gearbox guru's

[Asa-James]

i have an f10 4 seed on my 1.2 at the minute, but i want a bit more peace at motorway speeds, if i throw on my f10 5 speed
a) will the 1.2 pull roughly the same? i dont want it struggling, but i am carrying out some basic engine mods to up the power a little
b) will it alter the top end gearing, as in will it drop the revs from what they are in fourth atm to a lower rev in 5th on the new box?

thanks in advance


btw, i'm not overly concerned with mega speed and uber accelleration, its only a 1.2 :d

edit--

as my nova and the haynes are miles away, what are the final drives for each box? or do they differ (no pun intended) box to box?

[jimbob-mcgrew]

theres not much difference in it mate, probably 200 rpm ish.
i switched to a 5 speed a while back, didnt like the feel of it, i put the 4 speed back in. a bit more engine power's probably whats needed, dont think youll see much gain on a 1.2

[AlexW]

You wont do much at all tbh. Best off going for a F13. They pull fine still as thats what 1.2 corsa's have! My 1.0 has the same box too!

And seeing as some 1.2 novas came with the 5speed f10 there fine. Do it, you might find out theres a slight gain on the 70mph revs.

Idealy you want a WR box, but iirc all f10's are CR.

[Asa-James]

Right, Reading thru my haynes and both sets of gears are the same ratios, but the final drives are different
- 4 speed 3.74:1
- 5 speed 3.94:1 (or 4.18:1)

going off that, if it is a 3.94:1, will it pull better? And what bits would I need to swap in the boxes?

Cheers

[Welsh Dan]

http://www.xen0phobiak.f2s.com/novaload/gear_ratios.jpg

A 3.94:1 diff ratio will up the revs and improve acceleration in gear slightly compared to 3.74:1.

I'd pull the cluster out, swap the pinions over and put the 5 speed cluster in, keeping your current diff so that 1-4 would be what you're used to.

With the cluster removed (and hopefully the engine mounts and driveshafts untouched) you should be greeted with this:
http://www.xen0phobiak.f2s.com/novaload/forsale/cluster.jpg

Undo the circlip holding the wide gear on the end of the right hand shaft, thats the pinion wheel that turns the diff, remove the gear and swap it with the one from the other box. Take the end cover off the 5 speed box when you fit it so that you can spin the input shaft to line up the splines with the clutch.

[Asa-James]

Just a thought, can I retro fit the fifth gear from the spare box into the 4 speed box?

[Welsh Dan]

No, lol. Let me see if I can find pics to illustrate.

The shafts are longer because fifth is on the outside of the box:
http://www.xen0phobiak.f2s.com/novaload/fifth.jpg
..behind the larger end casing:
http://www.xen0phobiak.f2s.com/novaload/fifthcover.jpg

A 4 speed box doesn't have the extra length on the shafts:
http://www.xen0phobiak.f2s.com/novaload/4speed.jpg

[mowgli]

asa james. if you keep the 4speed diff (3.74) and swap the gears over for the 5 speed (remembering to swap over the gbox output gear), you will end up with basically a diesel gearbox. the 1.2 will struggle to pull it at lowish speeds. it will be ok at motorway speeds as an eco gear.

i basically did the same to the f13 in mine....

i am thinking of sticking the cr gears back in but keeping the wr top gear for motorway cruising

[Dervy]

http://img697.imageshack.us/i/gearratios.jpg/http://img697.imageshack.us/img697/2329/gearratios.jpg (http://img697.imageshack.us/i/gearratios.jpg/):d

[burgo]

sam you noob, look how old this thread is