What is the maximum amount of injector opening time (mls)

[hrdtail78]

The Delphi changes both.  It can change opening and closing.  Does it spray on a closed valve before it opens?  Yes, after a certain RPM it has no other choice.  This is where higher pressure and smaller duty cycle come into play.


Or you can listen to stroker up there and try to run it at 110% and get into the unicorn fueling approach.

[strokerjlk]

Great discussion guys, I think 80% to 85% is ideal and 90% is very borderline I think we need to allow time for the injector to actually open and close after the signal which is how duty is measured and for changes in engine temp, air temp and battery voltage which can all change the ms,so I think 80% is better than 90%. another thing that concerns me is if you extend the d/ cycle where does the injector stop spraying( does it spray onto a closed inlet valve ? ). my t/max has adjustable injection advance but I don't know if it adjusts injector opening or closing point. I did change this setting to 360% and it made a big difference to my cold and hot idle , light load cruise under 2300 rpm and hp but I don't really know why?? Max

It is a good discussion .
If your injector was at 20 ms at that Same rpm and throttle position   You would have a calculated 106 % duty cycle .  So does that mean you now have 84 % at 17 ms or is it still 90 % , remember D/C is calculated .

Based on the conditions you obtained your P/W data , do you think you could ever recreate that on the street ?
I am not against the 80-85 % rule of thumb. I like a big injector .
But sometimes you have to use some common sense .
I can guarantee you that your never gonna see 6400 rpm in high gear on the street .

[strokerjlk]

The Delphi changes both.  It can change opening and closing. Does it spray on a closed valve before it opens?  Yes, after a certain RPM it has no other choice.  This is where higher pressure and smaller duty cycle come into play.


Or you can listen to stroker up there and try to run it at 110% and get into the unicorn fueling approach.

Finally mr injector gets one .
Probably just another typo .

[hrdtail78]

I have never said anything different.  At least I am not spreading just complete crap.

Based on the conditions you obtained your P/W data , do you think you could ever recreate that on the street ?
...............
I can guarantee you that your never gonna see 6400 rpm in high gear on the street .

If you have your VE tables mapped correctly, and your injector pulse width indicates 20ms at 6400.  It just wont be tapped out in high gear.  It will be tapped out regardless what gear you are in.  ECM knows 100%, 100kpa, 6400rpm's.  I am sure most bikes on the street can achieve redline in at least the first 3-4 gears.

There is no reason to go to name calling.  That is what the weak and unintelligent do.  Why don't you instead, try and back up your theory on 106% duty cycle.  Sheesh, try and back up anything you type.  This is an open forum and when you spread misinformation.  It needs to be called. 

[strokerjlk]

I have never said anything different.  At least I am not spreading just complete crap.

Based on the conditions you obtained your P/W data , do you think you could ever recreate that on the street ?
...............
I can guarantee you that your never gonna see 6400 rpm in high gear on the street .

If you have your VE tables mapped correctly, and your injector pulse width indicates 20ms at 6400.  It just wont be tapped out in high gear.  It will be tapped out regardless what gear you are in.  ECM knows 100%, 100kpa, 6400rpm's.  I am sure most bikes on the street can achieve redline in at least the first 3-4 gears.

There is no reason to go to name calling.  That is what the weak and unintelligent do.  Why don't you instead, try and back up your theory on 106% duty cycle.  Sheesh, try and back up anything you type.  This is an open forum and when you spread misinformation.  It needs to be called.

Mr unicorn better
Just because you don't understand it , doesn't make it misinformation .
Continue to tell us how you have the Same PW at the same rpm in every gear .

[hrdtail78]

"Continue to tell us how you have the Same PW at the same rpm in every gear ."

That is not what I stated.   It will depend on target AFR as well. That is why I stated 100% throttle, 100% KPA and certain RPM.  You conveniently left out throttle position and KPA to twist things around. Your MO.

Here is a test for the others that can keep up. Take a TP over RPM cal and set the entire AFR table to 13.2.  Pick a TP and RPM.  Hold it in 3rd. Then shift to 5th and hold same TP and RPM. 

