4.10 gears = lower top speed? - The Mustang Source - Ford Mustang Forums

Go Back   >

2005-2009 Mustang S197 Discussion & News

4.10 gears = lower top speed?

Reply
 
 
 
Thread Tools Search this Thread
Old 2/25/12, 11:27 PM   #1
Mach 1 Member
Thread Starter
 
mrp5150's Avatar
 
Join Date: July 5, 2011
Location: La Jolla, CA
Posts: 967
Thanks: 0
Thanked 0 Times in 0 Posts
4.10 gears = lower top speed?

Hey guys, I'm sure this is probably a stupid question, but if I had a stock 05-09 GT and wanted to put in 4.10 gears, how much would that lower the top speed...if at all? I'm not really worried since I'm not going to be racing it or driving 140 mph on the highways, just curious. And how much would that increase the 0-60 time by? Also, would I need any other mods if I wanted to do that? I read somewhere that if you change the gears like that, the speedometer doesn't give the correct reading? Thanks in advance!
mrp5150 is offline   Reply With Quote
Join The Mustang Source

Join TheMustangSource.com Today - It's Totally Free!

Are you a Ford Mustang fan? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's a great place for Ford Mustang Fans to meet online.
Once you join you'll be able to post messages, upload pictures of your stang, and have a great time with other Ford Mustang fans. Whether your an old timer or just bought your Mustang you'll find that TheMustangSource.com is a great community to join. Best of all it's totally free!

Join TheMustangSource.com Today! - Click Here JOIN FOR FREE


Old 2/26/12, 06:21 AM   #2
Post *****
 
Glenn's Avatar
 
Join Date: August 7, 2006
Location: Lockport il
Posts: 13,764
Thanked 30 Times in 29 Posts
I don't know how much top end you would lose but you would lose some. You will need a tuner to correct the speedo after a change of gears
Glenn is offline   Reply With Quote
Old 2/26/12, 09:25 AM   #3
Mach 1 Member
 
Kevin509's Avatar
 
Join Date: October 30, 2011
Location: Spokane, WA
Posts: 846
Thanks: 0
Thanked 0 Times in 0 Posts
You'd have to do some math with the gear ratios and tire size and what not, but potentially you could lose some top speed. However, you'd get to that top speed quicker. aggressive gears like that are going to affect your cruising rpms. If you do a lot of freeway daily driving that's something to keep in mind because your fuel economy is going to be affected.

Edit: I did the math, assuming your car is a 5 speed manual, with 4.10 gears 5th revs out at over 180 mph. So, you won't loose any top speed. Your car will loose it's battle with the air resistance long before it reached that point.

Last edited by Kevin509; 2/26/12 at 09:32 AM.
Kevin509 is offline   Reply With Quote
Old 2/26/12, 11:57 AM   #4
Mach 1 Member
Thread Starter
 
mrp5150's Avatar
 
Join Date: July 5, 2011
Location: La Jolla, CA
Posts: 967
Thanks: 0
Thanked 0 Times in 0 Posts
I do pretty even amounts of city and highway driving. I was looking at the FRPP 4.10 gears on American Muscle and most of the reviews said the gas mileage didn't change much at all, and some even said it improved by a couple MPG?

And just to give me a rough idea, how much would it cost for the gears to be installed and the speedometer to be tuned by a shop?
mrp5150 is offline   Reply With Quote
Old 2/26/12, 12:21 PM   #5
Mach 1 Member
 
Kevin509's Avatar
 
Join Date: October 30, 2011
Location: Spokane, WA
Posts: 846
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by mrp5150 View Post
I do pretty even amounts of city and highway driving. I was looking at the FRPP 4.10 gears on American Muscle and most of the reviews said the gas mileage didn't change much at all, and some even said it improved by a couple MPG?

