feel of the 3.55's versus the 3.31's
03-03-2015, 04:09 PM
#52
Join Date: Sep 2012
Location: illinois
Posts: 36
bumping this thread because I've decided I'm probably going with new gears as my next Mod but have some questions and found some youtube videos to go along with them(not my videos). I currently have 2.73's, and have seen a video on youtube of a 3.7 running 13.4 with a couple exhaust mods/o/r pipe CAI and a tune. He maxes out 3rd a few seconds after he crosses which im guessing is about 110-115mph. Here is the vid
The question here is - which is more efficient?- The shorter gears of a 3.73 or being able to stay in 1-3 gear longer and using one less shift?
Now here is one of a guy running with 3.73's
Sounds like he is getting close to redline in 4th gear right before crossing. SO
2.73 and 3.73 both seem good for the 1/4 mile due to getting to the end of the powerband just as crossing the line. Going from 2.73 to 3.73 makes a difference of almost one full gear in the 1/4. So which is faster the extra shift with shorter gears or one less gear change and pulling longer but a taller ratio ? Let's leave out MPG, city driving, all that non sense. Were strictly talking 1/4 mile.
As for launching- I would imagine it being easier to launch and hook the rubbers with a 2.73 regardless of having slicks. IMO the 3.73's would be a better launch ONLY if you pair them with a set of slicks, otherwise wheel spin would be inevitable on any hard launch over 2k rpm. Obviously tires are needed for any sort of good launch but more important if it's any gear higher than a 2.73.
The bottom video mustang has a few more mods than the top one which im assuming why it's .4 faster in the 1/4. Take away the extra mods of the red one (spec 1 clutch, driveshaft, and slicks) and there's your .4 difference. I guess in summary when comparing the two mod for mod with the only difference being the gears, it looks like a VERY close 1/4 mile comparison between the two and I can't see how changing the gears really changes 1/4 mile time that much without also adding slicks and other driveline mods. After thinking long and hard and doing research, 600-700 dollars to change a 2.73 to a 3.73 might not really improve 1/4 mile time as much as other mods for the same cost would.
One last question, the options in between 2.73 and 3.73. If 2.73 almost maxes out in 3rd gear at the 1320, and 3.73 almost maxes out 4th gear in the 1/4, both seem to be a good fit for drag racing, but where does that leave the 3.31 and 3.55 gears? Correct me if I'm wrong but wouldn't that mean these gears would be crossing mid of 4th gear ? So either that last shift to 4th is a time killer or not getting the full run through 4th would leave you with an unwanted shift.
The question here is - which is more efficient?- The shorter gears of a 3.73 or being able to stay in 1-3 gear longer and using one less shift?
Now here is one of a guy running with 3.73's
Sounds like he is getting close to redline in 4th gear right before crossing. SO
2.73 and 3.73 both seem good for the 1/4 mile due to getting to the end of the powerband just as crossing the line. Going from 2.73 to 3.73 makes a difference of almost one full gear in the 1/4. So which is faster the extra shift with shorter gears or one less gear change and pulling longer but a taller ratio ? Let's leave out MPG, city driving, all that non sense. Were strictly talking 1/4 mile.
As for launching- I would imagine it being easier to launch and hook the rubbers with a 2.73 regardless of having slicks. IMO the 3.73's would be a better launch ONLY if you pair them with a set of slicks, otherwise wheel spin would be inevitable on any hard launch over 2k rpm. Obviously tires are needed for any sort of good launch but more important if it's any gear higher than a 2.73.
The bottom video mustang has a few more mods than the top one which im assuming why it's .4 faster in the 1/4. Take away the extra mods of the red one (spec 1 clutch, driveshaft, and slicks) and there's your .4 difference. I guess in summary when comparing the two mod for mod with the only difference being the gears, it looks like a VERY close 1/4 mile comparison between the two and I can't see how changing the gears really changes 1/4 mile time that much without also adding slicks and other driveline mods. After thinking long and hard and doing research, 600-700 dollars to change a 2.73 to a 3.73 might not really improve 1/4 mile time as much as other mods for the same cost would.
