Educate me about diffs.

[Halle Terry]

I've got a bit of an interest in drifting, and obviously the stock Torsen can on occasion prove to be a bit unpredictable.

I want a new differential sometime soon and figure I'd best start educating myself on what is worth looking for and what suits my driving the best.

I know the basics, ie

1 way - lock up under acceleration.
1.5 way - lock up under acceleration, and partial lock up under deceleration.
2 way - lock up under acceleration and deceleration.

But a few terms allude me, ie Selective vs mechanical.

Also, diff gearing has me quite interested, the R154 as it stands is 80kmh in 1st, 2nd - 120kmh, 3rd 160kmh etc, goes all the way up to 280 supposedly.

Now that's all well and good but not very relevant to me, I imagine changing the diff ratio's will drop the total speed of each gear, thus allowing 3rd to become more usable to me. Are there any other ones besides 4:3? I seem to see that quoted a lot but never any other ratio.

I imagine the 1.5 way would be the best compromise between street and driving feedback?

[mitchy]

4:3 is a TV aspect ratio, not a diff ratio. :p

you can use your original diff gears on a different diff centre.

usually the diff gear options are limited to other models that share a diff, ie the A80 might? but that also doesnt make them compatible, the supra 6 spd might have some weird ratio to compensate for the 6 spd box ratios like the getrags in the R34 GTR's do.

a 1.5 way with your standard gears will likely be fine.

[Halle Terry]

Will the speeds in each gear change? I imagine I would have a wide-ish selection of diff gear options as R154 was in the Soarer, Supra and JZX models.

Like I said, I'd love to have 3rd gear usable, the car doesn't really have the power to do anything in that gear and I don't really intend on smashing big HP into it.

[mitchy]

yep, diff ratio will affect speed in every gear.
do you know what your current ratio is/what options are available?
you also have to note that pulling down the ratios will affect your crusing speed in 5th, and fuel economy.

[coFF33]

with a JZ and a 154 you want something like a 4.11 for drifting
Most LSD's will come as 4.11 or 3.9 ... but the combination of JZandR154 makes 3.9 really nice for doing long drives up to kalbarry....

but 4.11 has a bit more low end power and shifting to 3rd at 4000+ rpm will be blarting out max power to the rears .

[RELEASE]

edit...too slow mitchy and coFF33 beat me

[Halle Terry]

Yeah I realized that I would lose a good rpm on the freeways, but the car rarely goes out on long legs, my trips are generally pretty short as most things I need are close by. I figured it was a sacrifice worth making.

I just a quick Google, stock Torsen is 3.7

"massive difference with 4.3's now!!! Doing about 100km on the FWY and it sits on about 3000/3100rpm and the speedo says 140km lol."

Just found that too, surprised it also changed the speedo reading, thought that was in the gearbox?

[TJ]

1.5 way 4.11 from trd would be ideal.

[Halle Terry]

Also, I can't see myself affording a new diff in the next few months, will a change of oil make it perform better?

[coFF33]

1.5 way 4.11 from trd would be ideal.

^^^^

TJ on the money.


Yes your speedo will change tho Telly... but that can be changed easy enough..

[mitchy]

it will certainly help!

[Halle Terry]

So the 4.11 would be a good compromise between cruising speeds and making 3rd a gear I can use?

Selective or Mechanical?

[coFF33]

Mech
1.5 way

and yes

5th gear should sit round 2900-3000 on freeway at 110

and will light up 3rd.

[shifted]

If you ever see "WHIPPED" driving around, JZA80, he has either a 1.5 way or a 2 way TRD Diff in his Supra. He might also be able to provide you with some good info as he has gone through 2 of them already I think.

[TJ]

Also, I can't see myself affording a new diff in the next few months, will a change of oil make it perform better?

Fill it with welding - should make it predictable at least b

[Halle Terry]

Is that what you're currently running John?

[TJ]

FYI my Cressida had a trd 1 way but 3.9 iirc.... It never went 1 wheel.

[mitchy]

TRD diffs must be pretty average if you can smash 2 of them with the claimed ~500 ponies of "whipped"

maybe something like a tomei is a better option?

[180SXTCY]

get in touch with greg aka dalspec on silwa.

diff guru.

[Halle Terry]

Well Tomei, Cusco, TRD all make JZX diffs.

Anyone care to clarify the difference between Selective and Mechanical?

[SEXUAL TYRANNOSAURUS]

TRD diffs must be pretty average if you can smash 2 of them with the claimed ~1000 ponies (stock Internals) of "whipped"

maybe something like a tomei is a better option?

