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PostPosted: October 17, 2018, 10:53 am 
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Joined: October 10, 2010, 10:26 am
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Location: Guadalupe, CA
Hey guys, I'm soon ready to design and fab in the IRS arms (I'm using Miata uprights/brakes front and rear on the car), and I have a few questions... **TMI on this build: tiny car --1959 Berkeley-- with a custom 'frame'.. final wet weight will be about 950lbs / about 110HP.. Wheel travel will be limited to about 3.5" to 4"... car is very narrow, very short, street legal, RWD.. build at: viewtopic.php?f=36&t=19397

1. Is there a relationship/ratio between the size of the FRONT control arms and the rear control arms? An odd question maybe, but on this build my front control arms are very small/short due to space limitations up front, but in the rear, I can make the upper and lower arms longer if I wish as there's more space.. Are longer rear arms desirable, or should I just design little stubby arms as I had to do in the front? Wheel travel is limited on all corners, so I'm not looking for a big swing back there...

2. Is a 'limited slip' differential an issue? I've been chasing a torsen/limited slip rear end on this project for the last 6 months because I just assumed I wanted one, right :wink: ?! As I'm learning that the limited slip I'm seeking is hard to come by, now I'm wondering if my light, SHORT!! wheelbase, 8:1 power to weight, narrow car will benefit from a limited slip? This car will never see rain, and is just a toy... Pretty sure this thing will break the rear tires at will.. If a limited slip is the fun ticket, then I'll continue the search, but otherwise maybe the one legger is the way to go? Opinions welcome :)

**edited to say 'limited slip'

thanks guys-

--ccrunner


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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com


Last edited by ccrunner on October 17, 2018, 12:06 pm, edited 1 time in total.

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PostPosted: October 17, 2018, 11:53 am 
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Joined: October 19, 2012, 9:25 pm
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Limited slip yes, locker absolutely not.
For reference your Berkeley is about the same size as my A Mod. The A Mod had IRS with a spool and turning is a GIANT pain in the azz. At low speed it chatters, chirps, and complains through any turn at all. At high speed it pushes until the inside rear wheel lifts, then it either corners or snap spins.

I put a diff in place of the spool and it's 10,000 times better to drive.

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OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

Blood Sweat and Beers
http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216


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PostPosted: October 17, 2018, 12:03 pm 
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You're right on the verbiage.... I'm wondering if I should seek out a "limited slip" type diff; OR a simple 'open' one-legger type diff..

((I don't want a welded/spool diff at all))

--ccrunner

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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com


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PostPosted: October 17, 2018, 12:28 pm 
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Joined: August 21, 2017, 7:37 am
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i think your neighbor missed a spot pressure washing fence


but on a topic note. my only comment is to make sure your cv/axle shafts mover parallel with each other as the flex. I wanted to raise the inner joint on my rear control ars to make them more parallel with ground but after thinking about it, if i did that, it would basically shove my cv shafts into my differential as the suspension compressed

for rear, i dont know if you picked a read end yet but subaru R160 found in 95% of their cars from 93 to now are cheap and come in several gearing and differntial options. Mine is a basic 4kg VLSD out of an Outback. Never any binding but grabs both tires when i put all 420whp to it.

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Last edited by terryjr on October 17, 2018, 12:37 pm, edited 3 times in total.

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PostPosted: October 17, 2018, 12:32 pm 
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One wheel peel isn't too bad for casual fun. If you're thinking more spirited driving stay on the lookout for a Torsen or earlier viscous LSD.

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OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

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http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216


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PostPosted: October 17, 2018, 12:55 pm 
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TooBusy wrote:
One wheel peel isn't too bad for casual fun. If you're thinking more spirited driving stay on the lookout for a Torsen or earlier viscous LSD.

This one will be a quest for a 'spirited driving' experience :P

... I'll keep looking for the Torsen version (donor is a 1996-2005 Toyota Rav4 2.93 diff)... trouble I'm having is the wrecking yards SWEAR they have a locking (Torsen) Rav4 diff, then when I get it open after buying/shipping it, it's NOT a Torsen.. such a frustrating waste of time! I've never had such an issue before, which had me asking if the search for the Torsen version is even worth it... After opening diff #3 last night to find that it, too, is not a locker, I thought I should see about just settling on the old-school spider gear type :roll:

--ccrunner

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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com


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PostPosted: October 17, 2018, 1:44 pm 
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subaru LSD's are normally marked with a star on the diff cover :wink:

And normally only in the better models like the 2.5RS and the H6 Outbacks. Im will to bet the top of the line Rav4 diff is what your looking for, one from a model that probably has leather, sunroof, maybe a v6...

