Cusco LSD251 L15 vs VLSD

Auzzie370 · 03-12-2023, 01:46 AM

Hello all,

I have a Cusco LSD251 L15 that’s been sitting boxed for some months.

I’m curious, have many people run these? I’m expecting it to be loud, and have an understanding of how differentials and the types work, but will it change the handling of the car severely?

I believe the 1.5 ways work somewhat similar to the VLSD in forms of viscous clutch packs, and have heard it’s a huge upgrade but takes some getting used to.

I plan to run it on mild, 100% lock on accel (May reduce to 80%) and 37.5% on decel. Main focus is mountain driving and track, just worried I’ll bin my car lol.

What sort of significance is there with lap times?

Any input is welcome.

Spooler · 03-12-2023, 01:04 PM

The VLSD is terrible. A 1.5 way clutch diff is a big improvement. You will take seconds off your laps. The only bad thing is you will need to run a diff cooler to keep it from overheating on the track. Most folks install the OS Giken 1.5way. If you use the OS Giken fluid, it will be darn near like stock for street driving. There are no disadvantages. Just the cost.

filip00 · 03-12-2023, 02:46 PM

Everything is better than VLSD. Even an open diff. With it, at least you don't expect to get any power on the outside wheel.
Vote for OS Giken.

240se · 03-13-2023, 06:56 PM

I am looking for an upgraded street/track diff to replace my VLSD. I was leaning toward the Wavetrack instead of a clutch type because of lower heat, noise and wear. So many choices, which is best for street and HPDE without a diff cooler? I need a decision tree/chart LOL.

Spooler · 03-13-2023, 07:30 PM

Quote:

Originally Posted by 240se

I am looking for an upgraded street/track diff to replace my VLSD. I was leaning toward the Wavetrack instead of a clutch type because of lower heat, noise and wear. So many choices, which is best for street and HPDE without a diff cooler? I need a decision tree/chart LOL.

Wavetrack is your best option.

ZoomZ · 03-13-2023, 09:20 PM

Quote:

Originally Posted by 240se

I am looking for an upgraded street/track diff to replace my VLSD. I was leaning toward the Wavetrack instead of a clutch type because of lower heat, noise and wear. So many choices, which is best for street and HPDE without a diff cooler? I need a decision tree/chart LOL.

I have 2017 Nismo with stock VLSD. My intentions, after hours of research,is to go Wavetrack, for cost, maintenance and enjoyability. Keeping same ratio.

If money was no object, OS Giken all the way. (still may do it

)

Rusty · 03-14-2023, 07:34 AM

Quote:

Originally Posted by Spooler

Wavetrack is your best option.

filip00 · 03-14-2023, 08:05 AM

Maybe a stupid question - but does the diff really overheat THAT much if you have a clutch plate LSD? I'm asking that because I got the OS Giken LSD, and as it's working flawlessly, I'm not even sure - how would I know if it's overheating? The diff has that one rubber-straw entering it from the top, not sure what is its function. Would the overheating diff trigger a warning of some sort? If not, what are the symptoms? And also - how hard do you need to push the car in order for the diff to overheat? I have a standard cover and I don't plan on changing it any time soon, as I'm not in the mood to pull down the diff yet again.....

ZoomZ · 03-14-2023, 10:36 AM

Quote:

Originally Posted by filip00

Maybe a stupid question - but does the diff really overheat THAT much if you have a clutch plate LSD? I'm asking that because I got the OS Giken LSD, and as it's working flawlessly, I'm not even sure - how would I know if it's overheating? The diff has that one rubber-straw entering it from the top, not sure what is its function. Would the overheating diff trigger a warning of some sort? If not, what are the symptoms? And also - how hard do you need to push the car in order for the diff to overheat? I have a standard cover and I don't plan on changing it any time soon, as I'm not in the mood to pull down the diff yet again.....

That rubber straw is only a vent.

I think people that track will encounter heat issues.

filip00 · 03-14-2023, 11:04 AM

Quote:

Originally Posted by ZoomZ

That rubber straw is only a vent.

I think people that track will encounter heat issues.

Sure, but some occasional track use with normal-length stints don't require specific cooling for diffs....right?

Averying · 03-14-2023, 01:14 PM

Quote:

Originally Posted by filip00

Sure, but some occasional track use with normal-length stints don't require specific cooling for diffs....right?

