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I dont want to be 1WD anymore!


Guest RCNSC

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Guest RCNSC

Ok so I've never actually DRIVEN my car yet but I don't want it to be 1WD. What are my options are far as LSDs and diffs? Both wheels must spin!

 

I know the Z31 Turbo diff works, but its waaaaay too expensive (one just went for like 500+ on ebay) so what else is out there. (Stock R180 right now)

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Your absolute cheapest option is a welded diff. But make sure this is what you want because it has some issues on the street. Do a search. Lots of good info on this here.

 

Next step would be an LSD R160 out of a Subaru. Cheap because no one thinks they want them. Do a search. Some people have good luck with them.

 

The turbo diff is what everyone thinks they want because in theory it is the cheapest option. But unfortunately they are not all that common and the people who have them know what they are worth. Plus they usually need rebuilding. Mo $$

 

Last there is the phantom grip. A poor man's LSD to be sure, but once again opinions vary. Do a search and see what I mean.

 

The undisputed champion is the Quaiffe. It has several advantages over either the viscous or clutch type LSD's. It may seem like a lot of money, but from what those in the know say it is money so well spent it is arguably the cheapest option in the long run. Once again, do a search.

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I think you can get the Nissan unit from Precision Gear for $500 new, rebadged as "Power Brute" or something like that. Should be available in R180 or R200. If you want to change gear ratios, this would be the time to do it. A stock 240 with 4 speed would have a 3.36 and an auto would have 3.54, neither of which is very aggressive.

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I don't know where people get $2,000 for the price of a Quaife untit for an R180. $1,200 max and I bet I can get 'em for under $1,000. As far as it being the "best" unit, you'll need to define for what use. It is the best as far as warranty - lifetime and that includes racing and it should never need servicing or rebuilding like a clutch pack (Nismo) unit.

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John are you taking into account the recent price hike from Quaife when you say you can get them for $1200? Or do your suppliers have stock left from before the price hike?

 

My (one) supplier changed the prices significantly lately to reflect the chances in pricing from the source... Or so I have been told.

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The Quaiffe is a gear driven unit. People think that there is some magical gear in there that doesn't want to turn, and that's what limits the slip. This is just not the case. I'm more familiar with the Torsen, I've had a few apart, so I'm going to use that as my example. The way it works is the spider gears spread 3 long helical gears against the inside of the case. These gears need to turn in order for the wheel speed to differentiate, so they are forced to turn while rubbing on the side of the case. So the friction of the "toe" of the helical gears against the case is what limits the slip. You can "adjust" the preload by using a bolt to spread the gears against the case.

 

Problems with this diff are: 1. They DO wear out. 2. They DO need to be readjusted from time to time. 3. They generate LOTS of heat since there is no friction surface, just metal on metal. 4. When a tire comes off the ground the gear type will transfer ALL of the power to that wheel instantaneously, in a Z this is bad because when that wheel comes down you've now broken a stub axle. Clutch style doesn't do that. 5. They slip! John Coffey has said on a few occasions that he's had problems with them slipping in high speed corners. He's also said that Quaiffe couldn't fix them. He did have another place to send them to that could get them to not slip anymore (EMI?) I've heard this same complaint from other racers now too. 6. Although I have to admit I haven't heard it in regards to the Quaiffe, I would estimate that I used to get 15-20 calls PER WEEK from Camaro owners with gear driven units that had just done their best grenade impression when I was selling diff parts.

 

When I worked for a diff parts supplier we sold hundreds of Eaton clutch style posis (the good one not the Gov-Lock POS that comes in GMs) to people who had destroyed their gear type LSDs, and we had 20 Zexel Torsens on the shelf priced at $135 and we couldn't get rid of them. That's right... $135!!! Why is the Quaiffe $1200 when a Torsen is $135? I don't know. I've looked at a diagram of the Quaiffe and they appear to be very similar. Even a Tru-Trac is only $350. Domestic clutch types are in the high $300 range just for price comparison.

 

To me the only advantage to the Quaiffe is smoothness and its low breakaway pressure. With such a low breakaway it doesn't tend to affect the turn in as much as a clutch style LSD. And you can use it as a cheater diff if you're in a class of racing that doesn't allow LSD.

 

The advantages of a clutch style are price, consistency, durability, adjustability, and rebuildability.

 

I know I stand in the minority on this one, but I have enough experience to feel that my opinion is warranted.

 

Jon

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When all is said and done, the viscous starts to look pretty good:

 

No clutches to wear out.

 

Did you know that the NISMO clutch won't take much over 300 ft/lbs

and live long? I believe Scottie-GNZ wrote something about this...

 

The NISMO unit is the clutch only, so you have to tear a diff apart to put

it in - more bucks.

