Power steering to manual conversion?
 

I'm toying around with the idea of converting my 1998 Jeep Cherokee to manual steering.
I know which steering box I need and have an idea how to get rid of the pump. Since I need a new steering box anyway, this could potentially be a pretty cheap fuel efficiency mod.
How much of a MPG bump could I expect from doing this, though? For 1/4 mpg I'd rather have power steering. For 1 mpg, I might do without.

I recently went to manual steering on my S10. With no A-B-A testing it has been really hard to say exactly how much I gained from the deletion. My best guess now is somewhere between 1 and 2 mpg. For me it has been a worthwhile mod. I have not gotten around to replacing the gear box yet, I've just gotten used to the extra effort required in parking lots.

quantified by TRW

EPS is extremely efficient when compared to a power rack and pinion pump, using only 10 percent of the energy and only when the driver demands it. With no energy drag on the engine, EPS systems offer a fuel savings of up to 0.33L/100km, with a corresponding reduction in carbon dioxide emissions of approximately 8g/km.

Electrically Powered Steering | TRW Automotive

using .33l/100km figure, if youre getting 19mpg in your jeep, using .33l/100km would put you around 19.5mpg

and same .33l/100km would take a 41 mpg car to about 43.5

im sure this wouldnt be quite right because the fuel consumption due to the power steering should be relative to the size/weight of the vehicle

There are a few easier things you can do to a Cherokee to get better MPG.

1) Get rid of the mechanical fan on the passenger side and replace it with an electric fan. Taurus electric fans are pretty popular for this

2) 4 hole injector swap - there are direct swaps from certain Neons and some Ford injectors can be used.

There's also the option of using an A/C clutch on the PS pump, I believe someone here did it on a Ranger

The return on investment on an electric power steering setup is going to be a bit too long for me, and that's assuming there is an old fashioned steering gear being made. All of the EPS I've seen is rack and pinion.
I've already got the electric fan, cold air intake and 4 hole injectors. I'm working on aero a little.
I'd love to see some honest to god before & after on mpg; I'd be surprised if it was as much as 1.5 mpg. I don't know how much work the PS does compared to the AC but I only lose 1 mpg or so with the AC on. Still, 1.5 mpg for a low-buck mod would be sweet.

I wonder if you could just do some fancy pulley swapping and slow the pump down, and back off the relief valve pressure? You'd still have assistance, but not the overboosted levels Jeep provides to all those tiny schoolmarms. You'd have to work a little bit but you'd still be able to park without adding a breaker bar to the wheel.

i wasnt actually suggesting electronic power steering, i was using their numbers because the fuel savings of electric vs. conventional would be virtually the same as fuel savings of conventional vs. manual steering

I think more and more people are starting to see the benefits of manual or electric PS. I would be really surprised if conventional power steering pumps make it to the year 2020, outside of maybe really big trucks and maybe some economy cars. I think that we going to begin seeing widespread adoption of electric PS. There are just too many benefits of electric, and no positives to conventional systems beyond price.

My intuition on this is there is no way you would get 1.5mpg savings on a Jeep. As 2000mc pointed out, the mpg savings is relative to how efficient a vehicle is in the first place, and the size of pump. As was pointed out, you'll likely get about 0.5 mpg better.

If you currently get 20mpg, then 1.5 mpg savings represents an 8% increase in fuel economy, which doesn't seem realistic. However, a 1.5mpg improvement on a car that already gets 50mpg seems realistic, since it represents a smaller % increase in economy (3%).

All of this just points out the superior nature of calculating efficiency by using L/Km rather than MPG. There is also less room for deception when marketing a product that saves x amount of L/km than marketing it to save x amount of mpg. Sure, I could save 10mpg by using Acme's fuel saving Widget; if I already drive a 1000 mpg car.

Cherokees steer different than any other jeep I have drove. I've been in numerous Jeeps and cherokees always steer "hard". Slowing down the PS pump is going to make it pretty hard to navigate in tight spots.