Flow Tested My Injectors

[letemlaf]

I bought some injectors a little while back and they seem to be getting more and more suss.

i got them flow tested the other day and these are the readings i got for some 555cc inj.

71cc @40 psi for 15 sec

69cc @40 psi for 15 sec

70cc @40 psi for 15 sec

71cc @40 psi for 15 sec

71cc @40 psi for 15 sec

72cc @40 psi for 15 sec

All done at 36ms

I don't know if he tested them correctly but the figures as far as i can tell dont meet 555cc however you work it out.

cheers

[RANDY]

424?

What pressure were they being tested with?

Edited November 29, 2006 by RANDY

[letemlaf]

424?

What pressure were they being tested with?

40 psi

[sloazr33]

a n00b question here...

how do you do the calcs to see what they are actually flowing?

[J_Red33]

Done a lot of this stuff before myself.

The info given is not the absolute flow rate of the injectors, but a flow rate for them being pulsed on & off for 15 seconds, rather than a minute.

However there is a lot of info missing. It doesn't tell you what proportion of the time the injectors are turned on (duty cycle) & what speed they are turning on & off at.

I think the 35milliseconds refers to how long the injector is on for each time it is pulsed, but without the other info it means nothing.

40psi is also an odd pressure to use as normally flow ratings on injectors is done using 3 bar of pressure or 43.5 PSI.

To put it in perspective the rating you have been given is from the people that tested it is:

284cc/min @ 2.76 Bar with ?% duty cycle & 36ms duration for each pulse

The rating for your injectors as you have stated is:

555cc/min @ 3 bar with 100% duty cycle (Ie it is on 100% of the time)

Edited November 29, 2006 by JazzaR33

[letemlaf]

Done a lot of this stuff before myself.

The info given is not the absolute flow rate of the injectors, but a flow rate for them being pulsed on & off for 15 seconds, rather than a minute.

However there is a lot of info missing. It doesn't tell you what proportion of the time the injectors are turned on (duty cycle) & what speed they are turning on & off at.

I think the 35milliseconds refers to how long the injector is on for each time it is pulsed, but without the other info it means nothing.

40psi is also an odd pressure to use as normally flow ratings on injectors is done using 3 bar of pressure or 43.5 PSI.

To put it in perspective the rating you have been given is from the people that tested it is:

284cc/min @ 2.76 Bar with ?% duty cycle & 36ms duration for each pulse

The rating for your injectors as you have stated is:

555cc/min @ 3 bar with 100% duty cycle (Ie it is on 100% of the time)

I think i understand what you mean.

So it is probable that the injectors will make 555cc at 100% duty

The reason im asking is because i just want to make sure i run them safely when i install and retune.

Do you think i should find someone else to flow test them?

[J_Red33]

Yes there is still a good chance they are fine. I'm guessing these are the Jecs body feed injectors (same style & brand as original injectors) never had much trouble with these in my experience, but yes it would be good to double check.

Ask them if they've tested other sets of these injectors before, they should have data on the other sets (I kept copies of all my testing data for future reference, which came in very handy) they may be able to tell you if the rates were normal.

Pulse testing injectors is a good way to test them, I did most of my testing that way. I'd also check the spray patterns too to make sure that the fuel is vapourising properly.

It's definantely a good idea to flow test them at maximum especially if you have little or no previous data on their 100% flow, just so you know what they're meant to be doing.

Your set looks like they're flowing fairly evenly from the results, if he wasn't using a proper flow gauge or timing setup that could account for some of the variation, still acceptable though.