[EECBandit]

I was hoping to get some idea of what a strong 5.0 would pull in terms of kg/hr.
My 5.0 has AFR 185, long tube headers, 600 lift cam, RPMII intake, 75 mm TB and a 90mm LMAF in front of an AOD with 373 gears.

At the max point I am around 4.45 Vmaf with the 90mm LMAF.

That correlates to approx. 1180 kg/hr on my scaled maf.

My AFR is about 11.3. Should I be pulling less air?

[85GT]

Sounds like a ok number if you didn't butcher the curve too much. It is a meter after all. You really wouldn't adjust a voltmeter to read 120volts just cause you think that's what your outlet should be :) Same would be for the maf. Should only need tweeking if your airpath makes it misread.

Looks like the stock curves show 1300-1500 for the lightning meters for that voltage.

[EECBandit]

Thanks for the feedback 85GT.
I was more worried about the 1180 being a realistic number or if it should be closer to what you posted the stock curves to be.

The LMAF has been one difficult animal to work with.

I've tuned the MAF in OL with adaptive's off and the car is pretty good in open loop. but as soon as I re-enable everything it's like a completely different animal.

For example, If I tune only using drive never shifting into OD, the same MAFV in overdrive would be really lean and the fuel trims go to max cruising at 55 to 60mph.
At roughly 60mph my engine in D is at 2500-3000 RPM and the curve in the 1.7 to 2.2v range would be much less than what is needed at 60mph in OD.

It's been a real challenging balancing it.

I suspect my engine is much more efficient at 2500 - 3000 RPM than it is at 1800 RPM in OD.

I've been debating whether I should run in OL more because of my combination.

[LeadHead]

Efficiency shouldn't matter. It sounds like your injector high/low slopes and breakpoint still need adjustment.

[85GT]

Like Lead says, it's not the efficiency.

What is happening, even though the MAFV's are the same at different rpm's, the result is that the injector pulsewidth HAVE to be different. Think about it, same MAF means same amount of air. If you have the same amount of air, what else do you need? Same amount of fuel. So if the engine is spinning faster and injectors are firing more often, then... the need to squirt less fuel each time. If it's turning slower, they fire less often so then need to squirt longer to get the same amount of fuel.

So, if you get the right squirt at one rpm (one pulsewidth) but the wrong amount at a different pulsewidth, then you're injector settings are still wrong. All 3 parameters are used to determine that pulse: slopes, breakpoint AND injector vs V offset.

[cgrey8]

Like Lead says, it's not the efficiency.

What is happening, even though the MAFV's are the same at different rpm's, the result is that the injector pulsewidth HAVE to be different. Think about it, same MAF means same amount of air. If you have the same amount of air, what else do you need? Same amount of fuel. So if the engine is spinning faster and injectors are firing more often, then... the need to squirt less fuel each time. If it's turning slower, they fire less often so then need to squirt longer to get the same amount of fuel.

So, if you get the right squirt at one rpm (one pulsewidth) but the wrong amount at a different pulsewidth, then you're injector settings are still wrong. All 3 parameters are used to determine that pulse: slopes, breakpoint AND injector vs V offset.

Ditto. As I was reading his response of it tunes right in drive but OD behaves differently, this is exactly what I concluded...injector slope/bp parameters are off making the same MAF readings lean at certain times, but rich at other times. That's not the MAF's fault.

[EECBandit]

So some more info, I am running the Siemens Deka 80 injectors, the PW it typically less than 3.5 ms.
And is usually around 2 to 2.5 ms around town below 45mph.


I have tried using EA to tweak the slopes and break points.

The suggested values have put the High slope between 77 down to 73 and the high slope from 93 up to 108. Break points have been from 1 up to 3.5

None of the slope changes ever modified the results.

Based on all the comments, I wonder if the low pulse width along with different vacuum is causing irregular fuel pressure differentials.

I am seriously considering putting my 24 lb Ford racing injectors back in to see if it helps.

Appreciate all the comments and I am open to any suggestions you guys think I should try.

[EDS50]

Correct me if I'm wrong but if your scaling your maf arent you supposed to scale your injector settings also?

[85GT]

Good point. Fuel, cid and a some others should be scaled the same amount if that is what he meant. Which is probably why it doesn't match the stock curves. Though seems hardly required for a lightning maf as it fits into the eec's max range.

