What's your A/F on Overrun?, 'Nother D-Jet A/F Question |
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What's your A/F on Overrun?, 'Nother D-Jet A/F Question |
BeatNavy |
Mar 12 2017, 12:28 PM
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#1
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
For those with D-Jet, what are you typically seeing for A/F ratio on a medium to hard overrun? Based on what I've read here mine seems too rich - like in 10's and 11's. Once the RPM's drop closer to idle it bounces back up to normal idle A/F ratios. Does A/F on overrun even matter?
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Mark Henry |
Aug 16 2017, 08:28 AM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I can't see a system that has no fuel cut having lower emissions.
My bet is with fuel cut the car had more engine braking, eliminating fuel cut might actually have better MPG as the car coasts more if it's still burning a bit of fuel. Likely VW eliminated the fuel cut to increase the cars MPG figures. Without coasting you would be on the gas more when cruising, because of more erratic speed control, thus burning more fuel. I see this in my bug (T4 conversion) that has full fuel cut, my engine braking is huge. In fact I could see the Joe average driver not liking how much engine braking my car has. You can't lug my car, I have to keep the rpm up around 3K as the engine braking action makes it a PITA to cruise at lower RPM's. You definitely wouldn't like driving it in constant stop and go every day. |
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