Fuel pump with flatslides

[george 1100]

Has anyone ever done this? I'm asking on behalf of someone that's has a 1340 race car and the tank sits lower that the float bowls. They're currently running a vacuum activated pulse pump but it's not coping

[clivegto]

Done it on turbo bike, would think just use a fuel pressure regulator and a return fuel line like a turbo setup. 

[george 1100]

Yes I was thinking this but wouldn't a turbo bike require more psi as the bowls are pressurised. I'm no turbo expert by the way.

Out of curiosity, what psi pump and reg are you using?

 

[Gixer1460]

Just find an interrupter type pump - H***a NTV's / Dullvilles have them. When the bowls are full the back pressure holds the contacts open so pump stops. I think Yam R1's have similar pumps before they went EFI and would be sized for 125 - 140hp?

[Joseph]

RF900 also uses a pump. It's not down to the type of carburetor used, just make sure pressure rating is right.

And on a set up like the one you mention you wouldn't need a return line to the tank and FPR

[george 1100]

38 minutes ago, Gixer1460 said:

Just find an interrupter type pump - H***a NTV's / Dullvilles have them. When the bowls are full the back pressure holds the contacts open so pump stops. I think Yam R1's have similar pumps before they went EFI and would be sized for 125 - 140hp?

Motor is apparently full house 1340 putting out 180hp+

I've been researching for him as curiosity got the better of me. Holley have some interesting products that are 2-4 psi and flow 30 gallons/hr . Have low pressure adjustable regulators also

Yes Joseph, will need a return line

 

[clivegto]

4 hours ago, george 1100 said:

 

Out of curiosity, what psi pump and reg are you using?

 

Malpassi fuel regulator, fuel pump of a golf car or similar. Last one I built using a facet fuel pump. I would just use a lower fuel pressure with the regulator.  

Edited October 12, 2022 by clivegto

[Gixer1460]

Trying to get those regulators down to 1-2psi for NA operation is tricky . . . . . can be done but they are better suited to 5+psi used with auto float needles or with turbo boosted pressure applications.

[Joseph]

It will need a return line to the tank only if you are pumping much more than the carbs need.

Like @Gixer1460said those basic motorcycle pumps function with a cut off system.

[george 1100]

He runs race fuel also which may affect how much capacity that's required.

So would a 3-5 psi 30 gallon/hr pump together with a regulator that operates in the 1-2 psi range with a return line, do it?

[clivegto]

1.5 to 2psi on turbo bike. As said I would probably go with the RF pump or one from a gsxr 1000 in tank. 

[george 1100]

1 hour ago, clivegto said:

1.5 to 2psi on turbo bike. As said I would probably go with the RF pump or one from a gsxr 1000 in tank. 

[Joseph]

RF pumps are around 60L/h

[george 1100]

58 minutes ago, Joseph said:

RF pumps are around 60L/h

That's good to know, cheers. Out of curiosity, why did the rf's have a pump fitted?

[Joseph]

Because of the downdraught carbs and where every component had to be in relation to one another (bottom level of tank, petcock position to carbs etc) meant that the bike couldn't go with the usual gravity fed system

Edited October 13, 2022 by Joseph

[Gixer1460]

12 hours ago, clivegto said:

1.5 to 2psi on turbo bike. As said I would probably go with the RF pump or one from a gsxr 1000 in tank. 

Ah - so it's an oldskool drawthrough set-up.

[davecara]

2 hours ago, Gixer1460 said:

Ah - so it's an oldskool drawthrough set-up.

Carb blowthru's only need to be 1 or 2 psi over the boost pressure. The couple I've worked on have only been set at 1-2 psi on those malpassi regulators

Edited October 13, 2022 by davecara

[Gixer1460]

5 hours ago, davecara said:

Carb blowthru's only need to be 1 or 2 psi over the boost pressure. The couple I've worked on have only been set at 1-2 psi on those malpassi regulators

Yes, but the pump has to be capable of supplying a) the fuel pressure required ie. Boost + static pressure and b) flow to match the power output @ the required boost pressure! A small EFI pump can usually do the pressure but flow can tail off to the point that bowls could run dry / not fill sufficiently. A Facet pump (as above) for instance would struggle with much more than 5-6psi boost.

[clivegto]

2 hours ago, Gixer1460 said:

 A Facet pump (as above) for instance would struggle with much more than 5-6psi boost.

Seems to work alright. 

[Gixer1460]

I see the pressure stated but according to Facet info here . . . . https://www.lasaero.com/products/article/G01J6S5HF

the max pump pressure is 8psi! Are you sure it was the facet and not the HP efi type pump?

Edited October 13, 2022 by Gixer1460