S2k Top Speed
Registered User
Joined: Apr 2011
Posts: 391
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From: Southern Maryland
If you wish to speak of theoretical speed limits, they can be calculated using engine RPM, gear ratios and tire rotations per mile.
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Registered User
Joined: Jan 2011
Posts: 329
Likes: 0
From: Milky way galaxy
If you wish to speak of theoretical speed limits, they can be calculated using engine RPM, gear ratios and tire rotations per mile.
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Registered User
Joined: Mar 2009
Posts: 8,561
Likes: 0
From: Miami
Originally Posted by wdtd' timestamp='1332124602' post='21521244
If you wish to speak of theoretical speed limits, they can be calculated using engine RPM, gear ratios and tire rotations per mile.
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Registered User
Joined: Mar 2008
Posts: 345
Likes: 0
Why is everybody referring to speed in relation to their odometer? Your odometer tracks the mileage of the car, the speedometer tracks speed. For most vehicles, the speedometer shows that you are going about 5% faster than you actually are... supposedly this is to err on the side of caution. Imagine if the speedometer showed that you were going slower than you actually were and a lot of people got speeding tickets as a result, lawsuits would follow.
Registered User
Joined: Jul 2011
Posts: 586
Likes: 0
From: Clarksville, Tn
If you wish to speak of theoretical speed limits, they can be calculated using engine RPM, gear ratios and tire rotations per mile.
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
Here’s the math: Take the RPM in question and multiply by 60. That will give you revolutions per hour.
In the AP1, we’ll start with 9200 x 60 = 552000. Dividing by a primary gear ratio of 1.16 = 475862; further dividing by the final gear ratio of 4.1 = 116064. The sixth gear ratio of the AP1 is 0.81, resulting in the rear axle making 143289 rotations per hour with the engine at 9200 rpm. Now look up your tire specs to find out the number of revolutions per mile. According to tirerack.com, new OEM tires, rear, will have 840 revolutions per mile. 143289 divided by 840 revolutions per mile equals 170.6 miles per hour.
In the AP2, 8200 x 60 = 492000. 492000 divided by 1.208 = 407285. 407285 divided by 4.1 = 99338. 99338 divided by 0.763 (sixth gear ratio) = 130194. 130194 divided by 847 (revolutions per mile, new OEM spec tires, according to tirerack.com) = 153.7 miles per hour.
Different tires? Worn, or under-inflated, or over-inflated tires? Different maximum RPM? Different rear differential ratio? Different transmission ratios? Then your theoretical top speed is different.
Realistic top speeds? So many variables!
owwww...my head hurts
