So..

My car was leaning way out when I hit 6psi of boost. Doing some math, I figured out that my fuel pressure was rising to a little over 50 psi.

There was a couple of scenarios that could have been happening:

1) My injectors were too small
2) My fuel pump was failing at high pressure
3) My injectors were failing at high pressure

I figured I'd buy some new injectors anyway, so I ordered some 80lb deka injectors. The ad claimed they were real legit Deka injectors, but the price told me otherwise.

Once I got them, the part # was chinese and they were in fact knockoff injectors.

So, I had picked up an injector machine anyway because I like tools. So I figured I'd perform some tests on the new injectors and a comp test on some actual real legit bosche injectors.

Check out my videos below:




Hope you enjoy. The moral of the story here is do NOT use knock off injectors in applications where your fuel pressure is rising 1:1 with boost. I set my fuel pressure to about 45psi on a 1:1 regulator, so I hit over 50psi at just 5psi of boost. The injectors start locking up at 50psi.

The Bosch injectors continue operating at 75 psi without an issue, and have a good spray pattern.

Oh, I'm using a fluid with a specific gravity of .78, for those of you doing the math to calculate the injector flow on these lol Pump gas is around .73-.76


-- Joe

 

that is interesting... so those injectors wouldnt even operate in a stock LS based car which normally have 50-something psi at the rail.

 

Injectors should not be skimped on. They are the heart of the engine in a sense lol

 

That seems to be the case.

Should be noted I also tested some stock rochester LT1 injectors out of a '97 trans-am, and they locked up around 60 psi.

The Bosch 3 injectors were fine at 75 psi. Gonna try some Bosch 4 injectors this week.

Yup, and it's tough when the internet is filled with knockoff injectors. Probably safe to test your injectors on your injector machine before installing them no matter where you got them from.


-- Joe

 

ive wanted one of those injector flow bench/cleaning stations for quite awhile. where did you get that one and do you like it?

 

I found the best deal on ebay, but you can also get them from amazon. I got the CT150 4 injector unit. There are some limitations and you have to get used to how the tests work. It's not like a digital machine that gives you a printout. You need to do the test, jot down the result, etc.

It has a PWM driven fuel pump (like a Ford). At first I was like "That's dumb" but the software change the rail pressure based on the test you are doing, so it makes sense.. You can override it as needed.

And of course it has the ultrasonic for cleaning.

It does 1 pulse per RPM. You are probably thinking to yourself, RPM ? It has various test programs that simulate various driving conditions, which is actually quite usefull. Acceleration tests, idle tests, various RPM tests. The pulse width and RPM various with most tests to emulate real world.

Then there is 'flow tests', of which I typically use the 7500 RPM (high RPM) test. It fires 1 pulse per RPM, for 10 seconds, at a 3msec pulse width. (1250 injections, or a total of 3.750 seconds open time).

So I will typically perform that test several times to get my dynamic flow rate. Multiple the number by 16 and you get your injector rate in cc/min.

Next is the static flow rate test. This works a little differently where it will open the injectors static for 1 second, several times. Then you can measure your flow based on iterations.

Again, things it won't do is report dead time, give you a nice little chart, etc. It's not a $6,000 machine. But for a hot rodder it's very useful.



-- Joe