speed vs rpm

slowpoke

Registered User
just got the new gear in for my m5r2 with 3.08's. it shows in 4rth gear 1200rpm 30mph, 1400rpm 35mph, 1800rpm 45mph. in 5th gear 1750rpm 55mph. does this look about right?
 
Just remember that your tach may not be accurate, they are usually off a couple hundred rpms.

What size is your rear tires?
 
Did you change the speedo gear on your car? If you are using the stock one it will be off I forget what color mine is.
 
mph RPMS RPMS RPMS RPMS RPMS
1st 2nd 3rd 4th 5th

5 646 400 246 172 129
10 1292 799 493 345 258
15 1938 1199 739 517 388
20 2584 1599 986 689 517
25 3231 1999 1232 861 646
30 3877 2398 1478 1034 775
35 4523 2798 1725 1206 905
40 5169 3198 1971 1378 1034
45 5815 3598 2217 1551 1163
50 6461 3997 2464 1723 1292
55 7107 4397 2710 1895 1421
60 7753 4797 2957 2068 1551
65 8399 5196 3203 2240 1680
70 5596 3449 2412 1809
75 5996 3696 2584 1938
80 6396 3942 2757 2068
85 6795 4189 2929 2197
90 7195 4435 3101 2326
95 7595 4681 3274 2455
100 7995 4928 3446 2584
 
mph RPMS RPMS RPMS RPMS RPMS
1st 2nd 3rd 4th 5th

5 646 400 246 172 129
10 1292 799 493 345 258
15 1938 1199 739 517 388
20 2584 1599 986 689 517
25 3231 1999 1232 861 646
30 3877 2398 1478 1034 775
35 4523 2798 1725 1206 905
40 5169 3198 1971 1378 1034
45 5815 3598 2217 1551 1163
50 6461 3997 2464 1723 1292
55 7107 4397 2710 1895 1421
60 7753 4797 2957 2068 1551
65 8399 5196 3203 2240 1680
70 5596 3449 2412 1809
75 5996 3696 2584 1938
80 6396 3942 2757 2068
85 6795 4189 2929 2197
90 7195 4435 3101 2326
95 7595 4681 3274 2455
100 7995 4928 3446 2584

thats gotta be with a 2.73 rear gear right ?
 
It sounds about right with Your rpms and mph. Assuming Your tire is 26 inches. I am not sure how SC's speedos work assuming by transmission. So 3.08s will make Your speedo think You are going fast then You really are. Its probably off by 5%. so if You speedo says 60mph - 5% Your actually doing 57.
 
got out on the interstate and with my trusty CB i had several truckers help me find my speed. the speedo is within 2-4 mph higher then my actual speed. considering it was 17-20 before i can live with this :) tyvm every1 for the help with this.
 
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