NA EMU Tuning
03-09-2007, 03:38 AM
#51
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I recently ran into trouble with my tuned emu. Somehow the rx8 ecu learns to lean out and as such my tune went off by alot. I thot I had encountered fuel pump inefficiency but it turn out to be just a simple case of resetting the ecu. Does this happen often or is it because I placed some negative value in the airflow map under close loop condition?
Surprisingly, after resetting the ecu, my car's power went up without tuning and now with tuning I manage to get 209whp at a safer afr of 13.2.
Surprisingly, after resetting the ecu, my car's power went up without tuning and now with tuning I manage to get 209whp at a safer afr of 13.2.
03-09-2007, 01:49 PM
#53
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Originally Posted by MazdaManiac
Are you using a circuit to shut down the front O2 sensor?
I cant seem to find the thread on when the ecu goes into open loop. Seem like it is not possible to tune the close loop section at all.
03-09-2007, 01:55 PM
#54
You can tune the closed-loop operational areas with the airflow map, but it will fight you with LTFT, so you will have a difficult time making the changes "stick".
Tuning with injector duty will also cause the PCM to attempt to make corrections until it goes out of range.
The WBO2S dongle that GReddy includes in the upgrade kit sends a fully-lean (22:1) signal to the WBO2S, which causes the PCM to not use the affected ranges to adjust LTFT.
However, I have not played with load points that aren't in boost on my setup, so I don't know how the PCM will react if you use it N/A.
I suspect it will work, though.
Tuning with injector duty will also cause the PCM to attempt to make corrections until it goes out of range.
The WBO2S dongle that GReddy includes in the upgrade kit sends a fully-lean (22:1) signal to the WBO2S, which causes the PCM to not use the affected ranges to adjust LTFT.
However, I have not played with load points that aren't in boost on my setup, so I don't know how the PCM will react if you use it N/A.
I suspect it will work, though.
03-09-2007, 02:06 PM
#55
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I dont have that dongle. Is it possible to get it seperately? Right now, I only input values after 30% throttle and 3k rpm. Still monitoring to see if the problem will reoccur. Another question..will I be able to install a knock sensor(turboxs) or is our ecu so unique that it requires a special knock sensor?
03-09-2007, 02:18 PM
#56
The PCM already has a knock sensor (that doesn't work).
Installing another will do nothing.
Now, an aftermarket knock suppression system like the J&S might work, but the main problem is that "knock" on the Renesis doesn't sound like knock to the knock sensor.
It is a real problem.
The fundamental and harmonic frequencies of pre-ignition on a rotary are way higher than a regular piston motor and there is no "onset" - it is all or nothing, so a timing control that uses a sensor can't work proactively.
Installing another will do nothing.
Now, an aftermarket knock suppression system like the J&S might work, but the main problem is that "knock" on the Renesis doesn't sound like knock to the knock sensor.
It is a real problem.
The fundamental and harmonic frequencies of pre-ignition on a rotary are way higher than a regular piston motor and there is no "onset" - it is all or nothing, so a timing control that uses a sensor can't work proactively.
03-09-2007, 02:36 PM
#57
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Shucks. Now I wont know if my car is pinging or not. At high rpms sae 6500 onwards, there seem to be a sparking sound. I doubt that is knock as the car is still pulling. If it knocks, power should drop off. The strange thing is I have never heard tat sound before. Last time when I was running 13.8 afr with 3 deg advance timing it was ok. Now with 13.2 afr and 3 deg advance timing, it have tat sound tat comes in only at high rpms.
03-09-2007, 02:57 PM
#58
Ping sounds like stepping on dry leaves and twigs. It is quite loud, but you need to have your windows up and stereo off.
It is possible to have just one ping here and there. It will sound like cracking one knuckle on your hand.
In theory, it only takes one good ping to break a seal. On the Renesis, it is possible to break a seal and not know it for many, many miles because, unlike a peripheral port motor, the seal can't leave its groove, so you have to wait for it to degrade enough and deform the corner seal before it lets loose.
