Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: wazza on April 03, 2008, 08:41:34 PM

Title: 4.56 an 31's???
Post by: wazza on April 03, 2008, 08:41:34 PM
ive got myself a zj 4.0ltr an even befor its on the road fitted a set of 31's
 :-D

im already happy as ive found out the standard diffs are 3.73-1 but im going to be doing alot of towing an have been toying with the idea of swaping the gearing,

i know on the towing side of things it would be great
but when not towing im not sure how the speed an revs would be? so any experiance or views would be appreciated!!!!

im not bothering to ask the yanks cos they'd all come back an tell me to go 4.88  or lower, as they love low gearing!!!

thanks
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Post by: dtooth on April 04, 2008, 11:53:48 AM
I ran 4.56 on 31's on my 4.0 manual XJ for a while and around town it was fine using 5th gear more didn't notice any MPG drop off .

Used 500/700 rpm more revs on the Motorways  if i drove at normal speeds .

What you towing a house ? :roll:
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Post by: wazza on April 04, 2008, 05:46:54 PM
(http://http://birtydastardsjeepclub.com/forum/userpix/902_SP_A0034_2.jpg)
thats what ill be towing, that and the trailer i recon will be 2.1/2 to 3 ton

my plan was to originaly run it on the road but now ive realised its going to cost too much for the novelty of it breaking 9 times out of 10 so im going to run it off road for a year an get it trouble free(hopefully) an then try to mot it.

also 4.56 on the grand gives me fuel in the future for 33's :wink:
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Post by: garyf on April 04, 2008, 10:31:55 PM
watch the 100% ruling,  :arrow: think you will be slightly over weight, the grand will be slightly heavier but the extra weight youve put into the Cherokee will soon take up the slack especially if youve got it on a trailer
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Post by: Bubba on April 06, 2008, 09:23:32 PM
put a v8 in and fit what the hell tyres you want
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Post by: tim_aka_tim on April 06, 2008, 11:10:59 PM
The only law regarding weight is that you must not exceed the rated towing capacity. There is an 80% guideline, but without a full size pickup or something like a Ford Excursion, you're never going to meet that guideline.
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Post by: wazza on April 07, 2008, 06:26:47 PM
that was going to be my next question on the weight. as i was going to just go with the rated tow capacity of the grand (3300kg) which i won't be exceeding anyway.

if it makes any of you feel beter ill let you all know when an where ill be on the road with it, so you can all avoid me :lol: