Twin pump twin tank fuel system speculations....
Thread Starter
Joined: Oct 2003
Posts: 2,702
Likes: 4
From: Rosedale, IN
Twin pump twin tank fuel system speculations....
Hey guys,
I wonder if there is space under the car to replace the stock saddle style tank with two separate 10 gallon fuel cells for a larger fuel capacity while maintaining trunk space? If I had a spare car as a daily driver I think that is the experiment I would work on.... Looking at the tech manual for the car in the fuel tank area it looks like there is quite a bit of extra space that would allow for a 10 gallon cell on each side. It would be complicated to set up, but worth it to people looking for a greater than 300 mile per tank range of travel.... or especially worth it for people wanting to run E-85 with it's lower energy density.
The more I think about it the better this sounds. Maintain the ballance of the car and low center of gravity (fuel cell in the trunk RAISES the center of gravity), and you could probably set it up to work with the stock filler neck if you want to avoid having to pull out your back seat to fill the tanks.
In the stock setup, the return line from the fuel rail and the supply line from the passenger side tank join up at the fuel pump assembly in the drivers side tank, I suspect that there is a venturi in that line so the returning fuel from the fuel rail flowing through the venturi provides a suction on the supply line from the passenger tank. If this is correct, I suspect that the passenger tank drains first with the drivers side tank staying full until the passenger side tank is compleaty emptied out. That is why when people use a fuel cell with the stock sending unit the fuel gauge only reads half full.... the other sending unit in the passenger side tank is not providing a level to the fuel gauge. This same system would be used in a twin fuel cell system.
But what about the filling system? I think (not positive) that the stock system just overflows from the top of the drivers side into the passenger side for filling... could a similar method be used for twin fuel cells by mounting one slightly higher than the other and having a large hard line setup form the top of one tank to the top of the other?
Just some food for thought that came from seeing "Full Blown" (new vendor here) mounting their twin fuel pump system into the stock fuel tanks.
Keith
I wonder if there is space under the car to replace the stock saddle style tank with two separate 10 gallon fuel cells for a larger fuel capacity while maintaining trunk space? If I had a spare car as a daily driver I think that is the experiment I would work on.... Looking at the tech manual for the car in the fuel tank area it looks like there is quite a bit of extra space that would allow for a 10 gallon cell on each side. It would be complicated to set up, but worth it to people looking for a greater than 300 mile per tank range of travel.... or especially worth it for people wanting to run E-85 with it's lower energy density.
The more I think about it the better this sounds. Maintain the ballance of the car and low center of gravity (fuel cell in the trunk RAISES the center of gravity), and you could probably set it up to work with the stock filler neck if you want to avoid having to pull out your back seat to fill the tanks.
In the stock setup, the return line from the fuel rail and the supply line from the passenger side tank join up at the fuel pump assembly in the drivers side tank, I suspect that there is a venturi in that line so the returning fuel from the fuel rail flowing through the venturi provides a suction on the supply line from the passenger tank. If this is correct, I suspect that the passenger tank drains first with the drivers side tank staying full until the passenger side tank is compleaty emptied out. That is why when people use a fuel cell with the stock sending unit the fuel gauge only reads half full.... the other sending unit in the passenger side tank is not providing a level to the fuel gauge. This same system would be used in a twin fuel cell system.
But what about the filling system? I think (not positive) that the stock system just overflows from the top of the drivers side into the passenger side for filling... could a similar method be used for twin fuel cells by mounting one slightly higher than the other and having a large hard line setup form the top of one tank to the top of the other?
Just some food for thought that came from seeing "Full Blown" (new vendor here) mounting their twin fuel pump system into the stock fuel tanks.
Keith
Keith,
Come on brother, you know if you want to know something like this coming directly to me is the solution
The stock pump assembly is fairly complicated, the pump sucks fuel from the drivers side of the tank only, through the fuel sock. The return line has a fitting built into it that syphones fuel from the passenger side of the tank and just dumps it back into the drivers side. So the passenger side acts like a resevoir for the drivers, it's only purpose is balance and re-filling the drivers side. The passenger side has an assembly in it similar to the 1G AWD fuel pump assembly. The only thing in it is a tube with a sock on it for picking up fuel and sending it to the drivers side.
You could run two fuel tanks but it would be some serious fab work. Then you'd still need twin fill tubes installed to fill each tank.
I am surprised you haven't seen our double pumper fuel system that's been out for a few months already. We did twin pumps in the tank already and it uses all the stock lines, regulator, sending unit etc. Super clean, super simple and has supplied my car with more fuel that it needed to run 9.90's at 142+ mph.
The stock tank could be seperated with some work to give two 7 gallons side, seperate from each other. A additional pump could be built in the passenger side. It would get complicated in a hurry though. You'd need a way to switch from one tank to another, another fill tube for the 2nd tank, additional wiring etc.
