My awesome daily project 35mpg/150whp highway donut
#141
Tour de Franzia
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Does anyone have a log and or a pic of your enrichments working perfectly? Is there any way to eliminate the lean-spike on accell? I don't really understand the practical application of the transient fuel theory stuff. I get how pooling works but I don't understand if its possible to eliminate the over-richness post throttle application.
#144
Our last motor took a solid 60+ hours of racing before it spun a bearing, but really that was because it consumed WAY more oil than we thought and ran low. LeMons doesn't allow you to check those things in hot pits. It also had 270,000 miles on it when we put it in.
This motor should be pretty on par by the sound of it.
#145
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Where it will live out the rest of its life in style, in a LeMons car.
Our last motor took a solid 60+ hours of racing before it spun a bearing, but really that was because it consumed WAY more oil than we thought and ran low. LeMons doesn't allow you to check those things in hot pits. It also had 270,000 miles on it when we put it in.
This motor should be pretty on par by the sound of it.
Our last motor took a solid 60+ hours of racing before it spun a bearing, but really that was because it consumed WAY more oil than we thought and ran low. LeMons doesn't allow you to check those things in hot pits. It also had 270,000 miles on it when we put it in.
This motor should be pretty on par by the sound of it.
#146
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Originally Posted by Wikipedia
EGR in spark-ignited engines
The exhaust gas, added to the fuel, oxygen, and combustion products, increases the specific heat capacity of the cylinder contents, which lowers the adiabatic flame temperature.
In a typical automotive spark-ignited (SI) engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR. The maximum quantity is limited by the requirement of the mixture to sustain a contiguous flame front during the combustion event; excessive EGR in poorly set up applications can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. The impact of EGR on engine efficiency largely depends on the specific engine design, and sometimes leads to a compromise between efficiency and NOx emissions. A properly operating EGR can theoretically increase the efficiency of gasoline engines via several mechanisms:
Since the EGR system recirculates a portion of exhaust gases, over time the valve can become clogged with carbon deposits that prevent it from operating properly. Clogged EGR valves can sometimes be cleaned, but replacement is necessary if the valve is faulty.
The exhaust gas, added to the fuel, oxygen, and combustion products, increases the specific heat capacity of the cylinder contents, which lowers the adiabatic flame temperature.
In a typical automotive spark-ignited (SI) engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR. The maximum quantity is limited by the requirement of the mixture to sustain a contiguous flame front during the combustion event; excessive EGR in poorly set up applications can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. The impact of EGR on engine efficiency largely depends on the specific engine design, and sometimes leads to a compromise between efficiency and NOx emissions. A properly operating EGR can theoretically increase the efficiency of gasoline engines via several mechanisms:
- Reduced throttling losses. The addition of inert exhaust gas into the intake system means that for a given power output, the throttle plate must be opened further, resulting in increased inlet manifold pressure and reduced throttling losses.
- Reduced heat rejection. Lowered peak combustion temperatures not only reduces NOx formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.
- Reduced chemical dissociation. The lower peak temperatures result in more of the released energy remaining as sensible energy near TDC, rather than being bound up (early in the expansion stroke) in the dissociation of combustion products. This effect is minor compared to the first two.
- Reduced specific heat ratio. A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.
Since the EGR system recirculates a portion of exhaust gases, over time the valve can become clogged with carbon deposits that prevent it from operating properly. Clogged EGR valves can sometimes be cleaned, but replacement is necessary if the valve is faulty.
#147
Tour de Franzia
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Where it will live out the rest of its life in style, in a LeMons car.
Our last motor took a solid 60+ hours of racing before it spun a bearing, but really that was because it consumed WAY more oil than we thought and ran low. LeMons doesn't allow you to check those things in hot pits. It also had 270,000 miles on it when we put it in.
This motor should be pretty on par by the sound of it.
Our last motor took a solid 60+ hours of racing before it spun a bearing, but really that was because it consumed WAY more oil than we thought and ran low. LeMons doesn't allow you to check those things in hot pits. It also had 270,000 miles on it when we put it in.
This motor should be pretty on par by the sound of it.
#148
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As I understand, its only active under cruise-type conditions but I can't tell if its more for emissions or fuel economy. I know there are a couple threads on here where people ask about adding it, but no one ever really looked into it further. Is there a way to activate an output at say 48-70kpa between 3000-4000rpm, switch to a second table, and save money?
#152
I have an extra one somewhere... It just occurred to me that I only have an NB2 EGR pipe, which is apparently somewhat shorter than the NA EGR pipe, and has a different fitting than my NA header. Gonna have to do some welding, I think.
#153
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It probably just needs the valve and EGR passage in the intake manifold cleaned out.
I have an extra one somewhere... It just occurred to me that I only have an NB2 EGR pipe, which is apparently somewhat shorter than the NA EGR pipe, and has a different fitting than my NA header. Gonna have to do some welding, I think.
I have an extra one somewhere... It just occurred to me that I only have an NB2 EGR pipe, which is apparently somewhat shorter than the NA EGR pipe, and has a different fitting than my NA header. Gonna have to do some welding, I think.
Next time I go to Houston, we should meat up and eat pig guts tacos.
#154
Thoughts on increased gas mileage, HDR apocalypse front lip with birch splitter running all the way back to the trans, wheel spats front and rear /, straight shot intake, light eBay flywheel, with 1.6 6 puck, rear bumper vents, ls1 coils, 100% real gas / no 90/10, do they make 3.30 gears?
#155
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Thoughts on increased gas mileage, HDR apocalypse front lip with birch splitter running all the way back to the trans, wheel spats front and rear /, straight shot intake, light eBay flywheel, with 1.6 6 puck, rear bumper vents, ls1 coils, 100% real gas / no 90/10, do they make 3.30 gears?
Edit: Pool Noodle MPG mod via M.net: http://forum.miata.net/vb/showthread.php?t=342172 Do it! You know you want to...
#158
Tour de Franzia
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Thoughts on increased gas mileage, HDR apocalypse front lip with birch splitter running all the way back to the trans, wheel spats front and rear /, straight shot intake, light eBay flywheel, with 1.6 6 puck, rear bumper vents, ls1 coils, 100% real gas / no 90/10, do they make 3.30 gears?
#159
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Make sure your <1500rpm high-load cells are properly tuned, otherwise your are band-aiding the actual problem. 1st/2nd gear in an empty parking lot and use the brake to simulate the load.
Last edited by Reverant; 04-10-2012 at 08:49 AM.