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I think everyone's always interested in dyno results and time slips, so I just thought I would share the timeline of my car's modifications and the results over time. I've got a 2016 R/T with the 345 ci (5.7L) currently running with the 392 cam, 392 intake with active runners, Hellcat airbox, JBA short tube headers, and a Corsa Xtreme catback.

I never did a true stock dyno pull so unfortunately we won't have an absolute baseline. Reports vary a bit, having surveyed a lot of threads I think 318 whp is reasonably typical for the R/T's.

At the time of my first dyno pull in Attachment 1, the only modifications I had which could conceivably add power were the hellcat airbox, catback exhaust, and I was running the Diablosport canned 91 octane tune. There was no tuning performed with the first dyno, it was only a baseline, which yielded 330 whp and 362 torque. So if 318 whp is an accurate stock value, then we can attribute +12 whp to the catback and canned tune, and potentially a bit more if the car would have been tuned from the dyno.

Some time later I had the 392 intake and short tube headers on the car, and this time I got dyno tuned. This days results are given in Attachment 2, but we have some details that need to be discussed to fully understand them. In the attachment the red curve is the before and blue curve after. The headers provided significantly improved torque and power throughout most of the band, just falling off at the higher RPM's like one would expect. I drive in the low-mid RPM range, so that's primarily why I forewent the long tubes in favor of short. We would have expected the 392 intake to have improved the peak horsepower at the high RPM range, and the fact that it didn't and that we don't see any kind of inflection point at the 4800 RPM runner switch point is a dead giveaway as to what happened. Later that night I used my trusty borescope to verify that my runners weren't switching. The runners were in long mode, so the intake was probably not too different than the stock intake's long runners, and that explains why we have next to no change at the high end. I eventually determined that the solenoid was bad and replaced it, so we'll have active runners by the time we get on the last dyno session.

Now here we are in the present. I just got the 392 cam installed a couple of weeks ago and had it tuned, so this final tune will be for the 392 cam and the functional 392 intake. on top of everything else. At the end of the day, 382 torques and 376 horsepower! Not the 391 horsepower seen in this youtube video (
), but in my research it looks like 376 horsepower is perhaps a more typical result for our cars with the same modifications.

At the dragstrip my quarter mile pass is 13.7087 sec and 101.63 MPH at 6010 ft density altitude in Attachment 4. Obviously your results may be better at lower altitudes, but this density altitude is pretty typical for my elevation and I'm confident that if I get a good day where its even a little bit lower that I'll get into the 13.6's. I also feel like I probably have room to improve in the 60 ft, so I could get a little bit better on that front as well. Other than that, since I can't afford forced induction this is probably close to as good as I'm going to get at my elevation.

Since then I went ahead and ported my intake manifold and bought a larger throttle body to match just to check those last two things off the list. I'm not sure its worth the money to dyno tune again just for those two things, what do you all think?
Preston Dyno Baseline 2020-03-09.png
Dyno 2020-07-30.jpg
2021-03-25 Dyno Results.jpg
Best timeslip 2021-03-27.jpg
Engine bay 2021-04.jpg
 

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Nice write up, always like to see the dyno and track times side by side.

I would have the tune checked after the TB and intake porting. At a minimum if you are running a wideband at least check the AFR to make sure it's not leaning out. If you don't have any throttle response or other issues after the changes you may be okay, but you could fine tune things to get the full benefit of the TB change IMO.
 

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I wish when my car was tuned they would have printed it out in color and graphed the before and after.
 

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Discussion Starter #4
Nice write up, always like to see the dyno and track times side by side.

I would have the tune checked after the TB and intake porting. At a minimum if you are running a wideband at least check the AFR to make sure it's not leaning out. If you don't have any throttle response or other issues after the changes you may be okay, but you could fine tune things to get the full benefit of the TB change IMO.
Thanks! I didn't need much more convincing, I'll get it tuned so we don't have to wonder.

I wish when my car was tuned they would have printed it out in color and graphed the before and after.
Yeah, and the guy tuning my car always spends plenty of time on it, which always amazed me as this place is full of these dedicated high horsepower monsters.
 

