My E85 as a Octane Booster Experiment
Drifting
Joined: Sep 2008
Posts: 1,389
Likes: 3
From: somewhere shooting my assault rifles
It lets you run more boost, higher initial timing (boosted engines are often run severely retarded to prevent detonation) and lets you pull less timing when IATs go up. That's were the power increase comes from.
Gains would be minimal on a NA setup unless you're running into detonation, or have built extra compression into the engine. Advancing timing beyond 22 degrees may not increase power. It's an efficient combustion chamber, doesn't need as much advance as some other engines, and there's no benefit beyond a certain point.
Gains would be minimal on a NA setup unless you're running into detonation, or have built extra compression into the engine. Advancing timing beyond 22 degrees may not increase power. It's an efficient combustion chamber, doesn't need as much advance as some other engines, and there's no benefit beyond a certain point.
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
Also, YOUR FUEL TANK HAS A BALANCING LINE. No one tank will be drained first and contain more this or that. That would be stupid and cause horrible weight distribution... Ive replaced them before and seen the balancing line. Only thing is fuel pump is on the driver side.
When filling, the driver side tank will fill first. Once it's full, fuel spills through the top connecting tube to the passenger tank.
The pump in the passenger side is constantly pumping into the driver's side tank. The driver's side remains full, and spills over into the passenger tank until the passenger side is empty, and has no more to pump. Only then does the level in the driver's side tank start to go down.
Eventually, with enough running, E85 and gasoline which aren't premixed should mix evenly, but I'd be worried about what happens in the interim.
Thread Starter
Safety Car
Joined: Apr 2007
Posts: 3,582
Likes: 137
From: SoCal CA
That's not quite right.
When filling, the driver side tank will fill first. Once it's full, fuel spills through the top connecting tube to the passenger tank.
The pump in the passenger side is constantly pumping into the driver's side tank. The driver's side remains full, and spills over into the passenger tank until the passenger side is empty, and has no more to pump. Only then does the level in the driver's side tank start to go down.
Eventually, with enough running, E85 and gasoline which aren't premixed should mix evenly, but I'd be worried about what happens in the interim.
When filling, the driver side tank will fill first. Once it's full, fuel spills through the top connecting tube to the passenger tank.
The pump in the passenger side is constantly pumping into the driver's side tank. The driver's side remains full, and spills over into the passenger tank until the passenger side is empty, and has no more to pump. Only then does the level in the driver's side tank start to go down.
Eventually, with enough running, E85 and gasoline which aren't premixed should mix evenly, but I'd be worried about what happens in the interim.
Burning Brakes
Joined: Jan 2009
Posts: 918
Likes: 2
From: Lewisburg TN
St. Jude Donor '10-'11-'12,'14
The fuel system will mix even though there is two tanks. Here is a description of the system from the service manual please note the bold section on point #5 t that is a discharge from the left fuel pump and serves also as a feed to the right tank syphon pump. I cannot tell you what the total turnover is but I did a little test this morning. I have been doing some tuning on the Z06 with 93 only and toploaded ~3.5-4 gal of e85 through a funnel so I am essentially top filling the left tank only.
Due to tunning my LTFT's have been right around 0. Within a couple of miles they started adjusting and by ~15 miles where settled in at ~3.9-4.1 and stayed that way for the duration of my 32 mile to work trip.
I can tell you from memory that with my 2003 Silverado (one fuel tank) they will adjust to a substantial ethanol % change within 7-12 miles. The change will be evident through using a scanner that shows LTFT's because you don't feel it in the engine or throttle. I do not hammer the gas during the adjustment period, I just drive it regular. The tune will fine adjust itself more but those changes will be smaller and by ~50-60 miles in the past the adjustments are pretty much done!
Note: these are ECU internal adjustment to solution % changes.