And just to give me a rough idea, how much would it cost for the gears to be installed and the speedometer to be tuned by a shop?
Well, based on my math, stock, at 65 MPH the engine turns approx. 1900 RPM in 5th gear. With 4.10s, the engine turns approx 2200 RPM in 5th at 65. Not a huge difference, I admit, and we didn't buy mustang GT's for the gas mileage anyway
Kevin509 is offline   Reply With Quote
Old 2/27/12, 12:32 PM   #6
V6 Member
 
Franchi's Avatar
 
Join Date: June 16, 2010
Location: Columbus OH
Posts: 97
Thanks: 0
Thanked 0 Times in 0 Posts
It won't improve your mpg's at all that's for sure. It will knock it down, but not by a ton IF you keep your foot out of it. I saw only about average of 1 mpg less when I did 4:10's when I measured the gas MPG. But considering I normally get about 11 mpg now, I didn't care much. lol

The car will wind up MUCH quicker then before, esp first three gears.
Franchi is offline   Reply With Quote
Old 2/28/12, 06:40 AM   #7
Bullitt Member
 
Wades GT's Avatar
 
Join Date: April 25, 2010
Posts: 237
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Franchi View Post
It won't improve your mpg's at all that's for sure. It will knock it down, but not by a ton IF you keep your foot out of it. I saw only about average of 1 mpg less when I did 4:10's when I measured the gas MPG. But considering I normally get about 11 mpg now, I didn't care much. lol

The car will wind up MUCH quicker then before, esp first three gears.
I thought I was bad with my 13-15mpg
Wades GT is offline   Reply With Quote
Old 2/28/12, 10:18 PM   #8
Mach 1 Member
Thread Starter
 
mrp5150's Avatar
 
Join Date: July 5, 2011
Location: La Jolla, CA
Posts: 967
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Franchi View Post
It won't improve your mpg's at all that's for sure. It will knock it down, but not by a ton IF you keep your foot out of it. I saw only about average of 1 mpg less when I did 4:10's when I measured the gas MPG. But considering I normally get about 11 mpg now, I didn't care much. lol

The car will wind up MUCH quicker then before, esp first three gears.
11 mpg? That's insane, haha. So I'm guessing if the car is just totally stock other than the 4.10 gears, it would average around 18-20 mpg?
mrp5150 is offline   Reply With Quote
Old 2/29/12, 12:13 PM   #9
Cobra Member
 
Shotokan1509's Avatar
 
Join Date: June 22, 2006
Location: CT
Posts: 1,030
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by mrp5150 View Post
11 mpg? That's insane, haha. So I'm guessing if the car is just totally stock other than the 4.10 gears, it would average around 18-20 mpg?

That's about what I get, mixed driving, manual trans, 4.10's, heavy 20" wheels & bigger Brembo brakes, CAI, offroad Xpipe and a 93 tune (300rwhp/311rwtq).

The rpm with the exhaust, does get a little annoying at higher cruising speeds on highway for longer than say an hour.
Shotokan1509 is offline   Reply With Quote
Old 3/1/12, 09:17 PM   #10
Member
 
Heavy Metal Thunder's Avatar
 
Join Date: February 8, 2011
Posts: 27
Thanks: 0
Thanked 0 Times in 0 Posts
It will NOT affect your top speed. Our cars come with a speed limiter of 145 mph. So unless you disable the speed limiter with a tune that turns it off your top speed is 145 no matter what gear ratio. Now if you turn off the speed limiter in your tune, your top speed will be whatever speed you are going when you redline in 5th gear. HOWEVER, our cars don't make enough power to redline in 5th gear so it's a moot point. You'll never hit top speed anyways, even on a 1/4 mile dragstrip your nowhere near hitting top speed.
Heavy Metal Thunder is offline   Reply With Quote
Old 3/1/12, 10:19 PM   #11
Mach 1 Member
Thread Starter
 
mrp5150's Avatar
 
Join Date: July 5, 2011
Location: La Jolla, CA
Posts: 967
Thanks: 0
Thanked 0 Times in 0 Posts
Gotcha. Thanks guys!
mrp5150 is offline   Reply With Quote
Old 3/3/12, 10:35 AM   #12
Cobra Member
 
Bert's Avatar
 
Join Date: January 25, 2010
Location: Massachusetts
Posts: 1,053
Thanked 12 Times in 12 Posts
Quote:
Originally Posted by Heavy Metal Thunder View Post
It will NOT affect your top speed. . . . if you turn off the speed limiter in your tune, your top speed will be whatever speed you are going when you redline in 5th gear. HOWEVER, our cars don't make enough power to redline in 5th gear so it's a moot point. .
Exactly!

