6.1L Hemi fuel injector rating

[WhiteDiamond]

There is a thread on another forum where a member is looking for the fuel flow rating of the injector used in the 6.1L Hemi. Allpar.com states that the 6.1L uses an injector that flows 14% higher than the 5.7L hemi, so if you happen to know the 5.7L flow rating, please post it.

Todd

[330toSRT8]

Anyone got the 6.1 injector flow rate yet?

[6.1 Turbo]

Here you go:

5.7
----
26.0# @ 43psi
27.8# @ 49psi
30.5# @ 58psi

6.1
----
30.0# @ 43psi
31.8# @ 49psi
34.9# @ 58psi

[330toSRT8]

6.1 Turbo,
That's exactly what I wanted. Thanks!

[MikeEast]

Just out of curiousity, would there be any benefit to using 6.1 injectors in a 5.7? Is it even possbile?

More flow = more go?

Mike

[CoolVanilla]

Just out of curiousity, would there be any benefit to using 6.1 injectors in a 5.7? Is it even possbile?

More flow = more go?

Mike

Very possible, and if you're lean, you bet there's a benefit. We discovered that I'm running on the safe side of lean at the MFO5. Andrew (MagnumFreak) postulated that my particular setup might have maxed out the 5.7 injectors. We made a frantic search late Friday night for a set of 6.1s (they just drop right in place of the 5.7s; maybe 1/2 hour worth of work total) but we came up empty. Dealer quoted me $600+ for the set.

Having said that, unless you're way modified like I am, the 5.7s are most certainly enough, if not too much; all our tests of every other 5.7 showed a rich condition. Too much flow = no go.

Food for thought.

[6.1 Turbo]

Yes you can swap them in as stated above but only do it if you are in fact lean. Use a wideband a/f gauge to be certain you need them first. BTW, you can get a new set for about $400.

More flow doesn't always = more go. If you install them on a stock engine then you would be to rich and kill power plus wash down the cylinders.

[Beast 2]

I have a new set for sale $400 firm. I take paypal and credit cards.

[lafrad]

it will only really be too rich if the computer can't get the long term fuel trim back to Stoich.

Technically... the computer should be able to adjust a certian percentage and bring your fuel ratios back into "normal" for closed loop AND open loop WOT.

For me that took about a full tank of gas.. (about 350 miles)...
3rd gear is a little rich, but thats a torque management thing...

[CoolVanilla]

it will only really be too rich if the computer can't get the long term fuel trim back to Stoich.

Technically... the computer should be able to adjust a certian percentage and bring your fuel ratios back into "normal" for closed loop AND open loop WOT.

For me that took about a full tank of gas.. (about 350 miles)...
3rd gear is a little rich, but thats a torque management thing...

Very true lafrad, but lemme clarify that I was talking WOT only. To the best of my understanding, these PCMs go open loop at WOT and that is where we took our AF readings. I believe you're talking about any throttle position other than WOT, correct?

Edit: Just reread your comments... makes me think I've misunderstood how these things work. Can anyone shed some light on this for me, specifically speaking at WOT conditions? Do the adaptives have any effect on flow at WOT?

[6.1 Turbo]

The pcm does nothing for WOT(open loop) operation. If you put larger injectors in your LX the pcm will trim fuel in closed loop up to a certain piont but it will be rich at open loop and never adjust it because it disregards O2 sensors in open loop.

[lafrad]

the PCM DOES... i repeat DOES adjust the WOT fuel tables, based on what it learns the engine needs in Closed loop.

It WILL trim down your fuel over the long run... if your adaptives have room to adjust... There are preset values that they cannot exceed... and tuners can adjust how much can be adjusted.

Something that you see on the dyno with a freshly reset computer.. would be a rich condition... I would imagine Dodge keeps it a bit rich and it trims back to "ideal" after lots of miles...

[CoolVanilla]

The pcm does nothing for WOT(open loop) operation.

the PCM DOES... i repeat DOES adjust the WOT fuel tables

Very interesting. I'm going to PM MagnumFreak and ask he chime in here. I'll also see if fnky has any input.

[MagnumFreak]

no comment. LOL! JK!

I really do feel like we hit the limit with Jason's car with regards to the fuel injectors. In watching the starscan during the dyno run, during most of the WOT run the injectors were at or very near their max pulsewidth. Especially at the high end of the rpm range. At the upper end he was hitting 13 or so on the af ratio.

If I remember correctly which is hard to do at 40 LOL! the pcm can adjust plus or minus 30 percent under normal driving conditions. I know just recently I saw a -30 in one of the fuel adaptives on Redfox0099's car. I am not sure about under wot. I think, although not 100 percent sure, it just uses preset values for wot. That is what seperates closed loop control from open. It doesn't just dump fuel in the engine but makes adjustments based on engine load. I know under wot it ignores the o2 sensors which would tend to lean towards the side of not adapting. Again, I am not sure. Hopefully fnky will chime in on this.

now with the srt injectors on a 5.7.... since the pcm can adjust so much under normal driving, it will work just fine. For the first 100 miles or so it will run rich (which is not a bad thing). Then it should go back to normal fairly lean conditions. If my theory is right then under wot it will still think it has 5.7 injectors and pulse them accordingly. Since we are getting about 14% more flow it should richen the mixture and put Jason and others back down into the power creating band of the Af ratio.

I really want to test this theory without spending a ton of money. I didn't want to ask the one srt owner that was at MFO5 testing to "borrow" their injectors but it would be cool to see what would happen if you run a modified 5.7 on the dyno to see the af ratio and then swap injectors, run the dyno test again to see the difference and then drive for 100 miles and come back and run it once more to see if adaptives are getting in the way.

Sorry I am rambling but I am at work and in the cleanroom so I have all my cleanroom stuff on and can't think straight. Scary huh??!!

[lafrad]

Very interesting. I'm going to PM MagnumFreak and ask he chime in here. I'll also see if fnky has any input.

One thing to think about:

You add all that extra airflow from heads and cam, headers, intake... and are STILL rich... if the computer NEVER adjusted the fuel rate from its base barebones stuff from the factory.. you would be lean. The ONLY reason you would run against the top of the fuel flow of an injector is if the computer is adjusting up... any car company would NEVER run a component at 100% from the factory... mechanical things just don't work as reliably when they are utilized at full capacity... And what happens when it gets older and flows less... don't want it leaning out too soon...