Mods done to date on my SS, results and pics (as promised)
11-15-2005, 10:01 PM
#79
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Interesting post ...
Originally Posted by SCdyne
High IAT will pull timing and does pull timing. Also misfire counts will pull timing and so will knock counts.
Nothing against anyone, but this whole process is EXACTLY why you really need a scan tool when trying to get to the bottom of issues like this.
It would be real nice to see what the knock counts are for the vehicle also misfires and which cylinders are missing. IF the misfire counts were a problem then I would say re-gap the plugs - then if that didn't work go to a colder plug.
Also during a WOT stomp it would be invaluable to know what IPW and IAT looks like. Yes, A/F from a wb02 is nice, but if you don't know what is causing the A/F you are seeing then you can't even begin to adjust for it.
This is an OBDII vehicle and even a basic scan tool will provide the majority of the generic data you would want to see. Some of the DTCs will be inaccurate or vague, but the important things like RPM, IPW, Knock, Timing, IAT, CHT, MAP, etc are all defined in the OBDII Standard. If some values are wrong its easy to figure out whats what for the most part.
IMO I think that this may be a case of entering a lean area of the fuel table in the PCM. This is either caused from lack of tuning on GMs part or just much more psi than the stock fuel tables are set-up to handle. It is totally possible that GM placed very lean values beyond 13 psi on the fuel map and the sensor probably only goes to 14.7 psi or 2 bar absolute. Either case its possible a good value could be located at a lower position on the map and forced to the PCM with a signal clamp. It could also be as simple as the 15+ psi seen is making the PCM call an invalid memory location resulting in an out of bounds or divide by zero error. Its not a bad enough issue to cause the PCM to fail, but it could be interpolating one good value with one bad value in the fuel adder calculation resulting in a lean state.
I know this happens with the 2000+ Saturn PCM all the time and only ˝ the time does the PCM give a MAP signal High DTC. The rest of the time it just goes real lean for no reason other than having an invalid base injector pulse width. Problem solved by clamping the MAP voltage to 4.7v and operating normal under all other conditions.
While I would know that a good MAP filter like the SAFC II or E-manage would be the best solution it is totally possible that a $50 clamp could solve the problem once and for all.
Nothing against anyone, but this whole process is EXACTLY why you really need a scan tool when trying to get to the bottom of issues like this.
It would be real nice to see what the knock counts are for the vehicle also misfires and which cylinders are missing. IF the misfire counts were a problem then I would say re-gap the plugs - then if that didn't work go to a colder plug.
Also during a WOT stomp it would be invaluable to know what IPW and IAT looks like. Yes, A/F from a wb02 is nice, but if you don't know what is causing the A/F you are seeing then you can't even begin to adjust for it.
This is an OBDII vehicle and even a basic scan tool will provide the majority of the generic data you would want to see. Some of the DTCs will be inaccurate or vague, but the important things like RPM, IPW, Knock, Timing, IAT, CHT, MAP, etc are all defined in the OBDII Standard. If some values are wrong its easy to figure out whats what for the most part.
IMO I think that this may be a case of entering a lean area of the fuel table in the PCM. This is either caused from lack of tuning on GMs part or just much more psi than the stock fuel tables are set-up to handle. It is totally possible that GM placed very lean values beyond 13 psi on the fuel map and the sensor probably only goes to 14.7 psi or 2 bar absolute. Either case its possible a good value could be located at a lower position on the map and forced to the PCM with a signal clamp. It could also be as simple as the 15+ psi seen is making the PCM call an invalid memory location resulting in an out of bounds or divide by zero error. Its not a bad enough issue to cause the PCM to fail, but it could be interpolating one good value with one bad value in the fuel adder calculation resulting in a lean state.
I know this happens with the 2000+ Saturn PCM all the time and only ˝ the time does the PCM give a MAP signal High DTC. The rest of the time it just goes real lean for no reason other than having an invalid base injector pulse width. Problem solved by clamping the MAP voltage to 4.7v and operating normal under all other conditions.
While I would know that a good MAP filter like the SAFC II or E-manage would be the best solution it is totally possible that a $50 clamp could solve the problem once and for all.
