What AFR am I shooting for?
10-11-2006, 03:36 PM
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What AFR am I shooting for?
Hi Guys,
Got the EMU running pretty well in the car now, but one thing that I am still wondering about is what AFR I should consider my goal across the range of boost. For instance, should I try to get 11:0 across the board? Or 11:5? Or can I run leaner at lower boost and RPM? Should it get richer as boost and RPM build, or should it remain constant for all boost levels above 0 and across the entire RPM range?
Here's a shot of a run up the rev range at full throttle that shows the AFR staying below 11:5 for the most part. Before I started tuning, the AFR jumped up to 12 or so in several places. I do plan to try to smooth this out... but for now I just wanted to get the AFR into a safe zone.
Green line is AFR and the scale on the left side shows the 11.5 line. Blue line is boost and it's topping out at about 7.0 PSI and then dropping above 5400 RPM or so.
Does this look like total crap or am I heading in the right direction?
Got the EMU running pretty well in the car now, but one thing that I am still wondering about is what AFR I should consider my goal across the range of boost. For instance, should I try to get 11:0 across the board? Or 11:5? Or can I run leaner at lower boost and RPM? Should it get richer as boost and RPM build, or should it remain constant for all boost levels above 0 and across the entire RPM range?
Here's a shot of a run up the rev range at full throttle that shows the AFR staying below 11:5 for the most part. Before I started tuning, the AFR jumped up to 12 or so in several places. I do plan to try to smooth this out... but for now I just wanted to get the AFR into a safe zone.
Green line is AFR and the scale on the left side shows the 11.5 line. Blue line is boost and it's topping out at about 7.0 PSI and then dropping above 5400 RPM or so.
Does this look like total crap or am I heading in the right direction?
10-11-2006, 09:09 PM
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Edit: I just realized I should not post right before bed... I meant to write 1 ATM, not 1 PSI... duh...
Ok, thanks. And now... for my dumbest question yet... is "boost" considered anything above 1 PSI, or anything above 0?
I mean, NA cars run at 1 PSI, right? I guess it depends on if we are talking about absolute pressure or relative pressure, and which way the gauge is reading it.
Ok, thanks. And now... for my dumbest question yet... is "boost" considered anything above 1 PSI, or anything above 0?
I mean, NA cars run at 1 PSI, right? I guess it depends on if we are talking about absolute pressure or relative pressure, and which way the gauge is reading it.
Last edited by kenkamm; 10-11-2006 at 09:23 PM.
10-11-2006, 09:13 PM
#6
your engine will be running in negitive psi (vacuum), since it's sucking in air.
the turbo pushes air in, more than it would be normally sucking in, giving it a positive number instead.
the turbo pushes air in, more than it would be normally sucking in, giving it a positive number instead.
10-12-2006, 06:12 AM
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Yeah, that was the next thing I was going to try to figure out. That is the "I/J Output Duty Cycle." There are what, six possible injector related toggles you can log, and I don't what's what, so I don't know which one(s) I should be watching, etc.
Can watching those help me determine which Map to use to add/remove fuel?
Can watching those help me determine which Map to use to add/remove fuel?
10-26-2006, 09:13 AM
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Originally Posted by MazdaManiac
You look pretty good, though I'd shoot for 10.5:1 from 5000 to 6800 since that is where it knocks, usually.
10-26-2006, 12:43 PM
#13
Mine will run without bogging all the way down to 10:1.
I have to pull a LOT of timing right there to keep it from ringing. Ends up only being 5° total at that point.
At the torque peak, you want to run it as rich as you can without bogging on the street.
Now, once you are sure you have a safe tune, you can start to pull it closer to the edge.
I'd say that there are very few people that have actually acheived a safe tune at this point...
I have to pull a LOT of timing right there to keep it from ringing. Ends up only being 5° total at that point.
At the torque peak, you want to run it as rich as you can without bogging on the street.
Now, once you are sure you have a safe tune, you can start to pull it closer to the edge.
I'd say that there are very few people that have actually acheived a safe tune at this point...
10-26-2006, 02:58 PM
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Questions:
1) How do you know when it's "ringing"... the only way I know of is listening... you can tell when it's pinging a lot... but can you tell when it's just a little?
2) Why is Greddy advancing the timing at high RPM & Boost? Should I get rid of this? I don't hear any pinging now, but how can I be sure?
1) How do you know when it's "ringing"... the only way I know of is listening... you can tell when it's pinging a lot... but can you tell when it's just a little?
2) Why is Greddy advancing the timing at high RPM & Boost? Should I get rid of this? I don't hear any pinging now, but how can I be sure?
10-26-2006, 03:07 PM
#15
Originally Posted by kenkamm
Questions:
1) How do you know when it's "ringing"... the only way I know of is listening... you can tell when it's pinging a lot... but can you tell when it's just a little?
1) How do you know when it's "ringing"... the only way I know of is listening... you can tell when it's pinging a lot... but can you tell when it's just a little?
However, low-level detonation just sounds like a faint "crunching" sound in the same location.
It is mainly a problem between 5800 RPM and 6800 RPM or so.