Nobody has to take my word for anything.  That is why I try and back up what I am saying with test that show examples or try and find things on the net from creditable sources that everybody can find and understand.   

I encourage and recommend guys digging into things, read and learn.  Get a couple of creditable sources and don't blindly follow anybody.  It might just be the blind leading the blind.

Or you can follow a guy that thinks the temp sensor reports straight head temp, you can see beyond the rpm limiter if you switch to mph, lean idle surge can only be corrected by timing, and running an injector at 106% is possible and OK because you won't hit redline in 6th gear. 

It's your engine and I haven't seen anybody behind a keyboard take responsibility for advice they give freely on the net.  So, do whatever and take whatever advice.

HFT

[strokerjlk]

Based on what you thought I said. and what I actually said , Don't confuse yourself with other topics you couldn't understand either .

At least you learned that duty cycle can be calculated at over 100% . 

The best advice you have given was TEST for yourself .
That's the whole reason I bought a dyno .

Plain and simple
17 ms PW @ 6400 Rpm's is very acceptable . There is no reason to buy new injectors , and re tune .
If you were planing a build and had this same data , then buy bigger injectors .

[hrdtail78]

At least you learned that duty cycle can be calculated at over 100% . 

I have always understood the calculation but it doesn't mean you have control at 100% or you are going to get anymore fuel over 100%.

Here is a test for ya stroker.  Fill up a coffee cup 100% full with coffee.  Then add 6% more.  Is the cup any more full, or did you just spill coffee on the counter?

Nothing is based on what you said.  It is based on what you typed.  There in black and white for everybody to see.   First reply.

http://harleytechtalk.com/htt/index.php/topic,76803.0.html

I'm actually getting board with correcting and pointing out your BS babble.  No challenge in it.

[strokerjlk]

I suggest you go back and read the thread .
Your still 106 % confused .

[FLTRI]

An interesting read to toss a monkey wrench in:

What is duty cycle?

Duty cycle is the amount of time that the fuel injectors are switched on. A duty cycle of 0% means that the injector is not on at all, a duty cycle of 100% means the injector is on constantly. Duty cycle at idle is normally only a few percent, rising as revs or load increases.

Honda and duty cycle

Honda usually runs their injectors to 100% duty cycle at redline.

They appear to adjust the fuel pressure to achieve this. A good example is the early B16A and B18C engines. Both have 240cc injectors, but the B16A has 38 lbs fuel pressure and the B18C has 45 lbs fuel pressure. The difference in fuel pressure is roughly the difference between engine capacities (remember that fuel delivery from extra fuel pressure is not linear). If the B16A has a touch more fueling it is because it has a higher specific output. I believe that Honda runs their injectors to 100% to get accurate delivery at part load and revs, which in theory will help emissions, economy and drivability. The implication of Honda running their injectors to 100% duty cycle is that there is not much scope to increase the engine output on the stock injectors, since the only other way of increasing fuel delivery is to increase the fuel pressure. With forced induction you fairly soon get into crazy fuel pressures unless you increase the injector size.

We have not seen any problems with engines running rich or lean once the stock injectors get past 80-85%, but it is not recommended to exceed 80% duty cycle with replacement injectors. Otherwise you will run the risk of the injector not being able to open and close quickly enough, which causes the injector to float half open. This will lean the mixture out, which is not going to healthy for an engine at high revs and under full load.

In terms of power change from different sized injectors it appears that there is little difference with the Honda engine changing the injector size if the overall fuel delivery is kept the same by reducing the injector duration. We have dyno tested different sized injectors and did not find any difference in engine output between 240cc and 440cc injectors on a B16A engine (we adjusted the injector duration to give the same lambda readings).



Bob

[hrdtail78]

Bob,

How do you set an injector to be 100% at redline?  Is that worse case?  PE mode on or off?  holding 100kpa at redline through all the gears?  With the fuel adders based on temp?

Just asking.

I would think it would be impossible without a electronic controlled fuel reg.  PW is dynamic based on too many variables and engine conditions.  I can't see the same pw at an engine temp of 100f and 200f at say 100kpa.  Throw in a 2 bar and then what?  Even with our tractor engines, the same pw fuel flow at 98kpa is going to be different than it will be at 100kpa.  Even with targeting the same AFR.

