Ignition timing for turbo or supercharged renesis - post your maps
11-10-2011, 04:57 PM
#177
I would say that because of the relative lack of charge homogeny that occurs in the rotary motor for various reasons under differing conditions, there is almost always some form of detonation going on, purely by definition. This isn't necessarily a primary concern (though I would seek to minimise this as much as possible, which is difficult to do because only experience will teach you what to look for), it certainly speaks to the need to understand how the Renesis breathes before you can address the placement of maximum dynamic combustion pressure.
11-11-2011, 08:14 AM
#178
true that we have a very different combustion chamber that offers challanges. This engine also has to carry the charge a little distance before anything ignition wise occurs ( hopefully). In affect isnt the engine during its intake cycle causing its on charge turbulance and doesnt rely as much on port velocity to do this as recips?
I understand what yall are saying in reference to the difficulty in lighting the charge uniformaly. It seems to me that a 3 sparkplug design would be of help--but I really dont know.
But engine ignition timing in reference to detonation seems to be a wide variable depending on such things as your a/f's ( a/f's do affect flame propergation to a degree--right?), combustion chamber temperature, charge temperature, your octane level of whatever fuel you are running, baro pressure, driving characteristics ( what is being asked of the engine?) and port design? Is that a safe thing to say?
Does pre mix affect the flame? The people I ask tell me different things? Does pre mix affect ignition timing? I am pretty sure at levels like 200:1 is doesnt, but if you go 100--or 50:1 it may to a small degree?
I wonder if pre mix increases the possibility of the intake charge to wet out some? That certainly would affect the flame speed and increase chances of catastopic detonation?
I did read that pre mix can really affect the octane in the gas, especially at the level that some of the dirt bike racers are using. Some of them do run 50:1 for lower rpm tracks. One study done by them stated that at 25:1 the octane rating was reduced from 93 to 79!! I would like to see that report.
I understand what yall are saying in reference to the difficulty in lighting the charge uniformaly. It seems to me that a 3 sparkplug design would be of help--but I really dont know.
But engine ignition timing in reference to detonation seems to be a wide variable depending on such things as your a/f's ( a/f's do affect flame propergation to a degree--right?), combustion chamber temperature, charge temperature, your octane level of whatever fuel you are running, baro pressure, driving characteristics ( what is being asked of the engine?) and port design? Is that a safe thing to say?
Does pre mix affect the flame? The people I ask tell me different things? Does pre mix affect ignition timing? I am pretty sure at levels like 200:1 is doesnt, but if you go 100--or 50:1 it may to a small degree?
I wonder if pre mix increases the possibility of the intake charge to wet out some? That certainly would affect the flame speed and increase chances of catastopic detonation?
I did read that pre mix can really affect the octane in the gas, especially at the level that some of the dirt bike racers are using. Some of them do run 50:1 for lower rpm tracks. One study done by them stated that at 25:1 the octane rating was reduced from 93 to 79!! I would like to see that report.
Last edited by olddragger; 11-11-2011 at 08:18 AM.
11-11-2011, 11:15 AM
#179
But engine ignition timing in reference to detonation seems to be a wide variable depending on such things as your a/f's ( a/f's do affect flame propergation to a degree--right?), combustion chamber temperature, charge temperature, your octane level of whatever fuel you are running, baro pressure, driving characteristics ( what is being asked of the engine?) and port design? Is that a safe thing to say?
Yes, in a qualified way.
03-28-2012, 09:46 AM
#181
How'd you get the ignition table to reflect your higher calc load setting? No matter what I set my calc load max table to it doesn't reflect in other tables. More precisely what I am asking is how did you get more columns? I can edit the top row, but I only have 14 columns, vs your 20.
Last edited by slash128; 03-28-2012 at 09:52 AM.
03-28-2012, 11:35 AM
#182
How'd you get the ignition table to reflect your higher calc load setting? No matter what I set my calc load max table to it doesn't reflect in other tables. More precisely what I am asking is how did you get more columns? I can edit the top row, but I only have 14 columns, vs your 20.
Second, what software are you using as I see 20 columns in the ATR software for Calc Load on the Ignition tables? I've got both the 2004 and 2005 version FWIW.
Maybe a model/year difference?
Check again are you sure you don't have 20 columns.
If you don't you can still scale it up to 200% you just lose resolution on the table, as the ECU will have to extrapolate the data more between load ranges.
06-08-2012, 11:22 AM
#193
It looks kind of flat as well.
For example 4500 rpm and 200% load is 8 deg while 4000rpm 200% load is 9 deg.
I would stick with 9 degrees maybe even 10 through through to 7000rpm
--- edit ---
As mentioned already in this thread, its not apples to apples but check out Brett's tune in the first post
06-11-2012, 10:54 PM
#195
I apologize for my noob question, but is there any risk of damage if timing is too far retarded? Is there risk beyond reduced power? I realize too far advanced will cause detonation. Just trying to stay in a relatively safe zone until things get settled and I can get to a dyno.
06-12-2012, 05:05 AM
#196
actually looking at that map on the first page ... I think it is too advanced in the mid range high load areas - due to hearing some mild detonation on the earphones while on dyno ........ up to 6500 and 175% load i now run more like 9 degrees and taper up from there .
Last edited by Brettus; 06-12-2012 at 05:07 AM.
06-12-2012, 07:24 AM
#197
I apologize for my noob question, but is there any risk of damage if timing is too far retarded? Is there risk beyond reduced power? I realize too far advanced will cause detonation. Just trying to stay in a relatively safe zone until things get settled and I can get to a dyno.
Retarded ignition means that the combustion pressure rise in the working chamber occurs the rotor has moved beyond its ideal position for transferring pressure loads to the eccentric shaft, which is the source of torque production. The result of late ignition is lost power, higher emissions and poor gas mileage."
Street Rotary Pg 98-99 Ignition
Mark Warner, PE
06-12-2012, 06:06 PM
#199
"Actually to much advance can also cause power loss by due to the pressure rise from combustion which can actually push backward against the rotor.
Retarded ignition means that the combustion pressure rise in the working chamber occurs the rotor has moved beyond its ideal position for transferring pressure loads to the eccentric shaft, which is the source of torque production. The result of late ignition is lost power, higher emissions and poor gas mileage."
Street Rotary Pg 98-99 Ignition
Mark Warner, PE
Retarded ignition means that the combustion pressure rise in the working chamber occurs the rotor has moved beyond its ideal position for transferring pressure loads to the eccentric shaft, which is the source of torque production. The result of late ignition is lost power, higher emissions and poor gas mileage."
Street Rotary Pg 98-99 Ignition
Mark Warner, PE