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Thanks! I didn't need much more convincing, I'll get it tuned so we don't have to wonder.



Yeah, and the guy tuning my car always spends plenty of time on it, which always amazed me as this place is full of these dedicated high horsepower monsters.
Nice to have something local like that. I had to do all remote tuning and the delays were a pain. Took a bunch of classes bought HP tuners and now do my own tuning.
 

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Nice job, nice results, and a great write up.

Thanks for sharing and enjoy that ride.
 

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Sorry seems slow to me for all that work...............

101 traps is the key here...............

MY bone stock 07 GT mustang was 97 MPH in the qtr
 

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Discussion Starter #9
Sorry seems slow to me for all that work...............

101 traps is the key here...............

MY bone stock 07 GT mustang was 97 MPH in the qtr
101 trap is not the key, the density altitude is. We can all drive down to lower elevations and go faster. There's a lot of cars faster than mine, but I'm sure a stock 07 GT mustang is not one of them.
 

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I think everyone's always interested in dyno results and time slips, so I just thought I would share the timeline of my car's modifications and the results over time. I've got a 2016 R/T with the 345 ci (5.7L) currently running with the 392 cam, 392 intake with active runners, Hellcat airbox, JBA short tube headers, and a Corsa Xtreme catback.

I never did a true stock dyno pull so unfortunately we won't have an absolute baseline. Reports vary a bit, having surveyed a lot of threads I think 318 whp is reasonably typical for the R/T's.

At the time of my first dyno pull in Attachment 1, the only modifications I had which could conceivably add power were the hellcat airbox, catback exhaust, and I was running the Diablosport canned 91 octane tune. There was no tuning performed with the first dyno, it was only a baseline, which yielded 330 whp and 362 torque. So if 318 whp is an accurate stock value, then we can attribute +12 whp to the catback and canned tune, and potentially a bit more if the car would have been tuned from the dyno.

Some time later I had the 392 intake and short tube headers on the car, and this time I got dyno tuned. This days results are given in Attachment 2, but we have some details that need to be discussed to fully understand them. In the attachment the red curve is the before and blue curve after. The headers provided significantly improved torque and power throughout most of the band, just falling off at the higher RPM's like one would expect. I drive in the low-mid RPM range, so that's primarily why I forewent the long tubes in favor of short. We would have expected the 392 intake to have improved the peak horsepower at the high RPM range, and the fact that it didn't and that we don't see any kind of inflection point at the 4800 RPM runner switch point is a dead giveaway as to what happened. Later that night I used my trusty borescope to verify that my runners weren't switching. The runners were in long mode, so the intake was probably not too different than the stock intake's long runners, and that explains why we have next to no change at the high end. I eventually determined that the solenoid was bad and replaced it, so we'll have active runners by the time we get on the last dyno session.

Now here we are in the present. I just got the 392 cam installed a couple of weeks ago and had it tuned, so this final tune will be for the 392 cam and the functional 392 intake. on top of everything else. At the end of the day, 382 torques and 376 horsepower! Not the 391 horsepower seen in this youtube video (
), but in my research it looks like 376 horsepower is perhaps a more typical result for our cars with the same modifications.

At the dragstrip my quarter mile pass is 13.7087 sec and 101.63 MPH at 6010 ft density altitude in Attachment 4. Obviously your results may be better at lower altitudes, but this density altitude is pretty typical for my elevation and I'm confident that if I get a good day where its even a little bit lower that I'll get into the 13.6's. I also feel like I probably have room to improve in the 60 ft, so I could get a little bit better on that front as well. Other than that, since I can't afford forced induction this is probably close to as good as I'm going to get at my elevation.

Since then I went ahead and ported my intake manifold and bought a larger throttle body to match just to check those last two things off the list. I'm not sure its worth the money to dyno tune again just for those two things, what do you all think?
View attachment 1019014 View attachment 1019015 View attachment 1019016 View attachment 1019017 View attachment 1019018
So when you did the install of the stick 382 can mmm did you have to change your internals ( heads, push rods, rollers, etc..,) been thinking about making the swap. What to know what I need to do specifically
 

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For reference the stock 5.7L intake manifold has short runners. The benefit of the 392 manifold is long runners until 4x00rpm and then short runner beyond that. That’s why, if done right, you gain down low with no difference up top.
 

