---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Sun 11/28/04: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:52 AM - 1.3L, 4 cyl. Suzuki (Geo) engine (Ron &Phyliss) 2. 09:48 AM - Re: 1.3L, 4 cyl. Suzuki (Geo) engine (Ed Anderson) 3. 05:03 PM - Re: 1.3L, 4 cyl. Suzuki (Geo) engine (Garth Shearing) ________________________________ Message 1 _____________________________________ Time: 08:52:49 AM PST US From: "Ron &Phyliss" Subject: Engines-List: 1.3L, 4 cyl. Suzuki (Geo) engine --> Engines-List message posted by: "Ron &Phyliss" Am a week away from initial run of the Suzuki engine in a CH-701. Wings were completed before engine choice, therefore , no provision was made for return fuel from the injector rail. I have a vertically mounted 5" x 13" round aux. tank with a Walbro high press. pump mounted inside. The return line from the rail is at the top/side of the aux. tank. Gravity fuel from the wing/s tank enters at the bottom/side. There is a "temp" clear tubing from bottom to top to monitor action. Question: At worst condition, when eng. is at idle, will the return fuel merely keep more fuel from feeding from the wing tanks, or will it cause leaks? How many fire extinguishers should I have ready? Wing tanks have Zenith proposed 1/4" vent tubes on caps and fuel pump is controlled by the ECM. Any suggestions will be appreciated. Ron Dallmeyer rgdplg@radiowire.net ________________________________ Message 2 _____________________________________ Time: 09:48:36 AM PST US From: "Ed Anderson" Subject: Re: Engines-List: 1.3L, 4 cyl. Suzuki (Geo) engine --> Engines-List message posted by: "Ed Anderson" Ron, I have an electronic fuel injected set up somewhat similar to yours. While my pumps are on the outside of a small header tank on the firewall, the header tank is gravity fed from the wing tanks. In my case, fuel is drawn into the small header tank whenever fuel is injected into the engine - this (injection) maintains a pressure differential between the header tank and wing tanks when ever the engine is running and "sucking" fuel from the header. At low rpms more fuel is returned from the injector rail and at high rpms less fuel is returned. Any fuel injected, of course, reduces the fuel in the header tank (and the pressure differential ) "sucks" the fuel from my wing (low wing) tanks. Its fairly powerful effect in that when testing I had a marine plastic fuel tank on the ground (24" below my pumps) and once when I forgot to open up the tanks vents, the "suction" had practically sucked the tank flat. The thing that can happen is if the fuel gets too warm it can cause pressure to build up in the header tank and reduce the flow from the wing tanks. This generally would happen at high temps under the cowl and low fuel flow/usage like at idle. At high power setting, the fuel usage is high (less returned to the header tank) and less of a problem. I have a cooling air "blast" tube focused on my tank and pumps. I also have a 6 psi boost pump between the header tank and my wing tanks. When I used Mogas (which has more of a tendency to form vapor at lower temps than AvGas), I would notice the fuel pressure might start to vary on a hot day (indicating the fuel vapor was building) but turning on the boost pump always subdued the effect. So I don't think leaks would be a problem assuming the tank doesn't have holes in it {:>), but you might be on the look out for the fuel percolating in the header tank - generally first indication I see is fuel pressure starting to fluctuate. FWIW Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ----- Original Message ----- From: "Ron &Phyliss" Subject: Engines-List: 1.3L, 4 cyl. Suzuki (Geo) engine > --> Engines-List message posted by: "Ron &Phyliss" > > Am a week away from initial run of the Suzuki engine in a CH-701. Wings were completed before engine choice, therefore , no provision was made for return fuel from the injector rail. I have a vertically mounted 5" x 13" round aux. tank with a Walbro high press. pump mounted inside. The return line from the rail is at the top/side of the aux. tank. Gravity fuel from the wing/s tank enters at the bottom/side. There is a "temp" clear tubing from bottom to top to monitor action. > Question: At worst condition, when eng. is at idle, will the return fuel merely keep more fuel from feeding from the wing tanks, or will it cause leaks? How many fire extinguishers should I have ready? > Wing tanks have Zenith proposed 1/4" vent tubes on caps and fuel pump is controlled by the ECM. > Any suggestions will be appreciated. > Ron Dallmeyer > rgdplg@radiowire.net > > ________________________________ Message 3 _____________________________________ Time: 05:03:26 PM PST US From: "Garth Shearing" Subject: Re: Engines-List: 1.3L, 4 cyl. Suzuki (Geo) engine --> Engines-List message posted by: "Garth Shearing" Hi Ron. I have a similar system in my airplane. Just in case it's not already done, I would like to recommend that the vents from all three tanks go to a single manifold ideally located above the main tanks so that the air pressure is the same for all tanks. This means, however, that there will be fuel in the auxiliary tank vent line up to the level of the fuel in the main tanks, so install this line carefully. The auxiliary tank must be vented in any case. The vent from the manifold, or two of them for redundancy if you want, must exit into the air above the main tanks, obviously. If you really want to get fancy, you can run the vent from the manifold up to a point above the main tanks and then down to a point near the bottom facing into the wind. This way you can turn inverted for a little while without losing any fuel and no water can get into the fuel. :<). The return line running back to the auxiliary tank is fine. This reduces fuel management issues to near zero. The fuel pump pumps the same amount of fuel all the time. The excess fuel not burned by the engine is returned to the auxiliary tank. Therefore, there is less fuel being returned when the engine is at high power and conversely there is more fuel being returned when the engine is at idle. In my airplane I installed two fuel pumps in parallel for redundancy. You could have used the Suzuki fuel pumps I suppose. They are nice units and only consume about one amp of power. It took me quite a bit of designing so that I could use my Camry submerged pumps. You can test pump capacity easily with the engine off by sticking the return line into a pail and measuring the fuel pumped into it after a measured length of time. Fuel pump capacity must, of course, exceed the maximum fuel consumption of the engine at maximum power at sea level. Another suggestion: If the auxiliary tank can be located near the bottom of the aircraft, you can install a valve on the bottom of it for draining and preflight fuel sampling. No gascolator required. Garth Shearing VariEze and 90% RV6A Victoria BC Canada ----- Original Message ----- From: "Ron &Phyliss" Subject: Engines-List: 1.3L, 4 cyl. Suzuki (Geo) engine > --> Engines-List message posted by: "Ron &Phyliss" > > Am a week away from initial run of the Suzuki engine in a CH-701. Wings were completed before engine choice, therefore , no provision was made for return fuel from the injector rail. I have a vertically mounted 5" x 13" round aux. tank with a Walbro high press. pump mounted inside. The return line from the rail is at the top/side of the aux. tank. Gravity fuel from the wing/s tank enters at the bottom/side. There is a "temp" clear tubing from bottom to top to monitor action. > Question: At worst condition, when eng. is at idle, will the return fuel merely keep more fuel from feeding from the wing tanks, or will it cause leaks? How many fire extinguishers should I have ready? > Wing tanks have Zenith proposed 1/4" vent tubes on caps and fuel pump is controlled by the ECM. > Any suggestions will be appreciated. > Ron Dallmeyer > rgdplg@radiowire.net >