3.73 vs 4.10 gears - fuel economy?

[Jackstand78]

Hey guys, if there is a better spot to post this let me know and I can move it.

To keep a long story short, I have a 95 ext cab ranger with a 2.3L engine and 5 speed manual. A 7.5 open diff with 3.73 gears and I'm running some 27X8.50R14 maxxis buckshot tires on the rear. I'm planning on changing my rear end to an 8.8 limited slip. (And probably get a locker later down the road) I drive in a lot of hill country and the 3.73 gears don't have the tourque I'd like so I'm thinking of finding a rear end with a 4.10. my concern is what it would do to my milage. I'm getting between 19.5-22mpg right now driving mostly highway between 50-75mph.
How big a difference y'all think the 4.10s would make on my fuel economy?

 

[racsan]

well your rpm will increase from about 1900 to 2300 (in 5th gear) @ 55 mph.
depending in the situation you could gain or lose some mpg but I doubt much. In town milage most likely wont change.

 

[RonD]

+1 ^^^

On the hills MPG would be better but because of the 4.10 ratio you may tend to go Faster, lol, negating the change

On flats at 70mph the engine RPMs would be higher so MPG would be slightly lower on LONG TRIPS, over 100miles

Around town no difference
4.10 ratio will be a good upgrade for a 2.3l, in my opinion

Remember to re-calibrate speedo/odo if you use them to calculate MPG

 

[cbxer55]

Since you have a manual, drive it in 4th gear all the time and see what affect it has. Mine's an auto, and I have the OD off most of the time. I don't notice much difference, but then I am not observing the trip meter and doing the math to figure out my mileage either. Driving in 4th or OD off won't give you the power increase, but it will give you the rpm increase while driving and should be close to what the gear change will do. I am thinking of doing the 4.10s in my 98 3.0 V-6 as well. The way it's tuned, the intake and exhaust, it likes to rev high. The 3.73s just don't do it any more.

 

[DCman]

Hey guys, if there is a better spot to post this let me know and I can move it.

To keep a long story short, I have a 95 ext cab ranger with a 2.3L engine and 5 speed manual. A 7.5 open diff with 3.73 gears and I'm running some 27X8.50R14 maxxis buckshot tires on the rear. I'm planning on changing my rear end to an 8.8 limited slip. (And probably get a locker later down the road) I drive in a lot of hill country and the 3.73 gears don't have the tourque I'd like so I'm thinking of finding a rear end with a 4.10. my concern is what it would do to my milage. I'm getting between 19.5-22mpg right now driving mostly highway between 50-75mph.
How big a difference y'all think the 4.10s would make on my fuel economy?

You'll lose about 2 mpg.

 

[Dirtman]

You'll lose about 2 mpg.

Nope...

 

[19Walt93]

If the RPM was 1900 with 3.73's it will be 2088 with 4.10's. If you live in hilly country 4.10's may actually improve mileage because the engine won't have to work as hard. High load means low vacuum which means richer mixture. If the overdrive ratio is .70:1- like my T5 for example, those 4.10's act like 2.87's in 5th gear.

 

[DCman]

IF Jackstand78 is still using the stock 5-speed that truck came with, then its a Mazda M5OD-R1.
Ratios (from 1st to 5th) are; 3.72:1, 2.20:1, 1.50:1, 1:1 and .79:1.

 

[dvdswan]

Slow down and enjoy the scenery. Life is too short to race through it. Enjoy it while you can.

And you save some MPGs too.

 

[wildbill23c]

Can't say what 4.10's will do, but my 87 Ranger 4x2 2.9L V6 with 5 speed and 3.73 rear end will do 25mph on the freeway at 80mph, so going to 4.10's I'd assume it would drop maybe 1-2mpg but most likely in town you'd never notice a difference because you'd be running in 3rd or maybe 4th depending on speed limits in your town, in my town they seem to still be stuck in horse and buggy days so 20-25mph is max in city limits which means 3rd gear most of the time since people here can't seem to figure out how to even do 20-25mph, and they still have numerous wrecks somehow.

 

[4x4junkie]

4.10 was a factory ratio offered on some 4-cyl trucks.

Agreed with the above, 4.10 should do you well. In-town mileage could actually go up slightly (I doubt highway MPG will change significantly, 4-cyl engines don't mind some RPM).

 

[scotts90ranger]

I've got 4.10's in my '97 extended cab manual 4 cylinder Ranger, when I got it it had those 27" tires, it got 22mpg, I then got some 235 75 15's and corrected the speedo it still got 22mpg... then for fun I got some car tires in 225 70 15 (I think... whatever) and the mileage went UP to 23.5 consistently tank to tank with the speedo compensated again. I did a 1800 mile road trip with it in November with the 235's, over that it averaged 22mpg just like it did on my commute... I did go speeds that keeps it under 3000rpm which I'm pretty sure keeps it in closed loop fuel control, which is part of why I have played with tire size.

Speedo compensation was checked with the 5 mile speedo test section on the local freeway, the 235's I had to add 10%, the new tires are 7%...

Long story short, likely it won't make JACK of a difference, but drivability will improve...

 

[DCman]

Good point, Scott.
27x8.50R14 is an off-road tire.
If Jack swapped out to a P-metric radial tire, his gas mileage would improve.

 

[Shran]

I think you would be very happy with 4.10s. I would absolutely do it...speaking as a 4 cylinder owner, with 3.73s in mine as well... just the drivability factor would be plenty.

I went from 3.73s to 4.10s in my Explorer and saw very little change in gas mileage. I think I lost a little bit but it sees mostly highway miles and a 4.0 spinning at 3000 RPM will burn a lot of gas...and it's a pretty heavy rig to begin with. When it was stock, it was fun to drive with 3.73s but all the extra weight I added to it made it very sluggish. 4.10s really woke it up.

 

[cbxer55]

4.10 was a factory ratio offered on some 4-cyl trucks.

Agreed with the above, 4.10 should do you well. In-town mileage could actually go up slightly (I doubt highway MPG will change significantly, 4-cyl engines don't mind some RPM).

The 3.0 doesn't mind some rpms either. Talked with my friend last night at the watering hole, he has a auto shop. Asked if he could put a Tru Trac and 4.10 in my 98 Ranger. He said, no problem, and you'll love that combination. It will be an entirely different vehicle compared to the Open diff it has now.