The OEM ignition timing is unbelievably aggressive. In the past, rotary tuners shot for no more than 28° to 30° of total timing with 8° to 15° of trailing gap.
The Renesis can have up to 38° under heavy load with only 6° of gap (around 7800 RPM).
As a comparison, I shoot for only 7° with a 15° gap at peak torque (5500 RPM) at 12 PSI of boost. The OEM PCM is trying to set it at 25° at that point!
It is possible to have just one ping here and there. It will sound like cracking one knuckle on your hand.
In theory, it only takes one good ping to break a seal. On the Renesis, it is possible to break a seal and not know it for many, many miles because, unlike a peripheral port motor, the seal can't leave its groove, so you have to wait for it to degrade enough and deform the corner seal before it lets loose.
The OEM ignition timing is unbelievably aggressive. In the past, rotary tuners shot for no more than 28° to 30° of total timing with 8° to 15° of trailing gap.
The Renesis can have up to 38° under heavy load with only 6° of gap (around 7800 RPM).
As a comparison, I shoot for only 7° with a 15° gap at peak torque (5500 RPM) at 12 PSI of boost. The OEM PCM is trying to set it at 25° at that point!
Last edited by MazdaManiac; 03-09-2007 at 02:59 PM.
03-09-2007, 05:08 PM
#59
Originally Posted by CoupeM
I dont have that dongle. Is it possible to get it seperately? Right now, I only input values after 30% throttle and 3k rpm. Still monitoring to see if the problem will reoccur. Another question..will I be able to install a knock sensor(turboxs) or is our ecu so unique that it requires a special knock sensor?
30% throttle & 3000 is ok but you don't really get anything by doing it .
03-09-2007, 05:19 PM
#61
No, just WOT.
Even 30° is way too much for 5500 RPM and ANY boost.
At 11:1, the flame front is moving so fast that 30° of advance would have full combustion pressure happening 10° before top dead center! That can spell disaster.
The only thing that saves it is the longish combustion area. Go for a short trailing gap there and you are looking at serious detonation.
You want it at 15° after top dead center.
Even 30° is way too much for 5500 RPM and ANY boost.
At 11:1, the flame front is moving so fast that 30° of advance would have full combustion pressure happening 10° before top dead center! That can spell disaster.
The only thing that saves it is the longish combustion area. Go for a short trailing gap there and you are looking at serious detonation.
You want it at 15° after top dead center.
03-10-2007, 01:29 AM
#63
Originally Posted by CoupeM
Thanks Brettus for the tip. Same as Brettus, I have never seen more then 32 degree of advance timing at the leading plug. (Viewed by using the EMU)
03-10-2007, 03:37 PM
#65
Charles - I think you will be dissapointed with the real world results from a piggyback tune - I am .
I know we talked about what you wanted to do before . I think the unit I have could do what you want afterall .
It has a "nitrous" aux output that will turn on the solenoid under preset throttle & rpms . at the same time it will retard the ignition across the board by a preset amount.
Only drawback is the output will need to be turned off & on with the software when you want to use the nitrous otherwise it will do the timing retard under normal (non nitrous) acceleration.
It can also be set up to add fuel under nitrous which could be usefull for fine tuning .
I know we talked about what you wanted to do before . I think the unit I have could do what you want afterall .
It has a "nitrous" aux output that will turn on the solenoid under preset throttle & rpms . at the same time it will retard the ignition across the board by a preset amount.
Only drawback is the output will need to be turned off & on with the software when you want to use the nitrous otherwise it will do the timing retard under normal (non nitrous) acceleration.
It can also be set up to add fuel under nitrous which could be usefull for fine tuning .
Last edited by Brettus; 03-10-2007 at 04:10 PM.
03-10-2007, 07:26 PM
#66
On the EMU, you could tie the timing retard to your nitrous solenoid, so that the timing is only pulled when the solenoid fires.
You could also set a curve based on RPM and adjust the split, which is better than just base retard since too little split is as bad as too much advance in some ranges.
You could also set a curve based on RPM and adjust the split, which is better than just base retard since too little split is as bad as too much advance in some ranges.
