Fuel Injectors

[fadz]

hi just a question , iv been told bigger fuel Injectors, increase performance in a certain way... i have a 94 model vti civic
can anyone answer this and let me know if its worth doing, thanks cyaz!!

[BLKCRX]

That is 100000% absolutely completely wrong. Correct tuning produces more power with certain about of fuel and ignition, this can only be done via EFI devices, simply adding more fuel will almost most certainly decrease your performance and fuel economy.

[fadz]

i jus thought bigger injectors means mor fuel goes in...and wen fuel burns quicker...car wil get bit mor speed... anyways thnx for answering my question :D

[BLKCRX]

Not if there isn’t enough combustion for the fuel, or enough spark, everything has to be in correct and optimal doses for gains, if not you will lose power.

[ProECU]

i jus thought bigger injectors means mor fuel goes in...and wen fuel burns quicker...car wil get bit mor speed... anyways thnx for answering my question :D

you need oxygen to make fuel combust.

pick up a chemistry book if you want to learn more, its all in there

[Boost]

whats the approx. pulse width of each injector firing? im thinking its somewhere between 3ms - 10ms.. but can seem to narrow it down to an exact value..

[ProECU]

i'll look at some datalogs and post some data for ya

pw will typically increase along manifold pressure & rpm until peak torque and then either remain constant or decline (depending on tuning) after peak torque.

[Civic Type R]

i jus thought bigger injectors means mor fuel goes in...and wen fuel burns quicker...car wil get bit mor speed... anyways thnx for answering my question :DThats the same ideology as chopping your springs to lower your car.;)

[wynode]

i'll look at some datalogs and post some data for ya

pw will typically increase along manifold pressure & rpm until peak torque and then either remain constant or decline (depending on tuning) after peak torque.
So basically the duty cylce varies depending on load and rpm..... ?

[ProECU]

yes... and peak torque and volumetric efficiency

[Boost]

Cool can you post up some data ProECU for some typical injectors and high flow ones...
im thinking PW is proportional to the manifold pressure ( volume of air going in) so that you get the correct AFR and the injector frequency is proportional to rpm, so that the number of times the injector is fired is fired once every 2 rpms. hmmm

[ProECU]

RC 550cc injectors, stock fuel pressure reg.
ive even graphed the data for you guys.

this is live data from a WOT run of one of my customers cars.
(right click and save-as)

<link (http://www.b16a.kicks-ass.net/Book1.xls) removed>

[tinkerbell]

i am running 63psi of fuel rail pressure and an average of 12.7:1 AFR...

http://members.iinet.net.au/~joannepulis/sparefiles/TodaRacingB20VTECdyno001.jpg

will bigger injectors help me to reduce fuel rail pressure? i only have VAFC II to tune with...

i do not know the duty cycle.

[tinkerbell]

BTW - PW can be upto 100ms on a cold start scenario...

[weezer]

is that 63psi with the vacuum hose on or off? Im going to be installing my FPR soon and dont know what pressure will be ideal for RC injectors?

[tinkerbell]

vac off...

go here weezer:

http://www.rceng.com/technical.htm

[Boost]

was that reading taken when the hose is off and on idle? cause by taking off the hose.. the FPR sees atmospheric pressure.. so the spring stiffness will equal the fuel pressure..with the hose on & on idle, you should see a drop in fuel pressure cause this is when there is max. vacuum and the FPR valve is at its max. lift to regulate fuel back. I think on idle more than 70% of the fuel is returned back to the tank.

[tinkerbell]

vac off...



is short for 'vacuum hose off'...

[Boost]

hahha.. sorry my bad.. should have read it carefully..
yup well thats the reason why its high .. cause there is nothing assisting the spring to lift up the fpr valve.

[weezer]

i think with the vac hose off, its the reading at WOT since there is no Vaccum at WOT. In the workshop manual it says Fuel Pressure reading should be done with the hose off.

[Snoop_gee]

just want to know the different between high restitance fuel injectors and low resitance Fuel injectors?Explaining the benifits and problem with each?
....

