jst2878

How much was the purchase and cost of install. Next year addition

odb812

I'd have to look back and check on the cost, I ordered some fluids and stuff at the same time. I'm not sure if they're still running the group buy, but Matt(SpeedFreaksUSA) could probably get you a quote.

We did all the work ourselves, so there was no labor for the install, just $130 in bearings.

andrewhake

Great review! Looking forward to getting mine installed as well.

odb812

Thanks, man. I'm interested to hear your impressions. I think you'll like it.

satoman44

What are your thoughts on low speed turn-in? And also, is it the recommended OS Giken settings? I'm sitting on one right now, but my local region runs much tighter courses than national style courses so there's more low speed elements than fast sweeper stuff.

imstimpy

I've been running an OSG in my SCCA STR S2000 since ~2012. The car definitely tightened up when the diff went in originally. Some people have complained about understeer, however a minor suspension change balanced that. I recently had my Torsen re-installed for a few months and the throttle timing differences, and the resultant attitude, were startling. The snap-oversteer came back, too, caused by bumps or who knows what. All ill characteristics are, once again, gone with my freshed OSG re-installed.

An OSG car requires distinctly different throttle application compared to the factory diff. The Torsen is open on turn-in, or off throttle, allowing large variations in attitude through the early phases of the course. If throttle timing is wrong, the car oversteers. The OSG trailbrakes like a boss. The braking can be pushed deeper without fear of oversteer, and the longer I wait off throttle the more rotation I see. It is harder to "dance" the OSG, especially on the RE-71Rs, but it is so consistent and predictable that it more than makes up for it with extra throttle.

You will not be immediately faster by installing an OSG. However, it gives you opportunity for more throttle and better car stability and that will yield lower times.

djsilverjohnson

I've run a VLSD, a KAAZ 2-way, a NISMO 2-way and an S15 OEM Hitachi HLSD in a DSP classed 240sx, and the HLSD gave me the best results. I've now been driving and autocrossing an AP1 S2k for 2 years in B-Street class, but the HLSD in the AP1 is very different. During autocross, everything happens quickly and it comes across as snap oversteer. When driving the car on the street on some winding roads I figured it out. When going around a bend on power, I didn't really notice the steering being "tight", but when I would let off the gas, I could feel the HLSD unlock, the steering free up and the car would "turn in". I suspect the HLSD in the S2k either has more aggressive angles than the unit in the 240sx, or the suspension is more sensitive to the locking/unlocking characteristics of the HLSD. After that experience, I was more sensitive to it's action and was better able to adapt to it ("drive around it"). The advantage of the OSGiken is likely in it's consistent behavior compared to the HLSD.

odb812

The car feels more confident on low speed turn-in. Before I got the OSG I was worried it was going to push on the low speed stuff, but as long as you're setting the weight where you want it on turn in and drive the car hard, it doesn't feel pushy. You can feel it driving around tight stuff at slow speeds, like in parking lots, but not when driving the car hard on course. You can see my video in the first post the lot is pretty small and low speed and the diff doesn't hold the car back any.

It is the recommended S2000 settings from OS Giken.

Good point. It's not like losing weight where you can drive the car the same way and your time will be faster. The driver has to adapt to get the time and consistency out of the car with the OSG, but the adaptation was pretty straighforward for me.

manystyles

Nice write-up! Slowly bookmarking threads for research on building up my SSM.

youcandoitall

Thanks for the write up. A bit late to reading this thread, but wanted to know if you had any follow up comments about the OSG and how it affected your AX experience.