Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: dieseld4 on 17 March 2012, 11:43:36

Title: Diff with lower ratio than 3:45
Post by: dieseld4 on 17 March 2012, 11:43:36
Hi, Does anyone know if you can get a lower ratio diff than a 3:45, even in a old carlton/senator?
Title: Re: Diff with lower ratio than 3:45
Post by: tigers_gonads on 17 March 2012, 11:46:01
Have a look on here  :y

http://www.omegaowners.com/forum/index.php?topic=90497.msg1155330#msg1155330
Title: Re: Diff with lower ratio than 3:45
Post by: dieseld4 on 17 March 2012, 12:06:14
Yeah I have seen that, Thanks, I still want a diff lower than 3:45??
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 17 March 2012, 12:28:27
Lowest available is 4.22:1
Title: Re: Diff with lower ratio than 3:45
Post by: doz on 17 March 2012, 13:13:44
Throw lower profile tyres on it makes a good difference. I did this to my Gsi Carlton on a Marham track day it was bloody good. Loads of punch out of the corners and just reving out in 5th on the long straight. Which was fun.
Title: Re: Diff with lower ratio than 3:45
Post by: dieseld4 on 17 March 2012, 13:59:32
Sorry, I mean a higher ratio, like a 3.1 or something like that, I think I read somewhere that the opel omega 2.5dti has a 3:22, so something like that might be ok but hard to get in the uk. So maybe maybe a diesel carlton??
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 17 March 2012, 14:01:26
Is this for economy?
Title: Re: Diff with lower ratio than 3:45
Post by: dieseld4 on 17 March 2012, 17:34:12
Kind of for economy. I have fitted a 6 speed to a td, but it is very low geared, it go's like f**k  but at 2000rpm in 6th it is only doing 50mph, I havn't the car on the road yet but I imagine it would be realy sore on fuel
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 17 March 2012, 17:51:36
Christ I should think it does go like f*ck ;D

What was the 6speed box from?
Title: Re: Diff with lower ratio than 3:45
Post by: 2woody on 18 March 2012, 22:11:36
3.45 is definitely the lowest in the range.
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 18 March 2012, 22:18:28
Ok, confused now.
Title: Re: Diff with lower ratio than 3:45
Post by: 2woody on 18 March 2012, 22:20:44
lowest-revving
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 18 March 2012, 22:27:33
Ok, lowest gear being first. Highest gear being 5th. :)

4.22:1 gives 4.22 revolutions of the drive shafts per single rev of the prop shaft.
So he needs the opposite of that.

Although I suspect with this gear box the op will need something nearer 2:1 at a guess.
Title: Re: Diff with lower ratio than 3:45
Post by: 2woody on 18 March 2012, 22:33:31
the lowest numerically in the Omega A / Omega B / Monza / Carlton type is the 3.45 I'm afraid.
Title: Re: Diff with lower ratio than 3:45
Post by: feeutfo on 18 March 2012, 22:40:56
Modifiable?
Title: Re: Diff with lower ratio than 3:45
Post by: aaronjb on 18 March 2012, 22:45:55
Quote from: chrisgixer on 18 March 2012, 22:27:33
4.22:1 gives 4.22 revolutions of the drive shafts per single rev of the prop shaft.

Other way 'round Chris - 4.22 revolutions of the input shaft (prop) for one revolution of the output shaft (drive).


Anything is possible .. if you're willing to pay Quaife a ton of money.. (But I don't think there are any other production gearsets that would fit the Omega diff)

(aaand I just remembered I owe Mr 2Woody a phone call.. crap, sorry!)
Title: Re: Diff with lower ratio than 3:45
Post by: Lazydocker on 18 March 2012, 22:46:14
Quote from: chrisgixer on 18 March 2012, 22:40:56
Modifiable?

Everything's possible at a price ;)
Title: Re: Diff with lower ratio than 3:45
Post by: 2woody on 18 March 2012, 22:50:57
Quote from: aaronjb on 18 March 2012, 22:45:55
Quote from: chrisgixer on 18 March 2012, 22:27:33
4.22:1 gives 4.22 revolutions of the drive shafts per single rev of the prop shaft.

Other way 'round Chris - 4.22 revolutions of the input shaft (prop) for one revolution of the output shaft (drive).


Anything is possible .. if you're willing to pay Quaife a ton of money.. (But I don't think there are any other production gearsets that would fit the Omega diff)

(aaand I just remembered I owe Mr 2Woody a phone call.. crap, sorry!)

I'll have my phone with me all day tomorrow.......

Am changing a transmission in a new-shape Range Rover
Title: Re: Diff with lower ratio than 3:45
Post by: 2woody on 18 March 2012, 22:55:24
Quote from: chrisgixer on 18 March 2012, 22:40:56
Modifiable?

not really.

diffs are interesting things - the Gleason company own the rights to the calculations for the hypoid gears, meaning that all right-angle diffs must be designed with their input. Then, you need a "Gleason machine" to do the specialised gear cutting. As far as I know, Quaife don't own one of these.
Title: Re: Diff with lower ratio than 3:45
Post by: doz on 18 March 2012, 22:57:43
Aren't the old Carlton 2.3 oil burners a lower ratio than that?
Title: Re: Diff with lower ratio than 3:45
Post by: Zippy2012 on 18 March 2012, 23:48:57
Quote from: chrisgixer on 17 March 2012, 17:51:36
Christ I should think it does go like f*ck ;D

What was the 6speed box from?

?? umm be good to find out...

i want to change my diff from a 3.90 to a 3.45 for economy on motorway! coz atmo (3.0v6 manual box) its running 3500rpm @70  :(
Title: Re: Diff with lower ratio than 3:45
Post by: dieseld4 on 19 March 2012, 13:26:15
The gearbox is out of a 320d, I didnt think it would be as quick geared as it is, and I didn't think a td could be so much fun :) I think the diff in the car at the moment is either a 3.7 or 3.9 as it was petrol before converting to diesel, so a 3.45 should help abit but maybe not enough??
Title: Re: Diff with lower ratio than 3:45
Post by: Kevin Wood on 19 March 2012, 14:24:48
You need to know the ratios of your current gearbox and diff first. No point musing about what diff might or might not work unless you can calculate what it will achieve. :y
Title: Re: Diff with lower ratio than 3:45
Post by: Zippy2012 on 19 March 2012, 16:54:16
Quote from: dieseld4 on 19 March 2012, 13:26:15
The gearbox is out of a 320d, I didnt think it would be as quick geared as it is, and I didn't think a td could be so much fun :) I think the diff in the car at the moment is either a 3.7 or 3.9 as it was petrol before converting to diesel, so a 3.45 should help abit but maybe not enough??

is it easy enuf to fit or did you have to mod anything?? you could run a larger tyre... what sizes are u running?? & Are they 15" 16" 17"??