3:73s and couldnt be happier

myponyrocks said:

Unfortunately I cant get solid(scientific) gains as the car pre-geared with me recording the gas was during the winter. However I am attributing my gains to the stretch of road I run 2x a day on my commute. It was in that sweet spot on the stock gearing where 4th is too much but 5th isnt enough. With the 3:73s the sweet spot is now 5th gear, with 5th being just enough for everything except the big grade where I have to down shift to 4th. I used to drop it to 3rd to pass people (this is the only spot on this road where you can pass safely... ie 2 lanes) now 4th is enough to pass and 5th still keeps the speed up for normal driving. Just this small patch of road has netted me big gains. Also I now drive in 4ht more comfortably at 45, stock gearing in 4th just dint feel right for the whole drive, now I can even pop inot 5th some of the way. Total commute is about 15 miles, even though it takes 30-60 minutes 4:10s would have been great for city, but I also think that in my situation 4:10s would have put me out of the sweet spot I'm in now on the longer stretches.

PLEASE do not use my experiance to decide, I will make a video of my RPMs and Speed to compliment the 4:10s video if some one will host it?

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stepping up to a steeper gear will not increase gas mileage, it WILL decrease it. heres why:
your RPMs at a given speed will be higher. that means your pistons will move up and down faster. the more downward movement of the pistons, the more gas your injectors will spray. gas mileage will go down. myponyrocks, the reason you are getting more mileage now is b/c youre still in your break-in period. youre taking it easy. before the gears im sure you got oon it a lot w/o even thinking about it. now you consciencely have to go easy, so your gas mileage went up. when you finally get to romp on it (AFTER 500 MILES!!!!) your mileage will go down.

yeah, i'd love to see what 3.73s turn in a 3650. you should def make the video.

3.73 vs 4.10

Over the course of the past couple months I have been trying to make a decision on which gears to go with. As it turns out I had the opporunity to upgrade my 02' V6 to a 04' GT which to me made the swapping out of gears even more important. I have come to this conclusion when reading through various threads, the debate over which gears to go with sounds very similiar to which is better between BETA & VHS, MAC & IBM, NOVELL VS NT, etc... It's a no win situation either way and everyone has their own preference for why they choose one or the other. So I say, just do it up, either upgrade is a good thing!!

I personally just ordered 3.73's cause I got a good deal on them and when they come in i'm sure i'm going to be very happy with the purchase. In searching, I have found that 3.73's tend to hold a little less cost on avg. Mustangs are mod heaven when it comes to cars and I love it, gears are only the beginning, the list I currently have fills at least a page and many paychecks! Thank you aftermarket Ford guys!!

373S for this auto.......I fear the gear. Moreso the gear whine, so 373s is gona be the stoutest i go with. Hoping to have them in along with my headers by Mustang Week!

I did an experiment once to simulate 4.10s in my auto. I was cruising along doing 80 mph at 2400 RPM. My transmission fluid temperature was holding happily at 180*F and the engine coolant was at 194*F. To simulate 4.10s at 80 mph, I locked out OD and dropped down to 70 mph. This took my RPMs to 3000, which would be around what I would see with 4.10s at 80 mph. Within two minutes, my transmission fluid temperature reached 200*F. It had even gone past the engine coolant temp at 198*. I have never seen the transmission fluid go hotter than the engine coolant. I didn't want to take it any further so I clicked OD back in and backed off. If I get 4.10s, I'll probably limit my freeway driving to 75 mph without an auxillary transmission cooler.

Just when I was all convinced I will go with 4.10s... Damn you!

(j/k!)

No Not Kidding Damn him Now I will have to check that GD !!!

The Transmission Temperature Went up to 200 degrees huh!

you think the temp would do that in a manual? That really worries me. Everyone say not to fear the gear but this is the kinda s**t that makes me worry. :damnit:

DerekStangGT said:

stepping up to a steeper gear will not increase gas mileage, it WILL decrease it. heres why:
your RPMs at a given speed will be higher. that means your pistons will move up and down faster. the more downward movement of the pistons, the more gas your injectors will spray. gas mileage will go down.

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well your kind of right.. the higher rpm's does lower mileage but not as much as some peopel think.. it's a little more complex...

at no or light load conditions ( foot off gas or barley on it) your car gets much higher mileage then when your into it 1/8 throttle or more.. in fact if you monitored with wds using the fuel economy test you get less that 0 mpg when leaving from a stop or if you are more than 1/4 of the way down on the gas.. when your coasting regardless of rpm's your car gets over 40 per gallon... when coasting i have seen as high as 98 MPH on the wds.. ( this was not on a mustang.. i tested my mustang 60 somthing was the highest it would go coasting..

the reason why you average out at 15 or so city 20 something highway is nobody coasts all the time..

so the trick too good milage is a balance of keeping rpm's down and keeping damm near off the gas pedal..

so steep gears can HELP mileage by simpily allowing you too climb hills and such at a much lighter load on the engine..

this is how some people get tricked into thinking a smaller motor is better for gas mileage...

take a e-250 van for example... the 4.2 6 cyl gets worst milage than the 5.4.. because the 4.2 has too work so hard too get that truck moving.. the percentage of load on the engine is much higher.. and at higher loads when the truck lags the driver will step on the gas harder too keep the same speed or go faster.. so the throttle opens more... more air = more fuel that has too be mixed with that air.. you get the idea...

propellerhead said:

I did an experiment once to simulate 4.10s in my auto. I was cruising along doing 80 mph at 2400 RPM. My transmission fluid temperature was holding happily at 180*F and the engine coolant was at 194*F. To simulate 4.10s at 80 mph, I locked out OD and dropped down to 70 mph. This took my RPMs to 3000, which would be around what I would see with 4.10s at 80 mph. Within two minutes, my transmission fluid temperature reached 200*F. It had even gone past the engine coolant temp at 198*. I have never seen the transmission fluid go hotter than the engine coolant. I didn't want to take it any further so I clicked OD back in and backed off. If I get 4.10s, I'll probably limit my freeway driving to 75 mph without an auxillary transmission cooler.

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i recomend a good sized trans cooler for any auto with gears or a converter..

Well That about does it for me getting the 4.10's jeeze even 3.73's do you need to get a trans cooler???

Is there a break in period when you install new gears? I was planning on getting some installed friday and going to the track the following friday.

02camarokiller said:

Is there a break in period when you install new gears? I was planning on getting some installed friday and going to the track the following friday.

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there is a NECESSARY 500 mile break-in period. i personally wouldnt even go to the track until a good 1,000 miles after the install just to be safe