One last question, the options in between 2.73 and 3.73. If 2.73 almost maxes out in 3rd gear at the 1320, and 3.73 almost maxes out 4th gear in the 1/4, both seem to be a good fit for drag racing, but where does that leave the 3.31 and 3.55 gears? Correct me if I'm wrong but wouldn't that mean these gears would be crossing mid of 4th gear ? So either that last shift to 4th is a time killer or not getting the full run through 4th would leave you with an unwanted shift.
03-14-2015, 02:05 PM
#53
3rd Gear Member
Join Date: Oct 2014
Location: MD
Posts: 625
My mind is made up it's 355's for me, now I have to find a shop to install, some one that knows what they're doing, I live in Hagerstown, MD, so if anyone fom my town can help me out with a shop, I'd appreciate it
03-14-2015, 10:54 PM
#55
1st Gear Member
Join Date: Nov 2013
Location: AZ
Posts: 75
Today I went on my first highway trip since switching from 2.73 to 3.55 gears.
Once you get out of town around here the typical interstate speed limit is 75 and the flow of traffic is usually a little over that so my typical speed is 80 mph. With the 2.73 gears I was spinning about 2000 rpm at 80 mph, with the 3.55 gears I'm spinning around 2500 rpm at 80 mph, and it felt pretty comfortable cruising at that rpm.
One thing that looks like it took a pretty good hit is my gas mileage. With the 2.73 gears it was usually around 20 mpg around town and just over 30 mpg with all highway driving.
I checked it today and with about half city/half highway miles I got about 21 mpg (168 miles/8 gallons). Before I probably would have got around 25 mpg with that same combination of city/highway driving.
Although that lower gas mileage might be mostly because of the gear change, at the same time I went from stock 17x7 wheels to 18x9 wheels so I'm sure that will also have an impact on gas mileage.
Plus, I've also added an MPT tune so with the change in gears, wider tires, and tune I know I've been driving more aggressively lately seeing how it feels compared to when it was stock. I've heard you can increase your mpg with a tune if you can keep your foot out of it, well I haven't been able to keep my foot out of it, lol!
Once you get out of town around here the typical interstate speed limit is 75 and the flow of traffic is usually a little over that so my typical speed is 80 mph. With the 2.73 gears I was spinning about 2000 rpm at 80 mph, with the 3.55 gears I'm spinning around 2500 rpm at 80 mph, and it felt pretty comfortable cruising at that rpm.
One thing that looks like it took a pretty good hit is my gas mileage. With the 2.73 gears it was usually around 20 mpg around town and just over 30 mpg with all highway driving.
I checked it today and with about half city/half highway miles I got about 21 mpg (168 miles/8 gallons). Before I probably would have got around 25 mpg with that same combination of city/highway driving.
Although that lower gas mileage might be mostly because of the gear change, at the same time I went from stock 17x7 wheels to 18x9 wheels so I'm sure that will also have an impact on gas mileage.
Plus, I've also added an MPT tune so with the change in gears, wider tires, and tune I know I've been driving more aggressively lately seeing how it feels compared to when it was stock. I've heard you can increase your mpg with a tune if you can keep your foot out of it, well I haven't been able to keep my foot out of it, lol!
03-16-2015, 10:45 AM
#57
Join Date: Sep 2012
Location: illinois
Posts: 36
I've seen vids of mustangs with almost same exact mods and talked to mustang owners that have same mods as each other only diff is 2.73vs 3.73 and their 1/4 mile times are identical. I guess the only true way ill know is to install the 3.73's and find out lol
03-23-2015, 02:52 PM
#58
Ay yo choppa, you get your gears yet? I'm looking to get 3.73s as my next mod.