 

Whether R200 or R230, you can just get it and not have to dig into it -

total cost ~ same as NISMO, maybe less.

 

That said - if Auburn made an LSD for the R200, I'd be interested...I

love cones! 8)

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Auburns don't wear out clutches, they wear out the case itself. Kinda like the gear driven LSDs. They are not rebuildable, so as they wear they get less effective and eventually you just take them out and throw them away. They also chatter really bad, especially the Pro series.

 

Viscous is reactive, not active. I've never heard a serious racer say they wanted to install a viscous LSD. I've heard people talk about changing the fluid to make it more aggressive. Maybe I just wasn't informed... :wink:

 

I'll stick with my torque sensitive clutch style LSD, myself. Never heard that complaint about them not holding 300 ft lbs before. Good thing I don't make that much torque... :-D

 

Jon

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Guest RCNSC

So uh.. I'm not looking to race. I just want a 2WD drive car. Im putting an L28 in with the E31 head, so its not like its high HP... so any suggestions (CHEAP)

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Viscous is reactive, not active. I've never heard a serious racer say they wanted to install a viscous LSD.

 

How's F1 for serious racing? Yup, they use viscous differentials believe it or not. I can't really comment on the why, other than to suggest that it might be stated somewhere in their rules only passive or reactive differentials are allowed.

 

The Quaife:

 

atb_01.gif

 

So the friction of the "toe" of the helical gears against the case is what limits the slip. You can "adjust" the preload by using a bolt to spread the gears against the case

 

Not sure what to make of this, but I am a bit lost. I was under the impression (and I've had a couple Torsen's apart before too) that the differential action was simply a by product of the backlash in the gear system. Adjusting TBR on the particular units I've used basically was only available through shimming of the helical gears, and running a different viscosity fluid.

 

[EDIT:] I've found my point of confusion, the diffs I've used had needle bearings to reduce the friction between the helical gears and case, some older model Torsens didn't use this. As a result, you could raise TBR by replacing needle bearings with steel washers of a similar thickness

[/EDIT]

 

So the torsen is essentially a locked diff until you hit the torque bias ratio. If you exceed the TBR then you will get slip, which is exactly how you manage to turn without the locked diff skittering effect. If you are getting slip in a high speed corner as john was, isn't it simply a matter of adjusting the TBR as necessary?

 

As for price difference between Quiafe and Torsen, the quiafe comes from england... and they also happen to make a drop in unit for the R180 & R200's. Low production numbers, high exchange rate and significant shipping costs would be my guess as to why the quaife costs more than a Torsen unit. However, there are no Torsens for the Nissan diffs we use, are there? (or any nissan diff's to my knowledge)

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Ahhh. Knowledge is power.

 

JohnC has said before how much heat the Quaiffe generates. Heat means friction, thus something has to be wearing.

 

All good info.

 

The point about the Quaiffe directing all torque to the unloaded wheel is true. The Quaiffe site itself mentions how Hummer drivers have to use the brake should they get in a situation where one wheel is off the ground. Would only make sense that boucing through a rough corner will duplicate this problem.

 

Guess there ain't no free lunch.

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How's F1 for serious racing? Yup, they use viscous differentials believe it or not.

 

I'd always heard they used the gear type. Plus, it's hard to equate anything we're buying for a couple hundred bucks to something in an F1 car.

 

So the torsen is essentially a locked diff until you hit the torque bias ratio. If you exceed the TBR then you will get slip, which is exactly how you manage to turn without the locked diff skittering effect. If you are getting slip in a high speed corner as john was, isn't it simply a matter of adjusting the TBR as necessary?

 

My experience has been that with one wheel off the ground you can spin the lifted side tire with one finger. In fact, this is the circle track cheater diff because it acts really open until you put power to it, so you can get through tech and they'll think it is open. I sold quite a few to dirt trackers for just that reason.

 

I suppose you could adjust the TBR by shimming, but then you're going to wear the case that much faster. Ford had a different (possibly better) way of adjusting the bias on their Gold-Trak (I think?) with a differently cut set of helical gears. They were cut at a different pitch for different ratios. The Tru-Traks that I've seen have a block with a bolt and it's been a while, but I think they pull the side gears together or push them farther apart to adjust.

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Becareful when going for the cheap fix. It will end up costing twice as much with 4 times the work.

 

I'm always fighting my "cheap instincts" but still have a long list of cheap fixes that I ended up doing agian, "the right way", costing a lot more money and time than I wanted to spent (doing the job twice). "Do it right the first time" I tell myself, but still slip every once in awhile.

 

I would recommend saving up some money and converting a 3.90 gear R200 into a LSD. Go for the Preicion Gear center section and new axle bearings and seals.

 

So, live with the 1WD for awhile and save some money.

 

FYI, new tire rubber helps with 1WD traction.

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