SRT-4 Common Injector Flow - Math/Info/Chart!

[SY04SRT4]

I have seen a lot of posts and confusion about the commonly available injectors for the SRT-4 lately. Here is some math and some numbers to help clear it up. Add what u can! Maybe we can get a sticky!?! If anyone knows of any other injectors available PM me and I will add them!

*Thx to RC Engineering for some of the info! All flow numbers are rounded down to the nearest whole number.

The Mopar injectors (S0, S1/04, S2, S3R) are rated at 58 PSI fuel. Most aftermarket injectors and most OEM injectors are rated at 43.5 PSI.

The conversion to get a new flow rate at a new pressure is:



I also made a nice excel chart.
HERE is the link for excel format.

[Rydiak]

Awesome idea! This will make things easier.

[cali]

a little birdie once said the mopar injectors arent flowed with the same liquid as aftermarket. Dont think it makes MUCH difference, but just throwing that out there from a birdie.

[Rydiak]

And that little birdie failed to notice that SY04SRT4 already took that into account. :P

[cali]

Quote: Originally Posted by Rydiak

And that little birdie failed to notice that SY04SRT4 already took that into account. :P

I must have missed it....it in written in white?

[ToFu]

so why is psi-fi doing some funky calculations with their 530cc/min injectors? They say it flows more than the S2 even though it doesn't

S2 = 590 cc/min @ 43.5 psi, PsiFi Injectors == 530 cc/min @ 43.5 psi

[Jeremy]

Here ya go, from a PVO source:


I called RC and it sounds like they use 760 -770 kg/m^3 as the density of their test fluid. We use n-heptane which has a density of 685 kg/m^3. An injector's mass flow is dependent on the density of the fuel. If two different fuels are flowed through the same injector, the volumetric flow rate of each fuel should be the same. This said, both sets of numbers for the injectors that you have are wrong. The correct numbers are as follows:

For n-Heptane @ 58 psi,
2003 Injectors - 359.4 g/min = 47.4 lb/hr = 524.7 cc/min
2004 Injectors - 395.3 g/min = 52.2 lb/hr = 577.1 cc/min

RC Engineering and most aftermarket injector companies flow their injectors at 43 psi. Using Bernoulli's equation, the mass flow can be corrected to:

For n-Heptane @ 43 psi,
2003 Injectors - 309.5 g/min = 40.8 lb/hr = 451.8 cc/min
2004 Injectors - 340.4 g/min = 44.9 lb/hr = 496.9 cc/min

If RC Engineering flowed our injectors with their test fluid @ 43 psi, they would rate the injectors as follows:

2003 Injectors - 343.3 g/min = 45.3 lb/hr = 498.3 cc/min
2004 Injectors - 377.6 g/min = 49.8 lb/hr = 547.8 cc/min

Basically injectors are volumetric flow devices, so a more dense fuel will flow more mass flow than a less dense fuel at the same volumetric flow rate. This is a very confusing subject. As you can see, it is very easy for a company to skew their flow ratings in their favor. There will always be some error in ratings until all injectors in question are flowed on the same test bench with the same test fluid at the same test pressure.

[SY04SRT4]

Exactly... Technically there would be no way to tell without eliminating all the variables. I just thought there should be a post about it. I guess I skimped on the research!

The numbers can be adjusted based on fluid density as well. That should be no problem, we can get fairly close. #'s to the .XXX okay? It does make a difference.

[NeonWaSp]

so then what do the s1 injectors "really" flow at 58 psi? might make a difference in the injector size change on an e-manage.

[SRT-4 Neon]

I entered 500cc/min as Hector suggested and things are running perfect on my emanage.

C

[chris6543]

Thank you for taking the time to make that spreadsheet!

[NeonWaSp]

why enter 500? i understand thats what they are at 43.5 psi but s1 injectors at regular pressure the computer expects to see 577, not 500.

so any idea what s1 injectors at 58psi of the rc rated flow is? still curious.

[NeonWaSp]

you're an idiot. before you "raise" your tone perhaps try reading fully my above post where i specifically mention at 58psi.

here, i'll spell it out better.

rc uses a different density of fluid than does chrysler for rating injectors. in this thread there is no mention of what the chrysler injectors flow at 58 psi using the same density of fluid that rc does. what i would like to know, again, is what rate of flow the chrysler injectors have at 58 psi using the same density as the rc's.

[cali]

Quote: Originally Posted by NeonWaSp

you're an idiot. before you "raise" your tone perhaps try reading fully my above post where i specifically mention at 58psi.

here, i'll spell it out better.

rc uses a different density of fluid than does chrysler for rating injectors. in this thread there is no mention of what the chrysler injectors flow at 58 psi using the same density of fluid that rc does. what i would like to know, again, is what rate of flow the chrysler injectors have at 58 psi using the same density as the rc's.

Why dont u pay and get them flow tested for the benefit for the community?

[NeonWaSp]

i'm not that interested :P
i was hoping someone who knew how to do the math would plug in the numbers.