Petrol to AFN ETDi

[syncrowjoker]

Thought they were 225/70 16? If so 10.24% over,or if your correct 13.16%

[ninja.turtle007]

Opps, Stan's right. Just nipped out to check!

According to http://www.kouki.co.uk/utilities/visual ... calculator this I'm 10.7% over standard tyre sizes!

That gives me 30.11 MPG. Mainly motorway driving around 65-70 mph. I certainly wouldn't say I've be taking it easy! Next tank I'm taking a little more carefully to see what is possible and also to keep my gear box working until it goes to Aidan for oiling plates.

[jed the spread]

Ahhh thats all really good info chaps and very useful to me.

That means my new tyre/wheel set up will be 1.2% longer wheel radius Tom, but you have the petrol gear box and I am guessing the petrol gear box is quite abit longer than 1.2% against the diesel jx gear box I have with the oiling plates. Should be good off road though

What gear box do you have Tom? Hopefully I will be able to use your MPG figures to see what I can expect before I decide to go with the longer gears or not.

jed

[ninja.turtle007]

Ahhh thats all really good info chaps and very useful to me.

That means my new tyre/wheel set up will be 1.2% longer wheel radius Tom, but you have the petrol gear box and I am guessing the petrol gear box is quite abit longer than 1.2% against the diesel jx gear box I have with the oiling plates. Should be good off road though

What gear box do you have Tom? Hopefully I will be able to use your MPG figures to see what I can expect before I decide to go with the longer gears or not.

jed

What tyres/size will you be running? With the slider open my tyre misses it by only a couple of mm.

Mine gear box is 4.57 yours must be either 5.43 or 5.83. But these figures mean nothing to me.

[lloydy]

Ahhh thats all really good info chaps and very useful to me.

That means my new tyre/wheel set up will be 1.2% longer wheel radius Tom, but you have the petrol gear box and I am guessing the petrol gear box is quite abit longer than 1.2% against the diesel jx gear box I have with the oiling plates. Should be good off road though

What gear box do you have Tom? Hopefully I will be able to use your MPG figures to see what I can expect before I decide to go with the longer gears or not.

jed

have you thought about fitting the doka box and diff in the westy? Could give you good ratio's?

[jed the spread]

The Westy has a AHF box with 5.43 FD I wonder if any one would be kind enough to find out the % difference at the wheels between this and Toms AKG box with 4.57 FD.

I did think about getting the Doka box fitted with oiling plates when it has just been rebuilt (AVN 4.86 FD and the 2nd V gear would have been nice) and putting that and the front diff in the Westy, but the Doka doesnt have a front diff lock and although this is more than enough on a light weight the Westy could do with a front locker too. I didnt think it would be necessary to modify the gearbox on the Doka as it is all standard so would be pointless really. I am hoping to gear up slightly with a bigger rolling radius on the Westy and the terrain we drove on holiday last year was serious, especially with wild camping weight of full water tanks, fuel tanks, Jerry cans with fuel and extra water and fuel, food, extra water, kayak and three bikes as well as us three and all our stuff for a four week trip it all adds up It was a testament to the AAZ. We stopped for lunch on a mountain side one time and I remember sitting down and looking at the van and couldnt believe it hadnt blown up, 12 miles up mountain hair pin bends in second and first with the turbo spinning like a mother is never a good look. I am not in a mad hurry to get full on long gears yet as I am comfortable at 60-65 and I want to gauge what its like carrying weight. Saying that I am hearing all sorts off crazy s*^t from people about performance right now and am finding it hard to digest.

jed

[Aidan]

I generally suggest doing the engine conversion and driving it first before making any decisions unless you have a real low geared bus and are fitting a very low revving engine product

FYI
5.43 final drive TD 14" have a 0.78 4th
4.86 final drive WBX 14" have a 0.85 4th

which means your TDs are generally quicker off the line/through the box and have more slow speed control as pulling less revs per mile/hour

but in 4th gear they are both pulling the same revs pretty much and at that point the wbx is much less stressed

you often see it when we drive in convoy, often the TDs are in 2nd and pulling away on a hill while the wbx are still in first pulling 4k revs (which is fine for a wbx) but as the TDs hold the taller gear ( or try to pull 3rd) on the hill the wbx's catch up and as the TD revs drop and comes off turbo the wbx is still pulling and can change up just as the TD changes down and we get the concertina effect

sticking a standard petrol box in a TDi doesn't really help as the 4th gear is effectively the same as the TD one - the cheap option is to fit the TD 0.78 gear in the petrol box (Pete's old yellow doka has that set up), but unless you have the 0.78 gear or can find one that's not an option, used ones are making Euro 100+ on german ebay now and they are very often knackered and pop out of gear because I think they have been lugged in gear (using the torque not enough revs) and due to torque loading on the mainshaft causing wear on the mainshaft bearing and forcing the bearing forward in the case - if the gear is displaced by 1mm then 30-50% of the synchro contact area is lost it doesn't take much for it to start popping out and once it does it gets the habit (wears the dog teeth ) and that's the gear stuffed. (Ditto petrol to diesel conversions with linkage issues)