[strokerjlk]

The Honda guys do some pretty unique tuning .
Some of the guys even run 116 duty cycle .
They use peak and hold injectors , as well as saturated injectors .
Interesting read explaining the diff .

There are two basic types of injectors that work on Honda and acura cars. How they operate are totally different. Let's take a look.

Peak and Hold:

Peak/hold injectors are low impedence, usually in the 1-4 ohm range. When the ecu calls for fuel to be injected, it sends out voltage via the wire clips until a certain current level is reached (the peak part) (varies by injector size, company). For the duration of 1 pulse width, that current is slightly reduced and held (the hold part).

Advantages of this design:
minimizes the injectors "on" time, resulting in faster response
Disadvantages of this design:
increases coil heat, which can lead to failure over time
<hr>

Saturated:

Saturated injectors are generally higher impedence than peak and hold, running in about the 10-15 ohms range. Unlike peak/hold, a saturated injector remains "on" for the entire pulse width.

Advantages of this design:
reduces heat
Disadvantages of this design:
slower response time
can't handel large CC or lb/hr styles due to limitations in its speed.
<hr>

So, which should I choose?

There are a ton of factors involved in this.
First, power level. If you're going big, there simply won't be a saturated injector that will support your power level. The largest common saturated injecotrs on the market are 550cc, with 440cc being a common "cap" in saturated size. Most boosted people run peak/hold setups for not only their availibilty, but also their ease of upgrading later on if so desired. simply swap the injectors. no need to re-wire again.
How is your car wired? most obd0 civics and some preludes are wired for peak/hold and have a resisitor box already. No point in changing to a saturated. Obd1+2 civics, and most other honda/acura cars after 1992 are all saturated and are not wired with resisitor boxes. Again, if there is an injector availble in your power range for flow of your car's design type, there's little sense to change.
Price. DSM eclipse/talon 450cc peak and hold injectors fit honda rails and with just a minor modification plug right in. best of all, these can be had for about $50-75 a set of 4 instead of $350+ for a set of aftermarket injectors. Add a $25 resistor box from an obd0 civic/crx, wire it up, and you're good to go in you're saturated car.

[FLTRI]

Bob,

How do you set an injector to be 100% at redline?  Is that worse case?  PE mode on or off?  holding 100kpa at redline through all the gears?  With the fuel adders based on temp?

Just asking.

They simply size the injector so that when they are at their test points @ 100kpa, rpm redline the injector is basically open all the time.
Only thing that makes sense there is the smaller the injector at same psi the better the control for emissions certification....certainly not for best performance.

I would think it would be impossible without a electronic controlled fuel reg.  PW is dynamic based on too many variables and engine conditions.  I can't see the same pw at an engine temp of 100f and 200f at say 100kpa.  Throw in a 2 bar and then what?  Even with our tractor engines, the same pw fuel flow at 98kpa is going to be different than it will be at 100kpa.  Even with targeting the same AFR.

You are 100% correct there. All they can do is set up test points and develop calibrations using the data generated at those points.
Logically, the more test points (data points) the more capability to control fueling and timing events much tighter than ever before in order to pass stringent emissions standards.
Bob

[FLTRI]

Can't make an injector run its duty cycle higher than 100%... not possible. The injector has completely maxed out @100% duty cycle meaning its open all the time, you just ran it past its operating range and the over 100% calculation shows that.

Your data may report over 100% dc but physics dictates here.
Bob

[hrdtail78]

"What we end up with is a calculated pulse width that is longer than the time available between injector firing events. The injector is going to be open for the full 17ms of available time, and then before it can close it receives the next 18ms pulse in the cycle. The net result is that the injector never has time to close before receiving another pulse, so it's running wide open. In other words, we get a calculated IDC of 105.9%, but a true IDC of 100%... since an injector obviously can't be open longer than 100% of the time."

I see statements like this over and over on the net.  I have only seen one person make this statement.

It's possible to have 115 % calculated duty cycle , and still have plenty of injector .

