Do gears cut your top speeds down?
01-12-2006, 01:18 PM
#11
5th Gear Member
Join Date: Jul 2004
Location: Pittsburgh/Dayton
Posts: 3,062
RE: Do gears cut your top speeds down?
ORIGINAL: Sidewayz6.0
Wow! You guys are WAY off! Actually as far fetched as it seems, a 4.10 will INCREASE your top speed in a basicly stock Mustang. The reason being that the Mustang doesn't have enough horsepower to overcome the drag with the stock gearing. The 4.10 gear makes it easier for the engine to turn the wheels at higher speeds. So you will see an increase in overall top end.
Now this isn't true if you're making alot more power. Bolt ons probably aren't going to make a difference, but adding nitrous, or some other sort of forced induction will slow the top end down a little. But more than likely not enough for you to notice. 140 still won't be a problem. And honestly, how fast do you really want to go on the street?
Wow! You guys are WAY off! Actually as far fetched as it seems, a 4.10 will INCREASE your top speed in a basicly stock Mustang. The reason being that the Mustang doesn't have enough horsepower to overcome the drag with the stock gearing. The 4.10 gear makes it easier for the engine to turn the wheels at higher speeds. So you will see an increase in overall top end.
Now this isn't true if you're making alot more power. Bolt ons probably aren't going to make a difference, but adding nitrous, or some other sort of forced induction will slow the top end down a little. But more than likely not enough for you to notice. 140 still won't be a problem. And honestly, how fast do you really want to go on the street?
01-12-2006, 02:56 PM
#12
Super Moderator
Join Date: Jul 2003
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Posts: 14,917
RE: Do gears cut your top speeds down?
ORIGINAL: Sidewayz6.0
Wow! You guys are WAY off! Actually as far fetched as it seems, a 4.10 will INCREASE your top speed in a basicly stock Mustang. The reason being that the Mustang doesn't have enough horsepower to overcome the drag with the stock gearing. The 4.10 gear makes it easier for the engine to turn the wheels at higher speeds. So you will see an increase in overall top end.
Now this isn't true if you're making alot more power. Bolt ons probably aren't going to make a difference, but adding nitrous, or some other sort of forced induction will slow the top end down a little. But more than likely not enough for you to notice. 140 still won't be a problem. And honestly, how fast do you really want to go on the street?
Wow! You guys are WAY off! Actually as far fetched as it seems, a 4.10 will INCREASE your top speed in a basicly stock Mustang. The reason being that the Mustang doesn't have enough horsepower to overcome the drag with the stock gearing. The 4.10 gear makes it easier for the engine to turn the wheels at higher speeds. So you will see an increase in overall top end.
Now this isn't true if you're making alot more power. Bolt ons probably aren't going to make a difference, but adding nitrous, or some other sort of forced induction will slow the top end down a little. But more than likely not enough for you to notice. 140 still won't be a problem. And honestly, how fast do you really want to go on the street?
01-12-2006, 03:28 PM
#13
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Join Date: Jul 2004
Location:
Posts: 823
RE: Do gears cut your top speeds down?
Right, never factor 5th gear into the equation or 4th if you are driving an auto. All overdrive gears are not meant for WOT (wide open throttle), they are cruising, economy gears. If you even so much as reach 5th or 4th (auto) in the quarter mile, you are using way too high a ratio gear...unless you are pushing 600+ HP. As far as the basic question is concerned, I would think it all amounts to where your current set-up's new rpm redline is located. Higher ratio gears (lower rearends) will simply increase you rpm's faster which inturn provides you with quicker access to your power curve. If you redline at 6,000 rpm's, you naturally will reach that level in all gears much quicker with higher ratio gears (that is rpm, not mph). You simply rev much quicker. Sidewayz is just that, a little off should we say. If you were racing 4.56 on a road course, halfway down the straight you would be maxed out on your rpm's with nowhere else to go except your engine coming apart at 7,000 r's plus. If you had, let's say 3.55's, you could maintain a high constant speed in all gears to help increase your overall lap speeds.
Basically, the answer is yes, lower top end, as the higher the ratio gear, the faster you reach your redline in each gear and the higher the rpm's you turn at any given speed. A GT with stock gears, let's say 150 mph, with 4.10's (at the "same" rpm), maybe 135 to 140. If you have modified your engine to allow you to reach 6,500 to 7,000 rpm's in each gear (or increased HP beyond 400+), then perhaps your top end will remain much the same. Otherwise, look out, your engine may just come apart trying to reach the same mph in any given gear as you did with lower ratio gears. On the flip side, if you take a '99+ Mustang with standard 3.27 gears and put 2.73's in it, you may reach 160+. That same car would probably hit 60+ mph in first gear!
I probably made it sound more confusing than it really is, but I think you get the drift.....higher ratio gears, lower top end at the "same" rpm.
