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Close Ratio Gearboxes

maccattack
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maccattack Proficient

maccattack

Posted
Posted

Just looking for a bit of feedback from those who have tried various close ratio boxes.

I have a GTR which is fairly heavily modified. I have a habit of breaking synchros and am looking for a gearbox that will be used primarily for road use and about 10% for track work.

Should I be going to mission (helical) gearset as opposed to dog gears?

Are dog gears (straight cut) driveable on the street?

I like the price of the OS Giken gearsets however I have heard that I should be looking at PPG's gearsets as they are far stronger.

Those who have either of these or can shed a bit more "user knowledge" on these it would be appreciated.

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https://www.sau.com.au/forums/topic/177675-close-ratio-gearboxes/
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ssshonky Grand Master

ssshonky

Posted
Posted

Not speaking from user experience here but you might want to go and look at a PAR gearset.

Least they are over east vs overseas.

the only thing that might annoy you about straight cut is the whine they can generate.

but to get over that you could get straight cut 1-4 then 5th as non straight cut.

least then you can stick it in 5th to get a bit of peace and quiet.

saliya Rising Star

saliya

Posted
Posted

Hey,

you're talking about three different things.

* How the gear teeth fit together - helical, or straight cut. Helical gearsets

impose a lateral load on the gearbox but are quiet and generally used by OEM;

straight cut gearsets have no lateral load but make lots of noise.

You can get a combination set (e.g. straight 1-3, helical 5) so you can cruise

quietly yet have a strong-as-possible 1-4.

* How the gears are engaged - synchromesh, or dog engagement. Synchros

are regarded as nicer to drive and lower-maintenance, dogs permit faster (and clutchless)

shifting. Dogs can take up less space than synchros allowing for wider

(and stronger) helical or straight gearsets.

* The ratios of the gearbox - closer ratios allow for less RPM change between

gears and can suit a 'peaky' motor better than longer ratios.

If you're actually breaking synchros sounds like your shift technique could

do with some modification. This would be important even if you changed to

dog-engagement - even though the technique is different, bad shifting on

a dog-style box is probably more expensive than bad shifting a synchro box.

Regards,

Saliya

maccattack Proficient

maccattack

Posted
  • Author
Posted

Thanks for the feedback so far,

Yeah I'm aware of the difference in gearset types. The reason I was asking is for information on which may be best for the 90/10 usage of the car. Are dogboxes too noisy and clumsy for daily driving - should I be using helical cut for my application??

As far as breaking synchros - this usually is a result of track work. Generally it is 3-4. You can get around it by double clutching - but this doesn't help lap times.

Ultimately my questions are should I use, straight, helical, combo gearsets for 90/10 driving?

Are the OS Giken units any good or should I be looking at ther PPG which is reputably one of the strongest around??

Peter

scathing Grand Master

scathing

Posted
Posted (edited)
Are dogboxes too noisy and clumsy for daily driving - should I be using helical cut for my application??

Dog-engagement are completely independent of the cut of the gears themselves. You can have helical cut gears in a dog box, or straight cut gears with synchros.

Are the OS Giken units any good or should I be looking at ther PPG which is reputably one of the strongest around??

Also check out PAR for gearsets. I've heard good things about them, and they're Sydney-based so warranty and support should be easier to come by. They're strong enough that people overseas will buy them from us so they can't be all bad. They don't have Hollinger's reputation, but they also don't have Hollinger's pricetag either.

Edited by scathing
scathing Grand Master

scathing

Posted
Posted (edited)

Did you want to wipe his arse while you were at it? :thumbsup:

If he ran a search in the White Pages web site for PAR in Ingleburn NSW, he would find that PAR Engineering comes up as the first match (and only match in Ingleburn).

Give a man a fish and he'll eat for a day, etc....

Edited by scathing
  • 1 month later...
VB- Veteran

VB-

Posted
Posted

if your braking syncros,get a dog box with helical cut gears. will be a bit more difficult to drive, but should be easy enough to pick up, and will allow for full throttle upshifts (using the clutch is your choice) but with helical cut gears will remain quiet. if you dont have a problem with braking gears, i'd go for helical cut as your going to be driving on the street, the noise will sh*t you with straight cut gears

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