Gearbox/diff ratio`s

Post by **mattyboi** » 03 Jul 2007 12:13 am

When drifting my super 340 weapon the only problem i have is the really low gearing. Corners which everyone else in similar cars (86`s etc) are doing easy in second i`m being whooped and having to kill it to pull third.

Now my car was a 1.4l and is still running the boggo gearbox and diff, Are the 1.7l/2l ones any diferent? Could i fit a diff and use the same gearbox?

Something needs changing or big track comps are gonna be a no no

Post by **Chris_C** » 03 Jul 2007 09:41 am

Yeah, you'll be on a 3.84 (think it's 84... its 8 something!) diff. The 1.7's and GLT's are 3.64, and the GLE's are 3.36. It is a nadgers more complicated than that due to year...

Watch putting anything too far the other way in though, you'll uncover just how bad the hole between second and third is

I'm thinking of going for a higher ratio/lower geared just to spend my time rallying a gear up from what I do now

Post by **mattyboi** » 03 Jul 2007 09:48 am

So would the best thing be to keep my 1.4 gearbox for the close (well you know what i mean lol) ratio`s and bang in a higher ratio diff?

Post by **Ali** » 03 Jul 2007 10:31 am

I've got exactly the same problem with mine mate, my limiter is set to 6200 as thats as far as we mapped it to meaning I hit about 50-55ish in 2nd, which is bloody great for tight tracks with the boost coming in by about 2500rpm but runs out of puff way before the S bodies

What kind of speed do you hit in 2nd with more revs pressumably? I don't think swapping to a glt diff will help you as I still find mine a pain but if might give you a bit more if you can rev nice n high. I've got power low down in 3rd but haven't been on a track with a 3rd gear corner in it yet, tried snatching 3rd from 2nd before and revs went up, car straightened up

only time the clutch has slipped

Post by **Chris_C** » 03 Jul 2007 10:55 am

All the gearboxes are the same mate, it's only the diff ratio that changed...

(Steve has told me it's 3.82... so I stand corrected for 1.4 diff ratio)

I'm guessing you'll need different to me rallying, but my car I'm either redlining in second, or not quite on the power in third a lot of the time. Changing the ratios of third and fourth would be a superb plan... but that involves getting helical gears cut

Post by MJ » 03 Jul 2007 11:02 am

Of course, you could simply change to different tyres/wheels with a different rolling circumference, which will give the same effect. I'm sure you realise it already, but running small wheels will not be helping the low gearing problem

Post by **Chris_C** » 03 Jul 2007 12:28 pm

Brakes dear boy.... brakes

Well, they are useful for me at least... not sure if the drifters need them

Post by MJ » 03 Jul 2007 01:07 pm

Huh, brakes? What's that got to do with small wheels? Better cooling? But you could get more open large wheels... I think that comment either wasn't aimed at me or I missed sumpt

Edit: Oh, I suppose with the gearing after the brakes more effort is needed to stop, right. So smaller wheels makes the same braking effort more effective? Or am I confusing everyone including myself

Post by **Chris_C** » 03 Jul 2007 01:23 pm

Yup, think simpler

The wheels have to fit over the brakes

Post by **SteveP** » 03 Jul 2007 01:25 pm

I think MJ was suggesting the use of bigger wheels, maybe 15" instead of 13"...

Could always throw some more power at it to combat the problem

The 2nd-3rd gear 'hole' is nowhere near as obvious in Ali's car

Post by MJ » 03 Jul 2007 03:21 pm

Uh, have I made a silly mistake? You need bigger wheels to make the gearing higher don't you? e.g. slower acceleration/higher top speed?

At least it sounds like Steve understands what I mean

I'm not sure what size those are, but with the low profile rubber I'd guess it'd be shorter/smaller than stock circumference. Having said that the last photo seemed to show stock steels on the back, so my point maybe invalidated.

Anyway, the drifters like small wheels so it may be easier to just swap the diff, it was just a suggestion. And Chris, did you think I meant smaller wheels?

Post by **ajdubas** » 03 Jul 2007 03:59 pm

unless you're topping out surely you want to go with a larger final drive ratio... the 1.4 diff with the 5 speed (same ratios for all engine sizes) should top out about 110ish I think, if you're not getting there, then you want to accelerate faster, it'll also make a smaller hole between 2nd and 3rd.

Post by **Chris_C** » 03 Jul 2007 04:03 pm

Yeah MJ, I thought you ment smaller wheels, and hope you do, what Steve's going on (bigger o/a radius) about would make accelerating even worse!

Aleks has a big point, you do want the f/d to be matched to where you want to max out, although spacing the box ratios in that would be a nice touch

Foggy's away atm, but anyone know if anything else that have an M47 in it had different ratios? (Dave?)

EDIT: I get it now MJ... drifting on bigger o/a radius means staying in second for longer...!!!! Yes, might well work, although would need more power (would it put more strain on the drivetrain due to extra power needed to break traction though?)

Post by **SteveP** » 03 Jul 2007 04:06 pm

Chris_C wrote:Yeah MJ, I thought you ment smaller wheels, and hope you do, what Steve's going on (bigger o/a radius) about would make accelerating even worse!

Who was talking about acceleration

Bigger rolling radius = higher in gear speeds

Post by **Chris_C** » 03 Jul 2007 04:08 pm

See edit above

I was being self centered and thinking about my problem, which bigger wheels would do the exact wrong thing to!