MY FULE COOLING SYSTEM
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Joined: Jan 2008
Posts: 131
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From: Washington
02' C32 - 07' H2 - 07' BMW K1200R
) LOL....I was just trying to play around a bit. I beter stay out of the comedy business, and keep my day job 
Member
Joined: Jan 2008
Posts: 131
Likes: 0
From: Washington
02' C32 - 07' H2 - 07' BMW K1200R
Closed loop operation has nothing to do with whether an engine is supercharged/turbocharged or naturally aspirated. Closed loop operation means that an oxygen sensor controls the amount of fuel injected to yield a perfect chemical mixture of fuel and air. This is necessary in order for catalytic converters to reduce HC, CO and NOx. Too much or too little fuel and only one or two get reduced.
This works well at moderate loads, but not at wide open throttle. At WOT the mixture needs more fuel than air in order to avoid overheating important engine parts. So at some point when you stick your foot in it the engine controller decides to ignore the oxygen sensor and go to open loop operation using a pre-programmed map. The 95%+ bit is my guess as to how often you use WOT in day to day use. It's probably more like 80% in my wife's case.
As for the P-car fuel cooler, as I read the posts it sounds like they use it on the return line also. You don't want the gasoline getting too hot, as it cause vapor lock and evaporative control problems. There's a lot of heat coming from the engine, as well as energy from the fuel pump that's running a lot of gas around in a circle.
This works well at moderate loads, but not at wide open throttle. At WOT the mixture needs more fuel than air in order to avoid overheating important engine parts. So at some point when you stick your foot in it the engine controller decides to ignore the oxygen sensor and go to open loop operation using a pre-programmed map. The 95%+ bit is my guess as to how often you use WOT in day to day use. It's probably more like 80% in my wife's case.
As for the P-car fuel cooler, as I read the posts it sounds like they use it on the return line also. You don't want the gasoline getting too hot, as it cause vapor lock and evaporative control problems. There's a lot of heat coming from the engine, as well as energy from the fuel pump that's running a lot of gas around in a circle.
I was thinking about looking for a used Porsche unit for the fun of it, and seeing if I could modify it to work in my car.
Bad idea?
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Joined: Aug 2007
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From: Phoenix AZ & Cayucos CA
’27 AMG SL55(ordered), ‘23 EQS 580 SUV, ‘19 AMG E53 Cpe, ‘48 Willys Jeepster
In theory you could make a cooler easily enough, just find a metal section of the low pressure AC return line, wrap some steel or copper tubing around it and re-route your fuel return line through it. The BMW "cooler" was something like 6" long, so assuming you use 1/4" tubing you'd need around 24 wraps. Cover it all with roll bar padding and you're done. The trick is bending the tubing around the AC line without kinking it.
What I'm not so sure about is what it would do to your fuel pressure with the added length of tubing. Worse case is slightly higher pressure at the injectors. The fuel injection system should be able to accomodate it, but I don't know enough about the MB system to say so for sure.
Overall, it shouldn't hurt. I seem to recall that the fuel injection system on Volvo S60R/V70Rs measured fuel temperature as part of it's metering scheme, so it must make some difference.
But keep in mind also that you now have more places for fuel to leak from. An engine fire will not make your day any better.
What I'm not so sure about is what it would do to your fuel pressure with the added length of tubing. Worse case is slightly higher pressure at the injectors. The fuel injection system should be able to accomodate it, but I don't know enough about the MB system to say so for sure.
Overall, it shouldn't hurt. I seem to recall that the fuel injection system on Volvo S60R/V70Rs measured fuel temperature as part of it's metering scheme, so it must make some difference.
But keep in mind also that you now have more places for fuel to leak from. An engine fire will not make your day any better.
