Disable turbo on demand.
09-02-2011, 02:18 PM
#21
Tour de Franzia
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You can tune that lean with shitloads of adavnce even with high compression when at low load i.e. cruising.
16.5:1 and 40+deg advance here on an otherwise stock 2001 engine.
Low comp actually hurts your mpg, but your turbine makes up for the loss in engine VE.
Your setup on a higher compression engine would yield better MPG, but much lower power when at WOT.
16.5:1 and 40+deg advance here on an otherwise stock 2001 engine.
Low comp actually hurts your mpg, but your turbine makes up for the loss in engine VE.
Your setup on a higher compression engine would yield better MPG, but much lower power when at WOT.
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09-02-2011, 02:23 PM
#22
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Here is the problem with semi lean burn. When the fuel is injected the combustion starts from the center and leaves a layer of fuel on the outside near the walls. That protects the walls and keeps them cooler. When you're leaning at 16-17 you're using that layer up yet you still have enough power to do dmg. Super lean burn combustion is suppose to exchange that layer near the walls with air however i dont know how much fuel super lean burn is suppose to have. What i have read about it though is you need direct injection so you have a fairly good amount of concentrated fuel in the piston to burn.
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09-02-2011, 02:25 PM
#23
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It's not the pistons you should be looking at, it's the valves.
If you have an EGT sensor tuning cruise to be as lean as possible is easy, otherwise it's complete guesswork really.
However I've run for 6+ at 16.5:1 years via the following method
Lean out when at steady state until the car starts to surge, then add in a few points of fuel
Do the same with timing
Then revisit the fuel.
Done.
It's better on a dyno as then you can see at what AFR and timing angle picks up the most power. You want as much power with as little throttle position as possible.
EGR is nice if you have that as you can reduce pumping losses by being able to run the same afr/timing fuel PW at larger throttle openings.
If you have an EGT sensor tuning cruise to be as lean as possible is easy, otherwise it's complete guesswork really.
However I've run for 6+ at 16.5:1 years via the following method
Lean out when at steady state until the car starts to surge, then add in a few points of fuel
Do the same with timing
Then revisit the fuel.
Done.
It's better on a dyno as then you can see at what AFR and timing angle picks up the most power. You want as much power with as little throttle position as possible.
EGR is nice if you have that as you can reduce pumping losses by being able to run the same afr/timing fuel PW at larger throttle openings.
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09-02-2011, 02:26 PM
#24
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Here is the problem with semi lean burn. When the fuel is injected the combustion starts from the center and leaves a layer of fuel on the outside near the walls. That protects the walls and keeps them cooler. When you're leaning at 16-17 you're using that layer up yet you still have enough power to do dmg. Super lean burn combustion is suppose to exchange that layer near the walls with air however i dont know how much fuel super lean burn is suppose to have. What i have read about it though is you need direct injection so you have a fairly good amount of concentrated fuel in the piston to burn.
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09-02-2011, 02:55 PM
#25
Here's some good reading about mixture for you guys:
http://www.avweb.com/news/pelican/182084-1.html
Written from the standpoint of managing aircraft piston engines, but the concepts apply to us too.
Note that this would not apply to the new, direct-injection super lean burn technology being developed now.
http://www.avweb.com/news/pelican/182084-1.html
Written from the standpoint of managing aircraft piston engines, but the concepts apply to us too.
Note that this would not apply to the new, direct-injection super lean burn technology being developed now.
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09-09-2011, 01:39 AM
#26
To answer the original question, you'd use a solenoid hooked to a tee connected to the atmospheric port on an external waste gate. Trigger the solenoid with the ecu to switch between vacuum and atmospheric. You'd need to run a light wastegate spring to ensure your cruise vacuum can open the waste gate.
It probably won't help, though
It probably won't help, though
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09-09-2011, 01:05 PM
#27
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So been trying to find a way to manually open the wastegate on demand to help mpgs...freeer exhaust flow...no boost etc. I've looked at boost controllers and correct me if i'm wrong however those need some pressure to open the wastegate. Anybody have any idea for anything that can be used to open the wastegate on demand (other than full boost lol)?
Seems the newer cars are using these devices in line with the ecu to regulate boost that way.
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