Originally Posted by
BUIZILLA
look into a closed loop EFI system, as cool as marine engines run I don't see a need to run open loop...most if not all open loop systems stay in closed loop until 145-160* anywaysjust my .03c
Clearly, because I'm looking for O2 sensor solutions we're talking closed loop. Open loop (without an O2 sensor) is common on motorcycles and early marine FI applications but, relies on ECU programming and preset fuel / timing settings. Many closed loop systems run at open loop settings when at WOT to ensure a safe fuel map to protect the motor and as you mentioned, during warm-up.
The FI manufacturers rep convinced me that while open loop systems will work, they just don't run as well or, produce all the benefits the system is capable of in terms of performance or economy. In short... it's an efficiency thing. Further, recent O2 sensor technology (last 3-4 years) has produced at least two choices of marine designed sensors that are less sensitive to moisture (They still can't be in the water stream though) and tout greater durability.
As far as running engine temps, yes marine applications run cooler than automotive. However, this can also be addressed. I am undecided about running a closed cooling system (or 1/2 system) that can be set to run at a warmer temperature that is also a more consistent temperature (less fluctuation). But, this is down the road and I haven't really started researching this yet.
Sean Conroy,
1964 Formula Jr. (hull #2) project
1972 Greavette Sunflash III
1981 Kavalk Mistral project
"A man can accomplish anything... as long as he doesn't care who gets the credit."