Hi all,
I know that Kaaz, OBX, and Tomei are all pretty decent aftermarket brand names for LSDs. I'm doing my research on them but I want to make sure with the gurus here that I am well informed about the right one to get for my 1985 Zenki. I'm trying to get a 2 way LSD.
What brand and model aftermarket LSDs are meant for the 1985 zenki?
Thanks all!
Aftermarket LSDs for the 1985 Zenki rear-end.
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MisterJerk
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Re: Aftermarket LSDs for the 1985 Zenki rear-end.
O.S. Giken makes a good one.(pricy)
TRD- old but can be found still(used)
OBX... umm yeah. helical, machining might be required. not recommended.
TRD- old but can be found still(used)
OBX... umm yeah. helical, machining might be required. not recommended.
RTFM!!!!!!!!!!! --> http://www.aeu86.org/technical/
Re: Aftermarket LSDs for the 1985 Zenki rear-end.
Most of the aftermarket companies sell a zenki and kouki version. Whatever brand you choose make sure to get the correct part number so it fits your zenki axles.
Another piece of advice... As far as I know all the common aftermarket clutch lsd units (Cusco, Tomei, Kaaz, OS Giken) are set to 100% lockup with high initial tq. by default from the factory. This is only good for drifting imo, and makes for bad street manners. If drifting isn't your main objective I recommend looking into getting the lsd adjusted prior to installing (if possible). They often can be set to lower lockup rates which is better for grip. Also, the coil springs or cone springs can usually be tuned to lower the initial tq. (also good for grip).
A couple years back I installed a new cusco rs 1.5 lsd unit. Not having it adjusted before install was a HUGE mistake. When it's time to rebuild I'll change that.
Another piece of advice... As far as I know all the common aftermarket clutch lsd units (Cusco, Tomei, Kaaz, OS Giken) are set to 100% lockup with high initial tq. by default from the factory. This is only good for drifting imo, and makes for bad street manners. If drifting isn't your main objective I recommend looking into getting the lsd adjusted prior to installing (if possible). They often can be set to lower lockup rates which is better for grip. Also, the coil springs or cone springs can usually be tuned to lower the initial tq. (also good for grip).
A couple years back I installed a new cusco rs 1.5 lsd unit. Not having it adjusted before install was a HUGE mistake. When it's time to rebuild I'll change that.
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totta crolla
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Re: Aftermarket LSDs for the 1985 Zenki rear-end.
TRD is an excellent plate type differential and rebuild parts (wear parts, plates etc.the differential rarely breaks) are readily available at reasonable prices. The ramp angles are 45 degrees in each direction and it is this angle that primarily dictates how aggressive the diff will be. A 30 degree angle is more aggressive, it will lock easier. Some diffs have different angles in each direction 30/45 is possible as is 45/30, 45/45, 30/30. Ask the manufacturer what angles their diffs are before buying.
For rally use I find 45/45 to be ideal.
For rally use I find 45/45 to be ideal.
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gotzoom?
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Re: Aftermarket LSDs for the 1985 Zenki rear-end.
I track my car and I don't drift it (on purpose,) so maybe this will be useful to you. I have a TRD 2-way and a Tomei T-traxx. The Tomei is a vastly better diff, despite what you might read from supposed experts. IIRC, the Tomei comes set at 80% lock, and is the highest lock percentage available out of the box of any diff for the AE86. You can change the settings to get higher or lower if you want to. It is a Kaaz diff that has been tweaked by Tomei, so it's easy to find parts for it. Don't expect 100% lock to mean that the diff acts like a spool. I get inside wheelspin if I run too much rear swaybar on tight tracks, so it is possible to get wheelspin with any amount of lock percentage. The rear suspension will display any shortcomings of your diff.
Comparing the TRD to the Tomei, my feeling is that the car turns better, a lot better, with the Tomei. I can keep my foot on the gas and let the rear rotate with a high degree of confidence. Both feel comparable when trail braking. I don't trail brake normally. I prefer to do it when I need to rather than as part of my driving style. I let off the brakes as I enter the corner and roll right back on the gas. This is exactly what a 2-way is supposed to make difficult. It's simply not a problem with either diff. You may need to change your setup to get the same level of stability that I have, but the diff is probably showing you a shortcoming in your setup that was already there.
The OBX diff is a helical diff, aka Torsen. It's a good diff, but not for the AE86. Helical diffs are nice because they have no normal wear parts, but they don't work well on a live-axle rearend. Cars like Miatas, S2000's etc have independent rear suspensions and helical diffs work well with those applications. If you unload the inside rear wheel, they turn in to an open diff, though. With a clutch type diff, you get some resistance to wheelspin, but they will spin too.