I have to wonder how injector latency comes into play with our high impedance injectors, and has anybody ever flowed our white bands to see if they are dead time matched, or any injector that HD supplies?

[strokerjlk]

Your getting there .

[hrdtail78]

Getting where?  I'm waiting on you.



Quote from: strokerjlk on Yesterday at 02:25:42 PM

"It's possible to have 115 % calculated duty cycle , and still have plenty of injector ."

Start here, please?  How can you still have plenty of injector? 

[joe_lyons]

Marty McFly injector?

[strokerjlk]

Getting where?  I'm waiting on you.



Quote from: strokerjlk on Yesterday at 02:25:42 PM

"It's possible to have 115 % calculated duty cycle , and still have plenty of injector ."

Start here, please?  How can you still have plenty of injector?

you talk about testing .
so do a little testing of your own.
install a injector that will result in a calculated duty cycle over 100%
then see just how rich you can take the mixture.
once you see that it can bog the motor with the extra fuel, then try a 50 shot of nitrous and see if it still provides enough fuel .

[To The Max]

Gee, you guys have been busy. now where do i start, first of all you CANT run 100% duty cycle you have no room for the for the computer to adjust for change in conditions ie. colder air temp. with a computer that uses air fuel ratio sensors, you can set  your air fuel ratio to lets say 12.4 at full load from lets say 2000 rpm to 6400 rpm and the MS will all be different in every load cell in that range. and I forgot to mention there is no 101% and no 106% 80% is ideal(most efficient ), my 90% is over the top and I would be smarter to go up one size. just recently I took my big shots of and sold them to my mate and I fitted a Bassani two into one (best thing I have ever done) my duty changed by up to 5.7 MS in most of the map. more efficient pipe=more air=more fuel=more torque more horsepower 100% duty cycle=new pipe=seized Harley= BIG BILL. one more thing, most late model port injected motors start there injection before the inlet valve opens and finishes before the inlet valve closes what I would like to learn is what is the effect if injection cycle ends to late ie 95% duty cycle. I wont pretend to be a expert and am prepared to be WRONG but I do want to learn, lets be happy guys.Max

[Sunny Jim]

Maxo, HTT is addictive,
in a nice comforting way that is!
A bit like beef and beer!
Be careful what you wish for! Lol!

[hrdtail78]

Getting where?  I'm waiting on you.



Quote from: strokerjlk on Yesterday at 02:25:42 PM

"It's possible to have 115 % calculated duty cycle , and still have plenty of injector ."

Start here, please?  How can you still have plenty of injector?

you talk about testing .
so do a little testing of your own.
install a injector that will result in a calculated duty cycle over 100%
then see just how rich you can take the mixture.
once you see that it can bog the motor with the extra fuel, then try a 50 shot of nitrous and see if it still provides enough fuel .

You do know that the pw number you see in the data stream is calculated, and nitrous can change atmosphere in manifold?  As far as your test goes.  Is it safe?  How are the 2 nitrous bikes you have doing?  Still running since you sprayed them?  Or did something happen to both of them and you had to borrow a bike?

Here at my shop I address 115% calculated IDC.  If 115% calculated is good enough for you?  Let it roll out.  That is between you and your customer.

[FLTRI]

My rule of thumb is simple:
If the bike is going to be used for racing I make sure 80% is the max needed.
If the bike will be for street only with occasional WOT runs for a few seconds I will see 90-95% as reasonable.
Anything over calculated 100% is just info telling you the injector is hung open and power will be lost due to fuel control loss.
JME,
Bob

[strokerjlk]

Nope the bagger is just fine ( It's the EFI bike in question ) your welcome to come try your luck against it anytime you want . I don't need a rifleman thought . 
The sporty scattered parts everywhere . But it don't have injectors

Max
If you didn't get your answer yet, there is nothing more to say .
Flip a coin .
Bob .
So If you have over 100% calculated D/C and you can still control fuel your ok ?
If you can fatten the mixture up 1-2 Afr and make the engine lose power , is that enough control?

[Coyote]

I'm way down on the learning curve here and I find this interesting but I don't see how you can have fuel control if the required duty cycle is over 100%. Doesn't make any sense to me at all.