Saturday LT1 airflow project

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Carnut1
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Re: Saturday LT1 airflow project

Post by Carnut1 »

That may be true. It is interesting that the customer is thrilled with throttle responce and general feel of the engine now. Does anyone have info on removing the honeycomb on the mass air sensor and if that helps? We talked about programming and that may happen down the road. Thanks, Charlie
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Re: Saturday LT1 airflow project

Post by MadBill »

I measured ~ 4 kPa peak increase in my 3800 SC Buick when I removed the honeycomb, but the idle quality deteriorated a little.
When GM did the same on one Corvette model a number years ago in search of a few more horses, they had to calibrate the sensor to its specific air cleaner and intake system, rather than relying on the generic Dephi data.
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Re: Saturday LT1 airflow project

Post by Ed Wright »

Removing that "honeycomb" is popular on the LT1 diy message boards, under "free mods". It is a waste as well. They claim to "feel" all that stuff. Power of suggestion. A-B-A tested that as well. It it is anywhere near a stock engine, the MAF sensor is virtually no restriction. Graph the MAF data from your scan tool, the "screen" (as they tend to call it) is actually thicker than a screen, is an air flow straighter, to smooth air flow.
I found zero power gains on my dyno, on numerous customer's cars. "But, I could feel a difference". They usually said the same about "ported" (butchered) MAF sensors, which leaned the factory WOT air/fuel ratio, which is over rich. Down side is the hogged out MAF housing, of course, lowers velocity of air going through the MAF under normal driving conditions. Velocity is what the factory computer uses to determine air flow. Thus skews the fuel trim (a/f corrections) due to lower voltage required to maintain temp on those little heated wires you see glowing red in there.
Drive it a few hours with the fuel trims adding fuel at idle & part throttle, the factory computer adds the same percent of fuel at wide-open throttle as it was adding at part throttle to the WOT air/fuel to try to protect the engine. Most of the time they end up richer than they were originally, and make less power.

Demonstrated that to several guys, on my dyno, who could "feel the difference". Likely felt the initial leaner mixture, but not the eventual enrichment. There are shops selling larger MAF housings, that do the same thing. I can turn that WOT fuel correction function off in the tuning. O2 sensor deterioration, causing positive fuel trims to cause richer WOT fueling as well. Easily stopped in the tuning/programming.

The later Corvettes that had no "screens" used a different MAF Calibration table in the computer Calibration/programming.
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Re: Saturday LT1 airflow project

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Ed Wright wrote: Sat Jul 07, 2018 9:05 pm Removing that "honeycomb" is popular on the LT1 diy message boards, under "free mods". It is a waste as well. They claim to "feel" all that stuff. Power of suggestion. A-B-A tested that as well. It it is anywhere near a stock engine, the MAF sensor is virtually no restriction. Graph the MAF data from your scan tool, the "screen" (as they tend to call it) is actually thicker than a screen, is an air flow straighter, to smooth air flow.
I found zero power gains on my dyno, on numerous customer's cars. "But, I could feel a difference". They usually said the same about "ported" (butchered) MAF sensors, which leaned the factory WOT air/fuel ratio, which is over rich. Down side is the hogged out MAF housing, of course, lowers velocity of air going through the MAF under normal driving conditions. Velocity is what the factory computer uses to determine air flow. Thus skews the fuel trim (a/f corrections) due to lower voltage required to maintain temp on those little heated wires you see glowing red in there.
Drive it a few hours with the fuel trims adding fuel at idle & part throttle, the factory computer adds the same percent of fuel at wide-open throttle as it was adding at part throttle to the WOT air/fuel to try to protect the engine. Most of the time they end up richer than they were originally, and make less power.

Demonstrated that to several guys, on my dyno, who could "feel the difference". Likely felt the initial leaner mixture, but not the eventual enrichment. There are shops selling larger MAF housings, that do the same thing. I can turn that WOT fuel correction function off in the tuning. O2 sensor deterioration, causing positive fuel trims to cause richer WOT fueling as well. Easily stopped in the tuning/programming.

The later Corvettes that had no "screens" used a different MAF Calibration table in the computer Calibration/programming.
Thank you. Im over the "feel" thing from people.
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Re: Saturday LT1 airflow project

Post by Ed Wright »

The Power of Suggestion is more powerful than I ever thought.
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Re: Saturday LT1 airflow project

Post by user-23911 »

It works in exactly the same way with turbo Mitsubishis when you remove the side screens.
A "free mod" which is actually a downgrade and when you say so, you upset the ricers.
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Re: Saturday LT1 airflow project

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It is funny, years ago I bought into the "You can't port heads without a flowbench!" fair enough. No doubt I have had a steep learning curve since I bought the bench but stuff I did decades before was still pretty good. So now it is " You have no experience unless you have dyno experience!" Ok, next house has to have room for a dyno. I get it, it is on my list of things to do. Until then I will do what I can with what I have while supporting the wiffy and kiddies. Thanks, Charlie
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Re: Saturday LT1 airflow project

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Carnut1 wrote: Sun Jul 08, 2018 8:48 am It is funny, years ago I bought into the "You can't port heads without a flowbench!" fair enough. No doubt I have had a steep learning curve since I bought the bench but stuff I did decades before was still pretty good. So now it is " You have no experience unless you have dyno experience!" Ok, next house has to have room for a dyno. I get it, it is on my list of things to do. Until then I will do what I can with what I have while supporting the wiffy and kiddies. Thanks, Charlie
Quantifying results in one way or another is what makes all the work, time and personal money worthwhile. Until you do that you have theory. If your cool with just "flowz" "pullz" "feelz" "revs faster" "spinz" "energiezz" being your evidence of success. Cool for you. But that shit dont go very far in my circle. People get laughed at for saying those things and rightfully so in my opinion.

But......"If it makes you happy, it cant be that bad"
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Re: Saturday LT1 airflow project

Post by user-30257 »

Carnut1 wrote: Sun Jul 08, 2018 8:48 am It is funny, years ago I bought into the "You can't port heads without a flowbench!" fair enough. No doubt I have had a steep learning curve since I bought the bench but stuff I did decades before was still pretty good. So now it is " You have no experience unless you have dyno experience!" Ok, next house has to have room for a dyno. I get it, it is on my list of things to do. Until then I will do what I can with what I have while supporting the wiffy and kiddies. Thanks, Charlie
Are you going to build an engine to use the dyno?
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