 Speed vs RPM, How fast should I be going ? |
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| jim_hoyland |
 Apr 26 2014, 05:59 PM
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#1
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Get that VIN ?  Group: Members Posts: 9,467 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California 
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What's the speed of a typical 914 in 5th gear at 3,000 rpm ? My speedo have been under reporting for a while.
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| r_towle |
Apr 27 2014, 11:47 AM
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#2
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Custom Member Group: Members Posts: 24,638 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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165r15 are 25.4" in, diameter
205 60 r 16 are 25.685" in diameter. It matters exactly what tire you are running. 205 50/16 are shorter and have a smaller diameter than 205/60 Once you know the diameter, use a calculator to determine how far off from stock your speedo is. So, 25.4/25.685= 0.988 About 0.9% off. If you have found a tire you like, north Hollywood speedo, or Palo Alto speedo can redo your speedometer to be correct based upon your tire diameter. 165r15 rotates 207.8 times per miles 205 60 16 rotates 205.5 times per mile You are very close to correct, so if your speedo is reading wrong, it's just wrong and may need to be repaired. I bet they were all off.... |
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Posts in this topic
jim_hoyland Speed vs RPM Apr 26 2014, 05:59 PM
914itis I would say 60-65 mph
My speedo is also 10 mph adv... Apr 26 2014, 06:08 PM Tom Jim,
That would depend on your wheel/ tire co... Apr 26 2014, 06:15 PM jim_hoyland I'm running 16" wheels. My iPad speedo ap... Apr 26 2014, 06:34 PM
struckn
I'm running 16" wheels. My iPad speedo a... Apr 26 2014, 07:01 PM jim_hoyland
I'm running 16" wheels. My iPad speedo ... Apr 26 2014, 07:06 PM mepstein
[quote name='struckn' post='2029815' date='Apr 26... Apr 26 2014, 07:27 PM Hine62 My speedometer is also off because of tire size. I... Apr 27 2014, 05:53 AM toadman If the tires and transmission on your car are comp... Apr 27 2014, 08:11 AM jim_hoyland Just checked my manual. Says 3,000 rpm in 5th = 70... Apr 27 2014, 11:11 AM jim_hoyland Does the car go faster with smaller tires, given t... Apr 27 2014, 04:01 PM r_towle
Does the car go faster with smaller tires, given ... Apr 27 2014, 04:11 PM Big Len No, you would be going slower.
Try this - http://... Apr 27 2014, 04:07 PM pvollma
What's the speed of a typical 914 in 5th gear... Apr 28 2014, 07:34 AM jim_hoyland
[quote name='jim_hoyland' post='2029780' date='Ap... Apr 28 2014, 06:19 PM Elliot Cannon It doesn't matter what size tire you use or wh... Apr 28 2014, 10:56 AM ndfrigi Drove my 75 1.8 F.I. last weekend with 185x65x15 t... Apr 28 2014, 11:05 PM dlkawashima
Drove my 75 1.8 F.I. last weekend with 185x65x15 ... Apr 28 2014, 11:53 PM ndfrigi
Drove my 75 1.8 F.I. last weekend with 185x65x15... Apr 28 2014, 11:56 PM |
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