Discussion
I'm just getting a little confused by the 2 tank thingummy.
I thought about each tank having a single adjustable fuel pump with built in reg. That way I can play with pressures when setting up the engine and not have to worry about returns. One tank drains - switch over to the other tank!
It seems logical in my mind, but then again, Homer Simpson is a genius by comparison!
I thought about each tank having a single adjustable fuel pump with built in reg. That way I can play with pressures when setting up the engine and not have to worry about returns. One tank drains - switch over to the other tank!
It seems logical in my mind, but then again, Homer Simpson is a genius by comparison!
Edited by Scotty-Boy on Sunday 25th May 21:47
The swirl pot system ensures you have a good head of fuel above the high pressure pump (which will not suck fuel up) despite all you may be doing on the road such as heavy cornering, braking or accelerating. If you don't run one then you will have to have the tank modified so that it has the equivalent of a swirl pot (baffles) inside. You would then have to do this mod to both tanks.
If you wish to eliminate the need to switch the return back and forth then take your feed to the swirl pot from just one tank and link the tanks together so they balance out.
Steve
If you wish to eliminate the need to switch the return back and forth then take your feed to the swirl pot from just one tank and link the tanks together so they balance out.
Steve
The factory tanks have three fittings.
One half way down and two down near the bottom.
One of the fittings at the bottom has a pipe inside the tank that turns down to the very bottom of the tank so this is the feed to the pump so it can draw fuel right down to empty.
The other two can be connected to their opposite number on the other tank so the fuel can flow freely between the tanks.
You could run on the one low pressure pump from one tank. If you ran out of fuel you could switch to the other pump which would use the last 50mm or so of fuel remaining in that tank.
Steve
One half way down and two down near the bottom.
One of the fittings at the bottom has a pipe inside the tank that turns down to the very bottom of the tank so this is the feed to the pump so it can draw fuel right down to empty.
The other two can be connected to their opposite number on the other tank so the fuel can flow freely between the tanks.
You could run on the one low pressure pump from one tank. If you ran out of fuel you could switch to the other pump which would use the last 50mm or so of fuel remaining in that tank.
Steve
Scotty-Boy said:
I thought about each tank having a single adjustable fuel pump with built in reg. That way I can play with pressures when setting up the engine and not have to worry about returns.
A traditional fuel regulator adjusts the fuel pressure according to manifold vacuum/boost (its all just pressure) so there is a constant pressure differential across the injector and the manifold.You are describing a dead-headed fuel system, where the pressure is regulated at the pump - rather than at the end of the fuel rail via a bypass regulator. I'm not familiar with them, but thought they (the pumps) required control from the ECU to regulate the pressure.
I would be easier to run proper efi tanks but i think the costs would be prohibitive. The swirl pot system is an easier and cheaper solution. As i have found out the efi install also requires an alternator change as mine does not have the output to charge the battery if the extra bits are all running. Efi tanks would be a good factory option??
Going to talk to Andy Wiltshire to see what he can do.
He's a bit of a wizard when it comes to tanks. He made me a cracking injection tank for my R1 Caterham.
Will let you know how I get on.
He's a bit of a wizard when it comes to tanks. He made me a cracking injection tank for my R1 Caterham.
Will let you know how I get on.
Edited by Scotty-Boy on Monday 26th May 13:32
Scotty-Boy said:
Going to talk to Andy Wiltshire to see what he can do.
He's a bit of a wizard when it comes to tanks. He made me a cracking injection tank for my R1 Caterham.
Will let you know how I get on.
If you already have the tanks then this will be a rather expensive route compared to adding a swirl pot.He's a bit of a wizard when it comes to tanks. He made me a cracking injection tank for my R1 Caterham.
Will let you know how I get on.
Don't forget the tanks are foam filled making subsequent mods even more difficult.
Steve
Edited by Steve_D on Monday 26th May 19:27
Hi Scotty-Boy , its not so much of a swirl tank as a header tank of fuel to feed your injection pump ,the std carter pumps fill the tank which feeds the injection pump the overflow fuel can go back to the ht from the regulator or to the fuel tanks ,mine goes back to the header tank then there is a pipe from the HT that returns to the main tanks via "T" piece .
i control where the fuel flows by a couple of inline taps. hope that makes sense!!
i control where the fuel flows by a couple of inline taps. hope that makes sense!!
Am I right in thinking then that when Tank 1 goes dry, it's not just a case of flicking a switch for Tank 2 and hey presto... you have to manually switch the return feed in the engine bay to Tank 2?
Also, I take it the return from the Swirl Pot to Tank 1 / 2 is purely gravity fed?
Also, I take it the return from the Swirl Pot to Tank 1 / 2 is purely gravity fed?
Edited by Scotty-Boy on Monday 26th May 19:49
Scotty-Boy said:
Am I right in thinking then that when Tank 1 goes dry, it's not just a case of flicking a switch for Tank 2 and hey presto... you have to manually switch the return feed in the engine bay to Tank 2?
Also, I take it the return from the Swirl Pot to Tank 1 / 2 is purely gravity fed?
One of the tank pumps is running and supplying fuel to the HT.Also, I take it the return from the Swirl Pot to Tank 1 / 2 is purely gravity fed?
Edited by Scotty-Boy on Monday 26th May 19:49
Fuel not used returns to the HT which is at low pressure.
Excess fuel from the HT returns to the tank via a valve.
When you switch pumps the valve switches over so the fuel returns to the correct tank.
Steve
My swirl pot has 5 outlets. One at the bottom which gravity feeds the injection pump and 4 at the top. Two of the top ones are feeds from the two low pressure fuel pumps (one from the base of each tank) one is the return from the fuel rail and the other is the overflow from the swirl pot which goes to a "T" piece. Two pipes from the "T" then go to the top outlet of each tank, so this pipe also acts as a tank link. The only problem is that the returning fuel does not necessarily return to the tank from whence it came, which means that one tank empties into the other. I eventually overcame this annoyance by fitting a switching valve before the swirl pot, but that's another story!
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