"I wonder if the low pulse width along with different vacuum is causing irregular fuel pressure differentials."

If there is nothing mechanically wrong, that's the job of a vacuum referenced pressure regulator. It keeps the differential constant.

[EECBandit]

I am adjusting the MAF, it's not being scaled 10% across the board per say.

I know how to scale the cranking vs ect pulse width, how would I do a global scale on the injectors?

[LeadHead]

If you scaled your MAF, you need to scale your injector high/low slopes to match.

[EECBandit]

If you scaled your MAF, you need to scale your injector high/low slopes to match.

OK, so If I roughly took off 10% then I should reduce the High/Low slope by 10% too?


Do I raise the high slope 10% and lower the low slope 10%?

Should I leave the breakpoint per spec?



Thanks for the help.

[Paulie]

If you scaled your MAF, you need to scale your injector high/low slopes to match.

OK, so If I roughly took off 10% then I should reduce the High/Low slope by 10% too?


Do I raise the high slope 10% and lower the low slope 10%?

Should I leave the breakpoint per spec?



Thanks for the help.

Adjusting your maf transfer function by 10% is not the same as scaling.

[EECBandit]

Adjusting your maf transfer function by 10% is not the same as scaling.

That's what I was thinking.

[cgrey8]

Yes, you can expect to see this show up over and over...

[EECBandit]

Yes, you can expect to see this show up over and over...

[LeadHead]

Getting terminology right is important. "Scaling" the MAF is when you adjust the entire MAF curve in order to get your load below 200% on a high-strung engine. To keep fueling right, you need to scale the injectors to match.

[85GT]

Ditto.

IMHO, since you took 10% off the curve, the curve was probably good as it was. I'd put it back to original and take 10% fuel out of it (make high slope 10% larger and see where it gets you. Maybe low slope too as with large injectors, a good portion of the pulse may come from it's contribution.

[EECBandit]

Ditto.

IMHO, since you took 10% off the curve, the curve was probably good as it was. I'd put it back to original and take 10% fuel out of it (make high slope 10% larger and see where it gets you. Maybe low slope too as with large injectors, a good portion of the pulse may come from it's contribution.

I'm going to try this.

[EECBandit]

Just a quick update. I decided to put my original 24 lb ford racing injectors back in for a test.

The KAMRF's are much more stable and they don't vary more than 2 to 3 percent.

Incredibly, my 2nd to 3rd lean stumble is also gone. Where it used to shoot up to 18+ AFR before, the AFR never exceeds 15.3 now.

I can only surmise that the 80lb injectors are harder to manage in quicker changes, where a small change on a larger injector struggles with the older eec and the resolution.

Now my 24 lb injectors go up to 122 % duty cycle so I ordered a set of Ford racing M-9593-LU34A 35lb injectors.

I am convinced 80lb injectors were over kill and contributed to a majority of my tuning variations.

My 80 lb injectors idled great and had great drivability, but the tune was always all over the map.

My advice, don't buy 80lb injectors if you don't need them.

[lean]

No boost or spray? Target 1.5 AFR leaner for more power.

[LeadHead]

Where did you get your injectors? I've heard there are counterfeit Deka 80s on e-bay now.

[EECBandit]

Where did you get your injectors? I've heard there are counterfeit Deka 80s on e-bay now.

Summit. They came in the Ford Racing box.

[EECBandit]

No boost or spray? Target 1.5 AFR leaner for more power.

Yeah, ok. shoot for 20 AFR at WOT?

[lean]

No. If you're at 11.3 now, 1.5 higher is closer to what will make most power. 12.8:1 AFR.

[EECBandit]

No. If you're at 11.3 now, 1.5 higher is closer to what will make most power. 12.8:1 AFR.

Cool, thanks man.

I've been working on getting it closer to 12:8:1.

So far I have 12:8:1 at the top end and around 12:1 at 3000 rpm rising up to 12:8 at around 6400 rpm.

[decipha]

1180 is a bit over generous id expect it to be closer to 1020-1050

since u wont be needing the 80s, are they for sale ?

[EECBandit]

That's exactly where I ended up, right around 1043-ish

I'm going to keep the injectors as I see a supercharger on the horizon.