Learn me about differentials...
 

I went to a HPDE at Gingerman this weekend.
My goal was to get on the throttle sooner / carry more speed thru turns. In that, I was successful. The inside tire now lights up on turns for 20-30 feet.

I can manage the throttle and not do this as well... but isn't this what a differential is supposed to prevent?

Car has 4 track days and 33k miles. Mods in sig.


Update:
- Looking at Quaife rear diff @ Z1... suggestions?

Cusco type RS, OS Giken, Nismo Pro LSD. These are all quality clutch type limited slip differentials.

That depends on if you've got the VLSD from the sport package or the open diff from the base.

Do you have aftermarket swaybars?

Stock sport package vehicle... so VLSD is included, but not terribly effective.

OEM sway bars as well.

A set of aftermarket sways would be money well spent. It's a night-and-day difference from stock. It may even help with your traction issue. As cheap as they are, I'd try that first. Swapping the diff would be great, but it's a slippery slope of things to do "while you're in there". If you're dropping the pumpkin, maybe you want to do gears. Since it's already out, maybe a set of upgraded diff bushings. If you're opening it up, maybe that sexy finned Nismo diff cover. And so on. :rofl2:

I have one autox event with my quaife. I cant compare it to the VLSD, (base model), but i definately did not get any inside tire spin if you ease on the throttle. But if you MASH on the gas then i would power slide and oversteer. But once my race car fund gets alittle bigger i want to do the fined cover and bushings. I am pretty sure the helical type LSD is less suseptable to heat than the Clutch type or VLSD because its gears, but you also have to worry about the bearing surfaces too when it gets hot. For my install by a good dealer i paid $610 for the install but i already had the new bearings and ring gear bolts which is another $120, plus the new axle stub seals and drive seal, crush washers and oil $60. I didnt factor all this in when i was planning all this out but i can do the bushings and finned cover myself. It took them two days with juggling my car and a '09 GTR.

It could be the VLSD, they are only meant for light use. When the Diff Fluid (not the oil) heats up it won't work and will be an open diff until it cools off again. The sport diff will only last about 50K miles of street use before the hydraulic fluid wears out, tracking will wear it out much quicker so I would plan on getting a new, proper one sooner then later being at 33K miles.

Thank you for discussing my life right now. lol ;). I have decided to do the gears, but kitchen counters are coming first. I was able t finally land a nismo diff cover. HUGE thanks to Mike at corner3. I think he was like the first one in the country to get one in about 9 months.

In a nutshell...
Viscous LSD work, but are much less effective as the heat up. They can wear out as previously mentioned.

Cusco...many others, are clutch pack type diffs, and are generally the best performing diffs. They are adjustable for performance, And they tend to be lighter (rotating mass...important). Their issue is that they will require maintenance over their lifetimes...being clutches.

Torsen style diffs (quaife) is a gear driven differential, a bit heavier than a clutch pack, but bulletproof. Put it in and never worry about it again. It's issue is that if you ever lose complete traction on one wheel (lift in the air, water, ice etc) it basically turns into an open diff until you get traction again.

I know the next question ; Why did nissan put in a VLSD in our car? Easy answer...want to guess which diff is the cheapest to produce?

Tracy Ramsey
2012 Base/Sport
99 Spec Miata

Nissan for years loves OE equipping their cars with crap VLSDs lol. Honestly they should've put the VLSD into the base model 370 and a torsen in the Sport package and Nismo, plus made the finned cover factory

Very typical, save up for a new diff

Presuming my Z is a daily driver... I am looking at a 1.5 way... not fully locking 2 way.

Get the OS Giken. Smoothest 1.5 out of the box

:iagree:

FIRST let me learn you about grammar xD

:shakes head:





:inoutroflpuke:

No but seriously...

I like the idea of the Quaife that doesn't lock up under slow turning.

THIS is the model i was thinking of: QDF13L | Quaife USA


What's this about upgraded diff bushings? *strokes chin
- Anyone?

Yes the QDF13L is the one you want. I will warn you though, the Quaife is only a small improvement over the stock VLSD and you will still get wheel spin out of corners. I wish I went with a clutch type.

Are you upgrading anything else while its down?

Also make sure you buy new diff bearings and ring gear bolts. I bought mine from a near by dealer and i later after they were installed i saw it was wayyy cheaper on courtesy parts.com I also did not need shims but you wont know that untill you acctually install it and measure backlash, so that is a potential $50 or so on top of everything.