Think of it this way -- the only way that changing the rear end ratio would affect your top speed is if you are hitting redline in 5th right now. Are you doing that?

(hint: probably not . . . 6000 RPM in 5th with the 3.31 rear would be over 200 MPH)

Assuming you have the standard 18" wheels/tires which are about 27.25" overall diameter, 6000 RPM in fifth with 4.10 rear ratio is 175 MPH

On the highway, the 4.10 rear WILL reduce gas mileage for sure. RPM is directly proportional to rear end ratio (at the same speed) and fuel consumption is roughly proportional to RPM . . . so when you go from 3.31 to 4.10 rear you are increasing RPM by 4.10/3.31 = 24.9% (in the same gear at the same speed) so you are also going to increase fuel consumption by about 25%. (a little less in the real world due to other things like wind resistance) Around town the affect is smaller because you are going up and down through the gears so you are not just cruising along at 25% higher RPM.

Last edited by Bert; 3/3/12 at 10:40 AM. Reason: more
Bert is offline   Reply With Quote
Old 3/21/12, 09:04 PM   #13
Mach 1 Member
 
nonsensez9's Avatar
 
Join Date: July 8, 2005
Location: Northern BC, Canada
Posts: 525
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Franchi View Post
The car will wind up MUCH quicker then before, esp first three gears.
I did the 4.10's some time ago. First gear is pretty useless around town. I think the '05 was a 3.73 stock, so gas mileage down a tad, nothing serious.
nonsensez9 is offline   Reply With Quote
Old 3/21/12, 09:09 PM   #14
Swamp Donkey Man Cans
 
07S197's Avatar
 
Join Date: August 20, 2007
Location: Massachusetts
Posts: 4,056
Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by nonsensez9 View Post
I did the 4.10's some time ago. First gear is pretty useless around town. I think the '05 was a 3.73 stock, so gas mileage down a tad, nothing serious.
05-09 GT 5MT
05 & 06 stock rear gears were 3.55's
07 and up standard was 3.31's with an option for 3.55's
07S197 is offline   Reply With Quote
Old 3/21/12, 09:23 PM   #15
Bullitt Member
 
Wades GT's Avatar
 
Join Date: April 25, 2010
Posts: 237
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by nonsensez9 View Post
I did the 4.10's some time ago. First gear is pretty useless around town. I think the '05 was a 3.73 stock, so gas mileage down a tad, nothing serious.
No....... Thats the annoy all your neighbors gear
Wades GT is offline   Reply With Quote
Old 3/21/12, 09:25 PM   #16
Swamp Donkey Man Cans
 
07S197's Avatar
 
Join Date: August 20, 2007
Location: Massachusetts
Posts: 4,056
Thanks: 0
Thanked 2 Times in 2 Posts
I love the 4.10's in my car. I still average around 19 mpg on the highway and the response from the car is great.
07S197 is offline   Reply With Quote
Old 3/21/12, 09:39 PM   #17
Mach 1 Member
 
nonsensez9's Avatar
 
Join Date: July 8, 2005
Location: Northern BC, Canada
Posts: 525
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by nonsensez9 View Post
I did the 4.10's some time ago. First gear is pretty useless around town. I think the '05 was a 3.73 stock, so gas mileage down a tad, nothing serious.
but back to the original question.... I don't think top end was reduced. It might even have increased a bit. Hard to tell as the speedo isn't all that accurate over 100 anyways, and with a re-calibration, who knows.... However, I would suspect that the best top end would be with a gear that allows you to just barely reach red-line in 5th gear. Maybe a 4.3, or even lower. As an example, many corvettes reach top speed in 5th gear rather than 6th.
nonsensez9 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
FS: Boss 302 Gotta have it Green Shift Knob JJJTMC Parts For Sale 1 9/17/15 10:33 AM
FS: 2011 GT Coupe, Rochester MI. speedform Vehicles For Sale 5 9/11/15 06:31 PM
Hurst shifter for 68 mustang dbrinkley2008 1st and 2nd Generations 1 9/9/15 07:02 AM
Whiteline Lower Control Arms, 05-14 Mustang silverstate777 Parts For Sale 3 9/7/15 04:07 PM
First Mustang earl610 GT 1 9/6/15 05:48 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 07:40 AM.


2010, The Mustang Source