remat457
Founding Member
GEARS AND MPG? WHATS THE REAL DEAL?
- Thread starter Allforspeed
- Start date
Alright...well to a point I don't think the gears help or hurt in the city driving...because one can argue that you can cruise around in a higher gear (if you have ex. 373's 410's) compared to the stock gearing (ex. 273 or 308)...because it really is about the rpm your at and "cruising in"...nothing tells you computer that since you have it in 3rd gear (aftermarket) instead of second (stock gears) that it should "retune" your mpg meter 
At those "cruising speeds" around town wind resistance isn't to much of a factor and therefore the mpg should virtually be the same if you cruise around at a certain rpm/speed whether it be in second or third gear...anybody know what I mean...it is clear in my mind but I don't think I put it down right...
I don't believe you gain mpg around town but stay the same...because you have "pause" times in between shifts (you shift more with a steeper gear in town)...if you wanted to get real picky...I don't think the torque multiplication has much to do with the mpg if at all...just "pick up and go"...
v8only and ninety15.0 have good points...just leave it at that...my thought are above...
I see and notice in my car that the in town mileage is actually worse on my car than it would be stock geared...for example if I was pulling from a stoplight in 1st gear I usually would keep the revs up until I get a decent mph (15mph) until I switch to second...instead of moving a few feet (even though I would be at a lower rpm) to shift into second...but that is just the way I drive...well plus my first gear is traction limited
Alright...this may be a very dumb question here...but my 1st gear is VERY TOUCHY...its almost like I can't ease into first gear thru the powerband without it wanting to jump out...I can literally press the gas pedal down 1/4 of an inch real quick and the whole car jumps forward...I'm not a big fan of that "torque"...but I guess that is what you get with gears right? Is that why it is so touchy...and it is kind of embarrasing when pulling out after slipping the clutch out I can't "ease" on the gas because it wants to jump with even the slightest touch? Normal right?
At those "cruising speeds" around town wind resistance isn't to much of a factor and therefore the mpg should virtually be the same if you cruise around at a certain rpm/speed whether it be in second or third gear...anybody know what I mean...it is clear in my mind but I don't think I put it down right...
I don't believe you gain mpg around town but stay the same...because you have "pause" times in between shifts (you shift more with a steeper gear in town)...if you wanted to get real picky...I don't think the torque multiplication has much to do with the mpg if at all...just "pick up and go"...
v8only and ninety15.0 have good points...just leave it at that...my thought are above...
I see and notice in my car that the in town mileage is actually worse on my car than it would be stock geared...for example if I was pulling from a stoplight in 1st gear I usually would keep the revs up until I get a decent mph (15mph) until I switch to second...instead of moving a few feet (even though I would be at a lower rpm) to shift into second...but that is just the way I drive...well plus my first gear is traction limited
Alright...this may be a very dumb question here...but my 1st gear is VERY TOUCHY...its almost like I can't ease into first gear thru the powerband without it wanting to jump out...I can literally press the gas pedal down 1/4 of an inch real quick and the whole car jumps forward...I'm not a big fan of that "torque"...but I guess that is what you get with gears right? Is that why it is so touchy...and it is kind of embarrasing when pulling out after slipping the clutch out I can't "ease" on the gas because it wants to jump with even the slightest touch? Normal right?
ninety15.0
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- Mar 10, 2004
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Yup first can be a little jumpy especially with higher and higher gears. When you do quickly jab the gas in first with steep gears, the rpms jump up very quickly and if you let off quickly it can lead to a very rough ride. When im driving around town, unless i come to an absolute full stop i never use first. If i do use first, im only in it for about three seconds before i grab second. Most slow speed turns that i used to make in 2nd i now make in third. My buddy who also has a gt stang with 3.73's takes off in 4th from a slow roll once in a while without any problems. I personally think that steeper gears are a little more forgiving. just my opinion. good luck either way man....im sure your going to be happy with the swap whether u go with the 3.55 or 3.73
Michael Yount
Mustang Master
"Your mileage may vary depending on driving conditions...."
The biggest variable is how the car is driven and the terrain/traffic situation.
There's no rule that applies for everyone, but GENERALLY going with 3.55's or 3.73's, your around town mileage probably won't get any worse if your driving style stays the same. Some report a slight increase in mileage as mentioned before because it doesn't take as much throttle to move the car around with more torque multiplication. Hills you took in 3rd before you may take in 4th after - so engine rpm doesn't vary that much around town.
