Those who have Auto GT w/ 3:15 gears and went to a
12/2/13, 01:34 PM
#1
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Those who have Auto GT w/ 3:15 gears and went to a
went to 3:73 gears did u notice a nice difference? How much of a better time in the 1/4 mile? How much of a difference in your 60' foot How much of a loss in mpg?
12/2/13, 07:57 PM
#2
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Just had mine installed, It really made a noticeable difference in the car. Really woke the car up. Everything I've read on 1/4 mile times is that they will make the car slower in the 1/4 due to shifting into 5th gear before the end. No noticeable loss in mpg. I don't regret changing gears.
12/3/13, 05:00 PM
#3
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Are you saying that you're now slower in the 1/4 mile than with the stock gears? If so, what did you gain - going faster for the first 60 feet? I'm not following the improvement.
12/3/13, 05:08 PM
#4
Bullitt Member
With a 3.73, you are going to redline in fourth gear before you reach the end of the quarter mile, causing you to shift into fifth before you finish out. You will alternatively have quicker acceleration, which would in tun give you a better 60 foot.
12/3/13, 08:33 PM
#5
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I have 3.73 gears and I love them. Most people could care less of there actual "times" are a half second slower, but when you jump on the had you feel so much faster.
12/3/13, 08:45 PM
#6
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I have 3.73 in my 2014 GT TP with a 6 speed manual. I L O V E the acceleration on the street. I mean I can be in a lane that's about to end in 2nd right next a guy who's going the same speed (40mph). Then I roll onto the throttle still in 2nd, and the dude next to me is flabbergasted. Mostly because he didn't want to let me in, but the acceleration of the 5.0 with 3.73 in 2nd is UN-frikkin-REAL.
But than again, at road courses I wish I had 3.55 gears, as I run out of gear in some fast corners, and I have to shift to 5th on some straights where others can stay in 4th.
But all in all. I love my 3.73s
Relevant? No! Entertaining? I hope so!
But than again, at road courses I wish I had 3.55 gears, as I run out of gear in some fast corners, and I have to shift to 5th on some straights where others can stay in 4th.
But all in all. I love my 3.73s
Relevant? No! Entertaining? I hope so!
Last edited by 5.M0NSTER; 12/3/13 at 08:46 PM.
12/3/13, 09:25 PM
#7
GTR Member
Leave the stock 3.15's in it and get a high stall converter, will make the car LOTS faster in the 1/4, some cars drop over 1/2 second in the E.T.
No mod short of FI/NOS will make as much difference in an automatic car.
No mod short of FI/NOS will make as much difference in an automatic car.
12/4/13, 10:20 AM
#10
Cobra Member
12/4/13, 04:16 PM
#11
This isn't true. I have an AT and over 100 runs at the track this summer with 3.73's. My car traps 116mph and never shifts into 5th before the stripe. It actually shifts into 5th about 15 past the stripe which is perfect because it means I'm accelerating into the peak of the RPM range when crossing. I ran a 12.15 at 116mph in Sept. This is on a 26.4" tire. If you have a shorter tire than yes you may shift into 5th before the stripe. Sorry not targeting you, but I know a lot of people believe the blanket statement that you shift into 5th before the stripe with 3.73's and it's just not true at all. There are other factors that contribute to where your car shifts beyond just the gears such as tire size and tune.
Last edited by db2797; 12/4/13 at 04:19 PM.
12/4/13, 06:18 PM
#12
GTR Member
This isn't true. I have an AT and over 100 runs at the track this summer with 3.73's. My car traps 116mph and never shifts into 5th before the stripe. It actually shifts into 5th about 15 past the stripe which is perfect because it means I'm accelerating into the peak of the RPM range when crossing. I ran a 12.15 at 116mph in Sept. This is on a 26.4" tire. If you have a shorter tire than yes you may shift into 5th before the stripe. Sorry not targeting you, but I know a lot of people believe the blanket statement that you shift into 5th before the stripe with 3.73's and it's just not true at all. There are other factors that contribute to where your car shifts beyond just the gears such as tire size and tune.
12/4/13, 07:40 PM
#13
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This isn't true. I have an AT and over 100 runs at the track this summer with 3.73's. My car traps 116mph and never shifts into 5th before the stripe. It actually shifts into 5th about 15 past the stripe which is perfect because it means I'm accelerating into the peak of the RPM range when crossing. I ran a 12.15 at 116mph in Sept. This is on a 26.4" tire. If you have a shorter tire than yes you may shift into 5th before the stripe. Sorry not targeting you, but I know a lot of people believe the blanket statement that you shift into 5th before the stripe with 3.73's and it's just not true at all. There are other factors that contribute to where your car shifts beyond just the gears such as tire size and tune.
