heple1983

Just a general question (as per title) as i am interested. Heard about these a few times always wondered what the difference is between them and standard box

Spoon

Don't they normally get around a bit more?

Gear Head

iTrader: (2)

It means a box that is designed to shift a quickly as possible, ie, not very easy to control around town, louder operation and stiffer operation. however, excellent on the track!

heple1983

I weren't on about u mum mate

heple1983

Could u not just get an uprated box for increased bhp instead of a dog box which a lot of people on here seam to have done

Gear Head

iTrader: (2)

Spose you could but have no idea on cost or fitment etc. You could source a type r group n gearbox if you have a classic. May fit new age, sure to be corrected either way.

P1Fanatic

From the footage of cars Ive seen with a dog box its normally a box whereby the gearstick is just rammed into the next gear sequentially and limited or no need for a clutch. But I aint no expert.

Simon.

aurora

a dog box normally has the first gear on its own to the left and forward, 2nd, 3rd are parallel, along with 4th and 5th.. giving any car with enough poke to get off the line in 2nd without wheelspin and easy gear selection up to 5th

p.s. dog left first... not to be confused with a straight cut box

dibble wants a scooby

Think your on about a 'dog leg ' box. This means that first is back left on the gear pattern.
A 'dog box' has 'dogs' that pertrude on the gear cluster and engage together (easier to draw than explain !) so clutchless changes can be performed up and down and it can stand more abuse but would be ****e on the road as its clunky and v.noisy
Normal gears are 'helical' cut so they 'mesh' together without noise, which then goes on to explain 'syncro-mesh' etc etc ie a syncro that spins at the same speed as the layshaft there by meaning the next gear is spinning at engine speed and avoids the gears crunching (no double de-clutching to raise the gear up to engine speed )
Straight cut boxes are as the say the gears are straight cut rather than helical cut, they are stronger and make a nice noise but crunch on every gear
Phew
Hope thats right !

Nick98

Well its goes something like this. Standard road boxes have syncros between each gear which eases the gears in and out of mesh when you use the clutch, thus avoiding a crunch between gears which you get when either you are not quick enough with the clutch, or indeed the syncros are worn. They wear as they are made of a softer metal that the gears (e.g. brass) and thus don't last as long as the hardened gear.

In addition most road boxes have helical cut gears where the gear profile is cut at an angle to the gear itself, this allows the gears to mesh (and drive) in such a way that the noise of the gears driving each other is kept down to a minimum. However with the reduced noise you get weaker gears

When you get more power and torque out of the engine the geartrain is strained more and thus syncho boxes (with helical gears) won't last long.

The next step on is to put a gear kit into a standard box. These kits use many of the same bits as a standard box however the gears are straight cut (cut at 90 deg to the gear), the syncros are harder, and the bearings are uprated. The advantage of these, apart from being stronger, is that the gearchange is nearly as good as a road car and noise increase is kept to a minimum. You can spot a straight cut box tho as it whines when in neutral (and of course on the road) and sounds just like a bearing has gone !! The industry standard for these kits are either 'Quaife' or 'Possum Bourne' who between them manufacture about 80% of Subaru gear kits - for motorsport or uprated road car use.

As power increases then the next step is to go to a dog box. These boxes are normally reserved for competition car use, although some extremely modified cars need them. They can often be fitted into a standard casing (Impreza included) but sometimes are actually a special box. Leading manufacturers for Scoobys are 'TEG' and 'Quaife'.

Dog boxes work on the same principal as a straight cut box but have no syncros. Instead the sychro is replaced by a dog ring which is a hard ring which a number of 'lumps' (or dogs) on each ring that engage with the dog on the next gear. These typically vary in number beween 4 and 8 and allow the gearchange to occur very quickly, and importantly, without the use of the clutch. These are traditionally very strong and can put up with extreme amounts of power (and abuse). A clutch is still required as you would need it to get into first and reverse when stationary however when moving you can dispense with the clutch and literally ram it into gear. However to maximse the life of the dog (which is still slightly softer that the gear) using the clutch helps. On a competition car like ours this isn't too much of a problem as the box has to rebuilt every 1000 kms and the dogs always get replaced.

The disadvantage of a dog box is they are very noisy, the gearchange is a nightmare at low speeds (even with the clutch) and most people who don't understand, look at you as if you can't drive when you go past crunching gears.

Finally, just to clarify an earlier answer dog boxes are not to be confused with boxes that have a 'dog leg' first gear where first is normally back and left. Dog leg first boxes could be any of the above types of gearbox but again a more tradionally found in specially designed competition car boxes. As first gear is the one that is used the least it is moved to one side thus putting 2nd and 3rd, and 4th and 5th in straight pairs, as a result the gearchange becomes quicker as you don't have a sideways movement between the gears other that 3rd to 4th. Lotus Sunbeams and Mk11 Escorts with ZF gearboxes had dog leg firsts, although they have become less popular in recent years due to a number of factors, one of which being that most derivitives of modern cars have a Group N (or Production) class. Here the essential elements of the cars have to as designed by the manufacturer so coventional gearbox layout is required (unless a manufacturer is brave enough to make a road model with a dog leg first !!).

Sorry its long winded but I hope that helps. I am sure any technical inaccuracies will be corrected by fellow SNetters.

Nick

Leslie

I thought all manual gearboxes had dogs, with or without synchromesh.

Les

Playsatan

iTrader: (2)

Very informative Nick. I've a question about the syncro's tho.

On my sti 5 type R there's a snick when selecting 5th. I'd put this down to the known problem with series 2 boxes where the retaining nut on 5th works loose but I've noticed if I double de-clutch it's fine. Does this mean it may be the syncro?

Cheers

Nick98

Blimey - thats the $1,000,000 question. It could be either but sounds more likely to be the synchro as you can double de-clutch and its not a problem. I haven't experienced the nut working loose myself but would assume this is a more serious problem that double de-clutching wouldn't cure. I will seek some advice from our gearbox builder and get back to you though.

Nick

Playsatan

iTrader: (2)

Cheers Nick, fingers crossed for the most wallet friendly outcome.

heple1983

I have the same problem with MY99 UK Turbo with the snick in 5th. gonna take scoobyclinic i think and see what they say.

Cheers for the info lads- Defo answered the question. fully understand what a dog box is now!!!!

olliecampbell

iTrader: (3)

Sometimes those gear changes can be helped with uprated gearbox oil

CustomScoobyIOM

Most likely syncro. By double clutching you are ineffect bypassing the syncro rings like the old cars that didn't have syncro rings.

Playsatan

iTrader: (2)

Who need 5th anyway??

Pricey to put right?