After reading and reading and reading Adam's post, I think seriously this is one of the best post I've ever read. Now I understand it 100% and will make some testing according to it. I've ordered a Aeroforce Interceptor OBDII scan gauge, it will be very good to better understand what's going on. I will receive it probably on November 23, along with the Mini AFC 2.2 MAF signal tuner. I thought also to try a custom map clamp. I think that tricking the MAF and MAP signals within small values will permit to achieve some gains without any cells. Per example, a CAI or a high flow filter will give a higher percentage MAF signal, so with the Mini AFC you can lower the signal to the same value as stock. The increased air (as long as the MAF signal is tuned) could produce more HP (at least for mid RPM's). Same thing for the MAP sensor with a MAP clamp. What do you guys think ?
11-15-2005, 10:16 PM
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The AFC controller will only let you lean/richen up different mass air flow frequencies. It won't let you pull down the 14k value down to the 12k area, which seems to be what your saying. But scanning would let you know where your MAFF values are at at WOT and you should see if your just blowing it off the chart beyond PCM calibrations.
For example, if it just pegs at a number and doesn't change through the RPMs, I'd say its pegged.
For example, if it just pegs at a number and doesn't change through the RPMs, I'd say its pegged.
11-17-2005, 07:54 PM
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After talking to the GM engineer at SEMA in detail about the PCM config, I can say that my post above was accurate, but not all of the problem.
From what they are saying the injectors ARE actually too small for the higher boost pressures.
Siemens didn't even make one larger than what is in the car until GM started pushing the limits after the RedLine was already on the road. Now GM has siemens making larger volume injectors to address the needs, but IMEO a quick call to FiveO for 4 injectors and 4 harness adapters will solve all the problems..
I don't remember: Does the LSJ have a sub-harness injector harness like the L61 does (with a plug at the main harness) or is it all part of the primary harness? If it's a plug then it can be purchased and an old style harness built and used...
From what they are saying the injectors ARE actually too small for the higher boost pressures.
Siemens didn't even make one larger than what is in the car until GM started pushing the limits after the RedLine was already on the road. Now GM has siemens making larger volume injectors to address the needs, but IMEO a quick call to FiveO for 4 injectors and 4 harness adapters will solve all the problems..
I don't remember: Does the LSJ have a sub-harness injector harness like the L61 does (with a plug at the main harness) or is it all part of the primary harness? If it's a plug then it can be purchased and an old style harness built and used...
11-22-2005, 11:42 PM
#84
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These following injectors could fit with the stock connectors ...
http://www.racetronix.com/17113739.html
But like WOT told me, those are single spray (compared to our stock LSJ dual spray injectors) and would probably fit by replacing the cups (cylindrical part between the injector and the head).
For now I am still wating for a couple of weeks ... can't wait to do some datalogging !
http://www.racetronix.com/17113739.html
But like WOT told me, those are single spray (compared to our stock LSJ dual spray injectors) and would probably fit by replacing the cups (cylindrical part between the injector and the head).
For now I am still wating for a couple of weeks ... can't wait to do some datalogging !
11-23-2005, 12:05 AM
#85
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Any thoughts guys on a MAP clamp ? A guy on another forum told me that he get 5V at WOT (when seeing 14.5 PSI). Maybe clamp it at 4.7V could help ?
11-24-2005, 12:06 PM
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Anyway I bought 2 MAP clamps yesterday; I will try to install one on each MAP sensor (before and after the blower). I will receive them in a week or so ...
11-25-2005, 06:44 PM
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for the record, anyone wanting to try the MAP clamp, just get a 4.7V 1W zener diode from your local electronics supplier. Its the same thing, only you can get the diodes for $0.25. Then its just a matter of wiring it between the the signal wire to the ecu and i think the 5v reference wire, that way the diode will shunt any voltage in excess of 4.7V back to the reference and the ecu will see a max of 4.7V from the map sensor. The only problem as SCDyne brought up is that it may well be the injectors really are too small. If thats the case, you can clamp all you want and it won't make a difference. The only other thing is that being drive by wire, there may be a point at which the ecu will close the throttle plate if it starts seeing too much boost (this is common over in the VW 1.8T community which is where i learned the diode trick). MAP clamps also have a tendency to make the ecu advance the ignition timing more, since the ecu sees less boost and believes it is safe to advance... then it sees knock and retards the timing, which can cause other issues. Generally maximum power is pulling 3 degrees of timing, you don't want to be pulling more than 5 or so. However if you're not pulling any timing at all, than you are not making as much power as you could be.
