Gearbox people.

[Bennythew]

Just trying to figure out ratios.

How does this look for a 2wd panelvan (light camping interior) on big tyres with a 90/100bhp AHU engine in it?

Is 1st too long?
It's my stock gear ratios with a longer diff, plus the tyres.






My budget is snowballing as it is so I was trying to avoid new gear sets.

[bobby-gg]

What gearbox you running with a 4.12 diff?

I'm running an aap with a 4.571 diff and 215/65 16 tyres and I'm running 70mph at around 3100rpm on my camping caravelle

[Aidan]

I generally gear the TDi to 3150rpm at true 70mph +/- 150rpm depending on weight and profile
0.78 isn't stock 5th gear, 0.82 is, some early boxes have 0.765 fifth before emisions at speed were tested and they ran raised fuelling at the top end to pull it, the 0.765 gear is also very fine toothed so I don't use them in TDis as you can strip them booting to overtake, most diesel drivers won't change down and rev, though the 4th gear in the early boxes is also very fine toothed
4.14 final drive is 29/7 crown and pinion set
lower revs does not always equate to lower fuel economy unless you are travelling slower as the 8cu m of air to displace takes exponential amount of power to displace, as all the wbx boys know, 10% extra fuel for extra 5mph over 60mph
cruise control on TDis is brutal in it's implementation, better to drive with mechanical sympathy


just mho

[Bennythew]

Thanks Aidan, that exactly the kind of insight I'm looking for.

My box code is DW, as you said, an early petrol 5speed.

I lifted the figures from here





So would you say the tq of the AHU will be unsuitable for this box even with the much longer final?

If so I'd rather buy and recon a more suitable code now and sell the DW as a working long geared box.

[Aidan]

4.14 and 0.765 will work fine with standard tyres but the bigger tyres are pushing the envelope a bit
whatever you use as the core it wants to be good and that is the hardest bit to find, good 5 speed cores are few and far between, every 5 speed job that has come in last 6 months has been f'd to bits and I'm struggling to make them good without fitting new gears and mainshaft and often a bunch more, I don't have much good used 5 speed stuff on the shelf
ideally you want a post 1990 box with heavy case low corrosion and late synchrohub