Towing w/ a radix
10-15-2007, 09:35 PM
#25
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10-15-2007, 10:11 PM
#27
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To bad the COT tables were not in RPM scale because you can run a much leaner COT AFR at 2000- 2500 rpm then you can at 5000-7000 On a 2007 you can set the COT at 13.1 at 2500 with 4-5 lbs boost and maintain a constant 1680 degrees of cat temp with no climbing in temp but at 5000 RPM it takes almost 9.8 AFR to maintain the same temp and this is steady state testing.
10-15-2007, 11:13 PM
#28
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Also anytime you are in boost(turbo or SC) it requires a richer fuel mixture say 11-12:1 AFR rather than 14.7:1 when not in boost. So it is more than just increasing the fuel flow to match the airflow. That richer mixture is what makes the 2 MPG difference under cruising conditions in my case, even though I am revving a lot higher in 3rd gear. So the real loss from the richer mixture is actually greater than 2 MPG.
The SC does making passing and getting rolling a breeze when towing though.
The SC does making passing and getting rolling a breeze when towing though.
In fact if you are tuning for towing (that has a nice ring doesn't it), you can take the wideband and chuck it out the window.The thing to watch, EGT. Add enough fuel to suppress kr (or pull timing) and enough fuel to keep egts in line, other than that... as lean as you can safely go. Of course you will need to go back and pick-up that wideband you just through out.
There are times when it is more fuel efficient to drop a gear, and run only 1 or 2 psi of boost, rather than hold O/D and run 5+psi. I have logs showing Injector duty cycles dropping with down shifting...
Bottom line, you CAN get better fuel mileage with a gas/turbo while towing..
10-16-2007, 07:24 PM
#29
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You do not need 11.5 a/f at 2-3 psi of boost, 13.s will get you by. In fact tuning for towing is TOTALY different than normal track/street tuning IMHO.
In fact if you are tuning for towing (that has a nice ring doesn't it), you can take the wideband and chuck it out the window.The thing to watch, EGT. Add enough fuel to suppress kr (or pull timing) and enough fuel to keep egts in line, other than that... as lean as you can safely go. Of course you will need to go back and pick-up that wideband you just through out.
There are times when it is more fuel efficient to drop a gear, and run only 1 or 2 psi of boost, rather than hold O/D and run 5+psi. I have logs showing Injector duty cycles dropping with down shifting...
Bottom line, you CAN get better fuel mileage with a gas/turbo while towing..
In fact if you are tuning for towing (that has a nice ring doesn't it), you can take the wideband and chuck it out the window.The thing to watch, EGT. Add enough fuel to suppress kr (or pull timing) and enough fuel to keep egts in line, other than that... as lean as you can safely go. Of course you will need to go back and pick-up that wideband you just through out.
There are times when it is more fuel efficient to drop a gear, and run only 1 or 2 psi of boost, rather than hold O/D and run 5+psi. I have logs showing Injector duty cycles dropping with down shifting...
Bottom line, you CAN get better fuel mileage with a gas/turbo while towing..
How if it doesn't make the power down low how do you get better MPG then a radix. I don't know thats why I was askings.