Pulse width and ignition timing question.

fowljesse · Post by **fowljesse** » November 18th, 2012, 1:03 am

I wonder if larger injectors take longer to open and close, and if there are injectors (maybe for bikes) that open and close faster. That might be what you are looking for. If a larger injector can open and close faster than a smaller one, and you have high fuel pressure, you could get a fast squirt. The benefit I can think of for this, as mentioned, would be to get better atomization, and possibly less fuel sticking to the runners/ heads.

MrMazda92 · Post by **MrMazda92** » November 18th, 2012, 1:39 am

crazycanadian wrote:Higher fuel pressure = more fuel... so bringing down the pulse width on larger injectors but running higher fuel pressure will get you no where...

I understand that...

I meant instead of bumping up the pressure, why not use the larger injectors, stock fuel pressure, and narrow the pulsewidth as much as possible?

Wouldn't that have the same effect, without having to mess with the fuel pressure? Seems cheaper and safer to me.

crazycanadian · Post by **crazycanadian** » November 18th, 2012, 3:40 am

MrMazda92 wrote:
crazycanadian wrote:Higher fuel pressure = more fuel... so bringing down the pulse width on larger injectors but running higher fuel pressure will get you no where...
I understand that...

I meant instead of bumping up the pressure, why not use the larger injectors, stock fuel pressure, and narrow the pulsewidth as much as possible?

Wouldn't that have the same effect, without having to mess with the fuel pressure? Seems cheaper and safer to me.

KISS principle... Factory systems dont often run maxed out or close to it... NA builds are much more forgiving then boosted builds... Its much harder to run out of fueling on an NA build...

Beside you are pretty much doing the same KLG4 swap that I did with a whole crap load more complication to it...

fowljesse · Post by **fowljesse** » November 18th, 2012, 12:29 pm

It seems to me that you would dump the fuel in a tiny bit faster with bigger injectors, but you would get slightly less atomization, unless you raised the fuel pressure. I don't believe that there would be any benefit, unless you tuned it to squirt only exactly when the intake valve is open, which we currently can't do with MS.

MrMazda92 · Post by **MrMazda92** » November 18th, 2012, 12:32 pm

Fair enough!

Don't hate on creativity haha, I know you guys've thought of weird stuff too

fowljesse · Post by **fowljesse** » November 18th, 2012, 1:28 pm

I like it. The only thing I find wrong with more complication is more chance for failure.
A lot can be learned from it, either way.
Thinking outside the box has gotten me a DE engine that is stronger than the ZE, with just ZE exhaust cams, and ZE pistons. With the DE heads, I have less compression than a ZE. I have weird mods that people said wouldn't gain me anything, but with them all working together, I have good results

MrMazda92 · Post by **MrMazda92** » November 18th, 2012, 3:28 pm

There's always that, but where would we be without outside the box thinking? The first posts on this forum argued that the KL swap was impossible, and would never work...

Later on, it was "OMG ZE > DE y0!!"

The biggest problem, is that people go "I have this in my car, so it's automatically the best option out there."
I have no problem with people sourcing a "True KLZE" from an importer... I have a problem with them saying "It's better because it's a ZE".

My biggest problem with the KLZE are the heads themselves... It's been proven, time and time again(I have links to dyno plots, if you call BS) that a junkyard KLDE with KL31 Cams and Flat-Top pistons is BARELY below a "True KLZE" in performance. IIRC, it was around a 5-7 HP difference at the crank. Throw the KLG4 intake manifold on(unported), and that KLDE eats a KLZE for breakfast.

KLG4 w/ any of Colt's cam regrinds and a proper 2.5" exhaust will outperform a bolt-on KLZE. It'll cost about the same as importing one too, but people don't like to go beyond their comfort zone... If 500 people say the ZE is the best, sheople will fall into line behind them.

MrMazda92 · Post by **MrMazda92** » November 18th, 2012, 6:16 pm

This page: http://www.600scene.com/index.php/artic ... -injection
has me thinking... Who knows how drastically thermospacers alter the angle of our injectors spray path?

Looking at a set of heads, fuel rails w/ injectors, and thermospacers... I decided to line them up and take a closer look.

From what I can tell, the thermospacers actually move the injector farther away from the throat pocket, and place it in a more direct line to the intake valves. I may have found another benefit to using thermospacers, what do you all think?

I'm getting a little deeper into the fuel atomization and spray pattern information now, and am starting to think about playing with fuel pressure and injector pulse-width when I dyno... Normally I would say that's a colossal waste of money, but my dyno time will be free and I won't have a time constraint, so I may as well play with it a little bit.

Too bad I only have one set of Millenia S injectors, and 2 blue-top KL sets... If I had 2 sets of each, I could swap the pintles and play around with all 4 sets of injectors: Stock blue-top, Milli S red-top, blue-top w/ S pintle, red-top w/ blue pintle, and then fiddle with the fuel pressure to measure potential gains.

Jesse, I know this'll pique your curiosity as much as it did mine!

It may be silly, but better fuel atomization could be well worth the experimentation.

fowljesse · Post by **fowljesse** » November 19th, 2012, 2:03 pm

IIRC (and my track record isn't very good), babybluemx3 was the one that experimented with the pintle/ injector combo, and came up with the DE/ K8 combo.
It's funny; if you play around, and come up with this stuff without telling anyone anything but the positive results, you look like a hero. However, I really like all the input that comes.
If you have free dyno time, use it as much as possible! That would be a big help to this forum! I wish that I did, so much that I considered building my own. It wouldn't be accurate, but would serve the purpose.

That's quite interesting about the spacers. Maybe you could make a dyno run with only changing the spacers.

MrMazda92 · Post by **MrMazda92** » November 19th, 2012, 5:25 pm

I'm going to PM him now.

I don't have a set of K8 injectors free at the moment, but I will when I find a KLG4!
The Millenia S and KL injectors have different pintles, definitely. They both split the spray pattern into 2 directions, obviously to aim it directly at the 2 intake valves. The thing I wonder, is how far apart the Milli S intake valves are, compared to KL valves. If that gap is larger, or smaller, then many boosted KL owners are potentially throwing away free power.

I will have free dyno time, but it's not what I would call local... It's a decently long trip, that I'd prefer to only make once or twice. I will make the trip after I get this year's MX-3 plans out of the way though.

The spacers have already been dyno verified as a benefit, but who knows if that benefit was solely caused by reduced intake temps, or whether this contributed at all?

fowljesse · Post by **fowljesse** » November 22nd, 2012, 1:12 pm

Let me know if I can help with the dyno day.

MX-3.com

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