03-11-2007, 10:44 AM
#67
Why use a rare DPST when you can just use a DPDT and ignore one end?
The EMU can be wired to either end of the equation - it can control the nitrous or the nitrous can control it.
Timing split is not too critical if you are willing to just take a big chunk of everything out when you are spraying, which is probably satisfactory.
The EMU can be wired to either end of the equation - it can control the nitrous or the nitrous can control it.
Timing split is not too critical if you are willing to just take a big chunk of everything out when you are spraying, which is probably satisfactory.
03-26-2007, 10:41 AM
#68
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can i check with u MM..how do you set the throttle for emu? when the engine is not started but ignition on? if so, i can only get a voltage reading of 3.88 to 100% throttle and not 5V
03-30-2007, 03:23 PM
#71
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I just did a couple of runs today cause I realise that there is not much point in tuning anything above 4v(airflow voltage). I have gt a couple of questions though.
Throughout my runs, my ignition of the leading and trailing plugs remain about 7 to 10 degrees apart. Is that right? I gt about 33deg(leading) and 22deg(trailing) at bout 7200rpm onwards. Before that was 33deg(leading) and 17-19deg(trailing) between 6700rpm and 7200rpm.
Between 4300rpm and 4600rpm, i gt about 21-22deg(leading) and 7-10 deg(trailing). I wonder about the dip in advance timing for the trailin plugs. I got all this by logging my runs using emu.
Also, I used a canscan to read my ltft and it is at -13.6%. Is the afr shown on the canscan accurate? As in...is our first o2 sensor a wideband?
Last question for this post. How much pinging/detonation can a NA renesis take? I think my car ping while cruising on the highway for quite a distance(about 40km). I forgot to remove the ignition advance set by my tuner on the cruising section of my map.
Throughout my runs, my ignition of the leading and trailing plugs remain about 7 to 10 degrees apart. Is that right? I gt about 33deg(leading) and 22deg(trailing) at bout 7200rpm onwards. Before that was 33deg(leading) and 17-19deg(trailing) between 6700rpm and 7200rpm.
Between 4300rpm and 4600rpm, i gt about 21-22deg(leading) and 7-10 deg(trailing). I wonder about the dip in advance timing for the trailin plugs. I got all this by logging my runs using emu.
Also, I used a canscan to read my ltft and it is at -13.6%. Is the afr shown on the canscan accurate? As in...is our first o2 sensor a wideband?
Last question for this post. How much pinging/detonation can a NA renesis take? I think my car ping while cruising on the highway for quite a distance(about 40km). I forgot to remove the ignition advance set by my tuner on the cruising section of my map.
03-30-2007, 03:52 PM
#72
Timing sounds right, but is that before or after the EMU does its thing?
That is a LOT of fuel trim. You will want to scale your injectors in the setup screen 10% or so up to get rid of that.
The engine can "take" quite a bit without exhibiting damage.
However, that does not mean damage isn't done.
The lack of a peripheral port makes seal damage less obvious.
That is a LOT of fuel trim. You will want to scale your injectors in the setup screen 10% or so up to get rid of that.
The engine can "take" quite a bit without exhibiting damage.
However, that does not mean damage isn't done.
The lack of a peripheral port makes seal damage less obvious.
03-30-2007, 10:10 PM
#75
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Originally Posted by MazdaManiac
Timing sounds right, but is that before or after the EMU does its thing?
That is a LOT of fuel trim. You will want to scale your injectors in the setup screen 10% or so up to get rid of that.
The engine can "take" quite a bit without exhibiting damage.
However, that does not mean damage isn't done.
The lack of a peripheral port makes seal damage less obvious.
That is a LOT of fuel trim. You will want to scale your injectors in the setup screen 10% or so up to get rid of that.
The engine can "take" quite a bit without exhibiting damage.
However, that does not mean damage isn't done.
The lack of a peripheral port makes seal damage less obvious.
The only way is to do a compression test to know if any damage is done? I think I encounter mild pinging although I cant be sure is it my rp shifter or the engine making a slighty rough noisy sandpaper kind of sound.