Fixed :)

[mitchy]

what diff mentions 'selective'?

usually it's viscous, or mechanical. viscous are the usual cheaper factory diffs, mechanical are usually stronger and less prone to chicken.

ie, my 31 has a factory mechanical, and it's yet to chicken wing.

[RGVFAST]

I had a 2 way TRD diff in my soarer. It was great to drive and very predictable.

No horrible cluncks with tight turns, just a little tyre scrub noise.

[AGIT8D]

Kaaz are good fun eh.. You know what they say: Double or nothin!

[Bomber]

1.5 way KAAZ LSD ftw.

Ideally you want to get your peak torque coming into play for your drift purposes. Look at your dyno printout and judge where your useable torque is either side of the peak and relate that to your current road speed. Then you'll need to work out what diff ratio will best suit gears 2 and 3 as that's what you'll be using on just about all the corners, lighting up 4th would be a bonus if your keen on pretty high speed roll outs. As TJ said, 4.11 would probably be the go if your not chasing mad hp otherwise 3.9 would give you best of both worlds.

[Halle Terry]

what diff mentions 'selective'?

usually it's viscous, or mechanical. viscous are the usual cheaper factory diffs, mechanical are usually stronger and less prone to chicken.

ie, my 31 has a factory mechanical, and it's yet to chicken wing.

http://www.greenline.jp/catalogue/bccatpartlist2.php?make=Toyota&carcode=JZX100&intake=FI&category=drivetrain

The two TRD ones at the bottom.

[Joe]

Also, diff gearing has me quite interested, the R154 as it stands is 80kmh in 1st, 2nd - 120kmh, 3rd 160kmh etc, goes all the way up to 280 supposedly.



*sigh*

I can only dream of that with mine.. 96km/h at redline in 2nd gear... needs 3rd to get to 100.

Great for blatting out of corners though, not cool for having roll-ons!

[mitchy]

you have a 6spd dont you ballsac?

[Joe]

Ja

http://www.babble.com/CS/blogs/famecrawler/2007/09/16-22/ja-rule.jpg

[mitchy]

LOL, you have your own range of jocks too?

[cplagz]

I have a KAAZ 1.5way with 3.15 diff gears in my BMW and 2nd gear tops at about 120, 3rd is about 175 and 4th is 240ish (from what Sean said on the dyno) but again - speeds and diff ratios will vary with different gearbox ratios also.


It's great :)

[Joe]

LOL, you have your own range of jocks too?

Yes, I sell boxers for black people with large black penises.. they are modelled on my own physique.

[mitchy]

damn, i wanted a pair too. :(

[Bomber]

Yes, I sell boxers for black people with large black penises.. they are modelled on my own physique.

So no foreskin then

[yeahlow34]

ie, my 31 has a factory mechanical, and it's yet to chicken wing.

Doubt it would chicken wing when you push it on/off a trailer, brah.

[AGIT8D]

Yes, I sell boxers for black people with large black penises.. they are modelled on my own physique.

Junk in the trunk?

[mitchy]

Doubt it would chicken wing when you push it on/off a trailer, brah.

i can drive mine on and off the trailer, unlike your John Deere 1600.

[coFF33]

Telly, in my soarer i have a 4.3 welded diff, as :

1. i dont have $1k for a diff
and
2. welded is never gonna fail me until it completely fails..

in saying that, its got cheap ass lsd oil in it and has had its ass kicked for 4 years of drifting now... yet to have an issue with it.. and its completely predictable.

Im putting in a 4.11 this season as i dont like smashing limiter and not being able to push harder through the S's on barbs. This 4.11 will also be welded.

I drive my soarer to barbs and back to my garage and no where else though, apart from collie.... even then thats only once every 3 months

but as you will be driving you X100 daily... i suggest against this method of LSD

[Halle Terry]

What type of oil should I be putting in my diff then to get it to perform better?

API.GL-5,SAE85W-90 is the factory recommendation.

[coFF33]

oil wont do fuck all
its a myth

your shims in it are getting worn, oil wont help

[yeahlow34]

i can drive mine on and off the trailer, unlike your John Deere 1600.

I can drive it on. Just sounds like a giant rattlesnake.

pingpingpingping.

[mitchy]

I can drive it on. Just sounds like a giant rattlesnake.

pingpingpingping.

don't all SR20's sound like that?

