Fse ?

can sombody please give me info on these FSE fuel pressure things,

i always thought they were for the max power boys but quite a few people seem to be using/selling them on here,

i was told i need to get one with my uprated fuel pump, i belive the person that told me this i would just like to understand exactly what they do, the part i dont get is if my bigger fuel pump is ramming more fuel to my engine why restrict it with something in the line (ie an FSE) ?

i can tell u why u have the restrictor, basically fuel pumps may pump more in but fuel pumps are not relaible to keep the same amount of pressure and can fluctuate. So the fuel pressure things as u put it. Help maintain a steady pressure, to be honest all i know im sure there other reasons but i know main job is too maintain a steady fuel pressure, guess to protext engine

Don't bother!

i see what you are saying but if the fuel pressure is not steady from the pump and this keeps it at a steady pressure does this mean it hold fuel back at below the maximum pressure of the pump ? so instead of it occationally having low pressure to the engine it is low all the time ?

as you can see im no good at all this engine business, ask me one on paintwork

Originally posted by John Packham

Don't bother!

care to expand on that mate ?

Originally posted by lovatt

i see what you are saying but if the fuel pressure is not steady from the pump and this keeps it at a steady pressure does this mean it hold fuel back at below the maximum pressure of the pump ? so instead of it occationally having low pressure to the engine it is low all the time ?

 

as you can see im no good at all this engine business, ask me one on paintwork

yeh that is right, I am not sure how much they are below maximum pressure. Like to point out fuel pump will still be working at maximum pressure just low due to fuel pressure thingy, fuel will be getting to engine at lower pressure. on my escort for instance for my fuel pump restrictor brought the pump from something like i think 40psi down to 30psi...i think i cant remember properly!

Like to say on whole fuel pumps are very good, but for instance on the smaller cars like escort turning on lights or heaters there is that brief moment for instance when lights will dim at night coz not enough power for brief moment when u turn the heater on, well a electric fuel pump will also be witout that little bit of power for that moment so pressure will drop, obviously supra seems fine as when u turn lights on after start up u can hear revs pic up, i really dont know if u would need one on a supra though?!!?

so you keep the pressure lower all the time incase the the pump cant give full wack pressure all the time ? just seems a bit backwards to me

this is the theroy, say ur standard pump gives 30 PSI car gets set up for that runs brilliant, till u get drop in power and pressure drops causing less fuel to get in engine when valvle opens, making it run bit leaner (not good!) the fuel pressure regulator (i think correct name) changes the PSI to 25,so car is tuned to run at that runs fine, get slight power drop and fuel pump drops to 26psi, car will still run fine and not go lean. U upgrade to a uprated pump at 40PSI, fuel restrictor could then restrict it to 35 PSI incase of power drop to fuel pump, and still run fine. You have still uprated amount of fuel going through. But this deivce makes sure same supply of delivery in theory,they work well but i dont think you should need one on a supra, unless u got a big amp in ur boot eating battery juice,but if u got big amp in a supra boot u aint gonna have no subs!! lol

now i get it thanks mate

any more input on this would be appreciated, still seems expensive for what is basicaly an inline pressure regulator

I've got the FSE and Walbro, courtesy of Paul E and without playing with the settings on it, mine feels far more smooth that before. That's not necessarily a good thing as I have had experience with these before on a Vauxhall, and as standard they tend to put too much fuel in and run rich, i.e. lower economy. I need to get mine roaded and then set up from there, just need the damned money, oh yeah and a new clutch (slipping) and a new exhaust (hole)!! Where's that credit card application form!!

Ben..

Originally posted by lovatt

now i get it thanks mate

 

any more input on this would be appreciated, still seems expensive for what is basicaly an inline pressure regulator

like i said mate do more but i dont know exactly what...i just know the main principle,well think its the main principle. Helped my escort loads! as i modified engine. But like i said supra is a whole different ball game!

Would be interested in your thoughts John, and from some of the other big boys who now all their toys.

As with me and it seems a few others, we are/have bought these from Paul, I do hope that its a bit of valid kit that can help with the Supra, as we dont know everything and tend to rely on what others tell us, he already sold me a AFC that I cant use. Well soon maybe, as I have the pump, just need those injectors. Have you seen the 770 injectors for sale, £400 - thats cheap init, although you still need a fuel rail, any idea how much these are..??

