LSD: Clutch Type vs Helical ATB

[jeffball610]

I've been running my Tomei 1.5 way LSD for a few years now. It's always been clunky and noisey as clutch type LSDs tend to be. I've gotten tired of it driving on the street and I'm considering going with a Quaife ATB helical LSD.

I know that the draw of the clutch type is holding power, adjustability, and traction all the time. Downsides are that they are noisey and require more frequent maintenace.

The ATB is low maintenance, quiet, and also puts the power down. The draw back would be if one tire has no friction (lifted, ice, etc.) there is no power to that wheel.

I'd like to know some of your thoughts on this. I do 85% of my driving on the street and the rest is autocross and road course stuff. The car makes about 325whp and I'm currently running the new Bridgstone Potenza RE71-RS 205/45/16 with hopes of running a 245 in the future. I do have a longnose R200 with CV axles from a Z31 and there are plenty of LSD options for the R200 through S chassis cars. I don't plan to make more than 400whp ever as traction is already limited at my current power level. I don't want to drop $1000+ on a new LSD and set it up only to have buyer's remorse. I'm definitely leaning toward the Quaife unit, but I wanted some feedback from more experienced members before making a decision.

[icehouse]

Maybe it needs more slippy juice in the oil. Only one I have that clunks is in the racecar. We don't run any slip additive. All my other cars you can't even tell it has a LSD until you unleash the boosts.

[bertvorgon]

When I first put in my Nissan factory LSD, with some "slippy juice" as Jeff said, it was only kinda clunky on my race slicks, on tight slow speed turns navigating the pits. I think I have it set around 45-50 lbs breakaway. I only make 250 to my rear wheels. Over the years of competition and now street only, it makes no noise whatever. I have not put any diff additive in it now for 20 years. I run a Motul gear oil.

I kept my boost at 16 PSI as the balance of traction on 9.5" wide Goodyear slicks was just perfect for power application out of corners with minimal, controllable wheel spin. Excessive wheel spin, as you well know, can cost a few hundred's of a second, not great in a competitive class.

[jeffball610]

I'll try to add some "slippy juice". I currently run the expensive Tomei LSD fluid. It doesn't say to add anything else, but I do have some Ford "friction modifier" laying around.

I'm also wondering if everything is working correctly. I did get what felt like slip last week at autocross on a 130 degree bend. I was still feeling out the car after months of not racing and it's on new tires.

I'll toss some in and report back. If anyone else has other suggestions, I'm open to hearing them.

[icehouse]

I've been daily driving my 74 Z, it has a stock STI clutch LSD and you don't even know it's an LSD until you side step the clutch. Maybe the tomei breakaway is to much for street driving.

[datzenmike]

The early WD21 Pathfinders had high breakaway LSDs but after '96 they were reduced to (I heard) about 18 pounds making them all but useless. Too many soccer moms complaining about chirping and wheel hopping pulling out of driveways on a vehicle that never went off pavement anyway.


LSDs.... great for level straight ahead acceleration where traction conditions are poor or engine power is excessive. Designed to lock the two differing tire speeds together and at the same time designed to decouple based on tire traction and break away setting on corners that are anything but predictable with changing pavement cross fall, up or down hill, wet or dry and chassis weight shift from side to side.

[jeffball610]

I've been daily driving my 74 Z, it has a stock STI clutch LSD and you don't even know it's an LSD until you side step the clutch. Maybe the tomei breakaway is to much for street driving.

That was kind of my thinking. This is meant for an S chassis car with likely more power than I'm putting down. The shorter wheelbase and track width of the 510 may not be ideal for this particular unit. I did swap one disk when I assembled it in hopes that the breakaway torque would be more managable. I still haven't tried more slippy juice, but hopefully I'll get to test it tomorrow.

[icehouse]

The slip juice made a big difference in ours. wheel base lenght of a S13 is the same they are a mile wider though. Since I recently got a Z I looked up the wheel base. 510 is longer then the Z! but the Z is wider.

[cartel]

a 205 is a skinny ass tire for 300hp..

i will have a 400hp sr dime on the road next spring-- But it will be turned down to under 300 for driving on the street- R180 Nissan comp LSD
245s on rear 225 fronts--

i think a r2 is overkill for the weight of a dime personally- especially on 205s.. a lot of extra weight

your brake issue--can you lockup the rears ? goal should be lockup then dial prop valve back till they dont-- porterfield pads might be too much for street- Z31 calipers are heavy as well --

[Cmac]

I was just experiencing a similar clunking noise from my rear differential only to find out the drivers stub axle was not fully seated with the ring clip. The noise is now gone. Also found out that Wave trac is working on a R200 option right now that you may want to consider when it is released.

http://www.wavetrac.net/application.htm

[jeffball610]

I put more slippy juice in the diff and it didn't seem to help. I don't have a ton of miles on it yet, but it still clunks. Maybe I need to do more "performance driving" to loosen things up and work the additive in. I'll keep updating, but I'm not sure this is the right diff for me and my uses.

[datzenmike]

Drive 10 left and 10 right circles to get the oil worked up into the plates and clutches first before you say it didn't help.

[Byron510]

Jeffball, out of curiosity - what is the break away torque set at on your diff?
I run a precision gear LSD in an R180. Mine is set at 42lbs break away.
When I was running the Wolf Creek CV set up, it was horribly noisy due to the play in the CV set up. Oddly, I put good ole U joints back in (half shafts from a ZX) after running the CV’s for 10 years, and my clunking was gone. I still hear the diff working when it has to, but it does not wind up and clunk now as it did with the CV system that has play between the joints and the shafts.
Just sharing my experience.
Byron

[jeffball610]

Jeffball, out of curiosity - what is the break away torque set at on your diff?

I'm not sure how to measure that. I don't believe Tomei gives a spec. I did swap 1 clutch to reduce the breakaway torque before I installed it because I assumed it would do what it's doing. I have Z31 CV joints with the D21 Pathfinder axles. I likely need to swap in new axles anyway, but it's been like this from the intial install.

@datzenmike I didn't do the circles or the figure 8s, but I did take it out for a good drive to slosh things around. It actually seemed to be better when cold, but when it warmed up, it was back to the usual. I'm happy to update as I progress.

Other things I may note about my setup, since it's an R200, I had to make a custom mustache bar. It has stiffer bushings in it than stock, but not super hard poly bushings. I actually broke my initial mustache bar mod a while back. I think there are pics on my build thread. I'll climb under the car soon to check things over again. My garage is currently occupied by a leaky and finicky Starion project

[Cmac]

https://www.youtube.com/watch?v=XuqdWkYiO-M

Here is a good technical description of the wave track rear differential works by MotoIQ.