Opinions on Rear Gear Ratio
 

2000 Crown Victoria Police Interceptor

Vehicle Weight
3983 lbs

Factory engine specifications
HP: 215hp @ 4,500RPM
TQ: 285 lb.-ft. @ 3,000RPM

Transmission Gear Ratios
1st: 2.84:1
2nd: 1.55:1
3rd: 1.00:1
4th: 0.70 :1
Rev: 2.23 :1

Rear-end Gear Ratio
3.55:1

I drive approximately 80% HWY. Would it be worth my while to swap out the rear ring and pinion? My goal cruising speed is 60 MPH.

http://ecomodder.com/forum/attachmen...1&d=1409942127

How much would it cost you in parts? You would see an MPG increase.

3.08 and lower (numerically higher) is $180 for the ring and pinion.

2.73 is $257 for the ring and pinion.

I wouldn't pay that much. Keep an eye out for a deal to come along. You never know, buy a car for near scrap, take the parts you want, then scrap it yourself or something.

My basic rule of thumb is will it pay for itself in 2 years time. It isn't a hard and fast rule, but more of a goal.

I'm average about 72 miles a day with a fuel cost of $0.168 per mile.

Keep an eye on junk yards and peiple who just want to unload extra stuff laying around. Fyi, my v6 turns 1600 rpm at 60 and the car weighs about the same.

My personal opinion would be 3.08 gears. In a truck with a V8, 1634 rpm would be close to lugging... however, your Vic has a much lower Cd and drivetrain loses, you should be fine cruising around with that engine speed.

I would go 2.73 only if you are planning to do aero mods that would help it roll down the road easier.

As the others said, try to find either a complete axle or scrap car. You'll recoup your loses quicker :thumbup:

Im going to agree. With 2.73's 50mph would be essentially impossible in top gear.

X3 that the 2.73 gears would be too tall. Get instruments first to see what you are getting at what rpm. I know 50mph at x-rpm is different than 60mph at same rpm but it might give you an indication of where the mpg drops off from the engine running too low...

Guys my '91 5.0 has 2.73 and it cruises at 50 in 4th just fine? I don't drive it carefully so I can't vouch for MPG's, but yea. Was just tossing that out there.

Not slamming you Balto, but I'd imagine that the 5.0 has a good bit more bottom-end torque than the 4.6. Hence the better drive-ability with 2.73's :thumbup:

The 4.6 in a 99 2wd SCLB Ford F-150 I used to drive was... ahem, pathetic. I hope it fares better in the Vic!

3.08zzz

Well then, I learned something! I didn't think about the torque haha.

For comparison's sake, the pushrod 5.0L in the 94 GT made 285 ft-lbs at 3500 rpm compared to my 4.6L's 285 ft-lbs at 3000 rpm.

Also, I'm not disagreeing that 3.08s may be the better choice, but I do want to point out that 2.73s were standard in the civilian model Crown Vics. Just wanted to provide more insight to the discussion.

I would lean toward the 308 gears.
Your print out looks on the 308 looks likes the rpms on the Q45.
I was pretty happy w/ them.

Your power will suffer, but I highly doubt you'll be lugging the engine. Everything I've ever seen says taller gearing = better mpg (until you lug). I'd definitely go 2.73, especially if the civilian model came with it. You know its okay then.

I have 2.73s in my 93 Grand Marquis and I love them.
They are the shizzle on the highway.
I have 3.08s in my Town Car, and they are ok for what it is.
There is a 500# difference between the two cars as well.
I'd go 2.73s. Get them from RockAuto for cheap.
Then sell your 3.55s. People out there will buy them.
And thats how you make your money back.


-ryan s.

I'd only go with the 2.73 after some weight reduction. Or with some forced induction...

3.08 plus taller tires? Higher load ratings and pressures will decrease your rolling resistance. And filling in the wheel gap better will increase aerodynamics a bit(probably very small bit).

There are still plenty of old 94-96 D-Body Fleetwoods running around with 2.56 gears and 350 LT1 engines.

Lower engine RPM at a given road speed = better MPG. The trade-off is sluggish acceleration.

I thought this site was all about the MPG.

FYI, with 2.73s in my 93, I ran a 17.52 @ 81mph in the 1/4 mile.
Acceleration does suffer a bit, but you don't go to WOT while hypermiling.

I'd still go 2.73s.


-ryan s.

When I was younger, I wanted a car that looked good, sounded good, and went fast. Now I want a car that looks good, sounds good, and gets decent fuel mileage ... decent being a subjective term on a forum full of compacts, subcompacts, and hybrids. I know I'm working up hill. :-P

I'm leaning towards 2.73s but first things first; I need to pick up a sg2 or ultragauge.

For the sake of science, please A-B-A both the 2.73 and 3.08! :D

While I don't have the means to perform two gear swaps solely for the purposes of testing. I'll certainly perform A-B testing between the factory police spec 3.55s and their replacements (likely 2.73).

I am the only one absurd enough to even bring up A-B-A for this one. Honestly, it would have been A-B-A-B, unless you decided on the classic A-B-A-I am not testing it again, forget you, Xist!

I am curious how much quieter your ride would be after the swap, although I doubt that it would be much at economical speeds, but if you have a smart phone, you can download a sound meter.

You already have a better ratio than my Civic!

Actually the Police Interceptor models came absent any sound deadening or carpet they came with rubber matting instead so you can imagine the amount of road noise I deal with.

(I have plans to deal with that as well)