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Hemituner

On The Dyno, A Study Of The Effect Of Boost On The 6.4 Intake

88 posts in this topic

Man it feels great to be digging in again. On deck is a Procharged 2012 6.4 auto. One trend we have been seeing is given a specific AFR, IAT, ECT, Timing advance, Cam position, and Boost level some swings as much as 15 WHP are recorded Pull to pull in a 3 pull series for each test session. The standard Items all check out. After reviewing some data that Matt and Dave have collected over the last 10 months we are starting to see a trend. A quick pull with o2 sensors in both banks on the dynojet the same trend was observed on this vehicle using completely different equipment over 500 miles away. Pretty scary Stuff, Stay tuned its about to get interesting.

Thanks

AJ

 

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whoa......looks like the culprit of the broken pistons may have been discovered.

Indeed it's part of the problem. And it appears the more boost you throw at it the further apart your left and right banks get!

 

That active intake manifold on the 6.4?

This is the active intake yes.

 

AJ is this just happening with the FI gen II?

You get it even with n/a applications. Any introduction of additional airflow beyond what the engine was originally calibrated for compounds the problem.

Thanks

AJ

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Is the active intake the root cause, or the PCM? Are 392 motors that have removed the active intake for a PD blower at risk?

The engines that have had the intake removed and the calibration modified like what was done on your car will have no issues. Engines using the Active intake require a different approach

 

Woah, interesting.  WTF is it trying to do?

 

Or could it be starving of fuel on one side due to increased demand?

Its just doing what its told. The characteristics of the airflow and the fueling requirements for the difference are calibrated in the factory PCM, Just not for the additional airflow. The long and short of this is when using the factory intake the engine requires different fueling bank to bank.  My game plan today is to calibrate for the difference. 

Thanks

AJ

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The engines that have had the intake removed and the calibration modified like what was done on your car will have no issues. Engines using the Active intake require a different approach

 

Its just doing what its told. The characteristics of the airflow and the fueling requirements for the difference are calibrated in the factory PCM, Just not for the additional airflow. The long and short of this is when using the factory intake the engine requires different fueling bank to bank. My game plan today is to calibrate for the difference.

Thanks

AJ

Awesome info and breakthrough.

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Looks like 6.1 intake manifolds are about to get more expensive. . ..

Other way around. AJ has figured out how to calibrate the 6.4 manifold which will lessen the demand for 6.1 manifolds.

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AJ, which side is lean, and which is rich? I'm wondering if having the wideband sensor on one side vs the other protects an engine because the tune is written more conservative due to that side running leaner.

 

Which may account for the apparent randomness of the pistons breaking.

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The engines that have had the intake removed and the calibration modified like what was done on your car will have no issues. Engines using the Active intake require a different approach

 

Its just doing what its told. The characteristics of the airflow and the fueling requirements for the difference are calibrated in the factory PCM, Just not for the additional airflow. The long and short of this is when using the factory intake the engine requires different fueling bank to bank.  My game plan today is to calibrate for the difference. 

Thanks

AJ

 

What about per cyclinder? or is that just overkill? or can we even tune per cyclinder?

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Other way around. AJ has figured out how to calibrate the 6.4 manifold which will lessen the demand for 6.1 manifolds.

 

 

I hear ya . . .I was just poking fun at AJ that he couldn't do it since he is working on it as I type this  . . . . . .we all know if anyone can. . he will.

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I installed a 6.1 intake on my 6.4 based 426 about 3 weeks ago. AJ tuned on API's dyno. HP and TQ increased 10-30 points thru the mid range compared to the active intake. Peak RPM power was the same but we believe it may be limited by the ported OEM TB. AJ is going to retune with a 90mm TB when they come available.

 

Engine seems to be more responsive and smoother since inatalling the 6.1.....The main reason for me going to the 6.1 was at AJ's advice and he had told me a couple months ago that he was seeing an AFR issue with the FI active intakes.

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What about per cyclinder? or is that just overkill? or can we even tune per cyclinder?

Im not even aware of individual bank adjustments but AJ can expand on that Im sure.

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The Mad Scientist at it again!  Nice stuff AJ.  Will certainly help folks with 392s have more comfort in modifying the car once sorted.

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If I read that correctly, PCM is monitoring O2 noise and adjusting fuel trim bank to bank to control emissions.

 

Not sure if that is recent ability, but interesting info to give a look into what the tuners are up against.

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Im not even aware of individual bank adjustments but AJ can expand on that Im sure.

He told me not with Diablo, that he had to re-write a new cal in order to do it. He was strapping it down when I left with the new cal in it. 

Pretty cool stuff he does.

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