Aaron Klein

I did read through the post about how someone thought the 4-12 hole injector mod must be a myth. I thought we should revisit that from another more analytical view. I myself believe that there's in fact some benifets to be had with the upgrades injectors.

I think the stance that it's a myth is taken solely from the idea that there's no power to be gained while this is in fact should be true (you're not delivering more fuel so why would you have power gains) but these people obviously only consider power to be the only difference analogous to performance.

When I think of performance yes I do think of power as one of the criteria but it's about more then just power alone for me and I suspect it's the same for others as well. I do consider things like idle quality (smoothness) throttle responsiveness fuel economy and easier starts in colder weather as performance enhancing (mods made in order to perform better then in stock form).

That stated as someone deeply into engineering and how things work in physics and also having seen tests done comparing both the 4 hole injectors to the single stream as well as a new one posted by precision injectors comparing the 12 hole to the 4 hole it's very difficult for me to imagine that there could be no benifets whatsoever. Not likely on an appreciable horsepower basis but rather aforementioned aspects. And I'll go into detail.

Idle quality may be improved by burning fuel in a more even manner throughout the cylinder having a closer to ideal AFR throughout the eitire combustion chamber rather then having what could be a less uniform flame front acting on the piston.

Responsiveness may also be improved because in those short moments opening the throttle body when theres not as much turbulence to help atomize fuel it should already be better atomized and burn off earlier in the power stroke.

Fuel economy should surely go up slightly as the better atomization should as previously mentioned help with a more even AFR thus burning more fuel completely (harvesting more energy from the fuel) and additionally harvesting that power sooner in the power stroke where it has a better chance of acting on the piston in the most useful crankshaft/piston position.

Easier starts in cold weather should be a no brainer but I'll go into detail there as well with a bonus fact as well at the end. Our intake manifolds do get very heated by our exhaust manifold/header (unless you heat wrapped) and this can help atomize fuel of course but in the cold in the morning/upon first start this is moot. The fuel injecteed will have a lot more trouble atomizing making starts more difficult and also leaving being unburnt fuel in the cylinder. Having better atomization straight from the injector should surely help the spark to ignite the fuel even without that heat from a heatsoaked manifold. Here's the bonus also fuel injected enginestend to deliver extra fuel till the engine reaches operating temp and that compounded with the fact you're already leaving unburnt fuel in the cylinder is a major contributor to oil dilution with fuel so having the better atomization would be leaving less of this fuel in the cylinder to wind up diluting your engine oil thus having some positive impact on overall engine life.

I'll leave you with this. Try and remember there's more to "performance" then just power alone. I hope this is highly informational for some of you and those of you that already knew all these things then I'm surely happy for you. And if you believe that the 4.0 somehow "doesn't care" about atomization I'm sorry that I couldn't bother you to try and understand physics. I also forgot to mention the emissions advantage but I seem to be tired of typing for the time being but I'm sure some of you can surmise how they could be advantageous in that respect as well. Hope you all have a good day and enjoyed my article!

craigjacob1

Thanks for the information!

I installed 4 hole bosch injectors a little over a year ago.
The immediate improvements I noticed were smoother acceleration, and better throttle response.
I don't think I need any scientific evidence to back it up. It was a blatant observation. The fuel injectors were the only components changed.

I didn't notice an increase in fuel economy until a K&N intake was installed. The difference was dramatic. I imagine the 4 hole injectors help with that. I'm not going to post numbers, because I'm not in the business of defending estimates.

Cummins93

I saw no qualitative or quantitative differences with the 4 hole upgrade on my 95.

Bugout4x4

I have resisted converting because it is much easier for a four hole injector to plug up than a single larger hole injector.

Martlor13

you must hate the 12 hole injectors some put in haha

Bugout4x4

I think that there might not be any options with most of the other makes and models but the desert is hard on injectors. For an off road desert car I would rather have one larger squirt hole than more small ones that sand can plug.

There is a little difference in performance, But for this little difference I would rather have something in a desert rig that is less likely to plug up.

Tbone289

Are you assuming that a 1 hole injector might "pass" a larger grain of sand than a 4 (or 12) hole injector?

I would think that any grain of sand large enough to fully plug a hole in even a 4-hole injector wouldn't normally make it past a fuel filter. So, aren't we talking about minute particles building up over time? If so, how is minute particle build-up going to more negatively affect 4 holes than 1? When I say "minute", I mean particles smaller than the orifices.

I would be interested in seeing a study that shows that multi-hole injectors have more of a tendency to plug up than single-hole injectors.

Bugout4x4

Good morning T bone...

That's what I assume considering my 97 doesn't have a decent filter... Just a screen/coarse filter with fairly large holes in the tank. But I plan on implementing an inline because it really needs one. Then of course it wouldn't matter as much if 4 or 1. Prudence has paid off very well for me on stuff like this over the years. You don't have to agree, I'm gong to feel this way regardless, tests or not... lol

Fixmy59bug

Do you get a lot of sand in your gas tank that the fuel pump pre filter or the main fuel filter cant filter out?

Cause if so, That must be some NASTY ****...

Tbone289

I don't disagree, and I'm certainly not trying to change your mind. What is it they say about old dogs and new tricks?

I'm just thinking through this "out loud" as I normally do... An inline filter is a good idea.

Bugout4x4

Lol... I was messing with you my friend. I knew where you were going with that.

Anyways, I was going to look but haven't needed to since the Jeep got rolled and I can't drive it... but do they make a filter with quick disconnects for the fuel rail connection? that would be the cat's *** man. I'm sure it wouldn't be hard to make one up if not.

Tbone289

A small one right there easy to get to at the rail... That's good thinkin'. Seems like there are QD adapters made to fit just about anything.

Bugout4x4

Yep, just looked... They make just the ends that use fuel hose too. Mount one nice big canister and bracket on the air filter box and probably be done for the life of that vehicle... lol

Bugout4x4

Your idea is better, Just a small one that clips inline right there.

Bugout4x4

OK so they sell the female QDps and the plastic heat shrink line. So with the right QD filter choice all you would have to do is make up a female-female QD from the male rail to the male filter nipple. And the existing incoming line female QD would fit on the other filter male.

Edited for second hopefully better thoughts. lol