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S13sr95240
08-09-2005, 01:24 PM
I need recommendation on what LSD I should use for track race.(road course).

KAAZ, NISMO, or others?
1.0, 1.5, or 2 way?

The car is an S14 with Sr20 swap.

Thanks!

wootwoot
08-09-2005, 01:47 PM
I say other, s15 hlsd. Search on ebay, just make sure to get the half shafts with it.

stealthx32
08-09-2005, 02:10 PM
I really liked my Cusco RS @ the Streets of Willow. Low initial torque + preload using springs = smooth engagement and silent operation. http://forums.freshalloy.com/images/graemlins/cool.gif

But the S15 HLSD would be cool too.

steve shadows
08-09-2005, 02:53 PM
I need recommendation on what LSD I should use for track race.(road course).

KAAZ, NISMO, or others?
1.0, 1.5, or 2 way?

The car is an S14 with Sr20 swap.

Thanks!



Nismo 1.5 is my liking but many like the 2 way better.

Some suggest better braking ability on entry into turns without needing to apply brake pressure.

Kookz
08-09-2005, 02:57 PM
I really liked my Cusco RS @ the Streets of Willow. Low initial torque + preload using springs = smooth engagement and silent operation. http://forums.freshalloy.com/images/graemlins/cool.gif

But the S15 HLSD would be cool too.

Ditto on one of those 2, or an ATS Carbon diff. I also have the RS, and it rocks.

vitaminT
08-09-2005, 05:42 PM
I like the ATS 1.5way but if it was solely for road race I would get the Quaife. Basically an aftermarket/upgraded S15 diff.

alex_kors
08-09-2005, 06:02 PM
ive drifted an ATS carbon 2 way diff, i liked it a lot very smooth, and quiet, its not the greatest if you dont have any real expereince drifting becuase you can never feel it lock up, but if you are road racing, i bet it would be a great diff.

shoes59
08-09-2005, 06:30 PM
I've been running a factory VLSD at open track days for many years without issues. Unless your really after every tenth of a second or involved in sanctioned racing of some sort, spending the bucks on an aftermarket unit is a waste of money IMO.

_Def_
08-09-2005, 09:37 PM
S15 HLSD is good, but I can't see a VLSD really working well if you are hopping off curbs or picking up your rear wheel in corners. I tracked my car once with an open diff and it was torture in a few corners with only about 200rwhp. Pick the tire up and start slowing down as the inside tire would make a nice plume of smoke. The S15 HLSD I have in there now feels great. Very mild and controllable, which is what you want when you're going around a corner at 120mph. You can't afford to have a diff locking up on you all of a sudden when you're right at the limit of traction, as you'll probably find the nearest concrete wall.

KrazyZenki
08-10-2005, 08:52 AM
How much horsepower can the S15 HLSD hold?

S13sr95240
08-10-2005, 09:32 AM
Thanks for the inputs.

I think the most recommended here is the S15 diff (variable torque distribution, low cost). Then the Cusco RS.
then ATS.

Regarding to 1, 1.5 or 2 ways, which is the best suited for track use (road course)? (No drift)

vitaminT
08-10-2005, 10:30 AM
I would think the 1.5.

champa
08-10-2005, 11:47 AM
vlsd is junk for any type of track driving other then daily driving.

SequenceGarage
08-10-2005, 01:18 PM
I have an ATS Carbon 1.5way diff and it is amazing. I've driven cars with 2way diffs and they clunk like crazy and are not smooth, this thing is.. well i don't know.. perfect? Never have inside tire spin. Ever. But it also never makes noise. Ever. You never notice it coming on, but the turn in is exactly as it was before, and out of the corner if you feed it too much throttle you go sideways, but it never makes you understeer or anything like a more aggressive diff is known to do.

Sorry.. this is what love does to you. Its worth the cost.

wootwoot
08-10-2005, 03:46 PM
Well someone with an ATS could you show where you got it from? I'm curious to just check it out =)

knate
08-10-2005, 08:28 PM
I have an ATS Carbon 1.5way diff and it is amazing.



