Regear possibilities (01 Ford Ranger)
 

Been a while since i felt inspired to do any ecomodding. Been averaging 36 on my commute, on winter gas, so i have been feeling pretty good about that.

BUT I have an itch to mod something right now and I am leaning towards regearing. Right now I running 3.73 gears with 215/75r15s, and my best idea so far is to try and grab a 3.08 rear end out of an 1992 ranger, which is also 1" narrower on each side, and go with some 195/65r15 LRR tires (Michelin Energy Savers A/S??). By my calculations that should be 17.4% decrease in RPMs from the gears, and a 10.5% increase from the tires. Combined this should result in a 6.9% decrease in cruising rpms, with far less rolling resistance. It should also make it much easier to do a rear wheel skirt with the wheels sitting an additional 1" inboard.

Any idea what i can expect from this gearing change? I am expecting a couple MPGs highway, but dont want to cripple my trucks 4 cyl. Is there any research about ideal % change or am I going to need and just figure it out as I go?

Sure there are some limitations with a relatively small engine in a truck, but eventually you might overcome this issue messing with the camshaft, ignition timing, exhaust pipe... Well, the list goes on...

And some weight savings are also a good measure.

Looking into it deeper, many Ranger guys are running 31s on 3.73s with good results on the same 2.3l DOHC(154 ft-lbs), especially on the highway. Though most prefer to regear to 4.10, because they are more offroad or towing oriented. The difference between stock tires(225/70/15) and 31s is about 12%, so my thinking may be too conservative! With my improved aero and driving style I could probably get away with a 10% net gearing change after tires and rear end swap with no issues.

Unfortunately there is not much available for power/efficiency mods on this engine without spending big money... :(

How expensive might it be to get the head (including the cams) of a Fusion Hybrid and a supercharger? It may still be an efficient way to increase the efficiency minimizing any sacrifice to the performance, just like the old Miller-cycle engines.

That is an excellent question, i have no idea on the fusion hybrid head swap.

And it still seems to be the easiest mod to increase the efficiency in a 4-pot Ranger with the Duratec. Then, a supercharger would be needed to overcome the lower output due to the "Atkinsonized" cams.

the main issue with the fusion swap would be the vvt, which the ranger computer cant do

The main point is to get the cam setup and the increased static compression ratio, not actually the VVT. You could get a stock Ranger head modded for that matter.

A 3:08 might be a bit "tall" for the little 2.3l from a dead stop. Maybe research a 3:45 from a pre-'92 Ranger (shorter half shafts also). I think the next "taller" gear in the Ranger (pre-'92) was something like 3:27 (?). Too much gear from a dead stop and you might be wasting your "savings" in just getting up to speed. I am thinking about the 3:45's also. They seem to be about the "limit". the Duratech's probably make more torque than my little Lima so maybe you could get away with the 3:27 (?) but I still think the 3:08 is pretty tall. Just my opinion though.

i totally agree, thats why my plan would include resizing to LRR tires down 7% (205/65/15). Doing both would net me 10% or the equivalent of 3.36 gears and less rotational inertia.