Pro's and Con's in a two Fuel tank set ups

[Douglas P Shepherd]

I am looking for input on a two tank set up, in scale hulls. I have room for a one tank set up, But like the balance of a two tank set up. Pro's and Cons needs to be around 20oz and plastic tanks ? Thanks Doug

 

[Don Ferrette]

I am looking for input on a two tank set up, in scale hulls. I have room for a one tank set up, But like the balance of a two tank set up. Pro's and Cons needs to be around 20oz and plastic tanks ? Thanks Doug

Pro- easier to maintain good side to side balance and fit 10oz tanks in the boat.

Con- motor goes noticeably richer when first tank empties due to pressure increase, even with 5/32" tubing.

Been there done that, a few times. The only boat I ever got away with doing it and not have motor go rich was on the Bud T-4 because of how far forward the ram wings are I could keep the transfer line length real short. Also used metal tanks 3/16" line on the outlet of the first tank & the inlet of the second one. The metal tanks both had sumps in them but with the plastic tanks (no sump) you still should use a 1oz. header tank so it's really a 3 tank set up. :blink:

 

[Douglas P Shepherd]

I am looking for input on a two tank set up, in scale hulls. I have room for a one tank set up, But like the balance of a two tank set up. Pro's and Cons needs to be around 20oz and plastic tanks ? Thanks Doug

Pro- easier to maintain good side to side balance and fit 10oz tanks in the boat.

Con- motor goes noticeably richer when first tank empties due to pressure increase, even with 5/32" tubing.

Been there done that, a few times. The only boat I ever got away with doing it and not have motor go rich was on the Bud T-4 because of how far forward the ram wings are I could keep the transfer line length real short. Also used metal tanks 3/16" line on the outlet of the first tank & the inlet of the second one. The metal tanks both had sumps in them but with the plastic tanks (no sump) you still should use a 1oz. header tank so it's really a 3 tank set up. :blink:

I have been told by two tank builders. That if you use two 5/32 out of the tank you draw from first into the main . With one 5/32 out of the main to the engine That the system would not go rich? Doug

 

[Joe_Knesek]

Something Dick Tyndall showed me years ago when running 2 tanks is to run an extra vent line connecting the 2 tanks. This equalizes the pressure and you don't have the issue of going lean when the tank transitions over.

 

[Andy Greene]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....

Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

 

[shann harrison]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

 

[Andy Greene]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

Thanks Shann,

How about the vent tube addition with 2 / 10 oz tanks ??

 

[Don Ferrette]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

This is part of it but more importantly you won't suck air into the lines when the main tank gets below 1/2 full & the fuel starts sloshing around when you throw it in the corners.

No fire suit needed Andy.

 

[shann harrison]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

Thanks Shann,

How about the vent tube addition with 2 / 10 oz tanks ??

Okay this one could get ugly just MY 2 CENTS,I've experimentented with it with no real results.Some would say vent the main tank But my line off thinking would be Y.You'd lose all back pressure from the pipe with this type of setup.then there is switching the tanks around,in my testing I have found that by doing this would only vent one tank.Which in my mind is useless.The motor is a vaccum with its own draw its best just not to vent just my oppinion.

 

[shann harrison]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

This is part of it but more importantly you won't suck air into the lines when the main tank gets below 1/2 full & the fuel starts sloshing around when you throw it in the corners.

No fire suit needed Andy.

Yes I forgot to add that.VERY TRUE

 

[Douglas P Shepherd]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

The 1oz tank remains full at all times with no pressure disturbance.A constent fuel draw this is the ideal, setup but a pain to make sure there are no leaks or air by passing the stoppers.I've used this setup in my Miss Exide with great success.you just set your needle up as it was a single tank and no worries of starting out rich on main tank then leaning on the second.

This is part of it but more importantly you won't suck air into the lines when the main tank gets below 1/2 full & the fuel starts sloshing around when you throw it in the corners.

No fire suit needed Andy.

Yes I forgot to add that.VERY TRUE

I was also told that you could run two pressure taps from the pipe (Run a pressure line to each tank). Run a 5/32 out of both main tanks feed into a 1 to 2 oz.. Has anybody every tried this set up ?