So is it 1.5 or 2 way? Check your sig http://forums.freshalloy.com/images/graemlins/wink.gif I was seriously considering one of these a while back, but at the time I didn't know anybody running one and it was pretty expensive. So I went for an S15 diff. Anyone use the carbon for drifting? It sounds quite lovely.. I hate clunking.

SequenceGarage
08-10-2005, 11:52 PM
Lol long story about the sig. I ordered a 1.5way from ATS, i got it in a 2way Deftforce box with the wrong partnumber lablled on it, it said "2way" on it so I thought they sent me teh wrong diff, about 2 weeks later Warren G the guy i bought the diff from let me know that ATS japan contacted his us supplier and explained that it was just the wrong boxing but it is a 1.5way unit.

I've used it for drifting at 3 events now and i have no complaints, it works just like any other metal diff i've used.

_omg
08-11-2005, 10:58 AM
The S15 HLSD is a reall nice street diff but isn't up to it on the track. As soon as you pick a wheel up over a ripple strip it will send the torque to the now madly spinning wheel in the air.

Of the aftermarkets I've only used the kaaz, Cusco MZ and RS and a few of the Nismos(some standard and one the GT Pro with the wanky adjustment). Of those I preferred the 1.5 Cusco RS, lovely balance between bite and progression and gave the best "steering on the throttle" control. Fantastic diff for the money imo

019
08-12-2005, 07:07 AM
I've been running a factory VLSD at open track days for many years without issues. Unless your really after every tenth of a second or involved in sanctioned racing of some sort, spending the bucks on an aftermarket unit is a waste of money IMO.



i have to agree with this. the vlsd is more than fine for track events and autox. i've autoxed for 3 yrs in my vlsd with a few road course events here and there and have never had a problem with it.



S15 HLSD is good, but I can't see a VLSD really working well if you are hopping off curbs or picking up your rear wheel in corners. I tracked my car once with an open diff and it was torture in a few corners with only about 200rwhp. Pick the tire up and start slowing down as the inside tire would make a nice plume of smoke.


but if you're hopping curbs and lifting your rear wheel, you're also making your hlsd useless. with one wheel off the ground it basically acts as an open diff, doens't it?

trackstar
08-12-2005, 09:02 AM
You don't want a 1.5 or a 2 way for road courses. That's super tyte jdm drift crap. You want a helical LSD. Trust me, I did a ton of research before I bought mine. (search here and google, there is tons of info about it) The best of the best is Quaife, but you will pay for it ($1400). I opted for the S15 HLSD. Place called duaxmachine sells them on ebay with half shafts for $680. Vast improvement over stock or even vlsd IMHO, although you can get away with vlsd also if it's in good shape. I don't know anything about the cusco.

vitaminT
08-12-2005, 10:42 AM
I like the ATS 1.5way but if it was solely for road race I would get the Quaife. Basically an aftermarket/upgraded S15 diff.



Yeah what I...and he said.

killjoy
08-12-2005, 12:08 PM
So what about for drag and street only, no road, drift or auto-X? VLSD good enough?

stealthx32
08-12-2005, 04:26 PM
You don't want a 1.5 or a 2 way for road courses. That's super tyte jdm drift crap. You want a helical LSD. Trust me, I did a ton of research before I bought mine.



Yeah, but research isn't a replacement for actual driving experience, and I think everyone has that over you on this one. http://forums.freshalloy.com/images/graemlins/crazy.gif

Really, it comes down to preference, and driving style (which you will quickly adapt to either LSD quickly enough).

_Def_
08-12-2005, 05:39 PM
but if you're hopping curbs and lifting your rear wheel, you're also making your hlsd useless. with one wheel off the ground it basically acts as an open diff, doens't it?



Yes, but I've never noticed any wheelspin. When I say "lifting" the rear wheel, it's not like a Honda where the wheel is actually off the ground, but weight transfer reduces the traction on the inside wheel, allowing it to spin when you get on the power. I didn't change my suspension setup but installed an HLSD and all wheelspin was gone the next two times I went to the track.