On the highway your revs will go up the same % as the gear change (3.73/2.73= 1.37) about a 37% increase in revs at the same speed. So if 70 mph has you turning over 1800 rpm now, you'll be at almost 2500 rpm with 3.73's. If you have 2.73's and you want to know what 3.73's are gonna be like on the highway - there's a really simple way to find out. Your next highway trip, simply make the trip in 4th gear instead of 5th. The ratio difference between 4th and 5th is almost identical to the change between 2.73's and 3.73's. So you can actually EXPERIENCE what the change in mileage will be like without actually changing the gears. My guess - you'll lose 5-10% highway mileage running about 65-70 mph.
My car weighs a little over 3000 lbs., has worse aero than the Stang, has T-5 with mild H/C/I/Exh mods, has 3.73 gears with shorter tires than a Stang (like a Stang with 3.90's) and I get 18-20 around town and 24-26 on the road. But I suspect my 'around town' isn't as bad as yours is in SanFran.
The biggest variable is how the car is driven and the terrain/traffic situation.
There's no rule that applies for everyone, but GENERALLY going with 3.55's or 3.73's, your around town mileage probably won't get any worse if your driving style stays the same. Some report a slight increase in mileage as mentioned before because it doesn't take as much throttle to move the car around with more torque multiplication. Hills you took in 3rd before you may take in 4th after - so engine rpm doesn't vary that much around town.
On the highway your revs will go up the same % as the gear change (3.73/2.73= 1.37) about a 37% increase in revs at the same speed. So if 70 mph has you turning over 1800 rpm now, you'll be at almost 2500 rpm with 3.73's. If you have 2.73's and you want to know what 3.73's are gonna be like on the highway - there's a really simple way to find out. Your next highway trip, simply make the trip in 4th gear instead of 5th. The ratio difference between 4th and 5th is almost identical to the change between 2.73's and 3.73's. So you can actually EXPERIENCE what the change in mileage will be like without actually changing the gears. My guess - you'll lose 5-10% highway mileage running about 65-70 mph.
My car weighs a little over 3000 lbs., has worse aero than the Stang, has T-5 with mild H/C/I/Exh mods, has 3.73 gears with shorter tires than a Stang (like a Stang with 3.90's) and I get 18-20 around town and 24-26 on the road. But I suspect my 'around town' isn't as bad as yours is in SanFran.
ninety15.0
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- Mar 10, 2004
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ninety15.0 said:v8only said:
Who took a **** in your cheerios? Such anger. You're gonna die from a heart attack before 50 if you get so upset about little things in life.
I hold to my previous statement.
Despite the age of these cars, I guess Some people DO daily drive them. I gave up trying to modify and restore my daily driver years back. I have my gas saver for the week, and my mustang for the races on the weekends.
And yes, at 30 years old, everytime I fire it up, I drive it like I stole it, because that's what I ****ing bought it for, and that's the entire reason I threw mods at it like gears. Who in hell is gonna granny accelerate often enough to bring their gas mileage up?
the simple fact is, if you do a lot of freeway driving, it's near impossible now adays to keep it under 65,you're gas mileage WILL go down on the freeway.
I've stated before, it's completely possible to get the same or better mileage with these gears, but imo, you've got to drive like a complete.
When I drive my car on the streets, I prefer to keep it more in it's useable powerband, which is 2000 rpms or higher. Perhaps it's the general so cal agressive streets, but around here, if you drive like a
My brother does daily drive his notch, and he noticed a significant decline in gas mileage after the 3.73 gear install. He's not afraid to drive it hard.
From you're response, it appears that YOU are the one lacking maturity and needs to grow up a little. Don't get so offended when you read an opinion that doesn't agree with yours.
People in rough financial situations who have to daily drive these cars will be fully able to retain their gas mileage #'s from conservative driving, but for the rest of us who drive's the cars like they should, don't expect to get better mileage.
v8only - I'm going to have to disagree with you a little bit on how a mustang should be driven...you touched on the daily driver...but I'm not going to drive a mustang like "it should be"...I (as you mentioned) don't have the money to just replace my transmission when I screw it up or replace the bottom end because I overrevved it...I drive my car every single day (my only car) to work and college and can't afford to drive my car like it "should be"...though I take it to the drag strip a couple times a month and am not afraid to pass quickly or get in a quick little cat and mouse game...but I drive conservative up to a point...because I do not want to risk damage...you can drive conservative and still have fun...
If I had a another daily driver I would probably drive my car a bit harder but still would be conservative as not to break things that dont' need to be broke...and no one wants a beaten car if one day it came to selling it (don't plan on it)...