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PostPosted: October 18, 2018, 1:32 pm 
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ccrunner wrote:
...trouble I'm having is the wrecking yards SWEAR they have a locking (Torsen) Rav4 diff, then when I get it open after buying/shipping it, it's NOT a Torsen..
Any idea what criteria they are basing those claims on? Apparently there is a misconception that a '2' cast on the housing indicates a Torsen, apparently because one person had a diff with a '1' that was open and another with a '2' that was Torsen, but that has proven false through other '2' diffs being open also. If these are from wrecking yards, they should have the VIN of the vehicle it came out of. A call to Toyota with the VIN before you purchase should be able to confirm the exact options equipped on that particular RAV4, including if it was one of the ones to get the box checked for the rare and pricey Torsen limited slip...Assuming that the diff was never accidentally replaced with an open one for a more cost effective repair, and the VIN paperwork didn't get mixed up at the junk yard. Other than that, it would seem that opening it up and physically looking inside is the only way for them to know with any degree of certainty.

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PostPosted: October 18, 2018, 3:48 pm 
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I ran a Datsun 1200 for years in autocross in fairly stock trim. The two changes that made the most dramatic improvements were lowering it, and adding a clutch-type limited-slip diff (LSD).

Regarding LSD types, if you want something that's zero maintenance and zero noise, perfect for street driving, go for a Quaife or Wavetrac. The only downside of these is that if one wheel leaves the ground, like going over a bump or curb, it goes "open" and you lose all drive because it'll spin only the tire in the air.

For the absolute fastest track time, only a true clutch-type LSD will do it, but that's assuming everything else is already working perfectly. The downside with clutch type diffs is that (like a transmission clutch) they wear, and how long it takes before it needs replacement depends on a lot of things, but mine never wore out.

Fast forward to now and I recently switched from a WaveTrac to an OS Giken. The comments above regarding noise are probably unimportant in a Locost due to all the other sounds going on. Personally, I can't tell any difference between the two units, and I have yet to get it out on-track to see "what's what." I should note that my drivetrain is mid-engine, but all the above still applies.

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Last edited by KB58 on October 24, 2018, 3:15 pm, edited 1 time in total.

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PostPosted: October 18, 2018, 4:29 pm 
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Driven5 wrote:
ccrunner wrote:
...trouble I'm having is the wrecking yards SWEAR they have a locking (Torsen) Rav4 diff, then when I get it open after buying/shipping it, it's NOT a Torsen..
Any idea what criteria they are basing those claims on? Apparently there is a misconception that a '2' cast on the housing indicates a Torsen, apparently because one person had a diff with a '1' that was open and another with a '2' that was Torsen, but that has proven false through other '2' diffs being open also. If these are from wrecking yards, they should have the VIN of the vehicle it came out of. A call to Toyota with the VIN before you purchase should be able to confirm the exact options equipped on that particular RAV4, including if it was one of the ones to get the box checked for the rare and pricey Torsen limited slip...Assuming that the diff was never accidentally replaced with an open one for a more cost effective repair, and the VIN paperwork didn't get mixed up at the junk yard. Other than that, it would seem that opening it up and physically looking inside is the only way for them to know with any degree of certainty.

I appreciate the input guys...

@Driven5... you're dead-on about trying to ID one of these Toyota units.. it really comes down to Vehicle ID#, or, even better, open the back cover and LOOK inside! I tried not to be insulting as I explained this to the out of state wrecker that sold me this latest pumpkin, and sure enough he said this unit checked out... To be fair to this wrecker, he said he'd get me the proper part to make it right.. I hope he has more luck than I've had finding one of these :|

@KB58... I'm with you on the whole 'limited slip' making a difference :cheers: ...I LOVE mine in my Volvo 1800 :D .. It's a Ford 7.5 unit.. I think Ford calls it a 'trac-lok?".. anyway, it's the clutch type, and once I put the proper friction modifier in it to have it stop making ugly noises, it's been wonderful! I daily this car to work, and there's a long, straight freeway onramp on the way home... I love launching the car, allowing boost to build in, and having both sides clawing away for traction.. my little daily-dose of testosterone :twisted: At some point I'm going to get it on a track and see what it can do..

--ccrunner

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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com


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