard acceleration. The solid axle in our American cars will unweight the right tire because of torque transfer. The 240z diffy is SOLID mounted and won't unweight the right tire. It is possible that somebody did upgrade your car to an LSD, but, even with an open diffy, it will usually spin both tires while going in a straight line. With both tires off the ground, put the shifter in first gear and spin one wheel. If the other wheel spins the opposite direction, you have an open diffy or a broken LSD. If the other tire spins in the same direction you have a LSD. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 3, 2009 Share Posted November 3, 2009 With both tires off the ground, put the shifter in first gear and spin one wheel. If the other wheel spins the opposite direction, you have an open diffy or a broken LSD. If the other tire spins in the same direction you have a LSD. Or a helical LSD that functions normally. Quote Link to comment Share on other sites More sharing options...
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