And on the "buy a honda if you want good gas mileage" clause...that doesn't mean anything...I would rather get the best gas mileage out of my car that I can whether it is a I4 or V12...I would rather get 20mpg than 2mpg out of my car...but I guess since I would rather have the higher mpg possible then I guess I need to buy a civic? It is all a matter of making due of what you got...if two equal cars were side by side and one got worse gas mileage I'm going to pick the better of the two...is that wrong?
Their is nothing wrong with owning a mustang and wanting liveable gas mileage...I find that most people that say don't buy a v8 if you want good gas mileage are usually those who have another means of transportation...but some of us can't afford that "luxury" so we buy a car that is quick but still want the liveable gas mileage...nothing wrong with that...
To the original poster...get some 355's...and good luck with it...you will enjoy the all around perspective of the gain you get with them without your gas mileage being to affected if much or at all...
If I had a another daily driver I would probably drive my car a bit harder but still would be conservative as not to break things that dont' need to be broke...and no one wants a beaten car if one day it came to selling it (don't plan on it)...
And on the "buy a honda if you want good gas mileage" clause...that doesn't mean anything...I would rather get the best gas mileage out of my car that I can whether it is a I4 or V12...I would rather get 20mpg than 2mpg out of my car...but I guess since I would rather have the higher mpg possible then I guess I need to buy a civic? It is all a matter of making due of what you got...if two equal cars were side by side and one got worse gas mileage I'm going to pick the better of the two...is that wrong?
Their is nothing wrong with owning a mustang and wanting liveable gas mileage...I find that most people that say don't buy a v8 if you want good gas mileage are usually those who have another means of transportation...but some of us can't afford that "luxury" so we buy a car that is quick but still want the liveable gas mileage...nothing wrong with that...
To the original poster...get some 355's...and good luck with it...you will enjoy the all around perspective of the gain you get with them without your gas mileage being to affected if much or at all...
That link is pretty interesting but I have to imagine he's using a computer program to come up with all those numbers.. here he compares accelleration and 1/4mi times of a bunch of gear sets on "stock" cars, and they all end up running a 15.2 in the 1/4 (4.10's are actually 15.3). He also shows the 0-60 times getting longer with the higher gears.. I'd be interested in seeing some real world info on this. I know when I went from 3.08's to 3.55's my car "felt" quicker around town but I'm not sure I'm actually any faster.. I have to shift twice to get to 60 now too.
And as for gas mileage it's really a matter of how you drive. If you TRY to get mileage out of your car you'll probably do better around town with a lower gear (numerically higher - 355/373). That's if you use 5th and cruise low in the gears (what fun is doing that all the time?)
I am by no means well off. My gas sipper as I referred to is a 98 tacoma, not worth squat, but gets good gas mileage, has 100k on it and has never brokend down, and hauls all my mustang parts everywhere.
I daily drove my mustang for 6 years, and before that I daily drove my v8 crown vic, before that, it was v8 dodge dart, before that, my v8 maverick. I've grown up with bad gas mileage and big v8 cars, so I'm used to having to conserve. If I had to daily drive my mustang, then yes, by far I'd be conservative to get better mileage, AND to not break it, as it would be my soul source of getting a paycheck.
Maybe what I'm advocating more is not driving your toy for transportation. There is a certain point in everyone's life that's into this hobby where you realize this, and it doesn't mean spending 20 grand on a civic. Hell, I bought my truck for 8 grand, and only pay 200 a month. I did this for the soul reason of being able to drive and modify my mustang without worries that it would go down. I'm going to the strip now, to keep it as legal as possible also.
Even when i daily drove my mustang, I found it was still impossible to drive it so conservatively as to get the ultimate gas mileage. I don't think I've ever been through a tank of gas without mashing the pedal at least twice.
WHen we drive 15 year old cars every day, we have to be prepared for bad gas mileage and break downs. This means being mechanically capable, and setting aside larger quantities of cash for gas. I don't have any extra money for repairs, but I have found through my resourcefulness, trading, junk yards, etc, I've got enough parts laying around to build two foxes likely from the ground up. I do engine swaps and tranny swaps practically on a weekly basis.
I guess what I'm getting at is I find it ridiculous for someone to do a mod as aggressive as gears then really worry about gas mileage. If you're LUCKY then you'll get good mileage, but be ready to pay if you play. THIS is why I do my own work, why I can drive it like I stole it. Not because I have cash, but because I'm resourcefull enough and capable of replacing broken parts at little or not cost, and only driving my car a couple days a week at the most so I don't have to worry about gas mileage.