I did a lot of work on the stock tank to come up with the perfect twin intank (double pumper) fuel pumps. There isn't a lot of room between the tank and floor for new hoses etc. The stock tank is an all day job to remove if you were doing it in your driveway. Not easy even on a lift.
To do what you want to do I'd suggest running the fuel cell we are running in our Time Attack car. It's an ATL spare tire well system. We have a complete install kit for mounting it. Has it's own pump intank, which we could convert to twins if needed. You could then run a new feed and return line, twin inlets to the rail and just switch from one tank to the other very simply. Downside is fuel sending unit. The reason the aftermarket ones don't read correctly is the Ohms the sending units work from. So an aftermarket fuel level gauge would be needed for the 2nd tank. With it mounting in the spare tire well you still have good trunk space but will have to open the trunk to fill the cell. You would still have to have a way to switch maps on the fly. Once again, thought that out too.....you could set up a pump gas map and then use the nitrous ignition and fuel tables for E85, so a flip of a switch can change maps, pumps and even boost levels.
We know some **** over here
Come on brother, you know if you want to know something like this coming directly to me is the solution
The stock pump assembly is fairly complicated, the pump sucks fuel from the drivers side of the tank only, through the fuel sock. The return line has a fitting built into it that syphones fuel from the passenger side of the tank and just dumps it back into the drivers side. So the passenger side acts like a resevoir for the drivers, it's only purpose is balance and re-filling the drivers side. The passenger side has an assembly in it similar to the 1G AWD fuel pump assembly. The only thing in it is a tube with a sock on it for picking up fuel and sending it to the drivers side.
You could run two fuel tanks but it would be some serious fab work. Then you'd still need twin fill tubes installed to fill each tank.
I am surprised you haven't seen our double pumper fuel system that's been out for a few months already. We did twin pumps in the tank already and it uses all the stock lines, regulator, sending unit etc. Super clean, super simple and has supplied my car with more fuel that it needed to run 9.90's at 142+ mph.
The stock tank could be seperated with some work to give two 7 gallons side, seperate from each other. A additional pump could be built in the passenger side. It would get complicated in a hurry though. You'd need a way to switch from one tank to another, another fill tube for the 2nd tank, additional wiring etc.
I did a lot of work on the stock tank to come up with the perfect twin intank (double pumper) fuel pumps. There isn't a lot of room between the tank and floor for new hoses etc. The stock tank is an all day job to remove if you were doing it in your driveway. Not easy even on a lift.
To do what you want to do I'd suggest running the fuel cell we are running in our Time Attack car. It's an ATL spare tire well system. We have a complete install kit for mounting it. Has it's own pump intank, which we could convert to twins if needed. You could then run a new feed and return line, twin inlets to the rail and just switch from one tank to the other very simply. Downside is fuel sending unit. The reason the aftermarket ones don't read correctly is the Ohms the sending units work from. So an aftermarket fuel level gauge would be needed for the 2nd tank. With it mounting in the spare tire well you still have good trunk space but will have to open the trunk to fill the cell. You would still have to have a way to switch maps on the fly. Once again, thought that out too.....you could set up a pump gas map and then use the nitrous ignition and fuel tables for E85, so a flip of a switch can change maps, pumps and even boost levels.
We know some **** over here
Here you go Keith, this is the link to our twin intank pumps:
https://www.evolutionm.net/forums/sh...d.php?t=229034
https://www.evolutionm.net/forums/sh...d.php?t=229034
Here is the last post I made in the thread about the double pumper, this has a picture of the assembly:
I lost track of this post somehow and want to get some more information and pricing up. We have actually started making these for Subaru's now as nobody offered a drop in double pumper for them either.
First off I want to make sure it's understood how easy it is to install this. The complete unit drops directly into your fuel tank. The stock fuel lines both feed and return are retained, the stock regulator can be used and the stock fuel rail. My RS has made 590 whp on this set up on our dyno at only 65% duty cycle on 1200 cc injectors. The primary pump runs off the factory wiring that plugs right back in, the fuel sending unit also functions perfectly as it plugs right in with the stock plug. The siphon for the other side of the tank also simply plugs right in. The kit comes with pre-cut hoses to run from the new inlets for the twin pumps down to the new inline stainless steel 5 micron fuel filter. The factory fuel filter is built into the fuel pump assembly and CANNOT be changed. This filter is removable and you can change it if needed. The kit comes with a pressure switch. This is also easily installed. Tap it into a boost source under the hood. Run one wire to the battery positive and then the other back to the 2nd fuel pump. Ground the other side of the fuel pump and you are finished. The pump can also be wired into a relay and triggered through your fuel management with any parameters you like. For simplicity the supplied pressure switch works great and triggers the second pump at 16 psi.
