Gibson Headers and 6.5 Diamond Eye Diesel Exhaust on 454

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Crazydavez28

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Thanks to some fine folks here I have my exhaust all figured out, special shout out to member Crazeydavez28 for posting up his thread for me to stumble upon, below.

https://www.gmt400.com/threads/6-5-diesel-exhaust-on-454.40793/

This install will start next Monday, more completion pics to follow.

Glad it worked out for you. That intermediate pipe looks a lot different than the one I had. I put some auger flights in my muffler to make use of the glass packing without blocking flow. Works good but i kinda wish i had waited till my headers were on to see how load it could get.

I like your setup, looks nice and simple with the y-pipe coming from the headers.
 

Fez_Jet_Az

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Long story short, last weekend my motor tanked on me and was losing all power at 3500rpm. Turned out to be a faulty crank position sensor that was new.

Anyway, I have been watching the data stream and am curious where everyone sees their MAF g/s at under wot, I think I saw it at like 350. Its and old snap on scanner, i gotta figure out how to log it



Dual 3" factory cats. Dropping them probably gained 20 hp. I gained 15-20 gms/sec airflow from 4,000+ rpm when I did the swap. Ceramic core cats are horrible for flow and very restrictive.
 

Christian Steffen

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Long story short, last weekend my motor tanked on me and was losing all power at 3500rpm. Turned out to be a faulty crank position sensor that was new.

Anyway, I have been watching the data stream and am curious where everyone sees their MAF g/s at under wot, I think I saw it at like 350. Its and old snap on scanner, i gotta figure out how to log it

Is your maf table tuned with a wideband? If not, you can't really trust what it says.
 

Supercharged111

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Is your maf table tuned with a wideband? If not, you can't really trust what it says.

Not necessarily true. I tuned mine with a wideband (1500) and now the MAF pegs early. The logs tell me it's right and my fuel economy thing in the OHC is now accurate. Something is still wrong with my tune, so it has been tuned and can't be trusted. Some dyno tuners would give you just this. In theory I believe the MAF isn't supposed to be wrong until you modify the intake tract?
 

Christian Steffen

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Not necessarily true. I tuned mine with a wideband (1500) and now the MAF pegs early. The logs tell me it's right and my fuel economy thing in the OHC is now accurate. Something is still wrong with my tune, so it has been tuned and can't be trusted. Some dyno tuners would give you just this. In theory I believe the MAF isn't supposed to be wrong until you modify the intake tract?

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?
 
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Fez_Jet_Az

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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?


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?
 
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