Technical Hybrid/Close Ratio Gearbox

[Todger182]

Not straight cut final, I'm on about a fully straight cut box. So every gear doesn't use syncro's.

Thats what I was asking if it could be done or whether it's impossible with the fiat gearboxes.

Thanks

 

[rallycinq]

Not straight cut final, I'm on about a fully straight cut box. So every gear doesn't use syncro's.

Thats what I was asking if it could be done or whether it's impossible with the fiat gearboxes.

Thanks

Straight cut doesn't mean that they don't use syncros.

Straight cut gears are stronger than slash cut, but far noisier.

To remove the syncros you use dogs.

They give a very positive change but you need to learn to be brutal with the change or the dogs will miss.

Remember its not the actual gears you are changing, its the hubs.

Cheers

D

 

[ycming]

Isn't a dog box only useful when use with sequential like rallycar??

I'd pay for that up down gear change

 

[Brooky]

exactly I know of no one who run any modified fire boxes not even fiat used them on there rally cars (the most they did with the drive train is the shafts as i mentioned)

having a striaght cut final made means you need a crown wheel made along with a whole shaft that all the gears/selectors run on... I recon it would cos at least 2k to have it made.
A lot of money for a gearbox that will sound like someone emptying a machine gun in your engine bay and been only useful for pub talk

I thought the bacci diff came with a straight cut final drive, and thats less than 2 grand aint it?

 

[rallycinq]

Isn't a dog box only useful when use with sequential like rallycar??

I'd pay for that up down gear change

Yes and err, no.

Dogs were around long before sequential boxes. They are much stronger than syncros.

A while ago someone from this forum was going to design and build a sequential kit for the box as a practical for a college course. Shame it never happened.

Cheers

D

 

[rallycinq]

There you go, 5 spd dog box kit

http://www.bacciromano.com/index.php?p=prodotti&l=eng&cat1=24&cat2=30&mar=4

Only 2500 euros

Cheers

D

 

[rallycinq]

Or

http://www.bacciromano.com/index.php?p=prodotti&l=eng&cat1=24&cat2=26&mar=27&pcd=4594#4594

If you've got a few more euros tucked down the back of the sofa

Cheers

D

 

[Todger182]

I did mention dogbox in my earlia post .

Thanks for those links, i'm to ask on the polish forums whether theres a kit over there as there is a couple with dogbox's for their track/rally toys.

I'm not bothered over the noise as I think it's quite musical, it's the ability to be able to change gear without losing revs or planted power that's appealing to me.

Thanks

 

[RS-1989]

A while ago someone from this forum was going to design and build a sequential kit for the box as a practical for a college course. Shame it never happened.

Cheers

D

That twas me again, I did look into it, using a ratchet barrel type arrangement like in bikes, and I discussed it briefly with a lecturer who said he did the same using a Suzuki bike barrel in the Escort Cosworths. But nothing came of it I'm afraid. But I am still interested in doing it when I get some free time and a spare box.

My work at uni has taken a slightly different course to what it was then so that's why nothing has come of it yet. But the idea is defiantly not dead.

Thanks
Sion

 

[rallycinq]

That twas me again, I did look into it, using a ratchet barrel type arrangement like in bikes, and I discussed it briefly with a lecturer who said he did the same using a Suzuki bike barrel in the Escort Cosworths. But nothing came of it I'm afraid. But I am still interested in doing it when I get some free time and a spare box.

My work at uni has taken a slightly different course to what it was then so that's why nothing has come of it yet. But the idea is defiantly not dead.

Thanks
Sion

Well I am glad I didn't dream that bit.

Cheers

D

 

[ycming]

I did mention dogbox in my earlia post .

Thanks for those links, i'm to ask on the polish forums whether theres a kit over there as there is a couple with dogbox's for their track/rally toys.

I'm not bothered over the noise as I think it's quite musical, it's the ability to be able to change gear without losing revs or planted power that's appealing to me.

Thanks

heel tow ? left foot braking ?

 

[rallycinq]

heel tow ? left foot braking ?

You need a dog box for left foot braking.

Cheers

D

 

[ycming]

left foot heel toe?

