lack of power


Many thanks to everyone who helped me with my fourtrak lift over the past couple of months. I ended up doing a 2" body lift, it went smoothly and am happy with resuls.

My fourtrak has a lack of power due to the fact my tyres are 31/10.5/R15 MTs. This is changing my overall final drive ratio resulting in a big lack of torque and wrecking my fuel consumption! Is there any way i can put my ratio back to normal by using other daihatsu transmission parts???

Or if i up my power by adding an intercooler will this help??

Many thanks


I don't know what your gear r

I don't know what your gear ratios are, but I think most of the daihatsu tranny's have about the same gears in them I think (I could be wrong though). I have a '91 Feroza with an HD-E engine, and the fifth gear is .87:1, and my diff's are 5.29:1. As for the intercooler, it's always good to cool down the intake air temp, but it depends on how much boost you're running as to how much this will help.

Unfortuantely, the transmissi

Unfortuantely, the transmission parts are completely different between the Sportrak/Feroza/US Rocky and the Fourtrak/Rocky/Ruggers. Nothing is interchangable.
Yes 31x10.5R15 tyres will kill your power and fuel economy. It does to mine, an intercooler will help a bit with power, but not economy. You can do what I have done, have a second set of tyres and wheels. 31x10.5R15 agressive mud tyres for mainly offroading, and 30x9.5R15, or smaller, for everyday use. I either change them over prior to an off road trip, or trailer them on my camper if we are heading away quite some distance for an off road weekend or similar.
You could always forget 5th gear, which surprisingly does make a difference.


Growing old is compulsary, growing up isnt, and MUD MAKES EXCELLENT TOOTHPASTE.
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All views and advice offered are my own, from my own experiences. Take such advice at your own risk.

Growing old is compulsary, growing up isnt.
I use billion dollar satellites, to find Tupperware.
Please visit
All views and advice offered are my own, from my ow

Although the diff ratios are

Although the diff ratios are all the same on the 4trak, I belive you'll find the transfur ratios do change. The lowest is the F80 (Petrol) transfur. Next the 2.8 non terbo. Then the terbo. And finaly the terbo intercooler version.
Also, and this is going out on a lim, the pre 4trak petrol (F20) did have lower diff ratios than the F50 or later 4trak. It's possible that these diffs will fit into a later casing?

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.