Outer Limits 4x4 Board

I just read a tech article on Izook about using a 87 gearbox to get a higher 5th gear. Ive read about this on american sites before. Do our 87 gearboxes have this higher 5th gear? The article said it dropped revs buy about 500rpm in 5th this would be good for d/d.
Nik

0.865 pre 89 ? 0.795 pre 90? Maybe

Well Im running a coily gearbox already . How do I find out the ratios?
Nik

0.865 after 90


when you search for the ratios there are conflicting results ,

going to have another look im thinking it may have some relationship with the 3.9 to 3.7 final drive change.

So that seems to be the case , not sure how true but by what i can find
those fitted with 3.9 final drive have 0.795 fifth , those with 3.7 have 0.865 fifth .

Nik i just checked the difference in the ratios and is really close to each other

.865 - 2888 rpm = 80ks
,795 -2654 rpm = 80ks

304 rpm diff @ 80ks

Not much difference Was hoping if it was around 500rpm difference then it would be worth chasing one up. Yes I know I could change diff ratios to get better highway speed and then change transfer gears to get back the crawl ratio but I dont have the $$
Nik

Larry you gearing guru
How much would my rpm drop in high range by taking out the s1 rock hopper?
Nik

NIK wrote:Larry you gearing guru
How much would my rpm drop in high range by taking out the s1 rock hopper?
Nik

Approx 12%, as that is the reduction in high for a sieries 1

Layto....

I new it would drop it by 12% but how do I figure out the amount of actual rpm drop for any given speed?
I just had another look on Izook they are claiming the 87 gearbox dropped rpm by 488 rpm at 100mph. The amount of rpm drop in 5th wouldnt change at different speeds would it? I figure it shoul be an even drop through the rev range once your in 5th. Im not sure anymore Im starting to confuse myself
Nik

NIK wrote:I new it would drop it by 12% but how do I figure out the amount of actual rpm drop for any given speed?
I just had another look on Izook they are claiming the 87 gearbox dropped rpm by 488 rpm at 100mph. The amount of rpm drop in 5th wouldnt change at different speeds would it? I figure it shoul be an even drop through the rev range once your in 5th. Im not sure anymore Im starting to confuse myself
Nik

um....100MPH is about 160Km/h. You really want to drive at that in a zook

What is your current RPM. Divide it by 112 then multiply it by 100 to give you the new RPM. Your RPM will change in proportion the the ratio change, as a ratio is not a number, its is a way of comparing 2 numbers.

Edit cause i am spastic
Layto....

Thanks Layto, I realise how fast 100mph is but I was just transfering the data.
So my current rpm say 4000rpm / 112 = 35.75 x 100 = 3575 ?
Does that look right? So it should drop the rpm by 425rpm at any given speed. Think I got it.
Nik

NIK wrote:Thanks Layto, I realise how fast 100mph is but I was just transfering the data.
So my current rpm say 4000rpm / 112 = 35.75 x 100 = 3575 ?
Does that look right? So it should drop the rpm by 425rpm at any given speed. Think I got it.
Nik

Will not drop the RPM by 425 at any speed.!!! To calculate RPM drop, do the same calculation as before, but use the RPM you want to convert. A ratio isnt a definate number, as i said its a way of comparing one number to another, like a percentage. What is your current ratio, and what do you want your final conditions to be (rpm speed etc)?

Layto....

Sorry Layto you,ll have to break it down real simple.
If my zook does 4000rpm at 90km/h (speedo is probably out) with 4.88 diffs and s1 rockhopper which lowers high range by 12% (1.59 reduction) . If I put a standard transfer in it would take 12% of the final drive ratio (1.45 reduction) so Im trying to figure out how this will affect my rpm that was previously 4000rpm at 90km/h. Im trying but I cant get my head around it the calculations and I can only find references to work out crawl ratios not rpm.
Nik

mmm , .865 -1 , 1.58 , 4.88 , 33" , @ 4000 = 93.6 kmh

.865-1 , 145 , 4.88 , 33 , @ 4000 = 102.6 kmh

Or @ 90 kmh its a 350rpm diff .

Thanks Larry, I took it to the club meeting and thats what they came up with too
Sort of on topic has anyone ran a vit transfer instead of the seirra so you get 1.1 in high range?
I,l have a look around the web and see if its worth looking into.
Nik

Is good .


Im thinking 3.7 - 3.9 v6 centres ?

I found some info about swapping in a toy transfer (1.1 high) and there was concerns that with the big drop in reduction it would be strugling to push bigger tyres. Im just after a bit better drivability for through the week without the big $$ of changing both diff gears and transfer gears so I dont loose off road ability.
Nik

i dont think you can have both. without alot of money being spent.

Yeah thats what I was trying to over come by maybe swapping transfer case for d/d then back to rockhopper for offroad.
Oh well might just have to put up with the cries of " Its too slow, Its too loud, Its too uncomfortable etc etc "
I supose I could tell the girls if you dont like it stay at home
Nik

http://www.pitbulltires.com/calculate.php


Punch in your numbers here.

Layto....

Nik , done a little more research .

The diesels come with a 4.3 Ratio and i pretty sure every one wants the 4.8 s in the toy world so you should find a aset easy or a swap ?

Doing the numbers gives 3500 rpm @ 90 ks ,

= 106 @ 4000 do the .795 fifth as well = 110 @ 3800rpm

and it will still be 62-1 overall crawl in comparison to your 70 or so ,

Thanks for the info Larry.
I have a 4.5 r&p here I could use I supose. Talked about it at the club meet and it was suggested the .795 fifth gear might be to weak? Specialy pulling a trailer.
Id like to drive the zook more often not just on club trips but also concerned that long periods of high revs might do some damage.
Nik

would it be possible to get a custom gear box done so that 4th an fith are lower

... is there any chance of another suzuki or small car that could have a 6 speed box that could be bolted up or adapted

Anything is possible... for a price
Its a good idea though.
I just want to drive my zook everyday and not be such a hassle not to mention the cost of fuel with it reving so hard
Nik

Checked my actual speed with a gps. With s1 4.8 diffs and 33s at 4000rpm Im doing 85km/h.
Ill put up with it for awhile longer cause I love it offroad, no more low range just for the gearing uphills
Nik

Can anyone confirm coily 5th gear ratio? W/T is .eight six but they have three . nine centres, coilys have four . ones??
Numbers stopped working again no its not numlock the laptop dosnt have it .Maybe I should spend less money on the zook and more on this crap Im trying type with.
Nik

Took the zook for a spin today with coily gearbox standard transfer and 4.8s with 33s it did 100km/h @ 4000rpm by the gps. Its been a long time since driving a stock zook but that dosnt seem right! Im sure its supose to be around 3600rpm @ 100km/h?
For others that havnt read my other posts Ive finally got 6.5 gears so with 3.9 diff gears and 33s is this the road speed I will get? By the gear calculator 4.8 is the replacement ratio when going from 26s to 33s (measure 32) so by that my zooks top speed should be the same as a stock zook??
Nik