Verio 614D/814D Rear axle differential ratios

[demon]

Hi,
I've just bought our family camper conversion project bus!
It's a 2004 Vario 614D 4250cc/140ps minibus.
It's an ex-disabled passenger vehicle and as such was fitted with a town-ratio rear axle, or low ratio diff. It's no good for long journeys/touring and motorways are almost painful! She drinks like a fish at high revs, I estimate ~15mpg :/

My current diff is a 40:11 (3.636) but want to replace it.
I've found some 41:13 (3.153) for sale, but no others (yet!).

I'm told the Vario's were built with one of five different ratios but can't find any details of the others. I have EPC/WIS access, but can't seem to find info on alternative parts.

Has anyone had any experience with diff replacement or ratios on these vans?
Is going from 40:11 to 41:13 likely to make much difference?

Any advice will be gratefully received!

Cheers!

 

[turbopete]

obviously the diff ratio makes a difference to gearing so the 3.153:1 diff will cruise better than the 3.636:1. at the other end of the scale, it will also make acceleration slower and hills seem steeper.

put in its most basic form, if the bus was in a 'direct drive' gear (like 4th on an old 4 speed gearbox, 1:1 ratio) travelling along at, say, 60mph and running at around 3500rpm, the diff change would bring the engine speed down at 60mph to around 3k rpm. now I could be wrong, but I have a feeling the 'vario's' were automatic. this alone may be the reason the low speed diff was fitted, to enable the engine to run at maximum efficiency from an RPM point of view, in possibly top gear, but remain at a speed allowed by the town it was used in predominantly.

as for fuel economy, don't expect wonders from these. I knew a guy with a 410d van, converted to a camper, which then later had a turbo fitted, and it was never what you would consider 'good' on fuel. 30mpg was a pipe dream, even on the lighter van with the manual gearbox. as for motorway use, whilst the 410d I had experience of WOULD physically run to about 75mph, possibly 80 at a push, even AFTER the turbo was fitted, it was far happier around 55-60mph, so basically, expect to live life with the HGVs on the motorway, speaking from my limited experience

 

[demon]

Hi Pete,
Very many thanks for the info!

I didn't know if 3.636:1 vs. 3.153:1 was going to make enough of a difference, but if you think it will, I might go for it then.

I thought, perhaps, the 3.153 was just one small 'step up' from the 3.636 and that there might be other, better ones.

Acceleration doesn't matter to me, and 55-60mph is how I like to travel when campervanning (Had a 1975 Bedford CF for years, 55 was the sweet spot, and it makes holidays better to just 'pootle' there I'll probably just leave the governor fitted (56mph) to make things easier

From what I'm told, the low-ratio diff was fitted to these for just that reason - they drove at low-speed stop/start in towns, very rarely at high speed. Welfare buses aren't meant to drive fast

Most Varios are manual actually, but mine is automatic. If I encounter a steep hill, dropping the box down to a low gear should be OK? Or do you think the difference between 3.636 and 3.153 is too drastic?

Don't worry, I'm not expecting an MPG miracle!! But 20-25 would be more acceptable. In fact, the '15mpg' number I stated was the result of inaccurate 'beer-mat-maths' based only on the journey back from where I bought it (and guage needles!). Most of the miles this will do will be on faster roads, not in towns, so any improvement wil be good.

I've got to do some HGV-hugging then, understood

 

[turbopete]

when you look at the ratios. its based on the number of propshaft turns it takes to allow 1 wheel revolution. in a nutshell, to turn your wheel once, the propshaft has to turn 3.636 times, whereas your suggested replacement will only require 3.153 propshaft rotations to 1 wheel revolution.

whether it would be a step too far, it would really depend on the current weight of the bus, and the weight you will add converting it to a camper. whilst the welfare buses are not used for quick drives, its possible, depending on the conversion, it could have been geared in case it needed to run heavily loaded. you might swap the diff on an empty bus, think its perfect, then add all your camper stuff and find its short of power as its so heavy its 'over' geared.

I think you need to work out first how much (if any) weight you will be removing from the bus (seats or wheelchair lifts etc) then how much you will be adding (Furniture, cooking facilities, heating, water, sanitation etc etc) and then decide which way to go. the reason the 410d I had experience of had the turbo conversion was that even a simple, barebones camper conversion (windows, carpets all around the back, a couple of bunks, etc all extremely basic) added enough weight to make the turbo'd camper perform similarly to an empty original van!

 

[demon]

Yeah, that makes sense. It would probably be wise to consider the diff post-conversion.

Going to remove the wheelchair lift (probably nearly a tonne!) and most of the seats (KustomBuild - very heavy!). Will probably be adding about that weight back in. It's listed as 6.5T but not actually had it on a weighbridge yet.

I will wait until after the conversion and see how she runs then
That is unless I hear of other Vario conversion owners that have one of those diffs (there are two I know of, waiting to hear back from them).

Thanks for reining me in Pete!

 

[wanek]

hello!

i know this is an old post, but i have exactely the same setup (vario 614, 4.2 engine, 4 speed automatic and 3.63 ratio). i also would like to reduce this final ratio with ~25%.

@demon, did you actually changed the gearing? what is your experience with the 3.15 ratio? that should give ~15% increase in speed. what about mpg?

where did you find the parts?

thanks!

 

[demon]

hello!

i know this is an old post, but i have exactely the same setup (vario 614, 4.2 engine, 4 speed automatic and 3.63 ratio). i also would like to reduce this final ratio with ~25%.

@demon, did you actually changed the gearing? what is your experience with the 3.15 ratio? that should give ~15% increase in speed. what about mpg?

where did you find the parts?

thanks!

Sorry, just seen this (3 years later!)!
Actually, I never did find one, and due to an injury, my bus/motorhome conversion project got stalled so stopped looking. I'm back on the hunt now though - did you ever find a replacement diff?