Getting the 5.125 rear end should I also replace the lsd
 

The 5.125 is already pricey enough, but would it be worth while to get the os giken lsd and be done with the diff?

What type of racing do you do?

Track days with the local group not scca or nasa.

I got the tomei 2way lsd and its awesome! Highly recommend it.

Not much help from me, but I'll be interested to see what you decide to go with. I'm in the same boat.

What's the best price you've found on the OS-Giken unit?

Don't put a 2 way diff in a road course car you'll understeer like mad...

You're better off to go with a fresh OEM LSD if you feel yours is beat up. Especially if you will still be street driving the car

someone on here did a review on a 2way and went back to stock. try searching for it

Posted From RX8Club.com Android App

hopefully you are also installing an electric gear oil pump, oil cooler, and oil lines tapped into the rear diff cover to keep it from overheating

Great idea!

In all fairness, some tracks will heat up diffs quicker than others but I don't know of many people who can run upwards of 20min with the 5.12's and not overheat to some extent

You're right. I'm sorry. It won't happen again.

It's not that big if a deal. I was just pointing out that over 10 years of information and experiences are documented here if you take the time to look for it ...



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That will be part of the plan. Thank you.

Are you doing it on your own? Esther way make sure you get some set up info on the backlash. You do not want to run the stock recommendation. I can get specs if you need them. Replace the seals and such while your at it, that stuff is cheap considering your probably sending a solid 2k on this...

Stephen

I'll be having a shop to put it together.

Why not posted up the specs for everyone to see them? Figuring it needs to be looser to accounts for the heat load ...

I will be installing a 5.12 on my car in the next couple of days. Using the factory LSD. I'm not planning on oil cooling just yet. I won't be doing sessions longer than 20 mins.

I don't have the specs as I bought the whole pumpkin off of a race car.

I will report any weirdness I run into.

A diff cooler is always a good idea... that being said I've run my 5.12 diff in my car for three seasons now with no cooler and no problems. It does get hot and sometimes spit oil out of the vent on top... but it has held up so far. Most races are 25 minute sprint races but I've done some 45 minute races as well.

say again ... ?

https://www.rx8club.com/rx-8-racing-...advice-224093/

pretty sure you won't stay anywhere near 200*F without a cooler setup

You are like the search master... or you have a postographic memory! lol

It turned out that diff was built incorrectly. The problems I was having that I talk about in that post were not due to the gear ratio but due to incorrect assembly/setup. After that race I had the diff redone by a more knowledgeable shop and since then no problems.

I'm not saying a differential cooler isn't a good idea. It definately is - the rear end gets really really hot. I'm just saying that you might be able to get away without one... at least for a while... who knows... mine is probably a ticking time bomb! :)

For that cost you might as well get an OS Giken LSD. Maybe I'm the only one here who has one?


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I'm using the factory LSD.

Mazda only sells it as a complete assy; $640 + shipping from Motorsports. Might as well buy a tunable aftermarket LSD instead of ever replacing it.

my low mileage OE LSD is sitting in a box waiting for a new home if anyone ever needs one (approx. 5000 miles combined street/autox use)

Installation note: easier to pull the end links off from the inside (pulling the bolts off) than pulling the ball joints - you will need to realign the rear anyway. Check the diff mounts when you do so. Buy extra half shaft clips.

I can say it is amazing on track.