Here is a picture of the complete Buschur Racing Double Pumper:
As for pricing. We have some High Output Walbro pump that NOBODY else has, it is specially built and is not available directly from Walbro. Those are the pumps I am using in my RS. The pumps are $250 each and can be run as a single. Using two of those pump the complete fuel system is $750.
For someone on a tighter budget I can build the same double pumper using two normal Walbro 255 pumps like all EVO vendors offer for $500.
If you already have a Walbro 255 pump you can take off $85.
BTW, we have been dyno'ing a car here with a GT42R on it. Has a fuel cell, -10 fuel lines etc. The car is still on the stock fuel rail, so far it has made over 700 whp with no problems.
First off I want to make sure it's understood how easy it is to install this. The complete unit drops directly into your fuel tank. The stock fuel lines both feed and return are retained, the stock regulator can be used and the stock fuel rail. My RS has made 590 whp on this set up on our dyno at only 65% duty cycle on 1200 cc injectors. The primary pump runs off the factory wiring that plugs right back in, the fuel sending unit also functions perfectly as it plugs right in with the stock plug. The siphon for the other side of the tank also simply plugs right in. The kit comes with pre-cut hoses to run from the new inlets for the twin pumps down to the new inline stainless steel 5 micron fuel filter. The factory fuel filter is built into the fuel pump assembly and CANNOT be changed. This filter is removable and you can change it if needed. The kit comes with a pressure switch. This is also easily installed. Tap it into a boost source under the hood. Run one wire to the battery positive and then the other back to the 2nd fuel pump. Ground the other side of the fuel pump and you are finished. The pump can also be wired into a relay and triggered through your fuel management with any parameters you like. For simplicity the supplied pressure switch works great and triggers the second pump at 16 psi.
Here is a picture of the complete Buschur Racing Double Pumper:
As for pricing. We have some High Output Walbro pump that NOBODY else has, it is specially built and is not available directly from Walbro. Those are the pumps I am using in my RS. The pumps are $250 each and can be run as a single. Using two of those pump the complete fuel system is $750.
For someone on a tighter budget I can build the same double pumper using two normal Walbro 255 pumps like all EVO vendors offer for $500.
If you already have a Walbro 255 pump you can take off $85.
BTW, we have been dyno'ing a car here with a GT42R on it. Has a fuel cell, -10 fuel lines etc. The car is still on the stock fuel rail, so far it has made over 700 whp with no problems.
Thread Starter
Joined: Oct 2003
Posts: 2,702
Likes: 4
From: Rosedale, IN
Damn Dave, you posted about it here, but it was not on the Buschur web site until December 5, so when I was looking for X-mas preasents for my self last month I missed it! 
You at the shop right now? I will try to call you there.
Keith
You at the shop right now? I will try to call you there.
Keith
The same thing happened to me.. I need a core to send to Dave though since I can't spare the one in my car (I'm saving it as a backup) so once I find a core I'll be in business.
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Thread Starter
Joined: Oct 2003
Posts: 2,702
Likes: 4
From: Rosedale, IN
I wonder if I can push enough fuel with this fuel pump setup to stick with my 1000 cc injectors on E-85? I don't really want to spend the money on ANOTHER set of new injectors if I don't have to.
Keith
Keith
Thread Starter
Joined: Oct 2003
Posts: 2,702
Likes: 4
From: Rosedale, IN
To me on my current pump setup (regular walbro) I would not be able to run this much boost without being over 100% duty... so with the new pump setup I think I can manage.
Keith
If you two don't buy those pump assemblies from TurboDan.....Turbodan please contact me and I'd buy them from you. I really need them. Keith, Jack let me know if you are going to take them.
As for the 1,000's. My car is making 590 whp on 1,000 cc injectors right now at around 83% duty cycles.
Keith, not so sure my old theory of the AEM vs. Stock ECU was correct, as a matter of fact I'll just admit I was wrong. With no real ways to measure the duty cycles in the past it seemed as though you could go a lot further without running out of fuel. What was happening in reality was many cars I have seen were making big power on smaller injectors but the AFR's were 13.2:1!
With the power your car is currently making Keith I think with the double pumper and the 1,000's you will have more than enough fuel with E85.
As for the 1,000's. My car is making 590 whp on 1,000 cc injectors right now at around 83% duty cycles.
Keith, not so sure my old theory of the AEM vs. Stock ECU was correct, as a matter of fact I'll just admit I was wrong. With no real ways to measure the duty cycles in the past it seemed as though you could go a lot further without running out of fuel. What was happening in reality was many cars I have seen were making big power on smaller injectors but the AFR's were 13.2:1!
With the power your car is currently making Keith I think with the double pumper and the 1,000's you will have more than enough fuel with E85.
