Solid State Fuel Pumps

[qkingston]

I have read recent threads re Fuel Pumps with interest, is there any reason why the Facet Solid State (Fast Road 4-5.5 psi) doesn't seem to get a mention? Being Solid State it would sound more reliable and they claim it is quieter?

[slogger]

Originally Posted by qkingston

I have read recent threads re Fuel Pumps with interest, is there any reason why the Facet Solid State (Fast Road 4-5.5 psi) doesn't seem to get a mention? Being Solid State it would sound more reliable and they claim it is quieter?

Only really good enough for motors up to a Rover V8 in standard trim about sums it up. They just do not have the capacity needed for the bigger motors found in our Cobs.

I think you will find that the threads you have been reading come about because of the uncertainty of the fuel demands for modded engines especially our American monsters.

[qkingston]

Ok that's understood, I have a RV8 but somewhat tweaked (230bhp), what minimum fuel pressure should I be providing?
Rgds
QK

[Clarkson]

I had a red top on a std chevy,but not very relible and it packed up after 2 years. Now fitted a holley which is good but very noisy.

[wilf]

Originally Posted by qkingston

Ok that's understood, I have a RV8 but somewhat tweaked (230bhp), what minimum fuel pressure should I be providing?
Rgds
QK

Depends on what carbs you are running - SUs - 2.5 psi, Edelbrock/Holley - 4.5 psi. These are maxima as well.

EFI - different kettle of fish altogether.

[lutman]

Originally Posted by wilf

Depends on what carbs you are running - SUs - 2.5 psi, Edelbrock/Holley - 4.5 psi. These are maxima as well.

EFI - different kettle of fish altogether.

Above figures should be ok for carbs - the fuel pressure only has to refill the carb float bowls and usually switches off when demand is low, thats why you usually hear the pump running for a few seconds prior starting and then switches off until motor is running.

As stated though EFi is different altogether. The pump has to prime a fuel " rail" which has a return line to the main fuel tank or to a swirl pot tank. this as a positive pressure of around 8 psi is usual in the fuel rails - even if the engine is not running but ignition on you would expect to have around 8psi and flow through the rails. This is why EFi systems usually demand a reliable high flow pump to be installed.
The fuel pressure and flow flow rate in an EFi system is critical, which is why most will install a swirl pot in the system so that at least a litre or so of fuel is always available to the fuel rails, which is not always the case when cornering or with low fuel quantity from a standard system pick up point in the tank.

[Sidecarbod]

PSI is only one of the issues when it comes to fuel pumps, the total volume of fuel delivered per minute is very important and this is "sort of" independent of the PSI although the PSI will drop if the delievery rate that is required can not be met by the pump

In A.Bells book on 4-strokes He recons that you can multiply the expected BHP figure by 4.6 and that will give you the total amount of fuel required per minute in CC (More is required for "blown" engines for some reason or other).

I guess this is why you can find 2 or 3 pumps all working in parallel in some gas gusling monsters, the PSI will not be mutlipied by the number of pumps but the total amount of fuel will be assuming that they have separate feed pipes to the carb or a least one big one.

230 BHP is going to need just over a litre per minute to keep the float bowls full.

Thats my two pence worth!

Pete

[Sidecarbod]

Originally Posted by Sidecarbod

230 BHP is going to need just over a litre per minute to keep the float bowls full.

Pete

When running flat out....not all the time!

(But flat out is what the pump needs to be able to cope with, or you'll get a nasty lean off).

Pete

[dingocooke]

My old RAM (302 ford with full ED RPM kit heads etc Holley 600cfm mech secondaries) was on a Facet goldtop from being built (still on it too), ran really well, and the facet was actually a fair bit quieter than the Carter pump on my Crendon.