First Track day with OS Giken LSD and extreme noise
 

I just got a new OS Giken LSD 1.5 way plus new KW V3 Suspension with 4.09 Gear installed. I bought the built rear end from Z1 which includes the Z1 extra capacity diff cover.

When I originally got it I noticed extreme clunky catching noises from the differential and used the Motul Diff fluid. After posting about the horrible noise at low speed and turning, I then decided to listen to everyone and use the OS Giken 80/200 Diff Fluid. Had the fluid changed before going to track.

Got to the track and first session was about 10-12 laps. The interesting thing I noticed while running was the Oil Temp got to 250 degress. Which at first I thought was odd since I have the 32 Row oil cooler but I kept going.

When I left the track on the exist lane. Extreme clanking from the diff. Yes I am going slow and turning but holy Sh&* everyone was looking at me like I broke something. I got nervous as the noise was very extreme so I left the track to limit the amount of damage.

So I would like to see everyones opinion on these questions...

1. Oil temp was 250. I am guessing that is ok, but why so high when I got 32 row oil cooler plus I have the stillen front end which allows way more air into the engine bay.
2. Why the hell after running 10-12 laps and then exiting would the diff be so freaking loud. It continued to be load going slow and turning after that on the way home. After getting the OS Giken fluid previously installed made a big difference but after these hot laps it was back and back louder than ever. Did I burn up the fluid in that many laps? My last post folks said to get the MA Motorsports diff cooler which I am thinking is a must now. But this diff is extremely loud now when before going to track and going slow and turning it was not near as bad.
3. How much fluid is supposed to go in the Diff? This was a debate my mechanic was having with Z1. Z1 said with their extra capacity diff cover, it should hold 2.7L. Even with buying the prebuilt diff they give you 3L. But my diff only took 2L. My mechanic said the capacity was 1.5 in the stock LSD which adding the Z1 extra capacity which is stated to add .5L of fluid should make it 2L. But Z1 says 2.7L. Anyone know what the capacity should be?

All information is greatly appreciated!

For your first question, yes 250 is about normal with a 34 row oil cooler. Nothing to worry about here. Did you puke any diff fluid out of the overflow vent on the diff? I did at the Tail of the Dragon. My diff cooler was sitting in a box at home. LOL I just didn't have time to install it. Capacity is 2L with the Z1 cover. If you order a diff cooler from MA, make sure to tell them you have a Z1 cover. The clanking is normal when it get's extremely hot. Guess I will see if the diff cooler solves this issue. It should. As far as being embarrassed about the loud clanking, I just laugh. It's like hot racing pads, they just squeal.

You have 2 issues going on. You should try to keep them separate.

Running hard on a hot humid day. Your engine oil temps will go up.

The diff. The hottest temps I've seen so far is 255F without the diff cooler on. The noises. How loud is loud? Did the noises quite it down after the diff cooled off? My diff will make some noises and pops now and then making slow turn tight turns.

For the right fluid level with the Z1 cover. Use the bottom side port. Put fluid in until it starts running out.

What did the old gear lube look like when you changed it?

It was freaking clankidy clankidy clank all the one from exit pit to pit stop. Louder than it ever was before. With the original fluid I only drove it to work and back and then they dynoed. No major issues with original fluid. The initial loudness was weak compared to after the running on a hot day.

I would remove the diff. Pull the cover and inspect the LSD just for the peace of mind.

Does not sound right to me either. How much glitter is in the oil?

Pics are my 1st differential oil change after OS Giken install.

LOL, I got the same thing when coming off of the Dragon with an overheated diff. Clanking, Binding, and loud as hell when turning. Change the fluid again and get a diff cooler. Told ya. I obviously drove harder this year than last. I did a back to back run the first day because it was somewhat dry. I didn't have any issues last year running Motul 75w90, but I didn't do any back to back runs either.

Is the diff noise gone after it cooled down?

Yes, but the fluid is cooked. It will be noisier than normal until it is changed.

No the next day I backed out of the garage in a straight line and not loud but noticeable clunk, clunk, clunk.

I assume this is because the fluid is fried as my garage stinks like diff fluid something fearce!

Getting the diff inspected and fluid changed.

I have reached my limit with this car. Just put KWV3 suspension on it and didn't notice anything major at the track and now I put a high end diff that cooks fluid in 8-6 laps on a humid day that just requires me to buy another aftermarket part.

