2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Can too retarded timing blow an engine?

Thread Tools
 
Search this Thread
 
Old Oct 26, 2019 | 10:20 AM
  #1  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Can too retarded timing blow an engine?

I have a turbo fc with a microtech the engine has 88 turbo internals, doweled and street ported super seals apex seals, and Im starting to tune for high boost, curently running 8psi (wg spring) but heres my timing maps ive read that they are too conservative I put them that way for safety but can running too conservative damage the engine too? car pulls nicely for 8psi now
Keep in mind the real values are 5* less (CAS stabed on factory 5* ATDC Mark)


Reply
Old Oct 26, 2019 | 02:20 PM
  #2  
Hot_Dog's Avatar
Rotary Freak
Tenured Member: 20 Years
Liked
Loved
Community Favorite
 
Joined: Nov 2001
Posts: 1,521
Likes: 231
From: Alexandria, VA
To the best of my knowledge, the answer is no. Too retarded timing will cause power loss to the point where the engine fails to run.
Reply
Old Oct 27, 2019 | 08:30 AM
  #3  
WJM ROTARIES's Avatar
Rotary Freak
Tenured Member: 10 Years
 
Joined: Aug 2012
Posts: 2,872
Likes: 407
From: MELBOURNE AUSTRALIA
You should run +10 deg across all rev range as soon as u are in positive boost . This is a good safe tune
Reply
Old Oct 27, 2019 | 03:36 PM
  #4  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Ohhh well I suppose I'm on the right way because after 3k rpm im basiclly all the way at 10* (it says 15 but its actually 5degrees less)
Reply
Old Oct 29, 2019 | 07:30 AM
  #5  
driftxsequence's Avatar
Rotisserie Engine
Tenured Member: 15 Years
Liked
Loved
Community Favorite
iTrader: (8)
 
Joined: Jan 2007
Posts: 1,945
Likes: 107
From: Wilmington, DE
Yes too retarded of a timing can cause an improper flame front from the trailing plug's firing and pushing the rotor backwards. with a large amount of split you can actually cause it to ignite in the next rotor chamber.
I've been told 15 degress of split timing in boost is the safest way to go.
You're leaving a LOT of drivability power on the table as well. Most stock/streetport engines are going to be happy with 25-30* of timing in your vacuum cruise area so 2000-4000 rpm. Then as you raise into boost you want to start retarding timing. 18* is safe for about 5 PSI and taper to 15* at 15 PSI. Over 15 PSI I would taper down too about 10* of timing with 15* of split.

Last edited by driftxsequence; Oct 29, 2019 at 07:35 AM.
Reply
Old Nov 17, 2019 | 10:25 AM
  #6  
Aaron Cake's Avatar
Engine, Not Motor
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Those timing maps are a bit insanely conservative.

You can do a fair bit of damage by retarding timing too much. As already mentioned, competing flame fronts. But also lots of afterburn into the exhaust, super heating the manifold, turbine, etc.

Your T_RPM map is almost backwards.

It should be around 10 degrees at idle, then rise to about 30 degrees by 3000 RPM.

Your T_MAP then needs to be adjusted to pull timing down to about 15 degrees by about 8 PSI of boost. Above that, taper down to 10 degrees by about 12 PSI and run 10 degrees flat beyond that.
Reply
Old Nov 18, 2019 | 01:10 PM
  #7  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Ok Im going tl change the trpm* and use tmap to remove timing instead of using trpm... So even if I run up to 25psi I leave the timing at 10°? Sorry to ask so much is just that ive never tuned timing before so dont want to blow the engine... And also the fact the I cant hear or distinguish a rotary detonating...
Reply
Old Nov 18, 2019 | 02:17 PM
  #8  
Aaron Cake's Avatar
Engine, Not Motor
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Think of it this way, if it helps, because the Microtech timing paradigm is just plain weird. Instead of a 3D map like, oh, every other ECU, the use this strage virtual distributer model.

So, think of T_RPM as mechanical advance

And T_MAP as vacuum advance that is also retard capable

So just like a dizzy, you set your "base" timing curve on T_RPM which is typically something like 5 or 10 degrees at idle, a linear progression to about 25 degrees by 2500 RPM, then then flat to redline.

Your "advance/retard" curve on T_MAP then adds timing under high vacuum (in cruise it should add anther 5 or so degrees for a total cruise timing of 30 degrees), and retards it under boost by pulling it away from the T_RPM.

Just remember to START CONSERVATIVE. You can put in a massive timing retard in T_MAP when you start tuning, the pull out retard as you go to get the final timing curve.
Reply
Old Nov 18, 2019 | 05:49 PM
  #9  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Ok thanks man appreciate the help, the microtech indeed seems odd, way too simple compared to today's haltechs, adaptronics ect
Reply
Old Nov 19, 2019 | 03:19 PM
  #10  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Are these maps better?

Reply
Old Nov 23, 2019 | 10:42 AM
  #11  
Aaron Cake's Avatar
Engine, Not Motor
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
That looks like a good place to start.

And yes, you'll find the Microtech timing set up very limiting. Frankly, most things about the Microtech are limiting. Does work reliably however.
Reply
Old Nov 23, 2019 | 02:14 PM
  #12  
The Latin RX7's Avatar
Thread Starter
Full Member
Tenured Member: 5 Years
 
Joined: Feb 2018
Posts: 52
Likes: 0
From: Puerto Rico
Ok thank you
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
The Latin RX7
2nd Generation Specific (1986-1992)
1
Sep 29, 2019 05:33 AM
gabs88gxl
Megasquirt Forum
2
Oct 17, 2010 02:44 PM
Archangels
Power FC Forum
9
Oct 9, 2008 11:52 PM
GSLSE-YA
Naturally Aspirated Performance Forum
18
Oct 1, 2008 12:44 PM
BlackRx7
2nd Generation Specific (1986-1992)
2
Nov 4, 2002 06:38 AM




All times are GMT -5. The time now is 12:44 PM.