“My van is screaming its nuts off on the motorway”, is a common complaint & leads many owners of rear wheel drive Transits get in touch hoping a remap will fix it but it is a common misconception that a remap can change this.. Whilst more torque & a quieter tuned engine can sometimes give the impression of less rpm for any given speed travelled, its just an illusion.
The true solution is a different axle ratio, achieved by an axle or diff change.. on MK7 Euro 4 ( 2006-6 to 11-2011 if you have a 5.11 or a 5.13 ratio diff fitted currently, an indicated 70mph will be made using over 3000rpm.. Anything over 3000rpm can be noisy & uneconomical . I’d recommend around 1 “point” reduction so something in the low 4’s like a 4.27 would suffice without acceleration suffering too much. How about the 3.73 ? An excellent choice as 70 will come up about 2600-2700 rpm but a remap is needed to pull it if you’ve 100ps. 115’s & 140’s would pull that much better , so get in touch to discuss vantuner’ in house developed custom tuning options.
On Euro 5 MK7’s the axle ratios are taller to start with as the Euro 5 has 20% or more torque at lower RPM to start with & the axle choices can be as tall as 3.31. These axles can be fitted to Euro 4 MK7 no problem, so if youve 170ps plus, consider one of these.
How do you tell what you have already ? register & login to Ford ETIS & you can see what it came from the factory with. Or there is a tag on the diff cover with 3 digits that you can work out the ratio from. Or spin the wheels off of the ground & count how may wheel turns compared to one propshaft revolution.
A common query is if i fit a minibus axle what will the RPM be at 60 or 70 mph on my tipper . It depends on what diff ratio you have & what ratio the minibus axle is as the ratios can vary. Any seller worth his salt should be able to tell you the actual ratio of what he is selling.
MK6 Transits – only the 135ps came with anything lower than a 4.63 so maybe an axle or diff from one of them might be suitable. People do fit MK7 axles but its not a simple plug & play, as you need MK7 handbrake cables & MK7 ABS reductor rings ( if your MK6 has ABS )
Finally whatever you do , your speedo will read wrong untill new axle ratio is programmed in to the ECU/BCM.
Vantuner doesn’t actually do axle / diff changes or give advice on what your new RPM will be etc but recommended Transaxle Services in Halifax who fitted used diff’s at a reasonable cost but were considering retirement in 2018 so i’m not sure what option’s you have now