100% atf in w58 ?

[andrew_mx83]

it also helps going up a tired box, i limped an evo around tassie for 4 days like this at easter time, box goes back in next week with new 3rd and 4th synrcos

[andrew_mx83]

Andrew, my j160 has seen up to 8800 and was fine. You just have to be nice to them on the shifts otherwise KABOOM

neither me, or my button clutch are nice on the shift

you just get good at changing gearboxes after a while...

[allencr]

If you're worried about inertia load on a syncro, I don't think any twin plate with out cushioned hubs is going to be lighter then a single plate with cushion unless their diameter is a lot smaller.
Looking at a W58 manual, its got some kindofa mickeymouse 3 piece syncro that I can't figure out, nothing like the Porsche BMW Alfa that uses inertia to grip better at RPM.
Syncros need friction but even more, they need an angle on the dogs/teeth so they can shove past each other & not butt heads like worn rounded ones do & refuse to slide past.

[1gjet]

My osgiken twin plate was alot lighter then my 4 puck button, which sounds wierd

[Draven]

twin plates tend to be lighter than singles - I know I shed >5kg (iirc) when going from the (admittedly FAT) stock JZA80 clutch/fly to a twin jobbie.

[1JZ-Rolla]

Remember that most twinplates come with their own significantly lightened flywheel too Its not the weight of the clutch that matters in the synchro debate, its the whole rotating mass of the harmonic balancer/crank/flywheel/clutch.

Cheers
Phil

[fixeruperer]

thanx for the replies,

ive lightened my bottom end heaps, i cant remember the amount but it was a good few kg's. it has a dangerous looking lightened fly wheel, lightened crank and lighter forged rods. i reckon ive lightened it too much and the revs drop too fast when i let off the throttle.
changing lower isnt really an option, i dont make power till about 5k, and with an antilag launch its pretty hard to catch the clutch before 7k. i was thinking about just launching in 2nd but i know its days will be numbered.

with the machining of dogs, ive done that on my bike, and it made the world of difference. hopefully i dont have to do anything like that to this.

this is the same 1jz-rolla, it doesnt want anything to do with a 2nd gear change, all the rest are fine. has any one tried a rev cut shift control ? i dont have enough outputs to run antilag and shift control at the same time.
ill undust the car when it stops raining and have a play.


haha no mechanical sympathy here.

[NME308]

I would be pretty confident - alabeit from a non engineering background - that the weight or lack thereof from the engine rotating assembly including the flywheel and clutch pressure plate would not come into play once the clutch pedal is depressed.

The only thing I can think of affecting the box in terms of rotating mass would be the pressure plate. This is where the twin plate clutch could possibly be different i.e. smaller diameter if not lighter total weight. Could maybe even the harmonics and balance of the pressure plate(s) come into the equation I wonder...?

Is there a preliminary set of positive results for multi plate clutch users?

What about RPM threshold? Whereabouts in the rpm range do the W series boxes refuse a quick shift - or for that matter the J160? Both T50's I've used over the years refuse service if attempting to change in anger over 6500rpm.

Being that I've still got the longsuffering T50 I am checking the results for a potential box and clutch combo as a replacement in the future!

Cheers,
Jason

[andrew_mx83]

Remember that most twinplates come with their own significantly lightened flywheel too Its not the weight of the clutch that matters in the synchro debate, its the whole rotating mass of the harmonic balancer/crank/flywheel/clutch.

Cheers
Phil

excellent. my rotating mass has dropped from 55kg standard to 43


edit:thats without clutch, but everything else

[fixeruperer]

that is true, but i feel that the engine rpm drops so much that the box cant sync with it on a quick change.

with the twin plates vs single, wouldnt the two small plates be the same if not a touch more than a single ? as weight goes ?

i remember having less power and being able to half let off the throttle on a 1st-2nd change and the revs would stay around the same and fall into 2nd and send me sideways up the road, roasting tyres. now i cant catch it if i try the semi flat change, and it doesnt want to go mesh into 2nd.

yeh it was around 10-12kg i removed too.

thanx.

[LeeRoy]

It's not so much about the total weight as it is centrifugal force. If you have two objects of the same total weight the one with the greater weight at the furthest distance from the centre will have more momentum.

[allencr]

Yes, the weight of the disk/s plus the input shaft plus the counter/lay shaft plus the gears on the mainshaft are what the syncro has to cope with, nothing else but clutch drag. Also the considerable drag from gear oil everything is slogging through compared to ATF. This mostly happens on down shifting, what you'd double-clutch to overcome, on up shifts the input-shaft slows down to the speed of the gear on the main-shaft from the throttle change or the clutch dis-engaging.
How do you shift it?
a. WOT, stab clutch while shifting, no throttle change.
b. WOT, let off throttle while shifting, no clutch change.
c. WOT, stab clutch & let off throttle while shifting, then WOT.

[fixeruperer]

C.
but normally A. with a lil bit of back off.