Whiteline diff bushings. Less than $100, goes a long way toward fixing wheel hop. Money well spent, especially if you're pulling the diff out anyway.

Really?!? Wheel spin as in, inside tire lighting up?
or
Both tires sliding properly?

I don't want to have to do maint on the diff all the time either... that's another perk of the Quaife... but now i hear it doesn't really work well :shakes head:

It worked better then the VLSD, but its still limited by its design. If you want the most low maintenance/smoothest clutch type LSD, go OS Giken. If you want the most versatile and tunable clutch type LSD, go Cusco Type RS. If you want a affordable yet still decently smooth clutch type LSD, call Kaaz and have them setup a 1.5 way with "Super Q" clutches. If you want cheaper but still effective, go Nismo Pro LSD, regular Kaaz, or MFactory.

My only experience with a 1.5 way vs 2-way differential was with Gran Turismo.

The 370 is the first car i've purchased that's had a LSD... and it blows

- Any drawbacks of 2-way?
- Which one binds up when ur driving slowly?

I remember reading a thread about how someone's OS G LSD unexpectedly locked up on the track a couple of times. Did that ever get sorted out? That really scares me about clutch LSD's.

Even a torsen can fail the wrong way and lock itself. Usually failures like that are from over heating

when a Clutch type is noisey or "chirps" in low speed parking lot driving, it has to do with the Lock % setting, not the "way". a more aggressive lock setting with be rougher in low speed. 60% lock is good for DD and track fun on street tires. 80% is good for street and track on wide high grip street tires or R comps. 100% lock is good for drifting or a track only car on slicks.

In regards to the "way", that is the lock percentage rate during accelration and deceleration. if you have a 60% lock, then under throttle that is what you have, under decel, you have 30%. 2 way is the same lock % under accel and decel. road race setups tend to be good on 1.5 because there is less corner entry understeer, drifting is good on 2 way since you are constantly on and off the gas the lock % stays consistant

I'm currently going round and round in my head as to which LSD to upgrade to myself. I'm currently leaning towards the quaife b/c of the low maintenance but I'm afraid down the line I might wind up switching it out again for a "better" performing one like the OSG or nismo.

all the positive reasons people go quaife instead of clutch type are valid, and i myself even did that on past track car i had, and it was nice for the time i had on it. then i went clutch type and ill never go back HAHA

Helical only locks up 1 wheel at a time. Clutch type locks the whole axle. OS Giken has the most clutch plates. An aftermarket clutch type diff lets the car put down all of the power right away. No need to mess with anything else. But upgrading the diff bushings and to the finned diff cover are great ideas

Clint, I'm assuming you're on the OSG. How many miles do you have on it so far and have you ever had to service it (other than oil change)? Everyone is scared of the maintenance of clutch type LSDs but I don't know anyone who's had to service an OSG one yet. The same cannot be said for carbonetic and nismo, however.

No im not on a OS Giken, but ive driven on several in FWD, AWD, and RWD cars. Im actually on a Cusco Type RS, but mine is custom tuned. Im pushing the OS since its prolly the least maintenance from the get go. The Cusco is setup too tight for proper road course grip, but its easy to open and tune and even comes with instructions on how to, but most people here dont want to tune there diffs. OS giken's cannot be tuned privately, only by sending to OS. FYI ive had my Cusco for over a year now, lots of DD and track days and still no issues, just changing fluid.

This is why my first upgrade for <$500 was a diff cooler. Way easy to do and keeps the temps down so it works!

I have a set :tup:

But I prefer the solid SPL.

im on the solid SPL diff bushings too, but some people i dont think can deal with the low super charger style whine from the ring pinion once you go solid lol. but then again i dont know how the NVH is after the whiteline poly diff bushings is in comparision

You can't hear a difference with the whiteline ones.

that being the case the whitelines are better for a DD

Really? I hear nothing! Granted I'm stripped and have a no muffler exhaust. Only maybe have I heard something once or twice. I really wanted a loud whine. I was expecting something like poly motor mount bushings I did in a Wrx once. Being so quite I'll be doing solid tranny bushing and poly engine will be plenty for me if its like the jaw shattering rubble the WRX had.

Clint do you run the rs-spec f ? Just quicly looked at the cusco site and the spec f looked to be kinda road course specific. Do you also have to modify stub shafts or any other stock parts?

when you had yours tuned what torque were finally set at?

alot of questions I know just really interested in this LSD.

thanks