I wish I had a recording of it, but I'm not willing to subject my motor to any more ping for the sake of science.
Originally Posted by kenkamm
2) Why is Greddy advancing the timing at high RPM & Boost? Should I get rid of this? I don't hear any pinging now, but how can I be sure?
Generally, ping stops being an issue after 7k.
10-26-2006, 05:26 PM
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Thanks MM. Unfortunately for me, the only time I've heard pinging was the nasty kind you mentioned, when I made a mistake on one of the maps during tuning. It scared the crap out of me and I knew exactly what it was, so I let off immediately. But I still wonder how many miles I took off the life of the apex seals. 
I don't hear any of the crunching anywhere, but I guess it's because I'm running relatively low boost and pretty rich.
The map I posted earlier in this thread no longer represents what my logs look like. I found a leak in my wastegate line, and now that that's fixed, my boost rises to a peak of about 5.5 PSI and falls off quite gradually toward redline. I also got the AFR smoothed out a lot as well as the injector duties, so that they don't spike up to 100% (that's bad I'm told...)
I don't hear any of the crunching anywhere, but I guess it's because I'm running relatively low boost and pretty rich.
The map I posted earlier in this thread no longer represents what my logs look like. I found a leak in my wastegate line, and now that that's fixed, my boost rises to a peak of about 5.5 PSI and falls off quite gradually toward redline. I also got the AFR smoothed out a lot as well as the injector duties, so that they don't spike up to 100% (that's bad I'm told...)
10-30-2006, 11:32 AM
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Guys, I am having a problem sort of similar to Kenkamm:
Problem - Boost went past 7 PSI up to 10 PSI today which is set for "7 psi only". Then when I drive and come to a halt or idle. THe AFR goes to 16.5 / 7 (really lean) and then goes back to 15.2-5 (normal).
Situation - I recently had a HKS SSQV BOV installed by a tuner shop and the work looked good but the tubing for the recirc kit look like ****. WHat is possibly wrong based on my AFR going from normal to lean when I come to an IDLE?
Problem - Boost went past 7 PSI up to 10 PSI today which is set for "7 psi only". Then when I drive and come to a halt or idle. THe AFR goes to 16.5 / 7 (really lean) and then goes back to 15.2-5 (normal).
Situation - I recently had a HKS SSQV BOV installed by a tuner shop and the work looked good but the tubing for the recirc kit look like ****. WHat is possibly wrong based on my AFR going from normal to lean when I come to an IDLE?
10-30-2006, 11:58 AM
#18
hitting 17 afr when you're coming to a stop (or in idle) isn't a problem. Whenever you are engine braking your AFR is above 20. It's an issue only if you're boosting at that range.
10-30-2006, 01:21 PM
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Yeah, that's normal...
...but the boost going to 10 is not, unless you modified your setup to do so. Check to make sure your wastegate is still connected and that you don't have any new leaks as a result of what that shop did.
...but the boost going to 10 is not, unless you modified your setup to do so. Check to make sure your wastegate is still connected and that you don't have any new leaks as a result of what that shop did.
10-30-2006, 05:03 PM
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MYSQL101 and or KENKAMM, i did two things today, i put it back to open atmosphere and capped off the aluminum fitting that stemmed of off the air intake. Car ran the same as when I had it recirculated.....HUMMM......weird. Tried both set-up and you mention that this is normal for the AFR to shoot up to 17 afr. Wow, i want to tune it now and what are the normal (min and max afr) during boost from 1st to 6th gear. I don't want the motor to go to ****. What can i do to prevent detonation and what is sign of it? Thanks ya'll. A quest for this perfect set up is hard and but worth it. Thanks brothers! I salute you all.
10-30-2006, 08:14 PM
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Read Mazdamaniac's last post in this thread.
Typically you're looking for an AFR of 11 to 11.5 under boost. Someone can correct me if I'm wrong.
If you are still hitting 10 psi and you're kit isn't modified, fix that.
Typically you're looking for an AFR of 11 to 11.5 under boost. Someone can correct me if I'm wrong.
If you are still hitting 10 psi and you're kit isn't modified, fix that.
10-30-2006, 10:01 PM
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In 5th gear I shoot for an AFR around 11.5 with a 70deg ambient. I lean it out a little as it gets colder and richen it up when hotter. Detonation is largely influenced by the intake temps.
In lower gears, it will be leaner, which is fine since the load on the engine isn't as high. As long as it doesn't ping in 5th it won't ping in the lower gears.
The boost overshooting could likely be a result of the weather change. When the temperature drops the air becomes more dense and the turbo doesn't have to work as hard to pressurize it. It will take a few runs for your boost controller to relearn. I usually turn down the boost controller preemptively when the temp drops to prevent this.
In lower gears, it will be leaner, which is fine since the load on the engine isn't as high. As long as it doesn't ping in 5th it won't ping in the lower gears.
The boost overshooting could likely be a result of the weather change. When the temperature drops the air becomes more dense and the turbo doesn't have to work as hard to pressurize it. It will take a few runs for your boost controller to relearn. I usually turn down the boost controller preemptively when the temp drops to prevent this.
Last edited by rkostolni; 11-09-2006 at 12:22 PM.