Sam's build thread

[sambb]

excellent. Appreciate it Gary.

[sambb]

Alright I've had a squiz at those setup sheets Gary. So for my application -250hp, 215M fronts, 1200kg with driver at a guess, 10 events a year (wakefield, south circuit, rallysprint and state hillclimb tracks) and of course the boring old street. Should I be going for the 100, 65 or 35% locking setups - considering that I'd like the thing to last at least 2 years before I yank it again to service it.

[Sydneykid]

Alright I've had a squiz at those setup sheets Gary. So for my application -250hp, 215M fronts, 1200kg with driver at a guess, 10 events a year (wakefield, south circuit, rallysprint and state hillclimb tracks) and of course the boring old street. Should I be going for the 100, 65 or 35% locking setups - considering that I'd like the thing to last at least 2 years before I yank it again to service it.

Sure, how long is that piece of string?

FWIW, my views;
35% is for road cars, it allows quite a bit of inside wheel spin
65% should be OK for combo road and track cars
100% is what we use in the race cars and it doesn't allow any inside wheel spin

So it seems a fairly simple choice go 65%, the three bears analogy.

Personally I wouldn't, I'd go 100% for a couple of reasons. Firstly all 6 friction surfaces are being used so the wear is spread across them. With 65% only 4 surfaces and with 35% only 2. So when you use it on the track it's going to heat up the lessor number of friction surfaces more and faster. The plates themselves aren't that expensive, it's pulling and assembling the gearbox that costs (time or money). Secondly it's a 1.5 way, so it's going to unlock to 50% ('ish) on throttle off, which is OK for slow speed U turns and parking.

My experience has been that in 99% of the road driving you wouldn't notice any difference between 65% and 100%. But on the track you would notice it very easily.

Cheers
Gary

[sambb]

Ok cool. That's what I thought - that despite the road kays I do that the bulk of the wear would still take place on the track and if all friction surfaces are active = more locking but also shares the wear more evenly. I'm just too inexperienced with this stuff to be certain though which is why I asked. I'm happy to go 100% locking, because if I'm going to all this effort then I want the thing to feel like a mutant and if a spin off of that is that the service life is possibly extended then I'm happy. I ordered the Super Q treated plates (7-10 days) that apparently don't make as much racket as standard ones doing urban turns and don't need the figure of 8 break in procedure, if that's even applicable for a FWD? Hope they perform the same way on the track and aren't just more slippy.

Incidentally in a wavetrac/quaife/peloquin is there anyway of determining their theoretical peak locking % or is it just not possible to get the way they 'lock' into relative terms, apples and apples whereby they can be directly compared to a plate diff?

Thanks again Gary. I'll leave you alone now

[Sydneykid]

Ok cool. That's what I thought - that despite the road kays I do that the bulk of the wear would still take place on the track and if all friction surfaces are active = more locking but also shares the wear more evenly. I'm just too inexperienced with this stuff to be certain though which is why I asked. I'm happy to go 100% locking, because if I'm going to all this effort then I want the thing to feel like a mutant and if a spin off of that is that the service life is possibly extended then I'm happy. I ordered the Super Q treated plates (7-10 days) that apparently don't make as much racket as standard ones doing urban turns and don't need the figure of 8 break in procedure, if that's even applicable for a FWD? Hope they perform the same way on the track and aren't just more slippy.

Incidentally in a wavetrac/quaife/peloquin is there anyway of determining their theoretical peak locking % or is it just not possible to get the way they 'lock' into relative terms, apples and apples whereby they can be directly compared to a plate diff?

Thanks again Gary. I'll leave you alone now

Sorry for the delay in responding, Eastern Creek since Friday.

In a torque sensing diff (helical) the "speed" of take up is determined by the ramp angles, so it's easy to have a difference in drive and over run, just have different ramp angles. But once they are locked they are locked, if they don't lock they wear out real fast (ie; break) and knock like a jack hammer. That also breaks drive shafts/CV's real quick. Whereas I think of plate diffs like a clutch plate and pressure plate (dah), once the rotating surfaces are locked together they stay that way. But they can have different loadings (like a pressure plate action) determined by the cam angles, so the pressure on the plate increases or decreases at a predetermined rate. Plus the pressure can differ on power on or overrun.

The biggest difference is even the slowest helical diff gets to fully locked really fast and unlocks even faster. Whereas a plate diff is noticeably slower to fully locked but has progression whilst getting there. Plus it is the same on transition from power on to over run, so the attitude of the car doesn't change as much (as it does with a helical) ie; the clutch slips, which is why they wear out. Which, like a clutch plate wearing out progressively, you can feel. Each time out they just don't work as well, slip a bit more, then a bit more, until you either replace the plates are they stay open.

The theory with a helical diff is that, being gears, they are zero maintenance. They either work of they don't. But when they do fail, they go big bang and there are bits of gears everywhere and the diff is often throw away. If it is a transaxle then that too, often.

The more power a car has, the more slip potential and the quicker the plates wear out. That's why most V8 applications don't use plate diffs.


Cheers
Gary

[sambb]

Ok got it. I didnt realise torsens could achieve full lock. Maybe if I was still running softs and had 235's under me then the wavetrac would have been a bit more effective, but I think the Kaaz is going to go well. I've ordered the rebuild plates and I should have those in a 10 days and then I can open it up and see whats what. I'll be interested to see what locking % they set them up with from factory.

[simon k]

keen to see what it looks like...

[sambb]

Andrew did you see the changes to the MSW Hillclimb Champ rules. You now only have to complete 5/8 rounds to get a standing at the end of the year and they take your best 7/8 results when tallying up the point score. I like it. That means I can drop Grafton, making Kempsey and Tamworth at 5 hours the longest trips which are doable. Hmmm thinking about hillclimbing a bit more this year...

[metalhead]

Yes I saw that! I was at our club presentation night last night when I saw the email, it made several at my table more keen to consider running enough rounds to make up the Championship next year. I got an email reply to my email saying it had been forwarded to the committee for discussion too - have you sent an email about that yet?

[sambb]

Yeah thats a better system for mere street cars like ours. It'll all depend on work for me (rostered every second weekend) so it might go my way. I havent written the email yet, no. I'll get on it. Knowing Geoff after his big one at Huntley, he'll be onto them about safety again despite not being in our class anymore. There was a story in the paper that they'd analysed the biggest causes of death in road accidents and other than head on collisions, it was collisions with trees and poles that were the next thing even if speeds were low. Lots of trees in the hillclimbs…...Geoff was so lucky.