Go Back  RX7Club.com - Mazda RX7 Forum > Tech and Performance > Engine Management Forum
Reload this Page >

how are we supposed to tune timing on a rotary?

Engine Management Forum Use this area for discussing Haltech, Wolf 3D, Power FC, AEM and any other aftermarket ECU upgrades. Help/Questions/Tuning

how are we supposed to tune timing on a rotary?

Old 08-16-15, 11:03 PM
  #1  
Rotary Enthusiast
Thread Starter
iTrader: (1)
 
Join Date: Dec 2006
Location: east
Posts: 927
Received 5 Likes on 4 Posts
how are we supposed to tune timing on a rotary?

I have a single turbo 20b. Got a great base map from Howard Coleman, and the car runs great. I backed off timing ~5 degrees in all rpm, and even more in boost from the provided base map to be on the safe side.

I know my timing is too retarded. I'm waiting on a pulley to get here so I can set TDC. Once that's done, how do I safely advance the timing? what parameter do the rotary tuners use to advance timing? is it strictly experience? MBT? EGT? when "x" extra ft-lb is made with a degree advance on a dyno? Thank you for any advice in advance.
stickmantijuana is offline  
Old 08-26-15, 05:18 AM
  #2  
Full Member
 
Join Date: Jul 2006
Location: New Jersey
Posts: 153
Received 0 Likes on 0 Posts
Would love to see experience tuners chime in, this is a great question.
h_turbo is offline  
Old 08-27-15, 08:41 AM
  #3  
www.lms-efi.com
iTrader: (27)
 
C. Ludwig's Avatar
 
Join Date: Mar 2001
Location: Floyds Knobs. IN
Posts: 5,112
Received 30 Likes on 23 Posts
I haven't watched it, but their stuff is pretty on point.

https://www.hpacademy.com/previous-webinars/043-rotary-ignition-tuning-link-g4-vipec/
C. Ludwig is offline  
Old 09-15-15, 08:26 PM
  #4  
back with rotaries
iTrader: (7)
 
eddierotary's Avatar
 
Join Date: Nov 2001
Location: Watertown, NY
Posts: 2,224
Likes: 0
Received 0 Likes on 0 Posts
pretty good question to ask, i my self would like to learn how to tune timing on my 13b. i have my microtech setup good right now but i wish i have better understanding about to tune timing. C. ludwig. is a great video but you have to pay to watch it. and yes you have to pay to learn but most people just need some advice to what to look for.
eddierotary is offline  
Old 09-16-15, 09:17 AM
  #5  
www.lms-efi.com
iTrader: (27)
 
C. Ludwig's Avatar
 
Join Date: Mar 2001
Location: Floyds Knobs. IN
Posts: 5,112
Received 30 Likes on 23 Posts
Membership to the site is $20/month. You could watch every video they have and learn quite a lot for $20.
C. Ludwig is offline  
The following users liked this post:
Talkwrench (07-18-17)
Old 09-16-15, 10:22 AM
  #6  
Armchair engineer
iTrader: (2)
 
j9fd3s's Avatar
 
Join Date: Mar 2001
Location: http://www.k2rd.com
Posts: 24,643
Likes: 0
Received 130 Likes on 116 Posts
https://www.rx7club.com/engine-manag...etter-1089664/

another data point. i don't really have a conclusion, but the observation is to look at both FC timing maps and look how different they are. there is a bigger difference in timing than the power difference would suggest
j9fd3s is offline  
Old 09-16-15, 10:35 AM
  #7  
rotorhead
iTrader: (3)
 
arghx's Avatar
 
Join Date: Aug 2004
Location: cold
Posts: 15,640
Received 56 Likes on 54 Posts
^ combustion chamber shape changed between s4 and s5, so I wonder if some of the timing map changes are the result of faster burn on an s5. Maybe an s5 and later rotor/housing combo doesn't need as much spark because the engine burns faster.
arghx is offline  
Old 09-16-15, 10:48 AM
  #8  
Armchair engineer
iTrader: (2)
 
j9fd3s's Avatar
 
Join Date: Mar 2001
Location: http://www.k2rd.com
Posts: 24,643
Likes: 0
Received 130 Likes on 116 Posts
Originally Posted by arghx View Post
^ combustion chamber shape changed between s4 and s5, so I wonder if some of the timing map changes are the result of faster burn on an s5. Maybe an s5 and later rotor/housing combo doesn't need as much spark because the engine burns faster.
true. the intakes changed too, along with the exhaust manifold, and turbo. also in 89 they started having to warranty the cat for much longer (7 years instead of 3). the S4 and S5 NA cars run very different AFR's after 4000rpm, it wouldn't surprise me if the turbo was the same. weirdly i've never had a wideband on a stock ecu turbo car
j9fd3s is offline  
Old 10-26-15, 02:13 PM
  #9  
Junior Member
 
Join Date: Jan 2014
Location: Sedgefield
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by j9fd3s View Post
true. the intakes changed too, along with the exhaust manifold, and turbo. also in 89 they started having to warranty the cat for much longer (7 years instead of 3). the S4 and S5 NA cars run very different AFR's after 4000rpm, it wouldn't surprise me if the turbo was the same. weirdly i've never had a wideband on a stock ecu turbo car
Running an s4 Bridgeport turbo keg on s5 electronics, S5 turbo and rtek 1.5 n374 ecu. Idle ran @19 in the beginning, below 4000 rpm 12.1 cruise after 4000rpm 13.5 cruise and 10.8 under boost. Adjusted to 15 @ idle 13.5 below 4000 rpm 16 above 4000 rpm for highway cruise and 11.7 under boost because it was to rich and I gained 25hp in higher rpm.
Wraith Zero is offline  
Old 11-09-15, 11:41 AM
  #10  
burn to burn
iTrader: (3)
 
keithrulz's Avatar
 
Join Date: May 2005
Location: Rochester, IN
Posts: 1,622
Received 2 Likes on 2 Posts
If I recall correctly the leading and trailing spark plugs on the s4 housings are closer together than that of the s5 and fd housings.. which would alter the timing. no?
keithrulz is offline  
Old 11-09-15, 01:03 PM
  #11  
www.lms-efi.com
iTrader: (27)
 
C. Ludwig's Avatar
 
Join Date: Mar 2001
Location: Floyds Knobs. IN
Posts: 5,112
Received 30 Likes on 23 Posts
Sparks instant relative to crank position, no. You could place the plug in the exhaust port and telling the ECU to fire at 20 BTDC is still going to fire it at 20 BTDC relative to the crank. Now, does moving the plug position make the engine want different spark timing? That's the question.

Originally Posted by keithrulz View Post
If I recall correctly the leading and trailing spark plugs on the s4 housings are closer together than that of the s5 and fd housings.. which would alter the timing. no?
C. Ludwig is offline  
Old 11-09-15, 01:15 PM
  #12  
burn to burn
iTrader: (3)
 
keithrulz's Avatar
 
Join Date: May 2005
Location: Rochester, IN
Posts: 1,622
Received 2 Likes on 2 Posts
That is what I was trying to say. Theoretically the timing map should reflect the difference.
keithrulz is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
82streetracer
Haltech Forum
11
03-11-19 05:34 PM
stickmantijuana
Microtech
5
08-23-15 11:04 AM
stickmantijuana
20B Forum
10
08-19-15 01:47 PM
dkwasherexd
Far East Forum
1
08-17-15 11:26 AM


Thread Tools
Search this Thread
Quick Reply: how are we supposed to tune timing on a rotary?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: