PN Limited Slip Spur Test

Received mine on Thursday and had been using it since Saturday. Installation is the same as the v1 64 pitch spur and the requirements are also the same (shaved hub) but the v2 only goes one way.

I'm only using 5 balls since I'm only running stock or semi-stock class for my 2wd cars.

QteQ diff/PN Limited Slip Spur/Reflex Ceramic Balls/ Ceramic outside bearing/PN Ultra light shaft/Kyosho pressure plates

When using kyosho plates, the ceramic balls rides on the outside edge of the plates. As seen on the pic below:

Testing:
What I did on Saturday was build an identical diff. Everything the same from diff balls to thrust bearing, exactly the same but the spur. One is running v1 and the other is with v2 spur. This was on my MR03 car with speedy07. I chose speedy07 so that the speed is inbetween stock and mod.

Test 1: v1 spur
Best lap within 3 mins was 9.64 (new battery pack)

Test 2: v2 spur
Best lap within 3 mins was 9.42 (new battery pack)

I then switch off their battery packs and results are the same, v1 9.6x and v2 9.4x. This is what I'm getting with the lap timer.

Behind the wheel:
Well, the only difference between the two is:

1.when I get ON the throttle hard coming out of a turn, the car will litteraly jump out and straight into the wall. I had to go a bit easy on throttle when coming out because it's causing the car to push.

2. Off the line from dead stop, the car has minimal to zero torque steer. I never gun/full throttle the car from the grid but with this new spur, you wont have to worry about torque steering to the wall. :D

Everything else is the same as the regular diff. I didn't feel any difference between the two while on off-power. I honestly cannot tell the difference by "feel". It is quite similar but the time speaks for itself. I know for a fact that the car with v1 diff can drop 9.3x's but on this particular day, I drove hard with noone else on the track and just couldn't break-in to 9.5's with the v1. It was stuck in 9.6's while the v2 after few laps, it was already hitting 9.4's even after the test was done and just playing around the track, the car with the v2 spur was still hitting back-to-back 9.4's.

The torque or tightness on the diff was also the same. When v2 was a bit loose than the v1, it actually felt loose even on full throttle it felt like the diff was slipping which is not how its suppose to be but it likes it tight. Perhaps because of the traction we have at the shop? Who knows...

Which one is better?
-Like I said, it is very hard to notice the difference between the two however, I like the fact the 51t PN spur is now available. Gear ratio adjustability is always good to have. :)

Maintainance?
-v2 spur is a bit open to dust but this is because I am using kyosho plates. I believe if I was to use PN plates, it would be covered but just confirm with Philip Ng of www.PNracing.com to make sure. So far with at least 300+ laps that I did on this diff, the ball diff assembly is still as smooth as how it was from day one.

Quieter?
-With the ceramics balls sticking out, you can hear it more than the v1 spur. Just a tad bit louder but not noisy. As a matter of fact, it make this really cool sound like your motors RPM is peaking to its max. Sounds really cool!

Would I recommend it to others? (referring to novice and sportsman drivers)
-This is a good question. Yes, I would definitely suggest for others to try!

Update 11.23.2009:
Today I tested both spurs again and this time I tighten the v2 spur even more and WOW! The torque and speed that I get coming out of a corner is very fast with no spinouts. I didn't get any torque steer at all, even from dead stop!

I timed both cars today and with v1 spur the car was able to hit 9.5 but it took a while, maybe 20 laps while the v2 spur did a 9.5 on its second lap and drop a fast lap of 9.4's. You guys should definitely give this differential a try and make sure it is tight when adjusted. You'll see great results! ;)

Update 11.30.2009:
After a week of daily playing my car with this spur on I noticed few things:
1. Very dry diff balls than normal spurs. When I took it apart, all the diff balls fell off the spur. Usually mine stays on because of some left over grease in normal spurs.
2. spur was dirtier than normal spur.

This spur, when using kyosho plates will need more maintanance. I would prefer to use PN diff assembly.

I was also able to try mod and stock motor with this spur on my MR03 with 3010 FETs in 94mm configuration. Please see below.

For PNWC 33 turn motor.
Pros:
From dead stop, the car just grips and launches like I have spool,, it's crazy! I like having this a lot especially when starting off from the grid.
Coming out of a chicane and shooting straight, the car will put all its power to the ground without hesitation or worrying about torque steer.

Cons:
-hooking turns and exit turns sometimes takes a lot of throttle control. Since the the diff is not a diff anymore (lock) when coming out of a turn and at full throttle, the car will litterally jump out of a corner and straight to the wall however, if you get use to the power, you can actually make the rear wheel spin to make a sharper turn but it is not as consistent as normal diff.
-when full lock and you hit a bump on one side of the rear wheel, you'll feel like your cars steering just caught a big glitch... This only happened to me few times, so it does exist. ;)

For PNWC 70 turn motor:

It feels almost like a ball diff. The LSD action is barely noticeable actually even with the speedy07 (speedy07 has pretty close speed with atomic usa motor). It is most noticeable when launching off the line but other than that, it's almost a full time ball diff.

-Tj Macabuhay