Basically, the answer is yes, lower top end, as the higher the ratio gear, the faster you reach your redline in each gear and the higher the rpm's you turn at any given speed. A GT with stock gears, let's say 150 mph, with 4.10's (at the "same" rpm), maybe 135 to 140. If you have modified your engine to allow you to reach 6,500 to 7,000 rpm's in each gear (or increased HP beyond 400+), then perhaps your top end will remain much the same. Otherwise, look out, your engine may just come apart trying to reach the same mph in any given gear as you did with lower ratio gears. On the flip side, if you take a '99+ Mustang with standard 3.27 gears and put 2.73's in it, you may reach 160+. That same car would probably hit 60+ mph in first gear!
I probably made it sound more confusing than it really is, but I think you get the drift.....higher ratio gears, lower top end at the "same" rpm.
01-12-2006, 06:36 PM
#14
5th Gear Member
Join Date: May 2005
Location: NY
Posts: 2,518
RE: Do gears cut your top speeds down?
Thats exactly what im trying to say, you cant race in your 5th gear, its overdrive and too much stress. If you get 4.10's your race will end at 115 on the street.
It doesnt have enough HP to get to 160 in 5th gear, thats the problem...
if you take a '99+ Mustang with standard 3.27 gears and put 2.73's in it, you may reach 160+.
01-12-2006, 07:42 PM
#15
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Join Date: Oct 2005
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Posts: 850
RE: Do gears cut your top speeds down?
they do cut your top speed down... but if you dont have the amount of hp to get there then there is no need. i think that you could go faster on a stock gt with 3.73s then a stock GT with 3.27s, because the lower gears are kinda like haveing more power.
01-12-2006, 07:46 PM
#16
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Join Date: Jan 2004
Location: IL
Posts: 10,637
RE: Do gears cut your top speeds down?
ORIGINAL: Dark_Horse
they do cut your top speed down... but if you dont have the amount of hp to get there then there is no need. i think that you could go faster on a stock gt with 3.73s then a stock GT with 3.27s, because the lower gears are kinda like haveing more power.
they do cut your top speed down... but if you dont have the amount of hp to get there then there is no need. i think that you could go faster on a stock gt with 3.73s then a stock GT with 3.27s, because the lower gears are kinda like haveing more power.
01-12-2006, 08:57 PM
#17
Pro. B.S. caller outer
Join Date: May 2004
Location: IL
Posts: 9,644
RE: Do gears cut your top speeds down?
ORIGINAL: Deannostang
Basically, the answer is yes, lower top end, as the higher the ratio gear, the faster you reach your redline in each gear and the higher the rpm's you turn at any given speed. A GT with stock gears, let's say 150 mph, with 4.10's (at the "same" rpm), maybe 135 to 140. If you have modified your engine to allow you to reach 6,500 to 7,000 rpm's in each gear (or increased HP beyond 400+), then perhaps your top end will remain much the same. Otherwise, look out, your engine may just come apart trying to reach the same mph in any given gear as you did with lower ratio gears. On the flip side, if you take a '99+ Mustang with standard 3.27 gears and put 2.73's in it, you may reach 160+. That same car would probably hit 60+ mph in first gear!
Basically, the answer is yes, lower top end, as the higher the ratio gear, the faster you reach your redline in each gear and the higher the rpm's you turn at any given speed. A GT with stock gears, let's say 150 mph, with 4.10's (at the "same" rpm), maybe 135 to 140. If you have modified your engine to allow you to reach 6,500 to 7,000 rpm's in each gear (or increased HP beyond 400+), then perhaps your top end will remain much the same. Otherwise, look out, your engine may just come apart trying to reach the same mph in any given gear as you did with lower ratio gears. On the flip side, if you take a '99+ Mustang with standard 3.27 gears and put 2.73's in it, you may reach 160+. That same car would probably hit 60+ mph in first gear!
01-13-2006, 03:09 PM
#18
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Join Date: Jul 2004
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Posts: 823
RE: Do gears cut your top speeds down?
This will answer any questions about top speed and gears. It is a link to a calculator that will figure out your possible top speed in any gear with any tranny and whatever tire size you are running. You can also put in various ratios to try and figure out what you already have in your car so long as you know what rpm you are at in what gear and tranny combo.
To cut to the chase, here are some statistics from the site mentioned above based on an AOD tranny like those found in '98+ Mustangs. Of course your rated HP will also play a factor but this gives you a quick comparison.
3rd gear AOD at 5,700 rpm's with 245/45-17 stock GT tire size:
3.08 = 141 mph 3.73 = 117 mph 4.10 = 106
Top end in 4th OD at 5,000 rpm's (est):
3.08 = 177 (ya, sure) 3.73 = 146 4.10 = 133
So, you can see gears are definitely a factor in top end speeds. Here is the site link to do your own calculating:
http://www.tchracing.com/tech/gearcalc.php
To cut to the chase, here are some statistics from the site mentioned above based on an AOD tranny like those found in '98+ Mustangs. Of course your rated HP will also play a factor but this gives you a quick comparison.
3rd gear AOD at 5,700 rpm's with 245/45-17 stock GT tire size:
3.08 = 141 mph 3.73 = 117 mph 4.10 = 106
Top end in 4th OD at 5,000 rpm's (est):
3.08 = 177 (ya, sure) 3.73 = 146 4.10 = 133
So, you can see gears are definitely a factor in top end speeds. Here is the site link to do your own calculating:
http://www.tchracing.com/tech/gearcalc.php
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