A BRZ and a welder walk into a bar... - Page 47 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

DustinS · 09-17-2015, 05:22 PM

Quote:

Originally Posted by mrk1

Also in the works, more differential meddling. I picked up a MK3 Supra LSD. These got a bad rep after being set pretty loose from the factory, however Weir Performance has the upgrade to cure this.

In to see more of this. I know where one is. My old Supra got sent to the yard by the new owner.

mrk1 · 09-23-2015, 01:08 PM

As it sits this LSD has a breakaway torque of about 53lbs on my bench rig, with a heavier spring installed it should see closer to 100 lbs. In this test the stock Torsen LSD would score 0 lbs.

fika84 · 09-23-2015, 01:41 PM

The break away torque might not be that bad with the factory Supra setting with the lighter weight car!

mrk1 · 09-23-2015, 01:49 PM

Quote:

Originally Posted by fika84

The break away torque might not be that bad with the factory Supra setting with the lighter weight car!

53 is more then I expected with the bad rep these things get. I would like to try it both with and with out the spring but I'm running out of driving season so I'm just going with the upgrade.

fika84 · 09-23-2015, 02:02 PM

Quote:

Originally Posted by mrk1

53 is more then I expected with the bad rep these things get. I would like to try it both with and with out the spring but I'm running out of driving season so I'm just going with the upgrade.

Sounds good. I guess if it's too "hoppy" you can always try it with the 53 next season!

mrk1 · 09-23-2015, 02:38 PM

Quote:

Originally Posted by fika84

Sounds good. I guess if it's too "hoppy" you can always try it with the 53 next season!

Its hard to say what the down side of top stiff would be as these aren't really categorized as 1.5 or 2 way. Mechanically it sure looks like a 2 way but being simple in design and a OE part I have a hard time believing it will be as aggressive as a aftermarket 2 way even with the spring.

When I purchased the upgrade spring from Weir I described my car and usage and this is what we ended up with.

mrk1 · 09-23-2015, 03:24 PM

Googling around I am seeing the stock LSD seem to be 45-60 lbs, gravel rally cars set 150-175, and drifters shimming them up around 250. So using that as a scale 45-250 I think 100 is a fair start.

Link to Weir page, I have the #1 kit

http://www.weirperformance.com/maxgriplsdkits.html

Fastbrew · 09-23-2015, 04:46 PM

Really fun thread

mrk1 · 09-23-2015, 05:48 PM

Popped the LSD apart on lunch

Pretty straight forward.

mrk1 · 09-23-2015, 08:26 PM

With the new spring and all shimmed up to spec I'm seeing just over 100 lbs of break away. That's also a fairly dry lsd. When it's all installed I will test again.

I'm also curious to test the break away with just the shimming as mine was pretty loose.

mrk1 · 09-24-2015, 02:11 PM

Tested a few different combinations. These are averaged numbers.

Untouched with no shims, 53 lbs
Shimmed to Weir spec, 90 lbs (Dry)
Weir Spring with no shims, 100 lbs (Dry)
Weir Spring and shimmed to Weir spec, 108 lbs (Dry)

(Shimming is not really intended to raise the torque but to set the backlash on the spider gears. Weir gives a spec of .004-.005 while the shop manual says .002-.0079)

Sticking with the Weir Spring and shimmed to Weir spec I then lubed everything and re-tested, 100 lbs on the nose. I'm very curious to try this thing out.

mrk1 · 09-25-2015, 10:06 PM

Had to shave down the inner end of the axle a 1/4" or so to fit in the LSD. Weir gave me a heads up this may happen so its easy to work out while its still on the bench. Trimmed is on the Left, untouched stock on the Right.

