6TH GEAR IN AN 80?

[rowenb]

Always searching for a sixth gear in my 80 series when goin through the gears. I know there isn't one but i keep thinking there should be. Is there a decent overdrive or even a six speed gear box that can be hooked up to the tojo? I read that the OZ teams that raced the R32 skyline fitted with a six speed hollinger box. Now those put out alot of power in AWD and i think the box would be more than able to cope with 4WD conditions. I need dimensions and specs of this box to see if its suitable, etc. I want my truck to be doin about 2000 - 2200 revs on the HWY at 100-110KM's. I've heard about marks change over 5th gear (they make em for V8 swaps in the 80 i think),but unsure if there will be too big a step between 4th and 5th if changed over. Also seen two transfers used on some vehicles. Sorry for the ramble but i want to get results to help fuel economy and not hear the motor winding away at 3000rpm doing 120km's. Any suggestions would be much appreciated.

[hdj105]

Have you priced a Hollinger, probably need to sell the 80 to buy one?

Mark's don't do a taller OD 5th AFAIK, though they have discussed it a couple of times over the years (the box design with 5th in the middle means lots of replacement bits). They do make one for the Patrols (to work with the portal axle setups).

You could change the diffs to 3.7's, or look into the overdrive t/case gearsets Don Kyatt sell.

[80's_delirious]

yep, fitting a holinger would quadruple the value of the 80 in one hit

I dont know if any other 6speed manual that has been built for a car as heavy as the 80series, so strength and longevity would be an issue. and light truck gear boxes are too big and have the wrong ratios.

[oldmate]

are 3.7 diff gears readily available for an 80?

Bigger tyres are an option too. 33's put the revs at about 2600 at 110kph, a modest decrease. 35s would be a bit better again

I think 2000 rpm is a bit optimistic remembering that changing tyres, diff ratios and transfer gears affects all gears.

Another option is an auto box. the cruiser auto has a better over drive. i think about 2400 at 110?

The only other option is a coaster/dyna 5 speed gearbox. they have a taller 5th gear. It may be possible to mix n match parts to get that 5th gear in a cruiser. This is something i'd like to investigate, but coaster boxes aren't easy to come by.

The new coasters have a 6 speed, but it's behind a 15b motor, with i'm guessin a b motor input shaft.

[rowenb]

are 3.7 diff gears readily available for an 80?

Bigger tyres are an option too. 33's put the revs at about 2600 at 110kph, a modest decrease. 35s would be a bit better again

I think 2000 rpm is a bit optimistic remembering that changing tyres, diff ratios and transfer gears affects all gears.

Another option is an auto box. the cruiser auto has a better over drive. i think about 2400 at 110?

The only other option is a coaster/dyna 5 speed gearbox. they have a taller 5th gear. It may be possible to mix n match parts to get that 5th gear in a cruiser. This is something i'd like to investigate, but coaster boxes aren't easy to come by.

The new coasters have a 6 speed, but it's behind a 15b motor, with i'm guessin a b motor input shaft.

I'm not lookin at goin huge rubber or 3.7 gears as in the future i will be towing some weight around, running 285/75/16. I'd like to keep the same gears, or pretty much the same, looking for an overdrive box maybe? I've talked to a couple of people and they reckon it'd give up reliability. I,ve never seen something like a fairy overdrive in an 80, i'd bet someone in the forum would have though? Thanks for the feed back.

[me3@neuralfibre.com]

what's bad about the rev's? The 1hz is suited to that - look at the torque / power curves.

Mr toyota ain't so silly.

If it's the noise, turn the stereo up.

Paul

[fester2au]

If noise is an issue then that's another reason to ditch the Holinger, mind you a sequential 6 speed Cruiser sounds interesting on paper if not totally useless in real life.

If you intend to do a fair bit of towing is another overdrive gear really of any use anyway, this great brown land of ours is not all that flat. Lugging around in too high a gear outside of the engines efficiency range may not be that beneficial to economy for the dollars spend anyway. The trip computer on the boss's new DMax certainly shows up that cruising along in 5th at lowish speeds when you think it could be just cruising is not as ideal as first thought compared to 4th.