When hopping a curb you rarely want to be hard on the throttle anyway. Just enough to balance the car, but not enough to upset it and have it accelerating hard when you hit the gator.


Short and sweet is that my S15 HLSD works beautifully out on the track.


Clutch type diffs aren't bad for track driving, but they can't be harsh or "on-off" in their response. My M3 has a clutch type diff stock, but it's way milder than most JDM diffs.

vitaminT
08-12-2005, 05:54 PM
Yeah I think the helical is good until you fully pick one tire off the ground. Then it spins the one off the ground.

One other thing to note that some people might be able to chime in on is that the clutch type diffs wear out. Like need rebuilding AND frequent fluid changes. I know it might be good to change the fluid on a helical but I think the clutch types recommend it after every event.

I have a Nismo 2way, just their street diff or whatever the low end unit is and am pretty pleased with it. While I do think it is milder than say the 16 plate Kaaz it still makes the outside tire skip across the ground when making slow tight turns, say into a neighbor hood.

J_Rho
08-12-2005, 10:46 PM
A helical like the torsen, is only as good as how much weight you have on the inside rear, though this shortcoming isn't often experienced on the track, more often on twisty autocross-type settings. With a modified suspension you can do a lot to work around this problem, or you can get a helical with some preload built in like the Torsen T2R. A big advantage of these diffs is that they don't affect handling in the absence of input torque, behaving just like an open diff - indeed, it's nigh impossible to test for a torsen diff even with it sitting in your hands.

The harshness of a clutch-type diff is less noticeable in a track setting as throttle and brake transitions are fewer and farther between than in an autocross setting. One thing to remember is that a diff that's locked or nearly locked under deceleration will impart an understeer moment to the vehicle upon turn entry, which will only make a car that's pushing, worse.

The above opinions come from years of experience combating inside rear wheelspin on Stock-class autocross S2000s, trying to find the right amount of preload to use on a Mustang Mach 1's clutch-type diff, and in setting up an ATS carbon diff in an IS300 (http://www.driftday.com/dd27.htm) for STU autoctross competition on the National scene. Each diff type has its pluses and minuses, and until you've been tasked with getting the most out of each type the pros/cons won't really make sense.

_Def_
08-12-2005, 11:32 PM
The harshness of a clutch-type diff is less noticeable in a track setting as throttle and brake transitions are fewer and farther between than in an autocross setting.




I don't know, I'd think you'd notice an aggressive diff if it caused you to get a little "out of shape" at 100+mph. Autocross lends itself to a high preload clutch type LSD more than on track driving IMO, at least on cars with any sort of power output. On an autox course it's typically easily to make a quick correction and bring the ass end in line if the diff is hard to modulate, but on the track you're probably going into a wall if things get too "tricky" back there and you can't cope.

Not saying you can't drive either diff in either setup, but I'd much rather my power-on oversteer to be brought on in a parking lot at 45mph rather than T12 at Road Atlanta at 110mph.

_omg
08-13-2005, 12:06 AM
You don't want a 1.5 or a 2 way for road courses. That's super tyte jdm drift crap. You want a helical LSD. Trust me, I did a ton of research before I bought mine. (search here and google, there is tons of info about it) The best of the best is Quaife, but you will pay for it ($1400). I opted for the S15 HLSD. Place called duaxmachine sells them on ebay with half shafts for $680. Vast improvement over stock or even vlsd IMHO, although you can get away with vlsd also if it's in good shape. I don't know anything about the cusco.



I guess the difference between us is that we do our research on the track, not the net.

I think people are lumping clutch style diffs into the same basket in a manner similar to how people put all turbos into the same basket. Just like not all turbo cars are laggy and unresponsive ot all clutch diffs are "super tyte jdm drift crap". Which explains why the diff I recommended is a sprung style, clutch with a very mild (or none at all) dedel effect, not a cone engangement 2 way which is as you suggested more suited to drifting than to real circuit work. What I can say is that the cusco RS is not harsher than the S15 helical, it is more responsive to the throttle, it is more precise and it doesn't have the problems inherrant in a torsen style diff when you unload the inside wheel.

