Gears vs. Mileage

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bodabdan

New member
Any input on your experience with mileage after changing rear gear ratios? I really need to be able to run some open highway and don't want to kill mileage.
 
Changing to 4.10 gears from stock 3.55 gears, most have seen a 1-2 mpg decrease. The performance increase which a tune will be required to benefit from the gears and alter the shift parameters is well worth it.
 
when i bought my car it had 4.10's and no tune so as terry bradshaw would say my milage shot up faster than a bee stung stallion. since ive gotten a tune for 4.10's and the odometer tumble has decreased dramatically. dont know how milage was before though.
 
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You'll lose 1 to 2 mpg...... That's a given. The performance gained with the new gears and tune, yes you will need a tune, will put a smile on your face everytime you drive your MM.
 
My 2 cents I put the 4:10s in and love them. Then I had a stroker motor built and my Miliage is higher than stock Marauders and its awesome on the highway.
 
I don't know.... I appreciate the seat of the pants factor, no doubt about that. I will be using this car for business travel (and I travel a lot).
Anyone use a 3.73 ratio?
 
bodabdan said:
I don't know.... I appreciate the seat of the pants factor, no doubt about that. I will be using this car for business travel (and I travel a lot).
Anyone use a 3.73 ratio?
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Dont waste your time or money-I would either stay with the 3.55 if you are that concerned with mileage or swap to the 4.10's. What you dont realize is the tune in our cars was very conservative and had a lot of shifting schedule problems because they were detuning them.

Get a tune regardless which gears you have and you will be really surprised how nice your car runs and shifts. Tune and gears (4.10's) are probably the best thing you can do for your car- you will be shocked and pleased at the difference. If you want gas mileage you could always switch to a Fiesta!!!!
 
The difference between the stock 3.55 and 4.10 is 15%. Going to 3.73 is only a 5% difference and isn't considered to be worth the cost, unless you can do all the work yourself.
 
What ^^^^they say. I also have a 3500 RPM stall converter. At 70 MPH with A/C on, triple digit temps and cruise control on I still am getting 22-23 MPG. I'm supercharged too, that really helped.
 
If you want gas mileage you could always switch to a Fiesta!!!!
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No need for all that now......I don't want to have to get ugly in my first few posts...
I've had a 600 rwhp car before and that's not what I want this to be (it got 25 mpg by the way).
I will not accept that only a front wheel drive POS can get decent mileage, I know better. I'm not concerned about doing the work, I have three roll cabinets and a fully stocked service body on my F-350.
I'm only trying to do some due diligence and use the experiences of others figure out all the right combinations to get the results I'm looking for. I appreciate all the constructive input.
 
I would keep the 3.55 gear for now but get the sct tune from Mo's speed shop , a well involved vendor and member here. They can provide tune with different octane as well as both gear ratios. The tune will add 20 or so hp and revise the shift schedule from poor factory to much enjoyable. Then after you have run that and decide you want 4.10 , you can switch and already have a tune ready to download. This can all be done with a phone call and ups. Once received you plug the sct unit in the obdii port and download. The sct then remembers the factory tune to reload if needed
 
RubberCtyRauder said:
I would keep the 3.55 gear for now but get the sct tune from Mo's speed shop , a well involved vendor and member here. They can provide tune with different octane as well as both gear ratios. The tune will add 20 or so hp and revise the shift schedule from poor factory to much enjoyable. Then after you have run that and decide you want 4.10 , you can switch and already have a tune ready to download. This can all be done with a phone call and ups. Once received you plug the sct unit in the obdii port and download. The sct then remembers the factory tune to reload if needed
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I fully agree with this advice. My car had 4.10 when I bought it, but the tune I purchased, 3.55 and 4.10 ratios included, improved everything. Start there, if 3.55 isn't enough pull, the 4.10 swap will cost you 1-2mpg as stated. But will add major fun factor :burnout:
 
bodabdan said:
I don't know.... I appreciate the seat of the pants factor, no doubt about that. I will be using this car for business travel (and I travel a lot).
Anyone use a 3.73 ratio?
Click to expand...

I have 3.73 and am quicker and faster than most 4.10 N/A MM's.

Since everyone now Crusies at 80 mph now on the highway - with 3.73 you are right at 2500rpm. Past 2500 the gasoline goes fast.

4.10 @ 80mph = 2800-2900 rpm. Deal breaker for me. That and you might need a better drive shaft if you go 90-100 sometimes with 4.10's

If you want to accelerate quickly a high stall torque works well as it can slip when you floor it but locks up on the highway.
 
babbage said:
I have 3.73 and am quicker and faster than most 4.10 N/A MM's.

Since everyone now Crusies at 80 mph now on the highway - with 3.73 you are right at 2500rpm. Past 2500 the gasoline goes fast.

4.10 @ 80mph = 2800-2900 rpm. Deal breaker for me. That and you might need a better drive shaft if you go 90-100 sometimes with 4.10's

If you want to accelerate quickly a high stall torque works well as it can slip when you floor it but locks up on the highway.
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Thank you Babbage! Great info!
 
bodabdan said:
Any input on your experience with mileage after changing rear gear ratios? I really need to be able to run some open highway and don't want to kill mileage.
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It is more about the SMILES per miles.

That is all that matters. :burnout:

Love my gears. Best mod ever. Even when I daily drove it. The way I pounded it. I did not and still do not care about the MPG's.

It's all about the SPG ;)


Sent from The White House on taxpayers dimes.

DTR + 4.10's + Eaton swap = Wreeeeeeeeeeeeeeedom
 
babbage said:
I have 3.73 and am quicker and faster than most 4.10 N/A MM's.

Since everyone now Crusies at 80 mph now on the highway - with 3.73 you are right at 2500rpm. Past 2500 the gasoline goes fast.

4.10 @ 80mph = 2800-2900 rpm. Deal breaker for me. That and you might need a better drive shaft if you go 90-100 sometimes with 4.10's

If you want to accelerate quickly a high stall torque works well as it can slip when you floor it but locks up on the highway.
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he gets good mpg also ^^^
I spend more time cruising 65-70, so 4.10 = fun. good points to both - owner preference;)
 
with 4.10's and Lidio tune, I got a best of 25.2 mpg from Heber, AZ to Santa Rosa, NM at 75 mph... i probably had a tail wind and a majority of that stretch was going down hill from the continental divide.
Typical is 23 mpg's going 70+ mph
mixed driving around 17 mpg's
 
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