[cruiser60series]

towing in a too high gear is bad for most things that rotate and have bearings in your car.

Power=Torque x RPM. If RPM goes down, Torque required goes up. Things can break.

[DIRTY ROCK STAR]

man im not sure what you would be gaining with dual transfers?

wouldnt it be useless offroad with basically car ratios? low 1st wouldnt be so low?

[80's_delirious]

dual transfers wont increase your top gear ratio. also I am pretty sure fairey overdrive were fitted to cars that had divorced transfer cases, 80 series transfer case is mated to the gearbox, so it would not be a cheap excercise to engineer an overdrive case for it.

6 gear wont work well with the torque curve of the 80 anyway. Increasing tyres from 33"to3 5"sees mine in 4th gear alot more often as 5th is now just slightly too high, and torque is not adequate.

[rowenb]

Thanks for the info into this 6th gear issue, i won't be doing anything stupid and just use it as it is. I would be better off spending the money on getting the motor the way i want it and like you guys said probably won't notice any real fuel savings with an overdrive. It was nice dreaming of low fuel consumption and a 6th gear, thanks for putting me on the right track.

[thrashlux]

dual transfers wont increase your top gear ratio. also I am pretty sure fairey overdrive were fitted to cars that had divorced transfer cases, 80 series transfer case is mated to the gearbox, so it would not be a cheap excercise to engineer an overdrive case for it.

6 gear wont work well with the torque curve of the 80 anyway. Increasing tyres from 33"to3 5"sees mine in 4th gear alot more often as 5th is now just slightly too high, and torque is not adequate.

marks adapters were making an overdrive unit for the 80

dot know if they still do??

[bj on roids]

Try a turbo, simple, cheap and effective!

It will reduce workload, give you better economy, and quiet the motor down.

[rowenb]

Mine is an early 92 factory turbo and i've been told they have different gearing to the later ones. Is that correct?

[Kitika]

I think the ratios are taller in first and second in the turbo gearbox compared to the 1hz's. Other than that they are the same.

[midi73]

Mine is an early 92 factory turbo and i've been told they have different gearing to the later ones. Is that correct?

Yes I have the same car and same problem. A slightly taller 5 Is all I would like. do the later 80 boxes have a slightly taller 5 gear or are they all the same. Bugger about them being hard to change the fifth gear ratio.

[rowenb]

i think the diff gearing is different, not 100% sure though.

[thrashlux]

i think the diff gearing is different, not 100% sure though.

nup all the gearing is the same diffs are all the same ratio petrol , diesel ,turbo ,non turbo, early, late

5th is the same

the early 80 series ran 15 inch wheels which if kept std lowers the gearing

[hdj105]

marks adapters were making an overdrive unit for the 80
dot know if they still do??

Any details Jonathan? I know they have mentioned it, but I've never seen or read anything more.

[thrashlux]

marks adapters were making an overdrive unit for the 80
dot know if they still do??

Any details Jonathan? I know they have mentioned it, but I've never seen or read anything more.

All i know is i went to a 4x4 show and they had one in the flesh on display it was pneumatically actuated
it bolted onto the transfer
they had produced it to drop the revs when they fit the chev 6.5's in

they also had one in a white 80 gxl which had been set up for touring
it was in a 4x4 monthy mag once

so thats all i know maybe they never went into full scale production?

if you rang you have have to strike the right person to ask

cheers

jonathan

[80's_delirious]

marks adapters were making an overdrive unit for the 80
dot know if they still do??

Any details Jonathan? I know they have mentioned it, but I've never seen or read anything more.

All i know is i went to a 4x4 show and they had one in the flesh on display it was pneumatically actuated
it bolted onto the transfer
they had produced it to drop the revs when they fit the chev 6.5's in

they also had one in a white 80 gxl which had been set up for touring
it was in a 4x4 monthy mag once

so thats all i know maybe they never went into full scale production?

if you rang you have have to strike the right person to ask

cheers

jonathan

Was it an overdrive unit??