'Rollout' of a wheel tire combo is what needs to be looked at, as you mention. I agree making a blanket statement about gearing and trans shift points is pretty useless without knowing the tire rollout. As there could be huge differences when you take into account all useable wheel sizes and tire types (radial, drag/radial, slick...etc..)
Last edited by MKMotorsport; 12/4/13 at 07:44 PM.
12/4/13, 08:03 PM
#14
That is true. I guess my belief is that a person shouldn't start with a question of what gear they're going to be crossing the stripe based on on only looking at gear ratio. I know it's more complicated to figure out, but ideally it's better to ask the question what RPM do you want to be crossing the stripe at and then figure out which gears, tire size and where your limiter is to determine how somebody wants to set their car up.
Surprisingly the online calculators are very accurate at figuring this out. When I was first figuring out which gears I wanted, I was reading everywhere that I'd be shifting into 5th before the stripe, but all my calculations were telling me otherwise using the calculators. I rolled the die and thankfully found out the calculations were quite accurate.
Surprisingly the online calculators are very accurate at figuring this out. When I was first figuring out which gears I wanted, I was reading everywhere that I'd be shifting into 5th before the stripe, but all my calculations were telling me otherwise using the calculators. I rolled the die and thankfully found out the calculations were quite accurate.
12/4/13, 08:06 PM
#15
'Rollout' of a wheel tire combo is what needs to be looked at, as you mention. I agree making a blanket statement about gearing and trans shift points is pretty useless without knowing the tire rollout. As there could be huge differences when you take into account all useable wheel sizes and tire types (radial, drag/radial, slick...etc..)
12/10/13, 11:23 PM
#16
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No, he's right, I think there's some confusion over stock vs 3.73s; stock you run through the traps in 3rd; with 3.73s you're in 4th. Not redlining 4th, but getting somewhat close.
27.3" tire, with 1.14 4th ratio and 3.73s, you'll be at 133 mph at 7000 rpm. If you go to a 26" tire, that drops to 127mph. Try it out
http://www.4lo.com/calc/gearratio.php
With 3.15s and 27.3" tires you'll be at 118.8mph at 7000 rpm. with mild boltons and if you raise it to 7100-7200 rpm you can safely go through the traps in 3rd. Why so many go quick on stock gears and many lose time going to 3.73s - they already have the boltons for a 120ish mph, but not for a 130+, so they shift right before the traps into 4th, slowing down some.
For how fast people go with 3.15s and a converter, I'll second the converter idea before gears. And this is coming from someone who had 4.56s in the last mustang
My main dillema this xmas - 3C vs 4C
27.3" tire, with 1.14 4th ratio and 3.73s, you'll be at 133 mph at 7000 rpm. If you go to a 26" tire, that drops to 127mph. Try it out
http://www.4lo.com/calc/gearratio.php
With 3.15s and 27.3" tires you'll be at 118.8mph at 7000 rpm. with mild boltons and if you raise it to 7100-7200 rpm you can safely go through the traps in 3rd. Why so many go quick on stock gears and many lose time going to 3.73s - they already have the boltons for a 120ish mph, but not for a 130+, so they shift right before the traps into 4th, slowing down some.
For how fast people go with 3.15s and a converter, I'll second the converter idea before gears. And this is coming from someone who had 4.56s in the last mustang
My main dillema this xmas - 3C vs 4C
11/24/14, 10:49 AM
#17
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Just had mine installed, It really made a noticeable difference in the car. Really woke the car up. Everything I've read on 1/4 mile times is that they will make the car slower in the 1/4 due to shifting into 5th gear before the end. No noticeable loss in mpg. I don't regret changing gears.
11/24/14, 01:43 PM
#18
Just my .02 but with a Boss Manifold you can set the RPM limit to 7800 rpm. Helps get a little more out of each gear when going 3.73's. And I can tell you from having it on my 2014 Track Pack that it just keeps pulling right to the 7800 limit.
11/24/14, 03:15 PM
#19
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I am with guys saying you will be quicker with lower gears in rear (3.73's). If you have the right tire height to work with gears I don't see how you could be slower. I have a '14 auto that I just bought and trying to decide which gear to run. I know it will not be 3.15's. I had an '06 with 4.10 gears and many bolt ons and ran 7.80's in 1/8. Just curious to see how car runs with a tuner first.
11/24/14, 06:13 PM
#20
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And you would be wrong. Haven't we've been trying to tell you this on S197? There's a reason the fastest N/A autos are running a 3.15 or 3.31 gear. Just because they were the choice for your 3V doesn't mean they're the choice on these cars. Different transmission with different gearing. You will learn the hard way apparently.