Iv read on the mx5 forum about some of the guys with modded engines running the fuel return line from the afpr back to the fuel feed line before the reg instead of the fuel tank, anyone on here done this and does it work ?
Since the line from the tank is the the one from the pump , which will be at a higher pressure than the fuel regulator , then no - I would be very surprised if it would run at all !
That'll do 2 things. It'll render the regulator useless (it's return linked to it's input means it has zero pressure difference across it, which means it will stay closed). If the reg remains closed you'll see 5 bar + on the fuel lines (whatever the pump can deliver) and this will vary with injector duty cycle, meaning for any given injection duration you'll see more fuel input during idle than during WOT, what's more your injection pressure will vary with both battery charge and pump damage. All in all, it's probably the worst thing you could do to an EFI engine when looking for better fueling.
Adjustable fuel regs are really a bit of a botch IMO, unless you have the rest of the system designed to function with it. Stock injectors are designed to run at 3 bar usually, upping the fuel pressure may or may not be deliverable by the pump and huge increases in fuel pressure deliver very small increases in fuel flow (it doesn't scale linearly). You'll find out your pump can't deliver the fuel pressure at the one point you want it, at full throttle full load - when you least want to run lean. The only sensible option is to run the correct pump and injectors.
I'm runnin a zx10r and need to get the emissions down for the iva which is VERY soon , I was just looking at alternatives to removing the tank to fit a return as I don't have time and a few other things to do besides
The return on mine (truth be told its the bleed off from the top of the swirlpot - the true return from the FPR is piped into the swirlpot) enters the tank via a union that I drilled into the tank sender. Getting a union welded into the tank was going to be right faff but a simple 90 degeree union did the trick. Been like it 8 years now.
quote:
Originally posted by tcr
I'm runnin a zx10r and need to get the emissions down for the iva which is VERY soon , I was just looking at alternatives to removing the tank to fit a return as I don't have time and a few other things to do besides
i bodged mine for IVA (blackbird engine) tool out the stock 3Bar reg and replaced it with an aftermarket. gave me the ability to drop the fuel
pressure to meet the emissions since mine was running very rich.
its not a perfect solution and it only just passed. also the reg i got 20 quid of ebay used to creep like hell so it would alter itself slightly over
time.
hope this helps
Tilly