I’d get a finned cover which holds extra fluid and allows for more heat to be pulled away. You can probably avoid any overheating if you’re sensible about length of track stints. A cooler is still the best option though.

I bet most Z’s you see at causal track days DONT have a diff cooler.

Sent from my iPhone using Tapatalk

Rusty · 03-14-2023, 01:26 PM

I have an OS Giken diff, and the first MA Motorsports diff cooler. Have a SpeedHut diff temperature gauge installed in the Z1 diff cover. Without out the cooler pump and fan running. I see temps in the 245F+ range on the street. On the track, 270F+. Put the pump on by itself. It will drop the temps down 15F+. Pump and the fan running. That will take the temps down to 160F.

240se · 03-14-2023, 02:26 PM

Quote:

Originally Posted by Rusty

I have an OS Giken diff

What does the OS Giken diff do better than the Torsen types like Wavetrack? I know Wavetrack handles one wheel being unloaded better than a regular Torsen.

03-12-2023, 01:46 AM	#1 (permalink)
Auzzie370 Base Member Join Date: Jun 2022 Location: Austalia Posts: 3 Drives: Nissan MY19 370z 6MT Rep Power: 2	Cusco LSD251 L15 vs VLSD Hello all, I have a Cusco LSD251 L15 that’s been sitting boxed for some months. I’m curious, have many people run these? I’m expecting it to be loud, and have an understanding of how differentials and the types work, but will it change the handling of the car severely? I believe the 1.5 ways work somewhat similar to the VLSD in forms of viscous clutch packs, and have heard it’s a huge upgrade but takes some getting used to. I plan to run it on mild, 100% lock on accel (May reduce to 80%) and 37.5% on decel. Main focus is mountain driving and track, just worried I’ll bin my car lol. What sort of significance is there with lap times? Any input is welcome.

03-12-2023, 01:04 PM	#2 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 13,516 Drives: 2013 Nismo 370z Rep Power: 2684391	The VLSD is terrible. A 1.5 way clutch diff is a big improvement. You will take seconds off your laps. The only bad thing is you will need to run a diff cooler to keep it from overheating on the track. Most folks install the OS Giken 1.5way. If you use the OS Giken fluid, it will be darn near like stock for street driving. There are no disadvantages. Just the cost. Rusty and filip00 like this.

03-14-2023, 01:26 PM	#12 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 34,865 Drives: 2011 Nismo GM 6M Rep Power: 2684436	I have an OS Giken diff, and the first MA Motorsports diff cooler. Have a SpeedHut diff temperature gauge installed in the Z1 diff cover. Without out the cooler pump and fan running. I see temps in the 245F+ range on the street. On the track, 270F+. Put the pump on by itself. It will drop the temps down 15F+. Pump and the fan running. That will take the temps down to 160F. ZoomZ likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

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03-12-2023, 02:46 PM	#3 (permalink)
filip00 Enthusiast Member Join Date: May 2021 Location: slovenia Posts: 481 Drives: 370z pack Rep Power: 105292	Everything is better than VLSD. Even an open diff. With it, at least you don't expect to get any power on the outside wheel. Vote for OS Giken.

03-13-2023, 06:56 PM	#4 (permalink)
240se Enthusiast Member Join Date: Nov 2013 Location: VA Posts: 259 Drives: Gunmetal 12' Rep Power: 11	I am looking for an upgraded street/track diff to replace my VLSD. I was leaning toward the Wavetrack instead of a clutch type because of lower heat, noise and wear. So many choices, which is best for street and HPDE without a diff cooler? I need a decision tree/chart LOL.

03-14-2023, 08:05 AM	#8 (permalink)
filip00 Enthusiast Member Join Date: May 2021 Location: slovenia Posts: 481 Drives: 370z pack Rep Power: 105292	Maybe a stupid question - but does the diff really overheat THAT much if you have a clutch plate LSD? I'm asking that because I got the OS Giken LSD, and as it's working flawlessly, I'm not even sure - how would I know if it's overheating? The diff has that one rubber-straw entering it from the top, not sure what is its function. Would the overheating diff trigger a warning of some sort? If not, what are the symptoms? And also - how hard do you need to push the car in order for the diff to overheat? I have a standard cover and I don't plan on changing it any time soon, as I'm not in the mood to pull down the diff yet again.....