The reason the fse works so well is that it allows the fuel pressure to rise at an increased(quicker rate) rate to a standard regulator which has a 1:1 ratio , a for instance ive just fitted one to a customers car that had just had a walboro pump fitted and nothing else , when run on Thors dyno at the Pod it was running very lean at the top end of its revs , he was told to fit an FSE as quick as , its ok saying 'dont bother but why fit the uprated pump only , thats only doing half a job , bit like a De-cat and leave the stock exhaust !!!!!!

Dude:flame Dev

ASH

WTF - I have not sold you an FSE or S-AFC??

Also no intention ofselling anyone something that you dont want - or that you dont need - period

It improves responsiveness with increased boost - good enough for me!

Originally posted by Paul E

Also no intention ofselling anyone something that you want

Ooh, I'm going to quote that before you edit it

Who's selling these cheapo 770cc injectors then?

-Ian

Beat me to it!

Bitches:p

Are you selling these cheap injectors then, eh? eh? eh?

-Ian

Originally posted by Ian C

Are you selling these cheap injectors then, eh? eh? eh?

 

-Ian

No - thats on another F/S thread

Although thats probably my fault too - as they are not really needed to run 700HP!)

(as he armlocks the next unsuspecting punter, attaches electrodes to his genitalia and forces him to purchase a set of green second hand neons!)

The pressure regulator works like this:

You have a fuel pump in the petrol tank, sending fuel forward, through the fuel pipe (rail) that feeds the six injectors, which are electronically pulsed on and off for different on / off periods to give the amount of fuel the map in the ecu tells them to for any given engine operating sceanario. The fuel goes out the other end of the pipe, through the pressure regultor, and back to the tank. There is also a pulsation damper that absorbs the shock in the fuel line when the injectors are opening and closing slowly, at idle, to keep pipe noise to a minimum.

The fuel pump, if it was pumping against a blocked off pipe, which would be the case with the pump running and the engine not started, could probably manage well over 100 psi, but the injectors are designed for only about 40 / 50 psi, and the ecu is mapped according to a pre decided fuel rail pressure. So a regulator is factory set to (say) 40 psi, and excess pressure is just recirculated back to the tank. However, under boost the injectors are squirting into an intake that has (say) 18PSI pressure in it, so to keep the system balanced the regulator has an extra hose going to it that connects to the intake manifold and adds boost to one side of a diagphram within the regulator. The diagphram is sized so one psi of boost raises the rail pressure of the fuel by one psi as well. Under vacuum (light cruising, idling) there is a vaccum in the manifold (negative psi figure), the same additional hose reduces pressure by whatever the vac level in the manifold is by pulling the diagphram the opposite way, again, the status quo is maintained, fuel pressure wise in relatio to manifold pressure.

As for some of the aftermarket ones, they raise the fuel pressure by MORE than the amount of boost, so if the static pressure should be 40 psi, and you are running at 10 psi turbo boost, a normal regulator would run the rail at 50psi fuel pressure, but a "performance" one would perhaps run 55 psi.

HOWEVER, the map in your ecu is designed to expect fuel pressure to rise linearly with boost, so it doesn't know the injectors, still opening for the DURATION pre mapped, are now squirting more fuel in that given opening time, due to increased fuel pressure within them, and hence the engine gets more fuel and runs richer. Whether this is good or bad, planned for or whatever is another can of worms entierly. The FSE, to be a fairly universal item, relies on an adjusting screw to set the static fuel line pressure. This screw is very sensitive, and you need good high pressure measuring gear to set it up correctly.

Hope this helps a bit.

So if the mixture is OK under load, the FSE contributes nothing.

Under light conditions yes - under heavier boost it offers increase response

And if it in any way improves the fuelling then I'm up for it - and richer fuelling is surely preferable to the opposite?

This is one of those FMIC cover threads - going nowhere fast !

Many using heavier boost than stock use them to great effect

Good enough for me - if you dont want one - dont have one!

Nuff said:)

Originally posted by John Packham

So if the mixture is OK under load, the FSE contributes nothing.

If the mixture IS correct under load, and you add a device to enrichen it further it saps power...

Originally posted by Chris Wilson

If the mixture IS correct under load, and you add a device to enrichen it further it saps power...

How can it enrich a mixture - we are talking flow?

Originally posted by Paul E

How can it enrich a mixture - we are talking flow?

You are talking about an FSE rising rate fuel pressure regulator?

It has nothing at all to do with flow, it's a pressure regulating device with a none linear pressure rise over boost.

Read my explanation above.