snap-on

I sent in 18 (yes 18) inectors to cruzin performance for service/rebuild. (injectors from the 3 motors sitting in my garage at the moment)

my plan was to take 2 of the sets put one in my 4runner (currently pulled motor) and the other set in my truck in the future.

turns out there is somewhat diffrence between the 18. as 12 were high impedance and 6 were low.

Rich's comments are as follows from a follow up email to my question of "what do you mean high/low"

Hi Steve,
Twelve of the injectors you sent were part number 23250-65020. These are high impedance injectors and have resistance of approximately 13.7 ohms. The remaining six injectors were part number 23250-65010 and are low impedance. They measure approximately 2 ohms.

They are two completely different type of injectors and different injector drivers are in the ECU depending on what type of injectors were used. "Peak-Hold" drivers are used for the low impedance injectors while "Saturated" drivers are used for the high impedance.
The low impedance injectors were most likely from an earlier (before 1989) model engine. The injectors look the same and flow basically the same volume however they cannot be interchanged.

Rich Jensen


what do YOU guys know of the above situation.

and now it seems i have a set of cleaned/rebuilt injectors for an early 3vze that are now useless to me.

suprathepeg

Sell the older ones and maybe you'll get your money back.

Adam F

Do you still have the low resistance injectors? I have a set of high resistance injectors I need to swap for some low resistance ones.

banoobee17

Have you guys seen these injectors and what are you thoughts are they worth it
http://www.pirate4x4.com/forum/toyot...tors-free.html

MudHippy

I'd be semi-interested in getting some for my 3VZ-E...if there were some for 88 too. Just my luck...there ain't.

TNRabbit

Using the wrong resistance ones can ruin your ECU.

TNRabbit

I'd be very concerned if they have a different resistance than stock. This can cause issues with the ECU.

Also, the pattern shown for stock will happen if you're running low pressure to them. Are we sure this isn't just BS with the center injectors being run on lower pressure?

4runrjunkie

I am not every knowledgeable when it comes to injectors, but am I right in thinking that a lower pressure would equal a lower flow rate? The reason I ask is that the second part of the video shows him testing the flow rate of the injectors, and they appear to be equal, so I would have assumed the pressure was equal. I could be totally wrong though haha. maybe someone better informed can chime in and give a definitive answer.

mt_goat

That's correct

MudHippy

Pressure = resistance to Flow

IOW, higher Pressure is what you get when you have a lower Flow rate. A higher Flow rate is what you get when you have less Pressure. All things being equal systematically(which they don't appear to be in this case...)

A little counter-intuitive? Maybe. But true none-the-less.

4runrjunkie

Its funny cause you saying that has reminded me how to figure this out, and unfortunately you are not quite right because you have interpreted bernoulli's equation wrong. You are correct that as the fuel exits the injector, the pressure drops to atmospheric and that pressure drop means the velocity of the fuel increases. But comparing the two possible situations, the larger the pressure difference between the fuel line and the atmosphere, the higher the velocity of the fuel exiting the injector. And since we can assume that the density of the fuel is the same once it has exited the injector, regardless of the fuel line pressure, then the higher velocity means a higher flow rate.

Anyway, that was my little nerd moments haha. Either way, I think its safe to say the pressures in the video are the same.

mt_goat

Very good, I was hoping someone would bring some equations into this. I was flipping through my old fluid mechanics text to find an easier equation to prove the same thing. What I found was the section on measurement of flow rate in closed conduits. The flow rate (Q) through an given area (A) is "Q = A x V", where V is the velocity. Hopefully everyone can agree that as pressure goes up velocity also rises. So holding "A" constant, as pressure rises flow rate also rises.

Mudhippy I'll give you that, yes, IF you restrict flow then pressure rises holding other things constant, but the fuel system has a pressure regulator that makes that more of a constant than a variable. But I have seen adjustable pressure regulators as a crude way to increase the fueling needs for forced induction.