Busa/VW091 Adapter Testing Results

[Engineer]

There was really no evidence of it contacting the tube ID. The spider COULD have extruded enough though to allow the jaw tips to act like a pain of nipper jaws as the torque is applied and reapplied repeatedly and slowly eat away at the spider possibly. The factory lovejoy jaws have slightly radiused tips and the ones I'm using don't. A lot of possibilities . Gonna take some R&D to cure.

I thought that with the shape of the jaws it would almost want to squeeze the material into the center instead of to the outside.  With the centrifigal force added it would have been about equal.  obviousely something went wrong.

It seemed like the green was quite a bit tougher even if the specs don't seem to show it.

ETA: Actually machining a spider may be much better by getting rid of the 3-D present in the factory spiders.  The curve that allows for more angular misalignment greatly reduces the contact area and centralizes the loading.  There is virtually no chance of angular misalignment in your setup, so the added contact area of a machined 2-D spider will have more consistent loading and less peak pressure in the spider material.

[fabr]

Dayum.  Catostrophic failure..... 

As tight as the clearance is between the jaws and the case not very large of parts could have gotten out.  So if they grew out past the jaws then they would start burning on the case.  Can't see that in the picture but can you see rubbing on the removed part of the tube?  Probably not the way the outside of the jaws don't show anything rubbing.  O course if it was gone on your first trip then corrosion may have hid the evidence since.

Whatever material you put back in, I suggest running it for a short time then pulling the cover and taking a look before the evidence is ground to powder. 

I see no sign of any rubbing anywhere.  No sign of any melting anywhere.The PU either blew to pieces or was chewed up. I'm leaning towards a combination of both.This pic seems to show that evidence? 

[fabr]

I really think that the spider compressed enough to allow the jaw tips to contact,or near contact,each other and act like nippers on the spider tips. Slowly the tips were eaten away and as the spider was constantly being flung to the OD, the nipping away accelerated as the jaws were able to even more easily contact each other the more spider was lost/nipped away. I think it kind of fed on itself. I'll radius the jaw tips more like the OEM jaws are to hopefully stop that and test out the green spider. I think that it may cure the issue at current power but still need to explore other options as I doubt it will hold up to 300-400 HP.

[Engineer]

I really think that the spider compressed enough to allow the jaw tips to contact,or near contact,each other and act like nippers on the spider tips. Slowly the tips were eaten away and as the spider was constantly being flung to the OD, the nipping away accelerated as the jaws were able to even more easily contact each other the more spider was lost/nipped away. I think it kind of fed on itself. I'll radius the jaw tips more like the OEM jaws are to hopefully stop that and test out the green spider. I think that it may cure the issue at current power but still need to explore other options as I doubt it will hold up to 300-400 HP.

I agree with your assesment of what happened. 

I was suggesting that if you caught it before it was completely powder there might be more evidence to work with. 

The originals didn't have much radius either.







What do you think about a machined 2-D spider having lower pressure?

[fabr]

I thought that with the shape of the jaws it would almost want to squeeze the material into the center instead of to the outside.  With the centrifigal force added it would have been about equal.  obviousely something went wrong.

It seemed like the green was quite a bit tougher even if the specs don't seem to show it.

ETA: Actually machining a spider may be much better by getting rid of the 3-D present in the factory spiders.  The curve that allows for more angular misalignment greatly reduces the contact area and centralizes the loading.  There is virtually no chance of angular misalignment in your setup, so the added contact area of a machined 2-D spider will have more consistent loading and less peak pressure in the spider material.

The green is a good bit tougher than the red. There is a good possibility of angular misalignment at the engine adapter though. Due to suzuki sloppy tolerances there are no consistent mounting points so initial setup calls for a dial indicator and some simple drill press spot machining to try for perfect perpendicular.Most guys won't get it perfect so hence the need ,IMO , for some allowance for angular and induced parallelism misalignment.The spider allows for 1.3* and .027" parallel.   I still want shock absorbing and think that I'll contact LJ and see if there are any special unlisted offerings of tougher and more resilient materials . Other option is to have some waterjetted out of some elastomer of adequate properties and not worry about the curvature. . Then there is the big hole in the center. I don't need that. Perhaps just using a comparable Shore PU and leaving a more robust "hub" might keep the spider legs from extruding. Sounds like R&D will be in full swing soon as the tranny repairs are done and engine gets back in. Fast ,you up for a few day trips? 

[fabr]

I agree that a 2D profile can be no worse than a 3D so far as spot loading is concerned. I think a suitable resilient elastomer with a 2D profile will be thw answer. Doing a lot of research on that avenue now.

[fabr]

I wasn't meaning to say that there is any great difference between the OEM jaws and the ones you made. It is a very little small difference and I "blame" myself for not doing a small deburr and detailing in that area.  Maybe not have made a difference but sort of like a dull pair of scissors won't cut butter........ Anyway it can't hurt to do it now. I'm thinking of sort of taking your advice and putting in another red one and doing a 30 minutes at a time inspection for the first couple hours. Play it by ear then.

[Hammerworks]

Is there anyway to "bench" simulate the amount of torque your puting into it.Like one of those huge 8'(dont know the actual lenght) torque wrenches on one side and the other side mounted to a beam in your shop.Then have someone apply the torque while you watch the donut.

[fabr]

I've thought of that but I have no idea what that load may be. I feel that it's the torque spikes such as when running the whoops flat out,foot to the floor that did the damage and those are an unknown.

[fabr]

One things for sure. Peeks OUT~!!!!!! LOL!!!!!!!!
http://www.usplastic.com/catalog/item.aspx?itemid=65366&catid=618

[Boostinjdm]

I didn't know it was made of gold...

[BDKW1]

I remember now-a Guido Coupling.    http://cgi.ebay.com.au/BMW-drive-shaft-UNI-GUIBO-COUPLING-E46-E12-E28-E34-E23-/110590056947    Funny thing is that they aren't rated as high a torque capacity as the LJ coupling I'm using. Looked into them early on.

Where did you find the torque ratings. A 760 uses them and weighs 5026 empty with 550FTLB's of torque. With a first gear of 4.71-1 they should be good for at least 2600FLTB's of torque.............
 
Even the lowly 3 series with 200FTLB's and a 4.32-1 should be good for 900..........

[Boostinjdm]

Where did you find the torque ratings. A 760 uses them and weighs 5026 empty with 550FTLB's of torque. With a first gear of 4.71-1 they should be good for at least 2600FLTB's of torque.............
 
Even the lowly 3 series with 200FTLB's and a 4.32-1 should be good for 900..........

They're fairly cheap too.  I put one in my last skid loader before I sold it.  Here is a pic with part #'s if you want to track one down.  http://www.dtsfab.com/index/index.php?topic=1308.msg22103#msg22103

[fabr]

I know the big one is too large for sure.  What is the thickness  and what is the OD of the smaller one?  I can live with a max of 80 MM OD..

[fastcorvairs]