However diffs are a bit of a personal thing. While I prefered the cusco RS on the racecars (S15 and 350Z) the driver prefered the extra bite of the kaaz and on a couple of the club S15's the owners prefered the Nismo GT Pro's. One thing that is worth mentioning however is no-one who has changed their S15 helical for a clutch style had any problems or thought that the helical worked better on the track. Quite the contrary actually, most were changing as they were having major problems with the hlsd.

J_Rho
08-13-2005, 12:37 AM
Not saying you can't drive either diff in either setup, but I'd much rather my power-on oversteer to be brought on in a parking lot at 45mph rather than T12 at Road Atlanta at 110mph.

Well, if your motor has the beans to produce power oversteer at 110, I bow down! Again, a spool/locker or clutch-type LSD will produce a stabilizing, or understeer, moment while in effect, so at least you'll see that wall coming http://forums.freshalloy.com/images/graemlins/cool.gif. The exception is when available torque is sufficient to break the tires loose as the diff locks up, but even in the most powerful cars I've driven this is only a problem in second gear, at least on race tires.

_Def_
08-13-2005, 01:21 AM
Nah, it's not so much power-on oversteer, as it is just taking that little bit of traction away from the rear end. Plus the stock S13 hatch body shape makes mad aero lift above about 90-100mph it feels like.

I was definitely having some moments trying to find more speed in that corner, because every little bit more I would roll on the throttle would have me making some pretty sizable ~40-60 degree corrections.


Clutch type LSDs can be plenty fast around a racetrack, and lots of the JDM ones are well put together for this use. Some of them aren't though, and that's the type I'm talking about. I haven't driven an S13 with one, but I have felt other cars with harsh diffs and I didn't care for it(personal preference).

I choose the S15 HLSD because it was relatively inexpensive to get into, and it doesn't wear out, or the car will probably die before it does I should say. I really like how the stock FD3S diff feels, and the S15 HLSD is close to that IMO - so it satisfied what I was after. Got rid of my wheelspin and makes the car easier to rotate on the slower stuff.

stealthx32
08-13-2005, 03:46 AM
What's this, you have an FD along w/ your S13 and M3? I know who's house I'm hittin' next... http://forums.freshalloy.com/images/graemlins/grin.gif

vosko
08-14-2005, 08:59 AM
i had my s14 with a kaaz 2way @ lime rock time trials a month or two ago. i had no problems but i did have really sticky falken rt615's on all 4 corners

019
08-14-2005, 06:09 PM
Yes, but I've never noticed any wheelspin. When I say "lifting" the rear wheel, it's not like a Honda where the wheel is actually off the ground, but weight transfer reduces the traction on the inside wheel, allowing it to spin when you get on the power. I didn't change my suspension setup but installed an HLSD and all wheelspin was gone the next two times I went to the track.

When hopping a curb you rarely want to be hard on the throttle anyway. Just enough to balance the car, but not enough to upset it and have it accelerating hard when you hit the gator.


oh ok. i think i was just thinking of the extreme example of "lifting" the rear wheel, haha. i personally have never had the problem you speak of on the track (VIR and Road Atlanta), but then again, i drive a stock ka haha. i'm lucky if i can get my tires to chirp, haha.

back on the clutch vs. helical subject, i've had the chance to talk to Speakman Racing when i was down at Road Atlanta. they run a PS1 S14 and use a nismo 2 way lsd and really like it. like someone mentioned, it's obviously driver preference tho

_Def_
08-14-2005, 08:09 PM
What's this, you have an FD along w/ your S13 and M3? I know who's house I'm hittin' next... http://forums.freshalloy.com/images/graemlins/grin.gif



I wish! I wanted an FD so bad as my track car, but it just wasn't happening about a year ago. Plus for all the money I got in my S13 I could only buy a beat to chit FD.

One of my M3 buddies did sell his M3 and get an FD though and we took it for a long spin. Thing was majorly sweet - ~300rwhp on the stock turbos and some suspension mods.

