Kombi box ratio's
Bone - January 17th, 2013 at 02:02 PM
Currently running a 1600 3 rib box in baja and would like to get a slightly taller top gear. At present it rev's at 3000rpm at 100km's with the 33'
rear tyres but would ideally like 2800rpm @ 100. Really like the low 1st , 2nd gears for bush and beach but would love to knock it back a little @
100. Is the 5 rib box gears or diff interchangeable ? Any option other than a 1800 box swap ? Have access to a 5 rib box but needs work.
13bwagon - January 17th, 2013 at 06:55 PM
3000 is about stock for most aircooled engines and dropping it 200 wont make any difference and will also slow down your cooling fan with 33 i would
stay with your box
Bone - January 17th, 2013 at 07:24 PM
| Quote: |
Originally
posted by 13bwagon
3000 is about stock for most aircooled engines and dropping it 200 wont make any difference and will also slow down your cooling fan with 33 i would
stay with your box
|
Who said anything about aircooled ! Aircooled, WHY ? 200rpm will make a difference if you are driving TO the Cape or simpson desert.
h - January 17th, 2013 at 07:29 PM
throw in a taller top gear shane, if you are overall happy with it?
13bwagon - January 17th, 2013 at 08:50 PM
WHO said you didn't have an aircooled engine ?
yeah ok if drive a baja 30,000 k's a year it would make a big difference
Bone - January 17th, 2013 at 09:00 PM
| Quote: |
Originally
posted by h
throw in a taller top gear shane, if you are overall happy with it?
|
Paul if only it was that easy. I dont know anything about rebuilding g/box's and certainly dont have the tooling/jig to do it. If I
went that way you would certainly go the full reco. Not sure on $$ figure but $2000 I guess for a stock rebuild. Hoping for Subarugears to release a
entry level 5 speed for the ej22 boys and I would look at that option for sure.
dangerous - January 18th, 2013 at 04:49 PM
My maths say you should be right at about 2785-2813 now with a 33" tyre.(either 5.375 or 5.4286 diff)
If you have one of the less common "Alpine" 5.86 ratio diffs you will have about 3035rpm.
1800 bus has a taller diff, but lower 4th gear meaning rpm would be theoretically 2726rpm,
but lose your lower ratio crawl gears.
The suba gears are agreat box, but way too tall for 33" tyres.
Cheapest option would be a normal 1600 box, or rebuild with taller 0.77 albins 4th gear(if you find you have the 5.86 diff)
h - January 18th, 2013 at 07:01 PM
^ there you go shane 
11CAB - January 18th, 2013 at 07:09 PM
Try another Tacho to see what revs you are actually doing
Bone - January 18th, 2013 at 11:39 PM
| Quote: |
Originally
posted by 11CAB
Try another Tacho to see what revs you are actually doing
|
I will check the actual tyre height first. Remember the 31's are not actually 31 inches high so math theory is not accurate. Will
the number on box confirm alpine box ? Box was out of first IRS camper (68) ? which if I can remember correctly still had the large 5 stud 205 pcd.
Was there such a thing ??
Subarugears - January 19th, 2013 at 05:55 AM
| Quote: |
Originally
posted by dangerous
The suba gears are agreat box, but way too tall for 33" tyres.
|
Maybe not with our new 4.86 diff ratio.... :-)
The beach buggy guys reckon the 4.44 diff ratio is perfect for 31" tyres so I reckon 4.86 should be about perfect for 33"s.
Bone if you are after an entry level box for an EJ22 I might have something that fits the bill - just getting my hands on some 4 bolt EJ22 boxes now
to do a couple.
Bone - January 19th, 2013 at 05:56 AM
| Quote: |
Originally
posted by dangerous
My maths say you should be right at about 2785-2813 now with a 33" tyre.(either 5.375 or 5.4286 diff)
If you have one of the less common "Alpine" 5.86 ratio diffs you will have about 3035rpm.
1800 bus has a taller diff, but lower 4th gear meaning rpm would be theoretically 2726rpm,
but lose your lower ratio crawl gears.
The suba gears are agreat box, but way too tall for 33" tyres.
Cheapest option would be a normal 1600 box, or rebuild with taller 0.77 albins 4th gear(if you find you have the 5.86 diff)
|
Thanks Dave will have to try and find out what ratio 3 rib box is in it !
Bone - January 19th, 2013 at 09:53 AM
| Quote: |
Originally
posted by Subarugears
| Quote: | Originally
posted by dangerous
The suba gears are agreat box, but way too tall for 33" tyres.
|
Maybe not with our new 4.86 diff ratio.... :-)
The beach buggy guys reckon the 4.44 diff ratio is perfect for 31" tyres so I reckon 4.86 should be about perfect for 33"s.
Bone if you are after an entry level box for an EJ22 I might have something that fits the bill - just getting my hands on some 4 bolt EJ22 boxes now
to do a couple.
|
Sounds good !
Well as suspected the 33' tyre is not 33' but rather 32' tall with 18psi on a 8' wide rim.
Bone - January 21st, 2013 at 03:29 PM
Checked again and 100km's is 3000-3050rpm with the actual 32' tyre height .
11CAB - January 21st, 2013 at 05:16 PM
Next question, have you GPS'd your speed? Your 100km/h on the speedo probably isn't 100km/h
Bone - January 21st, 2013 at 06:06 PM
Graham, Graham why do you continue to argue with me ! Yes mate that is the GPS speed. There's the figures, you do the math and tell me the ratio !
Ps.. highly recommend EJ22's..see you at dubs.