Comparing the TRD to the Tomei, my feeling is that the car turns better, a lot better, with the Tomei. I can keep my foot on the gas and let the rear rotate with a high degree of confidence. Both feel comparable when trail braking. I don't trail brake normally. I prefer to do it when I need to rather than as part of my driving style. I let off the brakes as I enter the corner and roll right back on the gas. This is exactly what a 2-way is supposed to make difficult. It's simply not a problem with either diff. You may need to change your setup to get the same level of stability that I have, but the diff is probably showing you a shortcoming in your setup that was already there.
The OBX diff is a helical diff, aka Torsen. It's a good diff, but not for the AE86. Helical diffs are nice because they have no normal wear parts, but they don't work well on a live-axle rearend. Cars like Miatas, S2000's etc have independent rear suspensions and helical diffs work well with those applications. If you unload the inside rear wheel, they turn in to an open diff, though. With a clutch type diff, you get some resistance to wheelspin, but they will spin too.
Re: Aftermarket LSDs for the 1985 Zenki rear-end.
Maybe something else is going on with mine. It's my first aftermarket lsd unit. I'm also not an expert.
Mine usually feels what I'd consider normal for an lsd (good stability/grip, a bit obnoxious, grabby, slight po-going in turns from similar wheel speeds when commuting).
However, when the diff gets nice and warm (especially after doing u turn slides or donuts) the engagement gets really smooth and overall the feel changes, even at normal speeds. In general the car seems to glide around turns better, and when driving aggressive the rear wants to hang out. Very controllable, but when it's like this it seems to break away too easily.
Mine usually feels what I'd consider normal for an lsd (good stability/grip, a bit obnoxious, grabby, slight po-going in turns from similar wheel speeds when commuting).
However, when the diff gets nice and warm (especially after doing u turn slides or donuts) the engagement gets really smooth and overall the feel changes, even at normal speeds. In general the car seems to glide around turns better, and when driving aggressive the rear wants to hang out. Very controllable, but when it's like this it seems to break away too easily.
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gotzoom?
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Re: Aftermarket LSDs for the 1985 Zenki rear-end.
When I first installed my Tomei diff, I used the oil that was included with it. It chattered a lot at low speed and didn't engage very smoothly. Since then. I've switched to Motul P90 and all of those problems went away.
Have you verified that you don't have any thrust angle in the rear? I always had some on my car and I replaced my 4-links with fully adjustable ones last year. This enabled me to zero the thrust angle and the rear has never felt better. I've also found that the tried and true 8kg front/6kg rear spring setup only really works well with race tires. If you're using street tires (I'm currently running Hankook RS3v2's,) you'll probably want to go softer in the rear, and possibly a lot softer.
Have you verified that you don't have any thrust angle in the rear? I always had some on my car and I replaced my 4-links with fully adjustable ones last year. This enabled me to zero the thrust angle and the rear has never felt better. I've also found that the tried and true 8kg front/6kg rear spring setup only really works well with race tires. If you're using street tires (I'm currently running Hankook RS3v2's,) you'll probably want to go softer in the rear, and possibly a lot softer.
Re: Aftermarket LSDs for the 1985 Zenki rear-end.
Oil crossed my mind. Although my diff is relatively quiet now so I'm hesitant to change, but maybe I should give the motul 90 another try. I used it initially on break in when the diff was obnoxiously loud. It seemed to get even louder on longer drives. I switched to valvoline ns 85w-140 with 1 bottle of motorcraft friction modifier and it seemed to help on the longer drives, I've been using it since.
I had a diy short stroke setup with 8/6k rates, adjustable 4 link, and falken azenis tires. I was able to get 0.00 thrust angle with that. I've had a few other setups that were much more modest without the adjustable 4 link (all had an adjustable lateral bar though), and the thrust angle ranged from .02 to .08 on those.
I've had so many different combinations of suspension stuff, and diff always seems to act basically the same. The softer the setup generally the more noticeable it becomes. I think you're correct about the diff showing the shortcomings of the setup. Perhaps in my case this lsd unit is just to aggressive, at least for my taste and/or skill level.
I had a diy short stroke setup with 8/6k rates, adjustable 4 link, and falken azenis tires. I was able to get 0.00 thrust angle with that. I've had a few other setups that were much more modest without the adjustable 4 link (all had an adjustable lateral bar though), and the thrust angle ranged from .02 to .08 on those.
I've had so many different combinations of suspension stuff, and diff always seems to act basically the same. The softer the setup generally the more noticeable it becomes. I think you're correct about the diff showing the shortcomings of the setup. Perhaps in my case this lsd unit is just to aggressive, at least for my taste and/or skill level.