I have a diagram of the system :
http://forums.corvetteforum.com/albu...ictureid=54198
(1) Fuel Feed Pipe
(2) Auxiliary Fuel Feed Rear Pipe (left tank to jet pump)
(3) Auxiliary Fuel Return Rear Pipe (jet pump to left tank)
(4) Fuel Feed Pipe Check Valve
(5) Fuel Feed Pipe Tee with Orifice
(6) Fuel Feed Rear Pipe (to fuel filter/fuel pressure regulator and siphon jet pump)
(7) Fuel Return Rear Pipe
(8) Auxiliary Fuel Return Rear Pipe (jet pump to left tank)
(9) Fuel Filter/Fuel Pressure Regulator
2 fuel tanks store the fuel supply. An electric fuel pump attaches to the fuel sender assembly inside the left fuel tank. The fuel pump pumps fuel through the fuel feed pipe (6) and an in-line fuel filter (9) to the fuel rail. The rear fuel feed pipe (6) has an integral check valve (4) in order to maintain the fuel system pressure in the feed pipe. The pump provides the fuel at a pressure greater than what is needed by the fuel injectors. The fuel pressure regulator, part of the fuel filter (9), keeps the fuel available to the injectors at a regulated pressure. A fuel return pipe (7) returns the unused fuel to the left fuel tank. The fuel pump also feeds the fuel through a tee (5) with an orifice in the fuel feed rear pipe (6) and through the auxiliary fuel feed rear pipe (2) in order to supply the siphon jet pump inside the right fuel tank. The siphon jet pump transfers the fuel from the right fuel tank to the left fuel tank through the auxiliary fuel return rear pipe (3, 8).
Due to tunning my LTFT's have been right around 0. Within a couple of miles they started adjusting and by ~15 miles where settled in at ~3.9-4.1 and stayed that way for the duration of my 32 mile to work trip.
I can tell you from memory that with my 2003 Silverado (one fuel tank) they will adjust to a substantial ethanol % change within 7-12 miles. The change will be evident through using a scanner that shows LTFT's because you don't feel it in the engine or throttle. I do not hammer the gas during the adjustment period, I just drive it regular. The tune will fine adjust itself more but those changes will be smaller and by ~50-60 miles in the past the adjustments are pretty much done!
Note: these are ECU internal adjustment to solution % changes.
I have a diagram of the system :
http://forums.corvetteforum.com/albu...ictureid=54198
(1) Fuel Feed Pipe
(2) Auxiliary Fuel Feed Rear Pipe (left tank to jet pump)
(3) Auxiliary Fuel Return Rear Pipe (jet pump to left tank)
(4) Fuel Feed Pipe Check Valve
(5) Fuel Feed Pipe Tee with Orifice
(6) Fuel Feed Rear Pipe (to fuel filter/fuel pressure regulator and siphon jet pump)
(7) Fuel Return Rear Pipe
(8) Auxiliary Fuel Return Rear Pipe (jet pump to left tank)
(9) Fuel Filter/Fuel Pressure Regulator
2 fuel tanks store the fuel supply. An electric fuel pump attaches to the fuel sender assembly inside the left fuel tank. The fuel pump pumps fuel through the fuel feed pipe (6) and an in-line fuel filter (9) to the fuel rail. The rear fuel feed pipe (6) has an integral check valve (4) in order to maintain the fuel system pressure in the feed pipe. The pump provides the fuel at a pressure greater than what is needed by the fuel injectors. The fuel pressure regulator, part of the fuel filter (9), keeps the fuel available to the injectors at a regulated pressure. A fuel return pipe (7) returns the unused fuel to the left fuel tank. The fuel pump also feeds the fuel through a tee (5) with an orifice in the fuel feed rear pipe (6) and through the auxiliary fuel feed rear pipe (2) in order to supply the siphon jet pump inside the right fuel tank. The siphon jet pump transfers the fuel from the right fuel tank to the left fuel tank through the auxiliary fuel return rear pipe (3, 8).
