[Dubai944]

[quote name='flash' timestamp='1385478250' post='152860']

that split tube may be fine for your average street car, but it does not hold up to the harsh duty of track.

[/quote]



Not true in my case at least. My split tube hasn't come apart yet after 5 years of three full competition series and associated heavy track abuse, solid flywheel and I am making more power than most. The bearings probably could do with replacing, they are getting a bit noisy, but it keeps on working.



I think the difference here is perspective. Engineering perfection is not a particularly interesting goal for me. I use parts till they wear out, then fix them and use them again. If they break you either modify them to make them stronger or you replace them until they break again, but you don't expect them to last forever anyway. Fact is for practical purposes, it seems you can drive the hell out of these cars with big power and the split tubes for years without problems. Sure they won't last forever, but I don't want the car forever.



Flash's car on the other hand, probably will last forever <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[flash]

you don't know that unless you've taken it out. i've said this at least 3 times now. YOU CANNOT TELL FROM THE OUTSIDE. the fact that you have noise points me toward the fact that you do indeed have a migrated bearing. that's the first symptom.



this is exactly the problem though. people drive the car, don't see the actual issue, and think that it's fine. they don't consider the consequences, the first of which is the rear main seal. after that, it's input shaft bearings. the list goes on. unless that shaft is locked in place, with zero deflection, things get messed up. unfortunately there is absolutely no way to see if there is any play in there without at least pulling the clutch.

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[speedysprocket]

Sorry I started such a commotion! Didn't realize tube type was such a touchy subject...

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[flash]

lol - no worries. i just went through this, and spent a small fortune learning the hard way about it. it really sucked. it was not in my build budget, but had to be done nonetheless.

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[Dubai944]

[quote name='flash' timestamp='1385507465' post='152891']

you don't know that unless you've taken it out. i've said this at least 3 times now. YOU CANNOT TELL FROM THE OUTSIDE. the fact that you have noise points me toward the fact that you do indeed have a migrated bearing. that's the first symptom.

this is exactly the problem though. people drive the car, don't see the actual issue, and think that it's fine.

[/quote]



No need to SHOUT…lol



Of course, the fact that they are starting to grumble tells me they need to be looked at. Next time I have the engine or gearbox out I will replace them, it's on my to do list. But my point is they have lasted fine for 5 year of hard track driving before reaching this point, and considering they were already 18 year old, 50,000 mile torque tube bearings before I started racing, it has stood up pretty well. Anything that lasts 5 year without destructing in racing is pretty good in my book.

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[flash]

lol - when i get to saying the same thing the third time, i figure i wasn't heard the first two.



as for "lasting", just because they haven't flown out of the car, does not mean they have lasted that long. they may have been loose for a long time now, adding wear and tear to other parts. you just don't know until you pull it apart. if your rear main seal is weeping, or if there is the beginnings of backlash on and off throttle, you've probably already done some damage.



besides being lower in power, the S2 is a lot smoother than the 968 too, so that may be why we haven't seen as much of an issue with them.

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[Eric_Oz_S2]

You can tell when you remove the TT. After 3 hard years of track abuse the bearings are still quiet and the bearings are still in the carrier. I disagree that the S2 is smoother, having driven both.

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[Dubai944]

[quote name='flash' timestamp='1385526416' post='152917']

as for "lasting", just because they haven't flown out of the car, does not mean they have lasted that long.

[/quote]



Actually, that's exactly what 'lasting' means to me. If it's still attached, it's lasting….. <img src="/forum/images/smilies/968/laugh.png" class="smilie" alt="" />

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[flash]

lol - to me, unless it's a wear item (like tires or brakes) it's only "lasting" if it is operating in 100% new condition. anything less is at least worn, possibly ineffective, or worse, doing harm to other parts

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