 

[craigb244]

That twas me again, I did look into it, using a ratchet barrel type arrangement like in bikes, and I discussed it briefly with a lecturer who said he did the same using a Suzuki bike barrel in the Escort Cosworths. But nothing came of it I'm afraid. But I am still interested in doing it when I get some free time and a spare box.

My work at uni has taken a slightly different course to what it was then so that's why nothing has come of it yet. But the idea is defiantly not dead.

Thanks
Sion

i looked into it to... I recon it will be a right big headache.
finding a bike barrel that matches will be near impossible unless you worked at some mad motorcycle stripping place.

easier to have one made... which seeing as the rest of the bits will need making on a CNC then the barrel might as well me made on there to

 

[craigb244]

I thought the bacci diff came with a straight cut final drive, and thats less than 2 grand aint it?

dont think bacci do a straight cut final at all

I'm not bothered over the noise as I think it's quite musical, it's the ability to be able to change gear without losing revs or planted power that's appealing to me.

lol the noise will be fun for about 5 mins...
you wont gain much on gearchanges from a dog box without sequential
1-2 3-4 5-6 are good but 2-3 4-5 wont be.

 

[Brooky]

Nitranes sounds fairly straight cut, or maybe his g/box has on oil in it

 

[RS-1989]

i looked into it to... I recon it will be a right big headache.
finding a bike barrel that matches will be near impossible unless you worked at some mad motorcycle stripping place.

easier to have one made... which seeing as the rest of the bits will need making on a CNC then the barrel might as well me made on there to

That's what I had thought about, getting a suitable bike mechanism, right size is and making a new barrel for one. TBH you have put more into it, I've still got it in mind, but haven't even had a look at a bike box yet, without event thinking of how to get the mechanisms into a cento box. But still something I really want to look into.

It'll be getting the first one made and working that will be the hard bit.

Thanks
Sion

 

[rallycinq]

That's what I had thought about, getting a suitable bike mechanism, right size is and making a new barrel for one. TBH you have put more into it, I've still got it in mind, but haven't even had a look at a bike box yet, without event thinking of how to get the mechanisms into a cento box. But still something I really want to look into.

It'll be getting the first one made and working that will be the hard bit.

Thanks
Sion

I though because the way the Cento box selector mechanism sits on top of the box, actually working out the barrel would be the relatively easy bit, but what do I know.

Cheers

D

 

[RS-1989]

I though because the way the Cento box selector mechanism sits on top of the box, actually working out the barrel would be the relatively easy bit, but what do I know.

Cheers

D

Yeah I suppose it would be positioned similar to where it would be on a bike? On top/Front/In line with the actual gears. I think once I get a bike box open and see how it works I'll have a better understanding and can give it a go. Might go see what they have in the motorcycle lab in uni.

Thanks
Sion

 

[craigb244]

bike gearboxes are nothing like the cento box... thats the problem.
where the cento box has i think 4 selector type things....and its simple to understand as it works the same pattern as the shifter.

all the plates in the middle is neutral. moving the first one foreword is first, move it back is second. then the arm on the gearbox moves across to the next selector then forward is third... and so on

I cant really explain a bike box with great detail (been a couple of years since i had a bike engine in half)
but its nothing like the car. the bike does not have the selectors as such. the drum acts on each gear individually

so imagine a 6 speed bike box. the 2 shafts,one with gears that spin on the shaft and other with gears that dont. alongside these is a drum with 3 groves around the outside.
each grove will have two "wiggles" in each.
a selector runs in each of these groves with the other end going to the thing that locks the gear to the shaft(i forget what its called) that sits between two gears

as the drum rotates a couple of degrees one of the selectors will reach a "wobble" in the grove and in turn pushes the thing that locks the gear to the shaft onto the gear.


lol hope that makes some kind of sense.

I have got a fiat box in bits down the garage and also a suzuki DR bottom end so could have a look if i get time.

It will be a hell of a lot of work and if i or anyone managed to make it work(highly doubtful) you would want a lot of ££££ for them.

Another way I thought it could be done (might sound harder to some people but it would be much more simple) would be to make a new selector on the top of the box with a 3 solenoid on it and make the whole gear selection electronic.

all it would take is a very cheap and basic PIC chip a few switches (to tell the PIC which/when its in gear) and could be thrown together at home which is great for prototyping