308 vs 348 diff . . . why do they feel so different?

Hey all,

Was thinking about the 348 vs. 308 diff and how they feel so different when you turn one wheel with the other wheel locked. On the 308's there's a bunch of static breakaway but on the 348's doesn't seem to be any. The pics I've seen of the 348 diff look identical to the 308 diff . . what is actually different in there? Ramp angles and preload or ??

Thanks,

Sean

 

I have owned both cars it is ramp angle and preload. The 348 has almost no preload but the diff lock up so you can leave 2 black marks providing your tires are not too wide as the momentum allows the thingys to tighten along the ramps. We had an Fchat disscussion about this when Ernie was rebuilding his gearbox in my garage. Do a search it may have been under "Ernie's difficulties" in the 348 section. You can actually increase the preload by plate staggering and or adding a plate. This may help
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hey I'm not seeing the belleville spring that's in the 308 diff's . .. is there one in there?

 

There was a thread a year or two ago in the 348 section dealing with the subject in great detail, primarily from a track and handling perspective. I dont recall how much there is about the 308 or differences between, but there was a lot of theory of operation. I believe it was Ernie in that thread who was altering his ramp angles?

 

I read that thread . . . just looked like the internals of the diff were the same but now I'm not seeing any belleville spring on these pic's.

 

Hey FBB, you beat me to it, lol.

So the 348 has zero preload/loose clutch packs, and relies soley on acceleration in the ramps to lock it up?

 

I just looked at an exploded diagram and it looks like no belleville spring . . the radical difference makes sense now.

 

Do the 355 and 360 diff's have the same lack of static breakaway as teh 348?

 

So with the 348 up on a lift you can spin the wheels freely? How does this effect low speed handling then, less push, lighter low speed steering?

 

yep . . .don't pesonally know the effects on handling though