Nismo GT vs. GT PRO + Run in time

[sweefu]

Hi Guys,

 

I am planning to upgrade the diff in my car (S14 200sx).

From talking to mates and reading online I have settled on a Nismo 1.5way LSD. I use the car mostly for tarmac rally, hillclimbs and the occasional drift event. 

I'm looking for advice on the difference between the GT and GT Pro diff models and if it's worth jumping to the next model. My understanding is the Pro model has an adjustable lockup bolt with 3 different setting. The standard GT version does not have this same type of adjustment. 

 

The difference in price is $223 (both prices are without shipping).

GT $1,111 http://www.rhdjapan.com/nismo-gt-lsd-1-5-2-way-rs015c.html

GT Pro $1,334 http://www.rhdjapan.com/nismo-gt-lsd-pro-1-5-2-way-w-lsd-oil-rss15d5.html

 

So, my first question is as above, is it worth the extra money? How often would I really need to change the lockup setting?

 

Secondly, what is the best run in procedure for a new diff? I've read a lot of different ideas, a lot of people seem to suggest the following:

- 30min of 1st gear slow figure 8 after install

- 1000km of easy driving with left and right turns, preferably under 80km/h

Can anyone shed any light on the above? I don't drive my car on the street all that much, mostly to/from events or a weekend drive, but I don't want to damage the new diff by not running it in properly.

 

Any help/opinions would be great.

 

Cheers.

[V28VX37]

Magic timing mate – my 1.5-way Nismo GT was installed today. I'm getting the car back tomorrow so very keen to see some confirmed break-in instructions for it!

I didn't go the Pro as it was beyond my budget and I reckon I would rarely change the setting anyway. Greg (Kinkstaah) here was kind enough to let me take his car for a spin, he's running the GT also and it felt great, a bit noisy when cold but fine once warmed up even around tight bends.

> 30min of 1st gear slow figure 8 after install

This is what I've read also, primarily from Kaaz via http://www.drifting.com/forums/showthread.php?t=6800 and http://www.kaazusa.com/techhelp2.html

Their diagram still doesn't make much sense to me, are you meant to do the cornering with clutch in??

The Nismo installation manual doesn't talk about the break-in procedure: http://www.nismo.co.jp/en/products/competition/manual/

If anyone knows what the Nismo procedure is, please share!

[sweefu]

Awesome timing indeed! Very keen to hear your thoughts on the diff.

 

I think the RHD Japan sale ends tonight so I might have to bite the bullet. Where did you get yours from? Also, who did the install? I called a few shops today for quotes but unsure who is reliable in VIC.

[V28VX37]

7 minutes ago, sweefu said:

Awesome timing indeed! Very keen to hear your thoughts on the diff.

I think the RHD Japan sale ends tonight so I might have to bite the bullet. Where did you get yours from? Also, who did the install? I called a few shops today for quotes but unsure who is reliable in VIC.

I got mine from Jesse Streeter, great service as always.

I've sent you some more details by PM.

[Duncan]

Terry at  award gearboxes in sydney simply recommends light load (no skids, no towing etc) for first 500klm then an oil change, he is also strong on never using synthetic diff oil as it can be too slippery and lead to glazing of the gears (he correctly guessed I used to use synthetic by looking at the wear on my race car's diff).

Of course mine is a race and and it won't get any break in....I'll just change the oil after the first day.

[Duncan]

oh BTW....keep in mind, no-one ever ran in your factory diff....they just bolted it in, delivered the car to the first owner and told us to change the oil after 40,000klm or similar. That includes factory mechanical diffs in the GTR,

[sweefu]

Thanks for the info Duncan. 

Which diff oil do you use? Do you still use the Nismo (Motul I believe) synthetic oil that comes with the diff kit, or mineral oil from installation? 

Also, do you have any recommendation or advice regarding the adjustable Pro or non-adjsutable models? I'm a bit stuck trying to decide. 