Only the splines to the outside of the C clip are driven so trimming where I did shouldn't effect the axle at all.

mrk1 · 09-28-2015, 08:37 PM

First short ride with the LSD, holy braking stability! Previously the rear was a little twitchy on heavy braking but now it's planted as can be. Feels like there are some 315 meats back there.

mrk1 · 09-29-2015, 11:08 AM

stable, stable, stable. Decel and braking into a corner are completely transformed. There is a pleasant weighted feel to rear end now. Before I felt like the back end was tip toeing into a corner but now its composed. There is the slightest essence of push from the back end as turn in isn't as crisp from the front but its certainly not causing understeer (only noticeable when engine braking). I do think if I still had stock tires the diff would be too aggressive but with my 255 sticky street tires I feel the grip of the tires keep the diff in check.

Corner exit is largely the same accept I feel confident to get on the power sooner with the back end staying composed.

09-23-2015, 01:08 PM	#646
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	As it sits this LSD has a breakaway torque of about 53lbs on my bench rig, with a heavier spring installed it should see closer to 100 lbs. In this test the stock Torsen LSD would score 0 lbs. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD

09-23-2015, 03:24 PM	#651
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	Googling around I am seeing the stock LSD seem to be 45-60 lbs, gravel rally cars set 150-175, and drifters shimming them up around 250. So using that as a scale 45-250 I think 100 is a fair start. Link to Weir page, I have the #1 kit http://www.weirperformance.com/maxgriplsdkits.html __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD Last edited by mrk1; 09-23-2015 at 03:46 PM.

09-23-2015, 05:48 PM	#653
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	Popped the LSD apart on lunch Pretty straight forward. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD

09-23-2015, 08:26 PM	#654
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	With the new spring and all shimmed up to spec I'm seeing just over 100 lbs of break away. That's also a fairly dry lsd. When it's all installed I will test again. I'm also curious to test the break away with just the shimming as mine was pretty loose. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD

09-24-2015, 02:11 PM	#655
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	Tested a few different combinations. These are averaged numbers. Untouched with no shims, 53 lbs Shimmed to Weir spec, 90 lbs (Dry) Weir Spring with no shims, 100 lbs (Dry) Weir Spring and shimmed to Weir spec, 108 lbs (Dry) (Shimming is not really intended to raise the torque but to set the backlash on the spider gears. Weir gives a spec of .004-.005 while the shop manual says .002-.0079) Sticking with the Weir Spring and shimmed to Weir spec I then lubed everything and re-tested, 100 lbs on the nose. I'm very curious to try this thing out. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD Last edited by mrk1; 09-25-2015 at 11:44 AM.

09-23-2015, 04:46 PM	#652
Fastbrew Senior Member Join Date: Apr 2014 Drives: 2014 Pearl White BRZ Location: USA Posts: 764 Thanks: 123 Thanked 461 Times in 233 Posts Mentioned: 7 Post(s) Tagged: 0 Thread(s)	Really fun thread

09-25-2015, 10:06 PM	#656
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	Had to shave down the inner end of the axle a 1/4" or so to fit in the LSD. Weir gave me a heads up this may happen so its easy to work out while its still on the bench. Trimmed is on the Left, untouched stock on the Right. Only the splines to the outside of the C clip are driven so trimming where I did shouldn't effect the axle at all. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD Last edited by mrk1; 09-25-2015 at 10:17 PM.

09-28-2015, 08:37 PM	#657
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	First short ride with the LSD, holy braking stability! Previously the rear was a little twitchy on heavy braking but now it's planted as can be. Feels like there are some 315 meats back there. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD

09-29-2015, 11:08 AM	#658
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s) Tagged: 2 Thread(s)	stable, stable, stable. Decel and braking into a corner are completely transformed. There is a pleasant weighted feel to rear end now. Before I felt like the back end was tip toeing into a corner but now its composed. There is the slightest essence of push from the back end as turn in isn't as crisp from the front but its certainly not causing understeer (only noticeable when engine braking). I do think if I still had stock tires the diff would be too aggressive but with my 255 sticky street tires I feel the grip of the tires keep the diff in check. Corner exit is largely the same accept I feel confident to get on the power sooner with the back end staying composed. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD Last edited by mrk1; 09-29-2015 at 12:09 PM.

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