vq35de light load crusing a/f ratio
03-23-2012, 11:35 AM
#22
^ I think the answer to your question is yes, for the Haltech, map allows I think up to 720 degrees. The terminology used is firing angle though as str8dum1 stated.
Here is what I have from a Haltech engineer on that tuning element:
Here is what I have from a Haltech engineer on that tuning element:
The Injector firing angle is the angle at which the injector will SHUT after the injection even has occured (relitive to a full camshaft revolution). The injection angle depends on things such as camshaft profile, intake manifold design, fuel type, injector location as well as other external factors.
Injection angle is also used in certain applications to cool in the inlet valves.
When tuning the end of injection angle (with the exception of above) you want to make sure all injected fuel is taken in by the motor and not "blown" back up the inlet manifold. (Look on Youtube for old F1 engine dyno tests to see the fuel spraying all over the place)
In practice the easiest way to do this is by tuning your engine to a known AFR. Next, adjust the injector firing angle until the engine becomes as rich as possible, now we know that the engine is burning the maximum amount of injected fuel. Do this for each RPM site you require.
You will notice that the engine will be slightly more responsive at lower RPM with the correct injection angle.
Please note, if the engine is not tuned to accpetable mixtures (rich and lean spots all over the place) that injection angle will not make much of a diffrence and you should spend more time on the tune.
Injection angle is also used in certain applications to cool in the inlet valves.
When tuning the end of injection angle (with the exception of above) you want to make sure all injected fuel is taken in by the motor and not "blown" back up the inlet manifold. (Look on Youtube for old F1 engine dyno tests to see the fuel spraying all over the place)
In practice the easiest way to do this is by tuning your engine to a known AFR. Next, adjust the injector firing angle until the engine becomes as rich as possible, now we know that the engine is burning the maximum amount of injected fuel. Do this for each RPM site you require.
You will notice that the engine will be slightly more responsive at lower RPM with the correct injection angle.
Please note, if the engine is not tuned to accpetable mixtures (rich and lean spots all over the place) that injection angle will not make much of a diffrence and you should spend more time on the tune.
Last edited by rcdash; 03-23-2012 at 11:36 AM.
03-23-2012, 12:05 PM
#23
be interesting to know what the stock firing angles are.
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
Last edited by str8dum1; 03-23-2012 at 12:07 PM.
03-23-2012, 12:35 PM
#25
be interesting to know what the stock firing angles are.
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
This is a pretty interesting video I saw a while back, pretty related I suppose, and vinny ten has his credentials:
http://www.youtube.com/watch?v=tys6M_5Z_uk
03-27-2012, 04:49 PM
#28
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Wow I'm getting about 28mpg on the highway at 75 with my greddy twins. I'm in sixth gear at 3000 rpms and not making boost yet and the car does answer. I swear. I couldn't believe it the same highway before turbos I was getting 23mpg
04-01-2012, 07:43 AM
#32
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I can drive downhill on almost no throttle with my large injectors and it says I'm gettin 40mpg. It's based on pulse width which is considerably smaller with large injectors than with the oem stock injectors.
On that note with pump I average 26mpg per tank (calculated). I have been getting 19mpg per tank with e85 now.
04-01-2012, 07:50 AM
#33
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be interesting to know what the stock firing angles are.
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
If I could get good gas mileage with the stock injectors/ecu than I should be able to replicate that with my big injectors/standalone. Something isnt the same.
Not much to choose from since AFR's, rpm range, tps, engine temp, and vacuum levels were the same. could only be:
cam timing
ign timing
injector angle
Same thing with my ex. We bought a Milan with the 4 banger. She said it was horrible on gas mileage and was getting 25ish mpg. I decided to drive it for a week and averaged upper 30 mpg. She drives like a moron and drag races from stoplight to stoplight. She also loves to sit in the car on the phone while the engine is running. Driver mod needs to be performed.
04-01-2012, 05:02 PM
#34
You forgot the most important factor: drive style. As much as people don't want to admit when hp is upgraded and new goodies are on the car they tend to drive harder. Everyone says "no way, blah blah blah" but under normal daily driving instill remained same calculated mpg per tank through all my upgrades as I was stock. That's because I drive sensibly as a daily driver. Indot count the tanks that I'm tuning or racing on.
Same thing with my ex. We bought a Milan with the 4 banger. She said it was horrible on gas mileage and was getting 25ish mpg. I decided to drive it for a week and averaged upper 30 mpg. She drives like a moron and drag races from stoplight to stoplight. She also loves to sit in the car on the phone while the engine is running. Driver mod needs to be performed.
Same thing with my ex. We bought a Milan with the 4 banger. She said it was horrible on gas mileage and was getting 25ish mpg. I decided to drive it for a week and averaged upper 30 mpg. She drives like a moron and drag races from stoplight to stoplight. She also loves to sit in the car on the phone while the engine is running. Driver mod needs to be performed.
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