[saxman]

just want to know the different between high restitance fuel injectors and low resitance Fuel injectors?Explaining the benifits and problem with each?
....
it basically has to do with how the injector is told to fire

one says "open" and then stops saying open when it's time for it to stop, the other basically says "open", and then "close", when it is time for it to stop.

Using a resistance of injector that doesn't match how the car is set up can cause serious problems(frying the ecu very quickly), however, it is possible to wire in resistors to safely use non matching injectors.

[Snoop_gee]

saxman yo man thats realli not explaining the difference between high and low resistance fuel injectors... i'm still confused. can some1 serious explain this?

[saxman]

saxman yo man thats realli not explaining the difference between high and low resistance fuel injectors... i'm still confused. can some1 serious explain this?
I don't know how else to explain it... the difference between them is how they interpret the signal from the ecu. The biggest notable difference between the two is that with a low impedence injector, there is a slightly shorter triggering time, so on very high out put engines with super large injectors, idling is slightly improved.

[Snoop_gee]

so low resistance is always good for N/A and high restiance for turbo engines ?

[saxman]

so low resistance is always good for N/A and high restiance for turbo engines ?
I would say whatever is in your engine stock is best to stay with, but you would see the idling difference issue on an f/i engine LONG before an n/a one. Not sure I've ever seen a built n/a honda engine that needs injectors large enough for the benefit of the low resistance ones to even come into play

[BLKCRX]

read here... one of my hondatech articals

http://www.hondatech.com.au/forum/showthread.php?t=143

Regards James

[wynode]

read here... one of my hondatech articals

http://www.hondatech.com.au/forum/showthread.php?t=143

Regards James

Is that one of your articles?

Because I found the exact same article (word for word) on HondaSwap (http://www.hondaswap.com/forums/index.php?showtopic=31058)

[bennjamin]

Is that one of your articles?

Because I found the exact same article (word for word) on HondaSwap (http://www.hondaswap.com/forums/index.php?showtopic=31058)


No Way. This "pissedoffsol (http://www.hondaswap.com/forums/index.php?showuser=1)" guy OBVIOUSLY travlled into the future , to the date which James created his hondatech article ( on 11-01-2005, 01:33 AM ) - cut n copied the entire lot -
THEN travelled back to his time , almost 2 years prior ( Jan 28 2004, 04:00 AM) and posted it up.

The efforts some go to ;)

[Snoop_gee]

so in other words james "Saturated" means high resistance and "Peak and Hold" is low resistance.

[ProECU]

The correct term is IMPEDENCE, not resistance.

[tinkerbell]

The correct term is IMPEDENCE, not resistance.

um, try 'impedance'

*sigh*

[tinkerbell]

um, good to see you're still feeding those chickens.

huh?

no, i was just correctly correcting your 'correction'

do you have a problem with that?

[ProECU]

not with the correction, but your general derogatory tone blows

[tinkerbell]

if you have a problem with my tone, take it up with a mod,

otherwise, try to stick to the topic...

[ProECU]

if you have a problem with my tone, take it up with a mod,

otherwise, try to stick to the topic...

practise what you preach, oh, and yeah, I have reported you on occasion.

[bennjamin]

come on guys - we love both your work BUT plz keep the bickering to pm or just not at all :)

BTW the problem with the faceless and non-emotive internet , is that you cannot judge a persons "tone" by reading typed words - sometimes people are trying to help out and not personally attack ! *aimed at everyone here on OH :)*

Lets try to get the 100% correct answer - too many opinions seem to confuse all of us ?!?

[saxman]

Lets try to get the 100% correct answer - too many opinions seem to confuse all of us ?!?
too many opinions? everyone that's actually answered the question has basically said the same thing

[bennjamin]

too many opinions? everyone that's actually answered the question has basically said the same thing

i refer to more the "opinions" against each other and side-talk that is confusing others ! Peace everyone :)

[pgclee]

*Yawn*