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Discussion Starter #12
So when you did the install of the stick 382 can mmm did you have to change your internals ( heads, push rods, rollers, etc..,) been thinking about making the swap. What to know what I need to do specifically
Oh yeah! In the past I've made posts about my install experiences, but this one was so much more involved than anything I've ever done that its taking me longer to write up. I'm happy to give some of the key details here though.

I went with the Mopar 392 cam, part number 5038419AB for automatic transmission with VVT. Upgraded springs are required to handle the increased lift so I went with Mopar performance spring set with part number P5160074. While not a requirement, most people go ahead and replace the pushrods since they're right there alongside the springs, so I did the Manley 26640 pushrod set. A lot of folks will also do lifters as well, but I opted not to.

So those are the main items, but then you're gonna have to buy some tools and consumables.
  • You will need a harmonic balancer pulling tool, and you definitely want to get the tool designed to mate with your particular harmonic balancer.
  • You'll need replacement cam and crank bolts, conventional wisdom says its not worth the risk to reuse these bolts. My cam bolt was 6102430AA and my crank bolt was 6510763AA.
  • You'll need a spring compression tool for your engine. Be careful, some of them are clearly made to be used with cylinder heads off the car. Mine actually had some major clearance issues trying to use it with cylinder heads still attached, forcing us to modify the tool somewhat.
  • You'll need the fitting from a cylinder compression tester to plug compressed air to each cylinder that you're replacing springs on
  • And you'll need the chain case cover gasket with some black RTV gasket maker to reform a seal you have to break to gain access to the timing chain.
  • You'll need a ~1 foot long dowel rod, or something similar to use as your cylinder top dead center reference
  • You'll need assembly lube, and motor oil with a new oil filter for an oil change immediately after reassembling everything.

And while not truly necessary, I highly recommend getting a borescope. It was truly the MVP on my install, saving me from a nearly catastrophic mistake!

Those are the items that immediately come to mind anyways. I'd like to make a comprehensive post at some point in the future, but until then feel free to private message me if you have any detailed questions, happy to help!
 

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Discussion Starter #13
For reference the stock 5.7L intake manifold has short runners. The benefit of the 392 manifold is long runners until 4x00rpm and then short runner beyond that. That’s why, if done right, you gain down low with no difference up top.
That could be. Of course I hate to admit it, but I've been wrong before!

For reference the stock 5.7L intake manifold has short runners. The benefit of the 392 manifold is long runners until 4x00rpm and then short runner beyond that. That’s why, if done right, you gain down low with no difference up top.
That could be. Of course I hate to admit it, but I've been wrong before!
The curiosity was killing me, so I had to go pull my original 5.7L manifold out of storage and have a look. They look like they are in fact long runners, as each manifold port outlet runs over the top of the intake before opening into the main plenum volume.

My understanding was always that the 392 manifold's active runners were why the 5.7L on the ram trucks were rated at 395 crank horsepower, as they are otherwise identical but gain the benefits of switching to short runner. Obviously I'm speculating a little on that bit, but certainly I think the runners on my original 5.7L manifold appear to be the long variant. I don't know, what do others think?
 

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In Macks video the car with a 392 cam that made 390whp also had long tubes. I ran just 392 cam and long tubes before the blower and man it MOVED for an N/A 5.7. I have a roll race between 2 identical cars (besides mine being 6 speed, the other 5spd auto) to show the difference in power the cam and headers made.
In NJ DA it was probably capable of the 12.0-12.2 range, but I never got to run it on that setup
 
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Discussion Starter #15
In Macks video the car with a 392 cam that made 390whp also had long tubes. I ran just 392 cam and long tubes before the blower and man it MOVED for an N/A 5.7. I have a roll race between 2 identical cars (besides mine being 6 speed, the other 5spd auto) to show the difference in power the cam and headers made.
In NJ DA it was probably capable of the 12.0-12.2 range, but I never got to run it on that setup
Yeah that would certainly explain the difference, thanks!
 
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