Gingerman Raceway and Sport Package VLSD
 

Differentials
So i've been doing some investigation into differentials.

After my most recent track day, [footage coming tomorrow], ...I have determined that the VLSD, while inferior, is good enough for me.
I can still light up the tires and get it sideways @ 60 with the Sport Package diff. So my motivation to switch to a Quaife is decreasing.

Gingerman Raceway commentary
I just upgraded tires to Toyo R888 (from Sumitomo HTR III), so that in itself should prevent a lot of the drifting i had at this last HPDE.

Quote from corner workers about my driving this weekend:
- "Should we bring him in for drifting the corners?"
- "Nah, it's controlled, so should be fine."

For reference
Gingerman Extended track: 1:50.xx
...on hilariously slippery tires.



Not sure why, but some tracks don't like you sliding around the corners so much. Meh, that's 1/2 the fun! :stirthepot: But the only reason the tail was sliding was to decrease the understeer, balance 'er out.

Moral of this Story
To let you all know that unless you need the last 0.5 second out of the 370z's lap time, don't bother with a differential. But if you have $2k burning a hole in your pocket, it is a nice upgrade.

OH, and don't buy Sumitomo tires.

The VLSD does OK when it's new and you haven't heated it up from spinning the inside tire and all that, but with that kind of use, the fluid will break down and it will become an open diff before long.

Very true... which is why my diff and trans are on a 15k fluid cycle. :tup:

That's great, but you can't change the fluid in the part of the diff that actually does the limited slip coupling.

cute, i changed my diff fluid in my VLSD equipped Z prior to every track day with redline 75w90. after the 6th track day, it basically became an open diff after 1 lap. once the viscous fluid that is sealed goes, there's nothing you can do

My VLSD goes dead after about 10 minutes on the track. Hoping to get a new diff in the fall IF I can get the money manager's OK on it.

Stock VLSD definitely needs a cooler. Mine pukes fluid and has a nice little hum to is now when warm. Not sure if the Cusco or other aftermarket diffs run cooler by design or not but, a diff cooler is a good investment. If you run alot of track events keep a eye on the fluid levels and up your fluid change cycles.

I just switched from stock VLSD to Quaiffe+SPL solid bushings+ 4.08 FD+ Nismo finned dif cover. There is no comparison between the two in terms of being able to put the power down. I can pretty much drive my car sideways now if needed. I can't really knock the VLSD, it is what it is and performs fine for street, light track use, but it is ultimately very limited and limiting to the driver that has exceeded it.

Install+parts+millions of other little gaskets shims and rings, when it is said and done you are looking at more like 5K installed for the stuff I listed above. I decided on the Quaiffe over clutch types simply because I only do road racing, and I didn't want to have to do rebuilds. It also seems to make sense that heat will not affect the torsion type like it will a clutch type as severely. If I drifted, dragged, or did autoX I might have decided on a Giken or Cusco instead. It was 5K that could not have been spent better on the car save for maybe brakes or wheels+tires imo(but I already have those).

And what Davey said above is very true, the part of the VLSD that does the coupling, is sort of like a thick Vaseline for lack of better description. Once it has been heated up and stressed so many times, it eventually just wears out altogether. When you change the fluid, you are not changing the part that is doing the work.

This is why I'm not married. :tup:

This is why I have my own Davey Fun Time Slush Fund(tm). :tup:

Bump for +Added video :driving:

Didn't look like much drifting to me. I destroyed an R6 at Gingerman with inside wheel spin from the damn VLSD. I scrubbed the rubber off the inside shoulder of the inside tire.

I put a NISMO diff in the race car though. :)

I think you can pick up a good bit of time by taking 10 tighter and carry more speed and go wider on exit of 1. Looks really nice through 5 and 6.

Nahhh it wasn't crazy sideways, just power-oversteer after the apex.

And good point on the "wide on 1."
"Ten" is still a mystery to me, can't seem to find a consistent line. Stupid understeer / off camber.

Thanks for watching :tiphat:

A diff cooler really helps keeping it working. I can drop 40 degrees when I kick the pump on within a few seconds. it's not enough oil to keep it cool but with it on and cooling it's 100% colder than off all together. Doesn't matter though, I have a whooping 270's RWTQ and I can't touch the throttle with 285 RS3 without breaking 1st, 2nd and half of third. It's really getting old. Bout to just install a 300lbs fat chick in the trunk. Idk how FI guys drive these cars!

my last dyno put me at 265.3 ft/lb tq. either your RS3's are shot, or you're full of ****. i cant imagine 270 breaking traction in 1st, 2nd and 3rd in our cars.