Alternative

I believe that's who manufactures the K-Miata stuff.

Its possible that I that I have read into something incorrectly.

Alternative

I measure

3.5 deg of play through the driveline measured with both wheels in air and car in 1st gear
1 deg up on the pinion
6 deg down on the driveshaft
1.5 deg setback on the engine

75ft/lbs breakaway on the clutch in the differential

patsmx5

iTrader: (16)

I'm not quite following the measurments, but what is the angle of the output shaft on the trans? IE 1 degree up, 2 degrees down, etc. The diff and trans output need to be parallel, withing about .5* or so. On my C4 setup the trans is at 2.5* down, diff is 2* up, and that combo is smooth and silent. Also GM is not known for building high quality, tough, long lasting diffs. For example they make ford 8.8 swap kits for the CTS-V crowd.

Alternative

There is not a convient method to measure the output shaft on the trans, I will assume it is in line with the 1.5deg down of the engine. Given that the rear measures 1 deg up it should about right from your estimation.

The rear ear is made by Getrag not GM, same as the rear in the C5/C6 Corvettes. There are known weaknesses in the case due to GM purposely putting a differential in a car that exceeds the TQ capacity on a car that is much heavier than a Miata.

Art

.

Alternative

wat.....

I used the term assume loosely, moreso of an "as you should know".

I'm not sure if your just trying to stir up something but your post was of no help to anyone.

It looks like V8R has discontinued the PPF version of the Getrag swap, now if I could just get someone to answer the damn phone....

slmhofy

iTrader: (5)

If any of you is ever in San Diego, I can put my car on the lift and show you how mine turned out and take you for a drive.

I get a bit of clunking if I try to make it buck, but loaded or unloaded it is pretty good.

Oh. And I also did that $16 bushing in the front of the diff. It didn't hardly make any difference in how much the pinion angle moved. Only the bracket at the bottom fixed it.

I didn't cut the top of the C brace and it was REALLY close to the top of the rear subframe. I squeezed a piece of hard rubber in between the C brace and the sub frame and then tightened the 2 large bolts in the back up. This picture shows how little room there was. Rubber piece not inserted yet.

EDIT: This picture is also pre poly bushing. My diff only had 30k miles and the stock bushing was in ok shape, but still really sloppy.

Also, replace the oil seals where the axles go next time you're working on your diffs. They're only like $10/each. I did one, then the other started leaking a month later.

6strngs

iTrader: (2)

I've got the V8R getrag kit with PPF and I'm also getting a clunk when taking off from a standing start. Did any of you guys figure out the issue? If not, has it caused any other issues? I'm taking my miata for a 3000 mile road trip in a few weeks and I want to be sure this won't leave me stranded on the side of the road in the middle of nowhere... I'm going to try to clearance the PPF a bit more this weekend as I'm definitely still contacting the diff case right now.

gooflophaze

I'll throw this out as a possibility. We had a clunk in our LFX that took about a year to figure out, including swapping out the diff bushing, suspecting axle play, top hats, etc etc etc. We couldn't get it to reproduce while in the air on the lift with any manner of jackstands and pry bars. We could occasionally get it to pop by pushing down on the rollbar while on the ground, but once it popped it wouldn't clunk again until the suspension was out of compression (pothole, pavement seam, etc). Finally it would clunk/pop while being settled back down on the ground from the lift - from there, we raised and lowered it a dozen times while feeling components and honed in on the source.

Upper inner rear control arm bushings. I had lubed the outside of the metal faces of the rubber bushings with some superlube to help get them into place after we pressed new bushings in and the bushings weren't 100% centered. The rubber would act like a spring, taking up tension until it had enough force to overcome the lube and "snap" into position that sounded like a clunk. Cleaned up the lube, retorqued the bolts - no more clunk.

Alternative

It’s the PPF hitting the subframe, V8R has discontinued selling the PPF adapter for this reason.

To allow for max exhaust clearance the dif is pushed pushed up and clearance for the PPF is not given.

gooflophaze

Seems like that would be solutionized with the BFH.

Alternative

You could try a hammer...

slmhofy

iTrader: (5)

As explained throughout the thread, there are lots of points for "clunking" with this setup. It could also just be a loose diff. As long as all the nuts and bolts are tight on your kit, you shouldn't have any problems. Not a lot of failure points in my opinion. I even took my car to the track once before I built the front pinion support. The shifter was all over the place, but worked fine.

Alternative

V8R is/was working on a solution that entails deleting the PPF, welding the tabs to the rear subframe and using a transmission mount.

6strngs

iTrader: (2)

I saw in this thread that several had added rubber between the PPF and subframe and it still clunked. Didn't see anyone post any resolutions they found to their clunking. With my wheels up in the air if I rotate either tire back and forth slightly I can hear a clunk that seems internal to the diff. Don't know if that's normal for a clutch type LSD or not. When taking off from a start the sound sounds like exhaust banging against something, but I don't think it is as the whole car seems to shudder when it happens.

KMiata

Old post but just saw it. V8R manufacturers our subframes and engine mounts, that's it. We are two completely separate companies, they are a vendor of ours.

Alternative

Wouldn’t that make you a vendor for them?

KMiata

Quickbooks tells me they are one of our many vendors

We are a V8R dealer and sell this Getrag kit quite a bit now to pair with our BMW transmission upgrade. However, we only sell the PPF delete version. We have noticed a bit more NVH after installation, but nothing drastic. I've personally installed a couple myself so if anyone has questions I can try to help.

BGordon

Since you have installed several of them, how about answering a question that I had (but never asked) when installing mine.

For the front plate single hole bracket installation, the V8R instructions tell to maintain a specific angle when the differential is installed into the rear subframe (3 degrees up if memory serves).
Any idea what sort of tolerance is on that angle measurement to keep everything happy?
Mine was up 1 degree more than the instructions stated when I did the test fit after welding the bracket in place.

Since I was doing the Getrag as part of an LS V8 install and was using the Flyin Miata instruction booklet, I initially did as their instructions stated and gave a specific dimension when tacking the bracket in place.
It was 5 degrees off the degree that V8 Roadsters mentioned so I backed off and redid the bracket using the degree method.
The whole process made me wonder what sort of range of angles will work correctly, and therefore the question.
FYI, I did send an e-mail to Flyin Miata mentioning the difference between their instructions and what V8 Roadsters instructs so that hopefully somebody can update something to keep things consistent. Flyin Miata sells the V8 Roadster kit and it actually comes directly from V8R.

KMiata

That's a good question. I didn't have any instructions when installing ours, I just made sure the diff wasn't binding up or down in the subframe. I just centered it so there was equal play and tacked the plates on. Replacing the diff bushing with something stiffer is also helpful when lining up the plates. You should be able to drop the diff into place and have all the holes line up nicely without needing to force anything.