Anyone want to buy a 370Z for 25000 with over 25000 in after market parts for cheap! lol

You will see it posted on the for sale soon!

I see you have ported intakes. Did you do them yourself? Thoughts on HP improvement please. Considering doing a port match job on mine.

BTW, it's my opinion that if you run a clutch style LSD you need to cut the yaw sensor power wire. If you haven't, do it and give the car another chance. I went through a rear set of brakes super fast when I first put mine in and had not cut the wire yet.

I had Z1 port the upper and lower. Descent gains were made after dynoing.

You haven't reached the limit of this car. You just had the wrong expectations from what mods you were doing. Just like the KWV3's, that's not what you needed to get. Look in the track section/suspension section, track rats have many good things posted in each. There has been many knowledgeable folks post threads in each. Some are still here, some are not.

If you are going to track your car the three Rs will apply...race, repair and repeat. This is the reality with tracking...because race car!

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Did you turn off the TC l when you were tracking?

I had a OSG in the BRZ and they recommend we turn the TC off since you don't want sudden forces to hit the drivetrain.

:iagree:

I never have TC on. It is the first thing I turn off when getting into the car!

So after changing the diff fluid again. Found out the Whiteline bushing has melted that is next to the diff. Talking to company I bought it from, the diff should never get that hot. Definitely an issue with the diff I got.

That doesnt sound good, I hope you sort this out with them. Did you do the installation yourself?

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To melt the bushing. It got HOT. I would pull the diff out and inspect it. What did the fluid look like when you changed it?

Hot humid day, no way to cool the diff what do you expect. All high performance track cars come with some wAy to cool the diff and other components prone to heAt

Already ordered an OS Giken lsd and waiting for it to arrive still, but it looks like I’ll ya e to save some more for a diff cooler, if the extra capacity and the Z1 diff cover still didn’t allow the diff fluid to survive one full session.

I would remove the diff and inspect. I had a pinion on a diff come loose after a rebuild one time and it sounds a lot like what you're talking about. It will just get worse until boom.

<3 Gear diff. Clutch diffs have a lot of setup involved how aggressive is yours set to be, it should be on the less or even least aggressive engagement setting for road courses. How are your stack springs, plates active, etc setup?
Regardless there's no way you should be melting anything with a diff somethings defiantly wrong.

Mine looked exactly the same after 1st change new 4.08 installed at the same time. Was super grabby (sensitive for lockup) for the first 200kms and clunky/poppy but settled in fine. Only hit 80 degrees C (24 c ambient) on the weekend track outings. I did my first oil change 2000kms after install before I hit the track. I would definitely do the figure 8 break in even though OS giken says it’s not necessary if I had my time again.

This sounds more like an install issue than a diff issue. A few clutch plates should not generate that much heat to melt a bushing. Sounds like the gears were working way too hard.

Yep, I did the 10x figure 8 break-in first thing. I figured if it was good for other LSDs it couldn't hurt.

I bought the Z1 Prebuilt diff. So my mechanic just needed to just install the diff.

So Z1 is having me replace the melted Whiteline Bushing with their Z1 Solid Bushing. I have since replaced the fluid and added friction modifier per Z1. Next I will be taking back to the track and testing the temp after 8 laps as well as verifying it is even locking up.

Dude...

http://www.the370z.com/diy-section-d...er-switch.html

Don't forget to do this! It's a big deal. It costs like $15.

Yep and always turn the vdc off. I hate it when I forget to do it as the F-ing nannies kick in even on hard acceleration.

Yeah, the car won't try to kill you any more.:ugh2:

Amen to that. I hate those stupid nannies.

So even when you turn the traction controll off, this YAW sensor which notices if the car is sliding is still activated? And it may activate a rear brake caliper when accelerating out of a turn on track?

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YES. Disabled the one in my autox car last year after I finally had enough of it interfering.

I am tuned with EcuTek and the traction control function takes care of all of that.

Just an update. After installing Z1 Solid Aluminum Bushings the issue with the differential no longer exists. Last track day was extremely fun and enjoyable. Well at least until I got to 3/4 gas in the tank. Next up Anti-Fuel Starvation kit.

So the problem was the diff bouncing around because the diff bushing melted.