General Rotary Tech Support Use this forum for tech questions not specific to a certain model year

rpm confusion

Thread Tools
 
Search this Thread
 
Old 03-01-07, 01:46 PM
  #1  
Rotisserie Engine

Thread Starter
iTrader: (8)
 
driftxsequence's Avatar
 
Join Date: Jan 2007
Location: Wilmington, DE
Posts: 1,833
Received 48 Likes on 38 Posts
rpm confusion

ima lil confused about the rpms and all
i remember someone saying before that if your reving at 9k RPMS, that your rotors are only doing like 3k RPMS correct?

so does that mean if your idling at 900 RPMS, that your rotors are really only rotating at 300 RPMS?

i dont yet have an rx7 yet since im too young but i plan on getting one in the near future, probly start out with a 2nd gen for reliability reasons etc, but i was in my neighborhood and i was walking with friends and i heard a 3rd gen with an apexi n1 exhaust go down the road and i pointed it out and my friends thought i was a freak..hahaa
Old 03-01-07, 02:34 PM
  #2  
This is your exit

iTrader: (5)
 
NCMontegott's Avatar
 
Join Date: Apr 2005
Location: north carolina
Posts: 287
Received 0 Likes on 0 Posts
if the tach says its doing 9k rpms then you would think the engine is revolving 9k times per min
just the same for piston engines. they have 4 strokes does that mean they are only doing 1/4 of the actual rpm posted on the tach.
Old 03-01-07, 02:47 PM
  #3  
Goodfalla Engine Complete

iTrader: (28)
 
Monkman33's Avatar
 
Join Date: May 2005
Location: Kennewick, Washington
Posts: 3,233
Received 32 Likes on 25 Posts
Originally Posted by NCMontegott
if the tach says its doing 9k rpms then you would think the engine is revolving 9k times per min
just the same for piston engines. they have 4 strokes does that mean they are only doing 1/4 of the actual rpm posted on the tach.

RPM is in respect to the eccentric shaft (or crankshaft) in a rotary, 9k rpm of the eccentric shaft is 3k rpm of the rotors. in a piston engine 9k rpm is 9k ups and downs per minute for each piston and 9k rpm for the crankshaft.

Last edited by Monkman33; 03-01-07 at 02:53 PM.
Old 03-01-07, 02:56 PM
  #4  
Racecar - Formula 2000

 
DaveW's Avatar
 
Join Date: Sep 2002
Location: Bath, OH
Posts: 3,850
Received 277 Likes on 198 Posts
Remember that each of the three faces of the rotor has a combustion event each time around, so the power and exhaust pulses (for 2 rotors) are at the same frequency as those of a 12-cylinder piston engine (they have power pulses every other revolution) at the same RPM.

Dave
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
LongDuck
1st Generation Specific (1979-1985)
12
10-07-15 08:12 PM
eplusz
General Rotary Tech Support
15
10-07-15 04:04 PM
Captain Hook
2nd Generation Specific (1986-1992)
13
10-04-15 06:35 PM
FC3S Timmy
2nd Generation Specific (1986-1992)
8
10-02-15 08:08 AM
musker
New Member RX-7 Technical
1
10-01-15 05:58 PM



Quick Reply: rpm confusion



All times are GMT -5. The time now is 08:53 PM.