[Sciflyer]

Cant use Supra/Soarer diffs, they wont fit a JZX

I would agree something around 4.08/4.11 :1 is good with an R154 (thats what i run), dunno what sort of ratios you can get though

Its a little short for freeway use (5th is getting close to 3k rpm for 110km/h) but great for track work

As CoFF said 4.3:1 would be way too short

[ovaxitd]

ok telly you have 3.7 and auto jzx has 3.9's, your are able to get 4.11, 4.3 and 4.56 if your really keen. i know that the 411 will give you better acceleration. 4.56 the best but driving down freeway will have you in like 3200rpm @100

for street and your clutch kicking ninja moves i would look at a 1.5... get a spare diff and do the change as your luck you will need to change it for pits :p

the jzx diff housing is differnt to everything else in the world :( the center however will go in from a80,a70 x83,x90 and a few more.... as long as its a 8" diff....

[Halle Terry]

So general consensus is 4.11? I might as well invest in a Mechanical 1.5way TRD one, least that way I can try and pretend it's a factory option if I get yellowed again.

But thanks for the info guys, much appreciated!

[TJ]

Nothing wrong with the stock LSD!

[ovaxitd]

when you have one...

[TJ]

Terry knows I do :D

[Halle Terry]

I have a feeling you're about to find out if a certain white S15 and a grey 32 also have LSD...

[Fujiwara13]

If you ever see "WHIPPED" driving around, JZA80, he has either a 1.5 way or a 2 way TRD Diff in his Supra. He might also be able to provide you with some good info as he has gone through 2 of them already I think.

Ben said he ran a 2-way when I asked him about it a few weeks ago, but advice from him may be of the "this is how you most effectively break shit!" kind.

[d1mitch]

did you end up finding what gears you had in there atm? if you have 3.7's 4.11's will be optimal

[Halle Terry]

Fellas,

Saw a TRD 2-Way from a A80 at JPC, $895.


Any potential problems buying a second hand diff or is it pretty hard to fuck something like that up? I might be able to get it a bit cheaper as I don't need the housing, just the core.

Unsure what diff gears are inside it however.

[Joe]

Clutch plates can wear out.. but you can usually buy rebuild kits for a reasonable price.

Doesn't matter what ratio it is, if you buy the centre and its a drop-in for your car, you use your original crown wheel and pinion.

[Halle Terry]

Ok guys, spotted a JZX100 Cusco RS 2-way, unsure of gearing at the moment. Second hand, about 5000k's on it.

What's everyone's thoughts on it? Is it pretty hard to separate brands when it comes to basic things like LSD's?

[ovaxitd]

fuckin buy it... 5000kms are f all bro... as for gears rn106 hilux 8" crown/pinion go straight into x100 housings :) go 4.56, 4.3, 4.1 or even upgrade to an auto 3.9....

[Halle Terry]

Yeah it's $750 in the US, so I'm assuming about $100 to ship or so.

Either way I'm awaiting a reply from the seller, it's just the core mind you, but I'm sure that's irrelevant.

Thanks for the info on the gears, I'll have to track one down if I manage to buy this.

[Halle Terry]

So I ended up buying that Cusco RS.

4.11 gearing hopefully to suit soon, I'm also deciding if I want to buy another housing incase I get yellowed (again) so I can just swap my diffs around quickly without hassle.

Anyone got any leads as to where I can get this thing built?

[mark]

as for changing diff to go over pits couldnt you just put lots of friction modifier in there to take it over?

[mark]

Greg i think his name is. goes by the name of dalspec on the forums
0447710000.
apparently this guy is the shizz for diffs but if its just droping the centre in any diff place can do that or do it your self and get the backlash checked.

[Sfidz]

+1 for greg, the diff man.
He may have another stock diff to suit your car aswell for pits perposes

[Halle Terry]

Sweet, do you guys know if it's legal having a 2-way?

[carlos spicy wener]

Sweet, do you guys know if it's legal having a 2-way?

haha no.

i have heard of people passing with them still in, but 99% of the time you will get asked to remove it.

[Drift_R32]

once u take your foot off the gas its an open diff though.. a locker is illegal i know that cause its always locked. Pretty much can say an LSD is illegal cause once u get on it it has the potential to lock both wheels.

[Lonewolf]

once u take your foot off the gas its an open diff though.. a locker is illegal i know that cause its always locked. Pretty much can say an LSD is illegal cause once u get on it it has the potential to lock both wheels.

a 2 way is locked on accelleration and decelleration, hence why you get it skipping in car parks.
DPI would likely have issues with most 1.5/2 way mechanical diffs.
No issue with Torsen or Helicals as a lot of cars come with them from the factory.

[Drift_R32]

yeh i know ive got a 2 way in my R32.. its brutal as fuk,

[Halle Terry]

Hahha aw sheet :(

Guess I'm buying a new housing for my diff then haha.