I am a member of a maverick board, and their are still some people daily driving those beasts, and I just think that's crazy. I found I just could not restore a car faster than I would drive it into the ground from daily driving.
This has obviously become a push to not daily drive our cars any more, but also maybe for some to just loosen up and realize that breakdowns and bad gas mileage is an everyday part of this hobby.
best of both worlds?? get an 05 and not worry about any of this stuff. If I could only afford one of those!
I daily drove my mustang for 6 years, and before that I daily drove my v8 crown vic, before that, it was v8 dodge dart, before that, my v8 maverick. I've grown up with bad gas mileage and big v8 cars, so I'm used to having to conserve. If I had to daily drive my mustang, then yes, by far I'd be conservative to get better mileage, AND to not break it, as it would be my soul source of getting a paycheck.
Maybe what I'm advocating more is not driving your toy for transportation. There is a certain point in everyone's life that's into this hobby where you realize this, and it doesn't mean spending 20 grand on a civic. Hell, I bought my truck for 8 grand, and only pay 200 a month. I did this for the soul reason of being able to drive and modify my mustang without worries that it would go down. I'm going to the strip now, to keep it as legal as possible also.
Even when i daily drove my mustang, I found it was still impossible to drive it so conservatively as to get the ultimate gas mileage. I don't think I've ever been through a tank of gas without mashing the pedal at least twice.
WHen we drive 15 year old cars every day, we have to be prepared for bad gas mileage and break downs. This means being mechanically capable, and setting aside larger quantities of cash for gas. I don't have any extra money for repairs, but I have found through my resourcefulness, trading, junk yards, etc, I've got enough parts laying around to build two foxes likely from the ground up. I do engine swaps and tranny swaps practically on a weekly basis.
I guess what I'm getting at is I find it ridiculous for someone to do a mod as aggressive as gears then really worry about gas mileage. If you're LUCKY then you'll get good mileage, but be ready to pay if you play. THIS is why I do my own work, why I can drive it like I stole it. Not because I have cash, but because I'm resourcefull enough and capable of replacing broken parts at little or not cost, and only driving my car a couple days a week at the most so I don't have to worry about gas mileage.
I am a member of a maverick board, and their are still some people daily driving those beasts, and I just think that's crazy. I found I just could not restore a car faster than I would drive it into the ground from daily driving.
This has obviously become a push to not daily drive our cars any more, but also maybe for some to just loosen up and realize that breakdowns and bad gas mileage is an everyday part of this hobby.
best of both worlds?? get an 05 and not worry about any of this stuff. If I could only afford one of those!
Michael Yount
Mustang Master
"I guess what I'm getting at is I find it ridiculous for someone to do a mod as aggressive as gears then really worry about gas mileage."
Just as you have your preference on how you use your cars, others have their own preferences on what they're trying to accomplish with theirs. I ABSOLUTELY get a kick out of trying to build a package that outperforms the factory engine in all ways - power, drivability and fuel mileage. And so far I've been successful. As much of a kick as you get out of mashing the gas pedal - I get the same kick out of filling up the tank and discovering I've eeked out another 19.5 mpg around town tank.
So, drive yours as hard as you want. And understand that others will make different choices. And - I enjoy stepping hard into the gas on mine as well - I just don't choose to do it as often as you do. Great country we live in that way.
Just as you have your preference on how you use your cars, others have their own preferences on what they're trying to accomplish with theirs. I ABSOLUTELY get a kick out of trying to build a package that outperforms the factory engine in all ways - power, drivability and fuel mileage. And so far I've been successful. As much of a kick as you get out of mashing the gas pedal - I get the same kick out of filling up the tank and discovering I've eeked out another 19.5 mpg around town tank.
So, drive yours as hard as you want. And understand that others will make different choices. And - I enjoy stepping hard into the gas on mine as well - I just don't choose to do it as often as you do. Great country we live in that way.
ninety15.0
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- Mar 10, 2004
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Exactly....anyone can build a stang that runs 10's, but it would be just that much cooler to have a stang that runs in the 10's and still gets decent milage. Its not always about driving the fastest all the time...in fact, the majority of the time it absolutely isnt. When other cars are on the road, and when people are near the roads, and when you dont know the road very well, in traffic...you get the point that most of the time you can never open these cars up all the way, and thats what the track is for. Its just stupid and dangerous to drive balls to the walls all the time, and i know that most college kids cant afford the repair costs, the tickets, and the gas. Do what u will.....but honestly i thought at first that V8only was an immature teenager with his first stang, but i guess first impressions arent always everything...peace
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