[V28VX37]

Got the car back tonight, first impressions:

• The diff is less noisy and skippy around tight corners than expected
• The diff is more noisy in neutral than expected (see below)
• You feel like a total tool doing figure eights in a deserted shopping mall car park

I'm a complete noob with mechanical diffs - are they meant to be totally quiet in neutral/with clutch in?

With all windows down I can barely hear anything when driving slowly in first gear or braking from slow speed, however I can hear a pulsating 'rotating scuff' sound when just slowly rolling downhill. Is this normal? If so I'm guessing it's because the diff in in neither accel or decel mode so the clutch packs are disengaged...?

[V28VX37]

Found a couple of threads describing various Nismo/LSD noises:

• http://www.240sxforums.com/forums/general-tech/38460-clicking-lsd.html
• http://my350z.com/forum/engine-and-drivetrain/66361-does-anyone-have-a-nismo-lsd-w-no-noise.html
• http://www.gtiroc.com/oldsite/forums/general-r-discussion/64428-nismo-lsd-fitted-normal.html

Quote

Today after warming up the car, I noticed a random clicking comming from the rear of the car when driving straight. I know that its supposed to make clatter when turning slowly, but I never heard of an LSD sporatically clicking when driving straight. I'm hoping that this problem is simply because the LSD is still new and will dissappear as time goes by. 

^^^From the first link

Mine was occasionally clicking a little bit together with the rotating scuff/thump sound but only when coasting to a stop. It quieted down as soon as I accelerated.

I'm going to assume the install is fine and just put it down as break-in noise, fingers crossed.

[V28VX37]

Slowly getting used to the diff, it's pretty skippy when cold around tight bends, needs a fair bit of clutching in. Great for the grocery runs.

I haven't driven it a lot at higher speeds but I can hear it a bit more in 5th at 100km/h than the OEM, a bit of a whirr/hum type noise. I'm guessing this is normal too.

Putting in a mechanical diff is great, so many new sounds to understand and decode!  

 

[V28VX37]

On 8/19/2016 at 8:30 PM, V28VX37 said:

...

Mine was occasionally clicking a little bit together with the rotating scuff/thump sound but only when coasting to a stop. It quieted down as soon as I accelerated.

I'm going to assume the install is fine and just put it down as break-in noise, fingers crossed.

 

17 hours ago, V28VX37 said:

...

I haven't driven it a lot at higher speeds but I can hear it a bit more in 5th at 100km/h than the OEM, a bit of a whirr/hum type noise. I'm guessing this is normal too.

...

 

One more thing to add to the list of curiosities: I jacked up the rear of the car and when rotating the rear wheels a full circle it seems to jam/bind at one spot (neutral/no handbrake). I can rotate it through by hand but it's fairly tight. It's heavy-ish the rest of the way too but there's definitely a different feel to that one part.

Is that normal with mechanical LSDs when unloaded, or is there an issue with the install?

[Piggaz]

To calm the Nismo rear end down, try some OS GIKEN 80W-250 diff oil. Terry at Award diff and gearboxes recommends this. I'm currently running it in my GT Pro rear and Quaife front. Definitely shut that GT Pro up by a good 85%.

[V28VX37]

To calm the Nismo rear end down, try some OS GIKEN 80W-250 diff oil. Terry at Award diff and gearboxes recommends this. I'm currently running it in my GT Pro rear and Quaife front. Definitely shut that GT Pro up by a good 85%.

Thanks mate! It's currently got the Nismo competition oil 2189E 75W140 (by Motul) in it that Nismo supplied it with.

I'm actually not fussed about the noise or skipping, just want to be sure that the install is 100% right before taking it to the track in a month.

[sweefu]

Maybe it will be a bit quieter after break in? 

Did you settle on a break in procedure mate? 

 

I'm delaying the purchase of my diff, I didn't have enough time to get it done before my next event.

[V28VX37]

16 minutes ago, sweefu said:

Maybe it will be a bit quieter after break in? 

Did you settle on a break in procedure mate? 

