givemethebighammer
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| posted on 6/8/06 at 07:10 PM |
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The straight cut gearbox isn't too bad
I picked up a second hand Tran-X type 9 gearbox a while back;
ratios
1 - 2.38
2 - 1.69
3 - 1.27
4 - 1.00
5 - 0.87
Finally got round to fitting it to my 2.0L zetec. I was a little apprehensive as people had said that straight cut gearboxes were very noisey (whine).
So I was pleasantly suprised while it wasn't that bad. It does whine (loudest in 1st and 2nd and hardly at all in 4th), but the sound of the
exhaust and induction very quickly masks any extra noise the gearbox has added. The ratios feel very well suited to the car and I also have a very
usable 1st gear now.
So if anyone else is considering this option don't worry about the noise, a seven is loud enough anyway a little extra won't detract from
the experience.
Who knows? I think I like the whine anyway, certainly makes pulling away more interesting.
[Edited on 6/8/06 by givemethebighammer]
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Tim 45
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| posted on 6/8/06 at 07:41 PM |
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IIRC it shouldnt whine in 4th at all because its straight through ie no straight cut gears. Or at least thats what its like on a mates quaife.
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givemethebighammer
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| posted on 6/8/06 at 07:47 PM |
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Maybe you're right Tim, It is much quieter in 4th but I'd convinced myself that maybe it was still whining a little (lots of other noise
going on at this point). I'll have another listen tomorrow.
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Tim 45
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| posted on 6/8/06 at 07:53 PM |
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Just realised, if the ratio is 1.00 then its the same speed coming off the engine so no need for gearing at all just a straight through shaft.
The whine becomes an old friend after a while 
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smart51
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| posted on 6/8/06 at 07:58 PM |
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bike engines have straight cut gears. You can hear the whine at low speeds but the engine roar soon drowns that out
4th, on a car box, when it is straight through, is more efficient than the geared ratios because no power is being lost meshing the teeth. I
don't know how that is useful but it might be interesting to someone.
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Jon Ison
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| posted on 6/8/06 at 08:34 PM |
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When ever i here the "whine" on a car it tells me its either.....
A) a serious piece of kit........or
B) its got a knackered box............
That whine sounds great tootling down the pit lane
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ned
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| posted on 6/8/06 at 09:10 PM |
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quote:
Originally posted by Jon Ison
When ever i here the "whine" on a car it tells me its either.....
A) a serious piece of kit........or
B) its got a knackered box............
C) its time for the other half to get out
beware, I've got yellow skin
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daviep
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| posted on 6/8/06 at 10:05 PM |
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Is there an expert who can keep me right please?
Are gearbox losses affected by which gear is selected?
I only ask as I thought most boxes were constant mesh and losses would be reasonably constant as everything is going round all the time??
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DIY Si
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| posted on 6/8/06 at 10:08 PM |
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If one gear is 1:1 it just locks the input/output shaft and doesn't actually use the gears. Hence a lower loss.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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gazza285
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| posted on 7/8/06 at 03:13 AM |
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The gears are in constant mesh, but as all but one of them is freewheeling the losses from drag are minimal. Straight cut gears are more efficient
than helical ones as all the load is carried in line to the forces, where helicals carry them at an angle, exerting a thrust load on the drive and
driven gears. Straight cut are good at minimising losses, helicals are good for quiet, long life use.
DO NOT PUT ON KNOB OR BOLLOCKS!
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02GF74
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| posted on 7/8/06 at 06:29 AM |
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you don't know the meaning of whine until you have driven an old Land Rover with buggered gearbox, transfer box, diffs and worn overdrive so
quit complaining!
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NS Dev
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| posted on 7/8/06 at 07:10 AM |
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as was said, 4th gear in the type 9 box (but not all gearboxes by any stretch, even with 1:1 fourth's) just locks the input shaft to the output
shaft, saved ford a few quid on gears!!
A lot of boxes still use a gear pair for a 1:1 fourth gear but ford didn't!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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givemethebighammer
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| posted on 7/8/06 at 09:59 AM |
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OK, had a good listen this morning on the way into work. No it doesn't whine in 4th and there is very little whine in 5th.
Whoever said a straight cut box in a road car was a bad idea was wrong IMHO - I like it !
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NS Dev
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| posted on 7/8/06 at 10:19 AM |
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have you had a look inside it, daft question, but quaife do helical, semi-helical and straight cut, not just plain straight ones now. Often 5th gear
may be still helical or at least semi-helical.
The straight cut ones I have dealt with were loud enough to need ear defenders (and I certainly don't have sensitive ears, have already lost a
fair bit of my hearing according to my works medical! ) on a journey of any length in (each of) a mk 2 escort, rwd mid engined Nova and a sierra rally
car. Worst was the Nova though as that had a straight cut CWP in the (normally front drive, but now right behind you) box as well!!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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givemethebighammer
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| posted on 7/8/06 at 12:06 PM |
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My tiger is just plain loud , I generally wear earplugs anyway. But even without a helmet or earplugs this gearbox doesn't sound painfully loud.
But then the four carbs do kind of overshadow everything !
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DIY Si
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| posted on 7/8/06 at 03:19 PM |
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My mini's a bit like that! Straight cut race box with a 48 ida for induction roar! Can be heard over 2 miles away! I do need ear plugs for
journeys of more than 15 mins as my ears ring!
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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MikeRJ
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| posted on 7/8/06 at 06:38 PM |
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I was passengered from Plymouth to Silverstone for the Mini's 35th Aniversary in my brothers mini, which has a 45DCOE and straight cut box and
drop gears.
The ringing in my ears did eventualy stop after a few days...
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