2.5 NA in a 90

[Greg S]

A question for you D90 owners that have driven a NA 2.5 for awhile. Bill? Did you notice that you're one of the ones I'm asking?
I'm waiting on some repair pieces before I actually get to drive this new (to me) rig on the road. It has some perfectly good and almost new (okay, better than "almost" new) BFG MT's in 235/85 x 16. I fully expect this thing to be anemic, what with 65 HP compared to the walloping 80 hp in my 109. How much worse will it be if I mount my 255/85 x 16 Toyo tires?

[HeadDamage]

I run 255/85/16 bfg tires on my 2.5na diesel 90 but i do have a 1.667 lt230 not the 1.4. Often the military 90's have 1.667 so you may want to check yours.

[Bill E.]

Hi Greg,
I ran the 255's on my 90 for some time before installing the 200 tdi. It was only marginally more sluggish with the bigger tires. I say go for it, the difference between the 235 and 255 is academic when you're talking anemic vs. slightly more anemic :) FYI I'm running a 1.4 transfer box.

[Greg S]

This is sounding hopeful. BTW how do I determine T box gearing? If it were petrol I'd jack up a wheel and use the hand-crank to turn the engine 1 revolution and measure the rotation of the output when in 4th. How do I do it with the oil burner?

[red90]

There is usually a sticker on the back with the ratio. If not, you can figure it out from the serial number. You need the prefix, like 22D.

List of ratios and prefixes here: http://www.ashcroft-transmissions.co.uk ... oductId=45