xr2wishy

iTrader: (2)

basically i bought these years ago and haven't had any issues, but now on my zetec turbo they have reached 111% duty cycle on my megasquirt II v3.0 ecu when i reached 1.6BAR.
the pressure reg is fine with a base of 3BAR and rises as the boost does. now these injectors should easily provide 500bhp, so why is the duty cycle so high, could it be the way megasquirt is running and it's actually half as much?
i very much doubt it's anywhere near 500bhp, i reckon on around 300bhp a my current level of tune, or there abouts.
is there anyone local i could get these cleaned and checked with, seems very odd behaviour indeed.
they came from integrated engineering in the states, who seem to have a good rep and would assume genuine items.

anyone else had issues with these?

thanks
sean

stevieturbo

You're being a bit optimistic there....

And how much fuel the engine needs and how much it's being given are two different things.

xr2wishy

iTrader: (2)

the afr's are a little low in terms of over fuelling a little, but since the ecu is giving 111% duty cycle that's more than it should be.
the injectors should flow around 500bhp, certainly piss 400bhp with no bother.
if i up the number of squirts per cycle could this help?
currently on alternating two squirts per 720 degree cycle.

scoooby slayer

iTrader: (4)

i cant help on the injectors but i have had a car tuned to 100% duty and worked out a max hp per cc fuel. i work on ccs / 6 gives hp for 100 % duty at 11.4 afr, and imo that is giving it best as 1000 hp on 6 1000cc injectors is gonna be flat out at 3 bar base.
so your 4 x 630cc injectors are 2520cc total, /6 = 420 hp flat out, its easy to work out on a 6 cylinder as cc is roughly max hp at 100% duty.

how can you even see 111% duty ?

xr2wishy

iTrader: (2)

i'm not sure how i can even see 111% duty cycle, you just play with the numbers in the fuel map and it calculates duty cycle in relation to map reading too.
it could simply be that the injectors stay open into the closing time frame or something, i know i can bump up base pressure without issue though, just need a change in reg.
i think i need to find out if the fuel pressure is not dropping off on boost, previous test shows it's fine to a BAR.

stevieturbo

Many aftermarket ecu's will register above 100% DC ( as will any ecu really )

And you're dreaming if you think they'll support 500bhp

And it's equally as daft to think trying to open and close the injectors more often within the same limited time period is going to give you more fuel.....when they're already stuck wide open the entire time.
Might be difficult to achieve that.

xr2wishy

iTrader: (2)

I think it's been covered even by myself that these won't do 500bhp, but until I get it on some rollers I won't know how much I'm running either.
I was really asking if anyone runs these and if they didn't flow as expected.

scoooby slayer

iTrader: (4)

if your running 300 hp and its running 11 afr you should be in the 75% ish duty area.

Karlos G

iTrader: (4)

Sean what is your Req Fuel value?

stevieturbo

I do use them, they work great and they do flow as expected.

Just some people have strange expectations without any reasoning.

Stu @ M Developments

iTrader: (12)

Your missing a VERY important parameter here guys... BSFC.
I am just heading home, so please use google to progress.

Stu @ M Developments

iTrader: (12)

Doh, or review an article I wrote on it ages ago instead.
http://www.motorsport-developments.c...AF286_tech.pdf

Karlos G

iTrader: (4)

Does anyone one know the BSFC of a Zetec turbo?

Karlos G

iTrader: (4)

Found this for the Ford 2.0L Zetec, don't know if it's black top or silver top or if their BSFC is the same maybe?... And of course we lower the CR too which will reduce the BSFC I would assume (Dropping the amount of mechanical energy produced)?
Also the BSFC changes throughout the RPM range so not sure how you would get to the normal figure used in the injector sizing calcuation? lol

Stu!! Help!! lol

Karlos G

iTrader: (4)

Sorry that map is no use as we need to see the BSFC at say 400bhp to be any use really.

Canada1

BSFC is determined by power output and volume of fuel used - engine efficiency.
Camshaft changes, head flow, inlet manifold, exhaust manifold, turbo turbine size, down pipe and exhaust sizing, compression ratio etc.... all have an effect on BSFC.

BSFC is determined during a dyno testing session.
An experienced builder (with a specific engine and mods) will generally have a good idea what the BSFC typically is.

Regarding fuel injector sizing. I have found the RC injector site has a reasonable injector sizing calculator. http://www.rceng.com/technical.aspx


Using BSFC of 0.6 , 4 injectors, duty cycle of 80%, yields 350 hp (flywheel power)

Of course you will always get the guy that says his 630cc injectors were used for 500+ HP
good for a big laugh.

Cheers

xr2wishy

iTrader: (2)

yup i get BSFC, i understand that turbo engines tend to have a lower figure compared to N/A also.
the main reason i started this thread is that not for one second i thought my engine would be running anywhere near the sort of power levels the duty cycles are suggesting, new clutch going in will mean i can actually get it on the rollers to get some figures.
it's almost sounding like cossie4i has started an ASW post

studabear

it would be 10 pages by now if cossie4i had started it.

xr2wishy

iTrader: (2)

5.5 is the req fuel calc.
i just dropped it a little to give more resolution across the table.

xr2wishy

iTrader: (2)

without checking the pressure when it's hitting boost, could the 8mmOD fuel pipe feeding from swirl pot to bulkhead be a restriction?
could changing up to 10mm be better as i have plenty of that size pipe lying around, will check pressure first though, the pump is more than man enough to deliver, it is rated to 8BAR and can push to 10BAR comfortably.

scoooby slayer

iTrader: (4)

lines defo need to be big enough, in reference to my thread im running upto 788 hub hp on twin walbro 255s but mark at mad has seen evos on twin walbros struggling to do 600hp and i put that down to the lines being a restriction, mine are huge lines i havnt measured but id guess each line is 12mm id from each pump !

crazycage

i dont think its your line mate why dont you ask rick to have a look at the map for you ?

stevieturbo

Exactly what do you mean by 8mm od ? Because clearly if you have a flexible 8mm od line anywhere it will be miles too small. If you meant 8mm od hardline, then that will support 500hp

crazycage

he ment id .

stevieturbo

Sometimes you just never know.

xr2wishy

iTrader: (2)

re the pipe, i meant 8mm ID hoses to an 8MM OD hardline.
i think there may be more to it than just fuel supply, i have got the lift figures from Ian Howell for the cams and will be setting these up properly today, could be too much overlap wasting too much fuel.
engine is ou anyhow, so will investigate further for issues there.
rick has seen one of my older maps and apart from too much timing up high, nothing more has been said, i think i just need to find the dough and see mr rick before too long and persuade him to do some mapping