 

[Joe_Knesek]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

Most plastic tanks have a means to use 3 lines. The vent tubes just connect to each tank allowing the pressure to equalize.

 

[boatr46]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

Most plastic tanks have a means to use 3 lines. The vent tubes just connect to each tank allowing the pressure to equalize.

So you have a pressure line feeding tank 1 and a top vent line and a fuel pickup line to tank 2 then a fuel pick up feeding the motor or hopper tank?

How this will empty both tanks? Do they both go down equally or tank 1 then tank2? This setup will not affect needle setting as the tanks empty?

 

[Joe_Knesek]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

Most plastic tanks have a means to use 3 lines. The vent tubes just connect to each tank allowing the pressure to equalize.

So you have a pressure line feeding tank 1 and a top vent line and a fuel pickup line to tank 2 then a fuel pick up feeding the motor or hopper tank?

How this will empty both tanks? Do they both go down equally or tank 1 then tank2? This setup will not affect needle setting as the tanks empty?

You pressurize one tank and it feeds the fuel to the other. The tank closest to the pipe pressure empties first. The vent just balances the pressure between the tanks eliminating the pressure drop when the 1st tank goes dry.

I'll put together a demo and post a few photos for you this weekend.

 

[Douglas P Shepherd]

Sorry for the stupid question, but how would you do that esp using plastic tanks ? Vent tube that is ....
Don what does the 1oz header tank accomplish in your setup ?

Fire suit ON !

Most plastic tanks have a means to use 3 lines. The vent tubes just connect to each tank allowing the pressure to equalize.

So you have a pressure line feeding tank 1 and a top vent line and a fuel pickup line to tank 2 then a fuel pick up feeding the motor or hopper tank?

How this will empty both tanks? Do they both go down equally or tank 1 then tank2? This setup will not affect needle setting as the tanks empty?

You pressurize one tank and it feeds the fuel to the other. The tank closest to the pipe pressure empties first. The vent just balances the pressure between the tanks eliminating the pressure drop when the 1st tank goes dry.

I'll put together a demo and post a few photos for you this weekend.

Joe, That would be great if you could add a few pics. Thanks Doug

 

[Joe_Knesek]

Once I removed the tanks from my 21 Speedmaster I realized I did not describe the setup correctly. It's actually an extra set of pickups not vents. The 2 pickups work the same as using a larger fuel line. The tube on the left connects to the carb & the one on the right is for pressure.

 

[Douglas P Shepherd]

Once I removed the tanks from my 21 Speedmaster I realized I did not describe the setup correctly. It's actually an extra set of pickups not vents. The 2 pickups work the same as using a larger fuel line. The tube on the left connects to the carb & the one on the right is for pressure.

This is the exact set up that was described to me from a major tank builder from the west cost. He stated that you did not need the third tank,but stated it would not hurt ! Thanks Joe Doug

 

[Andy Greene]

Thanks for the visual aids Joe. Lets make sure Im clear. Center line on both tanks is the extra vent that is a pickup in both tanks correct?? The left tank is the carb feed the right has pipe psi- and the rest is business as usual ?? If thats the case its clear as mud to me now - LOL

Thanks Joe , Andy

 

[Douglas P Shepherd]

Thanks for the visual aids Joe. Lets make sure Im clear. Center line on both tanks is the extra vent that is a pickup in both tanks correct?? The left tank is the carb feed the right has pipe psi- and the rest is business as usual ?? If thats the case its clear as mud to me now - LOL
Thanks Joe , Andy

After loking at the pic a little more. I am also not clear as what line does what? I see the input pressure line and the fuel out. But the two center lines I am not clear on? Are they both fuel delivery lines to the last tank. Or is one vent line going to the top of the tank and the other a fuel delivery line? Thanks Doug

 

[Green Meany]

pipe--------------------vent to vent----------------------pickup to vent----------------pickup for carb

---------------------------balancer-------------------tank to tank fuel transfer

that's right isnt it ?