WBX generally don't suffer from this because we have to use the revs and tend to drop into 3rd and drive in the torque band around 3-4k, if we drop below 2800rpm our revs will tend to drop away, but we can pull 5k revs no problem, though ones ears are telling one "whoooaa"

so for your TDi that off roads keep the 5.43 final drive and lengthen the gears to keep the revs down and get the economy and longevity, if it's a distance eater that just goes to the beach (Dubrovnik etc.) then using a 4.86 (4.57 if you can find one) box with slightly different 3rd and 4th will get you max speed/economy at the expense of some slow speed control - that's what Jake's runs
It helps to have a V box (AVK etc..) with the taller second gear as that evens the step to the longer 3rd gear

hope this helps

[Titus A Duxass]

Interesting reading - thank you Professor Aidan.
Without wanting to hijack the thread what's your recommendations for those of us going to the 2.0l AGG motor.
With the current JX I am running 5% oversize rears at the moment.

[jed the spread]

I generally suggest doing the engine conversion and driving it first before making any decisions unless you have a real low geared bus and are fitting a very low revving engine product

FYI
5.43 final drive TD 14" have a 0.78 4th
4.86 final drive WBX 14" have a 0.85 4th

which means your TDs are generally quicker off the line/through the box and have more slow speed control as pulling less revs per mile/hour

but in 4th gear they are both pulling the same revs pretty much and at that point the wbx is much less stressed

you often see it when we drive in convoy, often the TDs are in 2nd and pulling away on a hill while the wbx are still in first pulling 4k revs (which is fine for a wbx) but as the TDs hold the taller gear ( or try to pull 3rd) on the hill the wbx's catch up and as the TD revs drop and comes off turbo the wbx is still pulling and can change up just as the TD changes down and we get the concertina effect

sticking a standard petrol box in a TDi doesn't really help as the 4th gear is effectively the same as the TD one - the cheap option is to fit the TD 0.78 gear in the petrol box (Pete's old yellow doka has that set up), but unless you have the 0.78 gear or can find one that's not an option, used ones are making Euro 100+ on german ebay now and they are very often knackered and pop out of gear because I think they have been lugged in gear (using the torque not enough revs) and due to torque loading on the mainshaft causing wear on the mainshaft bearing and forcing the bearing forward in the case - if the gear is displaced by 1mm then 30-50% of the synchro contact area is lost it doesn't take much for it to start popping out and once it does it gets the habit (wears the dog teeth ) and that's the gear stuffed. (Ditto petrol to diesel conversions with linkage issues)

WBX generally don't suffer from this because we have to use the revs and tend to drop into 3rd and drive in the torque band around 3-4k, if we drop below 2800rpm our revs will tend to drop away, but we can pull 5k revs no problem, though ones ears are telling one "whoooaa"

so for your TDi that off roads keep the 5.43 final drive and lengthen the gears to keep the revs down and get the economy and longevity, if it's a distance eater that just goes to the beach (Dubrovnik etc.) then using a 4.86 (4.57 if you can find one) box with slightly different 3rd and 4th will get you max speed/economy at the expense of some slow speed control - that's what Jake's runs
It helps to have a V box (AVK etc..) with the taller second gear as that evens the step to the longer 3rd gear

hope this helps

Thanks Aidan

jed

[syncropaddy]

Most vehicles built in the 70's, 80's and early 90's were set to run 60mph at 3000 rpm. It was an industry standard. In the early 90's because of loads of reasons the standard moved to 70mph at 3000. With the current batch of turbo diesels 70mph comes up at 2200 rpm or there abouts.

[ninja.turtle007]

Aidan

Interesting reading, thanks.

So keeping the revs up will reduce wear on the drive chain? Is it best to keep revs 2-3k?

[ninja.turtle007]

Jed are you going to be running standard AFN?

[jed the spread]

Jed are you going to be running standard AFN?

As far as I am aware. I keep getting little snippets and some cool surprises as its being done

jed

[syncroand101]

some cool surprises as its being done

Like a surprise picture of two blokes drinking in the back of your van?

[jed the spread]

some cool surprises as its being done

Like a surprise picture of two blokes drinking in the back of your van?

Yeh thanks again for that....

jed