 

I'm delaying the purchase of my diff, I didn't have enough time to get it done before my next event.

Yeah fingers crossed

Re break in, I've done mostly normal suburban driving and trying to take it easy for first few hundred km's. I did do about 10 min of figure 8's on the first day but it gets old pretty quickly.

I actually had the diff on order before my last event but it never made it on time. Probably better that way, at least it gets a more peaceful run-in period before Sandown on October 1st.

[V28VX37]

On 8/19/2016 at 8:30 PM, V28VX37 said:

...

Mine was occasionally clicking a little bit together with the rotating scuff/thump sound but only when coasting to a stop. It quieted down as soon as I accelerated.

I'm going to assume the install is fine and just put it down as break-in noise, fingers crossed.

 

On 8/27/2016 at 10:06 PM, V28VX37 said:

...

I haven't driven it a lot at higher speeds but I can hear it a bit more in 5th at 100km/h than the OEM, a bit of a whirr/hum type noise. I'm guessing this is normal too.

...

 

On 8/28/2016 at 3:52 PM, V28VX37 said:

One more thing to add to the list of curiosities: I jacked up the rear of the car and when rotating the rear wheels a full circle it seems to jam/bind at one spot (neutral/no handbrake). I can rotate it through by hand but it's fairly tight. It's heavy-ish the rest of the way too but there's definitely a different feel to that one part.

Is that normal with mechanical LSDs when unloaded, or is there an issue with the install?

 

Ok here's an update for those playing at home – I wasn't convinced that the above was right and took the car back to the shop for further opinion. Here's what transpired:

• Rear brakes binding: Issues with the handbrake mechanism, slightly exacerbated by incorrectly installed brake pad clips (oops my bad)
• Tail shaft split pin touching slightly, causing a clicking noise

What I don't quite understand is why the diff change would have upset the handbrake setup... But then again perhaps it didn't, it might have been me baking the brakes at Sandown a month ago. Anyhooooo

I filled up just before and fuel consumption was up heaps, which makes sense if I've been riding the brakes.

So yes, your fancy new mechanical LSD is meant to be heavier to turn than the OEM, but it's NOT meant to have stiffer spots or bind around the rotation.

The car rides better now (surprise) and is noticeably less jerky around tight corners too. The only remaining issue is a very faint 'rattle' noise from the rear, only when decelerating, not audible on acceleration or coasting. I'll just chalk that up as a feature of the diff I reckon.

[V28VX37]

22 hours ago, V28VX37 said:

The only remaining issue is a very faint 'rattle' noise from the rear, only when decelerating, not audible on acceleration or coasting. I'll just chalk that up as a feature of the diff I reckon.

Scratch that. That was the tail shaft balance weight just touching the mid muffler on decel only WTH. I got new Nismo engine mounts put in together with the diff, must have reduced the miniscule clearance it had just a tiny little bit. Random. 

Moral: 1. Go for a good drive near walls (congested freeway is great) with all windows down and carefully listen to the car's rear end before swapping your diff. 2. Fix all the s__t before installing the new centre. 3. Profit Remain sane.

[Dose Pipe Sutututu]

Then do a celebratory clutch dump in 2nd and do donuts (of course on private property).

[colourclassic]

So how are these on the street? I've been in a Kaaz 2 way equipped R34 and it was horrible in terms of noise and vibration. I'm looking at a GT or GT Pro. Is there a big improvement in handling over the VLSD? 

[V28VX37]

So how are these on the street? I've been in a Kaaz 2 way equipped R34 and it was horrible in terms of noise and vibration. I'm looking at a GT or GT Pro. Is there a big improvement in handling over the VLSD? 

Pretty s__t when cold to be honest. Ok when warmed up except in really tight turns i.e. shopping cente car parks. Whatever drivability I previously had left for my better half is now pretty much gone

In terms of performance there's no benefit on the street really, maybe on a mountain run. Yet to run it on the track, we'll see.

For a mostly-street car VLSD or helical is the better option.