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Discussion Starter · #1 ·
IF you're using a tune, how would you feel the pcm's increased tune parameters which kick in @ 3750 miles?
Unless you go back to stock I assume??
 

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Always wondered how it affected it, but until someone does a comparison analysis it will be guess work and assumptions.

Just to be on the safe side, wait till you hit the mark to tune it. IMO
 

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From what I understand, it only allows the cam phaser to operate in its full range (not limited).
It should be transparent to a CMR Tune as I don’t think the CMR tuning effects the phaser’s operation.
When we swap ECUs to the B&G ECU, we always loaded 10K into the new ECU along with the new VIN for max gains right off the bat.
 

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It is rumored that the stock tune would hold back (limit) some of the cam phasers operation until you hit 3750 miles. No hard evidence that I have seen but I think there was a vid where one of the Dodge or SRT Engineers mentioned this break in period. This came to light about the time the B&G ECUs started moving. (Marchish of ’12).
 

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Increased tune parameters at 3750 miles?
Explain please....
A break in period on the 5.7L engine limits the functionality of the variable cam timing until the vehicle registers 3750 miles and the engine is operating at 1200 RPM or higher. To operate fully, the engine controller has to record 3750 miles.
 

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Its funny I have installed and have done upgrades to the the new vvt motor plenty of which with less than 3750 miles. And being in the business I have never seen that picture or ever heard of such a thing before.

my 14 rt charger has never felt different or has done anything different with gas mileage etc. as it just passed 4k and no change in any performance or mpg. I would think if the VVT wasnt working When it was enabled you would see both more MPG and Power as the vvt is what makes the motor much more efficient Over the previous non VVT engine.

so in short I think its all BS. and Doesnt make any sense why chrysler would limits the engines efficiency until a curtain Mileage is reached.

Being in the performance side of things for many years now I have never heard of this before.
 

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Discussion Starter · #8 ·
so in short I think its all BS. and Doesnt make any sense why chrysler would limits the engines efficiency until a curtain Mileage is reached.
I think it makes a lot of sense.. limiting the engine slightly until there's plenty of heat cycles, mileage for components to sink in tolerances etc.. Lots of guys beat on these cars way too early & incur warranty repairs or other issues that "may" have been prevented if a pre determined time or mileage has been reached..

If this is the case, crummy for drivers/owners out of the gate, but forward thinking for Chrylser/Dodge...
 
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The only thing that needs time to seat are the rings, and honestly they should be set after 20 minutes of run time. The old thought of things having to gain clearence is BS. If anything in the motor clearences its self you would have metal to metal and thus a destroyed engine.

Being that the VVT doesnt really make a ton more raw power I cant even see where it would help with proper break in of the transmission or rear end.
 

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It does sound like a myth but out of the last 3 5.7's I have owned I have felt the difference right at the 4k mark. The first time it was on my 09 Ram, I remember driving to work one morning and it noticeably had more low end grunt. I remember looking at the mileage and I was just over 4k. I didnt hear about this VVT "unlock" till I bought my 13 Ram and had the exact same experience, then went to the forums looking for anything regarding that mileage.

When I bought my Challenger I was looking out for it and it hit right at the 3800 mark. Most people probably wouldnt recognize it since its not a huge difference but I notice even the day to day temperature differences in power.

If I hadn't noticed it myself I would also think it was BS.
 
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I recently crossed the 3750 mile threshold and paid some attention, looking for any performance changes.

Nada, zip, zilch, nothing, zero, no change.

Therefore, my empirical evidence tells me the 3750 thing is a myth.
 

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The very first 392 we had on our dyno when we started tuning the 11-up cars was right off the dealer lot, a 12 Super Bee with less than 150 miles. We developed tunes on it, and it made the same power that all others we have seen made (415/425 stock).

I call myth :)
If the supposed unlock had to do with the lower RPM of the cam phasing, then the top end would be untouched. Just my .02¢
 

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Fair enough, but if that were the case, why would they bother if its not going to limit power?

LOL.
Hey I never said it made sense!

Why would they do it? I have not a clue. But 3 times now on three different vehicles I have felt the difference. Its a subtle difference, like how your vehicle feels a little more peppy in cold weather, not a "snap your neck" difference. If anything I would just say its a smoother transition of power from 1-3k.
 

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Like, at part throttle maybe?

FWIW, something like the Coyote 5.0 has a wild VVT system spinning 4 different cams independently, and its really easy to see the system working on the dyno or on the street, and its fully functional on a brand new car...still makes me wonder why they would do it unless to limit peak power. Odd.
 

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Like, at part throttle maybe?

FWIW, something like the Coyote 5.0 has a wild VVT system spinning 4 different cams independently, and its really easy to see the system working on the dyno or on the street, and its fully functional on a brand new car...still makes me wonder why they would do it unless to limit peak power. Odd.
Possibly, I babied each one till the first oil change so I couldnt say if it had any affect on WOT.

I wouldnt even rule out that the change I felt was just the fuel trim maturing. Just like how I feel more pep with Johan's tune with the more mileage I put on it. But it would be a big coincidence if it happened at the same mileage in each 3 vehicles.

Like I said, if I hadnt first felt it for myself then came to the forums and read where other people are having the same experience, then see the SRT chat screen shot, I would have said it was BS.
 
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