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over fueling ?
could someone explain to me what overfueling is guy at work said to me subarus overfuel to protect the engine and when they get mapped the fuel econamy is actualy better because the mapper sorts this
how does over fueling protect the engine am guessing this is at high revs also i had no idea how gutsy these cars are i ran a 3.0 twin turbo for a fortnight and it didnt drink as mutch fuel as my uk classic lol |
You don;t want the engine to run lean, causes det and can create enough heat to do serious internal damage. running a bit rich just keeps it on the safer side of the line and doens;t relay bother the engine much. hwoever youc an go to far and run it too rich.
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ahhhh right have heard of this before but a while ago i get it now thanks
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Rather simple answer from Tidgy......
Most engines most the time run at Lambda1, this is the 'chemically correct' air fule ratio for complete combustion (although it doesn't actually happen), at wide open throttle most N/A engines will produce maxiumum power/torque running at about 10% rich of Lambda1. However that will frequantly result in some components running hotter than their safe temperature (Pistons, valves, cylinder heads - seats dropping, turbo's or catalysts) so most engines will run richer than that for 'component protection' that can be anywhere from 15% rich of Lambda one to, on some turbo engines (smaller turbo's higher CR), as rich as 30% rich of Lambda one. Nearly all petrol engines 'over fuel' (run rich of Lamda1) at some speed/load sites, turbo engines need to do it more often for sure, not sure the Subarus are that much worse than any other port injected (not direct injected) turbo. The original mapping is rich enough to satisfy Subaru's durability requirements, yes a mapper can lean it off, it may be a risk, or on your usage cycle it may not. Simon |
thanks that was a nice write up and well explained thank u
i am now off to go wash and wax ma baby and stick up some pics in the rides section :hjtwofing |
Originally Posted by The rookie
(Post 9565124)
Rather simple answer from Tidgy......
Most engines most the time run at Lambda1, this is the 'chemically correct' air fule ratio for complete combustion (although it doesn't actually happen), at wide open throttle most N/A engines will produce maxiumum power/torque running at about 10% rich of Lambda1. However that will frequantly result in some components running hotter than their safe temperature (Pistons, valves, cylinder heads - seats dropping, turbo's or catalysts) so most engines will run richer than that for 'component protection' that can be anywhere from 15% rich of Lambda one to, on some turbo engines (smaller turbo's higher CR), as rich as 30% rich of Lambda one. Nearly all petrol engines 'over fuel' (run rich of Lamda1) at some speed/load sites, turbo engines need to do it more often for sure, not sure the Subarus are that much worse than any other port injected (not direct injected) turbo. The original mapping is rich enough to satisfy Subaru's durability requirements, yes a mapper can lean it off, it may be a risk, or on your usage cycle it may not. Simon nothing wrong with a nice simple answer lol |
Originally Posted by The rookie
(Post 9565124)
Rather simple answer from Tidgy......
Nothing wrong with a nice simple answer. As the saying goes, the fule and his money are easily parted. ;) </humour> |
Argh so, the simple but misleading answer is better than the right one with a simple spelling mistake?
Spirit of scoobynet lives on in some obviously! Simon |
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