Gibson Headers and 6.5 Diamond Eye Diesel Exhaust on 454

[Supercharged111]

That's interesting about your 1500.. I assume injector data and all that are correct?

And you might be right in theory about it being very close to correct as long as the intake tract stay the same. I was thinking any engine change would affect it but yeah I guess it really shouldn't. Really just diameter changes should drastically change the curve right?

That said, the couple stock trucks that I have tuned did require some adjustment, but its probably more likely that they needed it due to fuel pressure being slightly different than factory rather than the maf curve being wrong.

So if we want to use the maf to compare engines, and the intake is stock we should use the factory curve. If the maf has been tuned to dial in fueling then the airflow readings can only be trusted if you are 100% sure the IFR matches exactly what is happening real world, which is tough to guarantee. Aside from engine comparisons though, I would still recommend tuning the maf so the AFR is on point. @Supercharged111 you agree with that?

So pretty much exactly opposite what I posted initially, aorrs for the misinformation.

So way way back to the op question, do uou know if blackbear adjusts the maf curve at all?

I suspect IFR is off for me despite using a calculator to determine flow. I was able to use ASA LS1 injector data with one caveat: it runs at 4 bar and my truck has a 3.5 bar regulator. The other thing is I started with MAF data for a van and it's a known fact that that is different from what's in the black box for the trucks. Unfortunately, the data points are different so one cannot simply copy/paste it all in. This is just the way it goes with the 411 swap.

 

[Christian Steffen]

No clue about anything in the tune.

I haven't spent any time in effort of understanding the parameters in the computer yet as I have the baststd 97 black box.

I did assume MAF g/s regardless of how much fuel dials in against it, is just a raw measure of how much air is pumped through the engine and measures volume, is this a wrong assumption?

You're correct with that assumption. The computer injects fuel based off of how much air it thinks is in the engine, so when the fueling isn't correct we adjust the airflow table to dial in the fueling.

The issue with this is if the injectors aren't flowing as much as the computer thinks (say fuel pressure is low and they're flowing 21 lbs instead of 22.5), then the o2 sensors show that its running lean, and we add airflow to correct that. So in this example the MAF will report a higher mass airflow than what is actually happening. The same can happen with the VE table.

 

[Christian Steffen]

I suspect IFR is off for me despite using a calculator to determine flow. I was able to use ASA LS1 injector data with one caveat: it runs at 4 bar and my truck has a 3.5 bar regulator. The other thing is I started with MAF data for a van and it's a known fact that that is different from what's in the black box for the trucks. Unfortunately, the data points are different so one cannot simply copy/paste it all in. This is just the way it goes with the 411 swap.

Ah I gotcha.
And yeah exactly, so its hard for us that are 411 swapped to really trust our airflow amounts.

 

[Fez_Jet_Az]

What is the scale range for the MAF in g/s?

You're correct with that assumption. The computer injects fuel based off of how much air it thinks is in the engine, so when the fueling isn't correct we adjust the airflow table to dial in the fueling.

The issue with this is if the injectors aren't flowing as much as the computer thinks (say fuel pressure is low and they're flowing 21 lbs instead of 22.5), then the o2 sensors show that its running lean, and we add airflow to correct that. So in this example the MAF will report a higher mass airflow than what is actually happening. The same can happen with the VE table.

 

[Christian Steffen]

What is the scale range for the MAF in g/s?

You can scale it to whatever you want, but the frequency range is to 12,000 hz.

 

[Sparkysikes]

This is good info. All my tuning was done with stand alone. Actually a piggy back the stole all the info before the stock computer and the stock computer thought all was normal lol. Smog checks too. E85 tune and no cats and passed smog. Computer showed the cats worked perfectly lol!

 

[tanman_2006]

Did you ever get a video of this exhaust set up running?

Would this muffler be better?

https://www.amazon.com/Donaldson-M1...ocphy=9026452&hvtargid=pla-570918363589&psc=1

 

[Sparkysikes]

That's a short muffler!

 

[454cid]

That's a short muffler!

If you look at the picture it's apparently a spin on muffler... I guess you have to change it when it gets too full of sound.

 

[Sparkysikes]

Nah just unthread it and dump the sound out than reinstall!