20 volt fuel pump boost?

[fj1289]

Since the large injectors I had will idle (at least well enough for a race bike!), no need to bump the fuel pressure to ensure I have enough fuel for the dry shot.   

Now I'm at the point with a fuel change and looking to  up the size of the shot another jet or two, the fuel pump will be getting close to its limit.   The first option seems to be to upgrade to a larger pump that will be way bigger than needed and will probably require a larger fuel pressure regulator to be able to bypass all that extra fuel.  Another option seems to be "boosting" the fuel pump with more voltage. 

I'm thinking a simple heavy duty 5 pin relay - NC pin fed by the fuse block for normal ops; and the NO pin fed by a 20 volt lithium tool battery - energized when the nitrous system is activated. 

Other than making sure the pack is charged before a run, anyone see any issues I'm overlooking?   The pump should be capable of supplying the demand with the normal 12 volt feed - I'm looking to build in some overhead to be safe.   

[RansomT]

Have you heard about this little device?

http://kennebell.net/products/accessories/boost-a-pump/

If got one on my Taurus SHO, with a Vortech T-trim.  Unless they have changed it, with a little ingenuity it could be activated with nitrous.

[fj1289]

Thanks Ransom.  More I thought about it, more I realized I would run a chance of fuel pump dropping pressure if the battery got weak - it wouldn't default to 12 volts or anything.  Better to have something that can be setup and left alone rather than adding something else to attend to between runs!

[Thomas]

to "default fuel pump to 12v" you can simply add a diode (anode to +12V, cathode to fuel pump, ideally some low-drop diode like schottky should be used).

Also you don't need 20 v lithuim battery, you need like 20 - 12v = 8 V or just two cells.

[fj1289]

to "default fuel pump to 12v" you can simply add a diode (anode to +12V, cathode to fuel pump, ideally some low-drop diode like schottky should be used).

Also you don't need 20 v lithuim battery, you need like 20 - 12v = 8 V or just two cells.

I think I'm following you.  Will a diode pass enough amperage to run a pump? 
On the 8volt "bump" - you are talking about a switchable series type setup sort of like a 24 volt starting mod, but with 12 volt at other times?  Interesting...


However, I found a tested, good used boost a pump -- so that'll be my first efforts.

[Oz Booster]

How much flow do you need ? Shouldnt be hard to match a pump to your needs, and even the small bosch and Sard regulators can cope with pretty big pumps

[fj1289]

How much flow do you need ? Shouldnt be hard to match a pump to your needs, and even the small bosch and Sard regulators can cope with pretty big pumps

Right now, I've got plenty of pump.  Over the next year will be working to up that a bit.   The existing pump will be "just" big enough with the switch to an ethanol based fuel and increasing the nitrous shot.  (We may not get that far on nitrous before we discover another weakness, but want to be ready.)  The current fuel pressure regulator mounts on the fuel rail.  So replacing that that quickly becomes rebuilding the entire fuel system...which may be the best way to go in the end...

[Thomas]

I think I'm following you.  Will a diode pass enough amperage to run a pump? 

It will, if you get 40-80 A one.

On the 8volt "bump" - you are talking about a switchable series type setup sort of like a 24 volt starting mod, but with 12 volt at other times?  Interesting...

Yep

However, I found a tested, good used boost a pump -- so that'll be my first efforts.