I know they developed a bolt on (more or less) dual reduction transfer case adapter so you had two low range ratios to choose from
they are expensive and I have read mixed reports on them.

http://www.marks4wd.com/products/gearma ... rawler.htm

Never seen any info on an overdrive unit for 80s

[thrashlux]

marks adapters were making an overdrive unit for the 80
dot know if they still do??

Any details Jonathan? I know they have mentioned it, but I've never seen or read anything more.

All i know is i went to a 4x4 show and they had one in the flesh on display it was pneumatically actuated
it bolted onto the transfer
they had produced it to drop the revs when they fit the chev 6.5's in

they also had one in a white 80 gxl which had been set up for touring
it was in a 4x4 monthy mag once

so thats all i know maybe they never went into full scale production?

if you rang you have have to strike the right person to ask

cheers

jonathan

Was it an overdrive unit??


http://www.marks4wd.com/products/gearma ... rawler.htm

Never seen any info on an overdrive unit for 80s

yes
a bit like a fairey but bigger looked like billet aluminium
they told me u need a slight body lift to get it under the floor
maybe they dropped it due to lack of interest
jonathan

[thrashlux]

marks adapters were making an overdrive unit for the 80
dot know if they still do??

Any details Jonathan? I know they have mentioned it, but I've never seen or read anything more.

All i know is i went to a 4x4 show and they had one in the flesh on display it was pneumatically actuated
it bolted onto the transfer
they had produced it to drop the revs when they fit the chev 6.5's in

they also had one in a white 80 gxl which had been set up for touring
it was in a 4x4 monthy mag once

so thats all i know maybe they never went into full scale production?

if you rang you have have to strike the right person to ask

cheers

jonathan

Was it an overdrive unit??


http://www.marks4wd.com/products/gearma ... rawler.htm

Never seen any info on an overdrive unit for 80s

yes
a bit like a fairey but bigger looked like billet aluminium
they told me u need a slight body lift to get it under the floor
maybe they dropped it due to lack of interest
jonathan

[Toyole]

nup all the gearing is the same diffs are all the same ratio petrol , diesel ,turbo ,non turbo, early, late

5th is the same

the early 80 series ran 15 inch wheels which if kept std lowers the gearing

I`m not sure. Here in north we got the HDJ80 whit 3,7 diff as standard. It looks like they got other diffgearing in US too. I think we got the Japanmodel, as two battery as standard too..
I run at 35" in a manual 1992 Miss some lower gear in transfer, and may some higher.

[rowenb]

Not sure but i thought i seen marks do a change over fith gear designed for the LS1 swap over to drop revs when cruising the hwy.

[Toyole]

[img][/img]
From http://www.marks4wd.com/press/pdf/OFF%2 ... 0BEAST.pdf

There is some options, but I can`t find them easy to bye..

[rowenb]

I've gone over looking at making my truck part time but always come back to driving in the wet, dirt roads ect, i think would be better done in full time 4WD. My old mans DX is loose in the wet and easy to get wrong on a roundabout. I do remember reading this article and Mark said he was looking at a range of different reductions to suit different needs but his setup would be too low for a diesel as another bloke said you need to keep in the right torque range. But then again if they're proven to be a good thing i might consider it down the track.

[midi73]

Not sure but i thought i seen marks do a change over fith gear designed for the LS1 swap over to drop revs when cruising the hwy.

This is what I am interested in. I reckon all the gear ratios are good in my 80, except 5th. There is only 100 maybe 200 rpm difference between 4th and 5th. Its almost like taking it out of 4th and putting it back in again.
And as far as torque etc, running in 5th gear at 100k it is pretty much running at 2600 to 2800 rpm, which is pretty well the top of the power sweet spot. The most power gained is around 2100 to 2200 rpm. 2000 and under is off the power so would be to low. so I reckon if another ratio 5th gear could bring it down about 300 or maybe 400 rpm, the box would be pretty much perfect.
My 2c.