Jsquared
08-14-2005, 10:19 PM
stock turbos = BAD. bad bad bad bad bad. and get an AST, radiator, intercooler, and downpipes ASAP http://forums.freshalloy.com/images/graemlins/laugh.gif

back on topic: I am going to be trying out an S15 as soon as I can get funds for one. I've had a lot of good experience with the Torsen-type diff in the 951... the turboS transaxle has a ~40% lockup clutch-type in it, will have to see what that's like when it's all back together http://forums.freshalloy.com/images/graemlins/grin.gif

handfulz28
08-15-2005, 09:12 AM
Guys, it all depends on how your car is set up, what your driving style is, and how you want the car to behave. And then there are maintenance issues with some clutch diffs, but they're pretty durable.
I've driven an open diff/4.08, Quaiffe/4.36 and recently a VLSD/3.91 I recently received an S15 from duaxmachine so I'll be trying that with a yet-to-be-decided ratio.
As someone mentioned previously, the biggest difference is how the car behaves under trail-braking. The Quaiffe make's the car loose, and a lot of drivers use a soft rear swaybar or none at all. The VLSD OTOH was opposite; the car didn't want to rotate on turn-in without being thrown into the corner.
As for the issues with lifting a wheel over a curb, you're probably losing time hitting the curb anyways. Soften the setup and/or use some slip-angle to keep the rear off the curbing. (or, and don't quote me on this, drive far enough inside the curb...used to do this on T6 at Rd Atlanta, but not regularly)
As for a diff engaging mid-corner, say at the apex, and causing an unexpected oversteer, I'd think that's unlikely, at least for a properly operating unit. I'd guess the diff is already engaged, and what you'd experience is the limit of tire adhesion at that point.
Good luck, have fun
Michael

_Def_
08-15-2005, 03:21 PM
On the curbing issue, the fast way around Road Atlanta is *definitely* on the curbs. I know a few guys that drive E46's in Speed World Challenge and they are all over the curbs, like wheel in the dirt going into the esses, hop the car completely over T3, up on the "table" of T5, all the way to the dirt on T7 and definitely drop a wheel at the apex of T10B. You go significantly faster if you have a bling-bling(Motons, JRZ's, Penske's etc. - all about $10-20k for a set) shock that can handle it and still give you traction. These guys run in the low-mid 1:30's with cars that probably make about 230-250rwhp - that's hauling arse in the corners!

For the average person, I'd say T3 is about the only place you want to kiss the curbing. If you don't go over at least a little bit of it you are easily going 5mph slower than someone who does. That's a huge difference through T4.

But make no mistake, the "fast" guys are all over the curbs.

wootwoot
08-15-2005, 04:45 PM
In a year when I can finally afford to go to RoadAtlanta and have my car in good enough shape you need to show me around.

_Def_
08-15-2005, 07:46 PM
If you're talking to me, I guess I should change my profile. I'm moving out to Fort Worth, TX in the next few weeks to work for Lockheed Martin. I'm going to make fighter jets mad pimp - they're going to have eBay manifolds and knock-off oilpans all over the place. http://forums.freshalloy.com/images/graemlins/grin.gif

handfulz28
08-16-2005, 07:16 AM
Yeah, T3 usually develops a hole so if you're not going around it, you better be going over it.
The table at T5, that's just regular track out area, not really hopping a curb.
T7, kinda like T6, everybody just wants to straighten it out to carry more speed, but not really hopping a curb.
Same with T10, dropping a wheel is different than hopping a curb.
Probably don't see many fast guys consistantly putting wheels on the curb at the bottom of the hill (T11 or 12)? Now that's a curb...
I'll give you T3 for hopping a curb, but if you're gonna do that, just run the left side wheels outside the curb and I think you miss the hole (used to at least). You won't get away with that for long though, before somebody black flags you...heh
Ft. Worth? I think Texas Motorspeedway might have some track days, and I don't know where Motorsports Ranch is, but it's out there somewhere. You might have to head up into Kansas for some tracktime too.
Got your PM, thanks, look for more.

Michael