As above. Should the stock rails handle flow to max out 800cc injectors? Car was running out of fuel at 732 rwhp on the dyno. Have changed the pump setup and bigger fuel lines and will be testing it again tuesday but wondering if anyone knows if the stock fuel rail can be a restriction at this HP? Thanks.
yes the rail will definately be a problem at that horsepower level, as is the piping to the rail if that is still stock
Oh no...it's happening again.. Another 3+ pages of "I don't beleive you" I say what harm is he doing.. He isn't like iCer making up sigs with the claimed power on them and his world wide ranking etc.. he's a doctor who is passing on the info his mechanic tells him. I hope to see a dyno graph too but everyone should just chill till then!
And he never said it is only 3 litres or what type of fuel it is using. Innocent until proven guilty I say.
I'm curious too as it isn't actually in the direct fuel flow path. Just there to absorb the fuel pump pulses
@732 rwh on 800cc injectors .... I'd be looking more at my fuel pump and injectors. Should be easy to work out the maximum fuel flow for any given diameter tube at any given pressure. Basic fluid dynamics. Anyone got a stock fuel rail handy and can give us the inside measurment ???
Inside of fuel damper : There are three points of fairly serious restriction (compared to simple bypass) and yes the fuel flows in the longer tube and out the shorter bent tube and from there in to the fuel rails. The entry tube for the rails (both of them) has the tube slightly crushed/bent over to make fitting the hose easier but does not help with fuel flow. We are talking a reduction in internal diameter down to just 5mm compared to the hoses diameter of 8mm, there are at least seven points in the fuel system on the high pressure side of the regulator like this = not so good for high HP beasts.
As in my post about the damper above there are a few points in the system tighter than other parts but overall any hose will be 8m internal diameter, any pipe will be approx 7mm internal, ends of pipes will drop to ~5mm and there are three main restrictions in the damper one being a small as 4mm for approx 10mm distance. I tell you what I will do (when I get a chance) rig up a stock system and flow test it to see what the maximum amount we can push through it is, it wont take much to do and I already have a lot of the gear required to do this (F all needed actually). It is standard practice in the aircraft industry to flow test fuel systems etc at various stages of maintenance - interesting not much is said about it in the automotive industry. It's so damn easy I will explain here: remove return line from regulator and fit hose to run into a large measuring container IE: fuel flows through entire system incl reg then exits to container NOT fuel return to tank. (20L or so at least with marked increments on the side - you may need two or three 20L drums given the flow of our pumps) Check fuel tank is at least half full (to avoid any errors) Get someone with a stopwatch to help Rig a safe system to run the fuel pump at full power - safe as in not twisting wires to make it go LOL! Count to three or what ever you like just as long as the stop watch and fuel pump start at the same time (as long as system has been bled of air!) and run the pump in multiples of minutes depending on the capacity of your container and volume of fuel. If say you can safely run the pump for two minutes and get 50Ls of fuel then the system at max can flow 25L per minute. Simple as that. If we get a few people to do this and check the pressure in the system while we are at it we can get an accurate indication of what the stock systems can flow at max. then if we repeat with some of the after market systems we can see if there are any benefits etc. Stay tuned for my first comparisons this week (fingers crossed). EDIT: Oh and for clarification Max power means the pump should be run on 13.6V so jumped from another running vehicle - preferably not parked at the front end of the Z next to the exposed fuel and vapours. And technically the line from the reg to the fuel drum should be the same for all tests but practically it wont make F all difference, just try to use 8mm line and about 1.5m length - advise if you do something wildly different and get an erroneous result.
