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ae86 gts differential... HELP!

Posted: Sun Jun 19, 2016 10:27 am
by ApeterE
I am in the process overhauling my ae86's rear end. and im trying to decide whether i should rebuild my torn up OEM LSD or look for an aftermarket LSD. I have looked into cusco and KAAZ and they do seem nice and impressive... But I really would like to hear from someone that is educated in differentials that could perhaps share their knowledge on what is the best/smartest decision. This car sees auto-x days and a lot of spirited driving with a 20v BT swapped into it.

Is it worth droppin the $$ for nice KAAZ 6-8 plate LSD or just sticking with my current OEM LSD and rebuilding it?
And also im not quite sure what the final gear ratios im seeing mean exactly, as shown in this link below: ... t-numbers/

If anyone has past personal experiences, please let me know what you think of like the differences between 1.5 way vs 2 way and final gear ratios.

The main objective of this post is to hear what people think of OEM LSD compared to a nice 2 way aftermarket LSD (KAAZ, cusco, etc...).

What diff are you all running on your hachi's??


Re: ae86 gts differential... HELP!

Posted: Sun Jun 19, 2016 3:31 pm
by Deuce Cam
It's roughly a $500 difference between the tomei 2 way lsd and the oem weir maxgrip rebuild kit. Imo it's not worth spending the extra cash on a cusco or kaaz lsd because they have basically the same quality, performance, design, etc. as the tomei.

I can't really help with comparisons since I've never had a good working oem unit or a 2 way, but I do have a cusco 1.5 rs (I like the concept of a 1.5 better personally). Usually the aftermarket units can be rebuilt (ie converted) to a 1, 1.5, 2 way if you don't like the original orientation, but I would ckexk to be sure on the tomei unit.

A stock gts has a 4.3 final drive ratio. The higher the number, the more geared down it becomes. Gearing down increases acceleration, but rpm also increases at every speed. Think of it like switching down a gear on a bicycle: one now has to pedal more revolutions.

I also have a toyota 4.778 final drive. If I could do it over again I would have stuck with the oem ring/pinion and rebuilt my oem lsd. Don't get me wrong my current setup performs great, but it's way overkill since my car is only used on the street.

Re: ae86 gts differential... HELP!

Posted: Tue Jun 21, 2016 3:09 pm
by ApeterE
Thanks a million for your input! It looks like im just going to do a full rebuild on my oem lsd. I sure would love a nice aftermarket 1.5 or 2 way but i think rebuilding my oem lsd will suffice just fine considering the amount of other things i need the money to put into

Thanks again for the info!

Re: ae86 gts differential... HELP!

Posted: Wed Jun 22, 2016 10:32 am
by chohdog
An aftermarket LSD is one of the modifications that can greatly increase the performance of an AE86..but like all good things it comes at a price. If you can save up for it, get an aftermarket. The increased levels of grip, ease of drift and throttle modulation are worth it in my opinion. I used to think a rebuilt OEM unit was fine, and that's what I did about 15 years ago. Then I bought a TRD, and it was awesome (and a big difference in grip). Then, a few years ago I got a Tomei, and it was even better. Keep in mind that there are many brands and they do differ, and one of the things that you should consider is the importance of support in the USA.

Quick breakdown of manufacturers (yes they are mostly different)

TRD: readily available in Japan, and has support in the USA (rebuild kits). Lockup is relatively mild, has cast housing. Tried and true LSD, but working on 30 year old designs. Has the least amount of clutch plates in LSD, so will wear the quickest.

KAAZ: Great LSD, forged housing, good number of clutch plates (12 I believe), has support in the USA (There is a KAAZ usa). Lockup is adjustable by sequence of clutch plates.

Tomei: Made by KAAZ, but has a higher initial torque setting. Exact same as KAAZ except for this reason.

Cusco: They manufacture an LSD for every taste. Higher cost of entry, but has support in the USA, and can choose between RS and MZ (you can do your own research here). I believe they have 14 clutch plates.

ATS: Awesome LSD with a great resume of motorsport experience, but withdrew from the USA market (no support anymore). If you can find one for cheap they're great, but good luck finding a rebuild kit.

OS Giken: Perhaps the best LSD for the AE86. 16 clutch plates, USA representation, proven faster lap times, and long term reliability. These are the most expensive LSD's for the AE86, but many will tell you well worth it.

So between those choices, you have multiple price points, periods of wear, support, response/lockup. The OEM lsd will work, but it is nowhere near what these can offer.

Re: ae86 gts differential... HELP!

Posted: Wed Jun 22, 2016 11:35 am
by Deuce Cam
Great points.

The aftermarket units are not only brand new, but stronger, and should have better support if a part breaks and needs to be replaced since oem stuff is probably dicontinued. Also consider that the oem units are only 1 way (I think).

My gripes with the 4.7 r/p and cusco lsd are mainly comfort related (and cost). I hate them when commuting, but love them when driving spiritedly.