Just for knowledge's sake though, the ECU's on the other ecotec engines(at least the newer ecus) are notorious for not excepting changes in A/F ratio to richen the mixture more than the ECU is programmed to request. This makes it necessary to reflash the ecu, since all the other bandaid fixes will be outsmarted unless a way to send a flase O2 sensor signal to the ecu is found (telling it that its leaner than it wants to be in order to add more fuel). The problem with that is that eventually it will start throwing lean condition codes and the fuel trims will be way off. Its best at this point to be patient and hope for the speedy release of the GM upgrades.
Just for knowledge's sake though, the ECU's on the other ecotec engines(at least the newer ecus) are notorious for not excepting changes in A/F ratio to richen the mixture more than the ECU is programmed to request. This makes it necessary to reflash the ecu, since all the other bandaid fixes will be outsmarted unless a way to send a flase O2 sensor signal to the ecu is found (telling it that its leaner than it wants to be in order to add more fuel). The problem with that is that eventually it will start throwing lean condition codes and the fuel trims will be way off. Its best at this point to be patient and hope for the speedy release of the GM upgrades.
12-04-2005, 09:45 AM
#88
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Some nice results ...
Yesterday, we've done one full hour of dyno tuning, and as expected the Mini AFC 2.2 works ! It allowed to fine tune the air fuel curve, even if the stock injectors haven't a lot of room to play with them. Even without any tuning from the Mini AFC 2.2, the stock PCM still seems to keep the air fuel ratio not higher than 12.5 at WOT.
I didn't receive my bigger injectors in time for the dyno tuning session. So we doesn't measure any fuel pressure or neither the stock injectors flow. About the bigger injectors, maybe I will need them only with an even smaller pulley than 3".
Here are my current setup as tested yesterday :
2,5" catback
3" pulley @ 15.2 PSI
SCdyne Header
Denso Iridium #IK20 Spark Plugs (gap 0,035")
K&N high flow filter #RU-2710 with lower lid removed
We also get the Aeroforce Interceptor gauge installed, but unfortunatly the cable they sent me caused an interface conflict with my SS PCM. So we haven't been able to get the gauge work properly, neither measure the Injector Pulse width for the stock injectors.
Results: We consistently went to 222 WHP and 192 WTQ; giving 285 SAE BHP and 250 TQ.
My previous setup (with CAI, but without Iridium Plugs and without Mini AFC 2.2) was roughly 212 WHP and 185 WTQ.
When we compare the current setup to my stock dyno runs of 190 WHP and 170 WTQ, that's a 17 % increase in HP and 13 % increase in torque.
Have a nice day !
I didn't receive my bigger injectors in time for the dyno tuning session. So we doesn't measure any fuel pressure or neither the stock injectors flow. About the bigger injectors, maybe I will need them only with an even smaller pulley than 3".
Here are my current setup as tested yesterday :
2,5" catback
3" pulley @ 15.2 PSI
SCdyne Header
Denso Iridium #IK20 Spark Plugs (gap 0,035")
K&N high flow filter #RU-2710 with lower lid removed
We also get the Aeroforce Interceptor gauge installed, but unfortunatly the cable they sent me caused an interface conflict with my SS PCM. So we haven't been able to get the gauge work properly, neither measure the Injector Pulse width for the stock injectors.
Results: We consistently went to 222 WHP and 192 WTQ; giving 285 SAE BHP and 250 TQ.
My previous setup (with CAI, but without Iridium Plugs and without Mini AFC 2.2) was roughly 212 WHP and 185 WTQ.
When we compare the current setup to my stock dyno runs of 190 WHP and 170 WTQ, that's a 17 % increase in HP and 13 % increase in torque.
Have a nice day !
12-04-2005, 11:10 AM
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good stuff man,
i havent read alot of the other posts in this thread, but why does his dyno read so low?
also, what duty cycle were the injectors running before you started playing with them?
i havent read alot of the other posts in this thread, but why does his dyno read so low?
also, what duty cycle were the injectors running before you started playing with them?
12-04-2005, 02:08 PM
#90
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Low numbers come from a precise Mustang MD-250 dyno. About the injectors duty cycle, most said that it's 100 % at 6000 RPMs, but I haven't been able to see it by myself yet. But soon I will ...
12-04-2005, 04:50 PM
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Originally Posted by Jmc007
Low numbers come from a precise Mustang MD-250 dyno. About the injectors duty cycle, most said that it's 100 % at 6000 RPMs, but I haven't been able to see it by myself yet. But soon I will ...
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