 Speed vs RPM, How fast should I be going ? |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
| jim_hoyland |
 Apr 26 2014, 05:59 PM
Post
#1
|
|
Get that VIN ?  Group: Members Posts: 9,467 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California 
 |
What's the speed of a typical 914 in 5th gear at 3,000 rpm ? My speedo have been under reporting for a while.
|
   |
 
|
  |
Replies
| toadman |
Apr 27 2014, 08:11 AM
Post
#2
|
|
Member Group: Members Posts: 168 Joined: 26-December 05 From: Cincinnati, OH Member No.: 5,316 |
If the tires and transmission on your car are completely stock, and you have the owners manual, you can look in the manual for this information. I have a 1976 car and the owners manual, too. In my manual there is a transmission diagram that shows engine rpms and ground speed information for each of the five forward gears. The diagram specifies a pinion to ring ratio of 7:31 and a tire size of 165R 15. The ratios for each gear are also listed. According to this diagram, for my car, 3000 rpm in fifth gear equals a ground speed of 70 mph.
Changes to tire size or transmission modifications affect the accuracy of the diagram. If this is the case for you, I think using a GPS to measure ground speed is a good method. |
 |
|
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 jim_hoyland Just checked my manual. Says 3,000 rpm in 5th = 70... Apr 27 2014, 11:11 AM r_towle 165r15 are 25.4" in, diameter
205 60 r 16 are... Apr 27 2014, 11:47 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 |
3 User(s) are reading this topic (3 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 31st October 2024 - 08:25 PM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.