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The timing pull accounts for a substantial loss on this car. That’s a huge difference, and this would account for why the newer cars have been performing worse in the tests in magazines. Heat soak and higher charge air temps, along with fuel quality, absolutely wrecks output with the way the factory tune is setup on the newer vehicles.

It makes me curious what changed, because the newer engines have a number of differences that make them mechanically better, but with in real world conditions those tables you posted are a massive power difference. It really explains why the newer vehicles feel almost embarrassingly slow on hot days.
The timing only accounts for a small portion, you may be giving it too much value. This a 9.5:1 engine with an effective CR of ~14:1 under load, and that makes it prone to knock retard which negates the added benefit of more timing.

That said, the simple solution is to restore power with methanol/water injection.

In my Turbo Buick days, when running a closed loop system, I would use the "test button" on my meth injection kit to cool the slow to react IAT sensor before a run to ensure it wouldn't pull timing. These Hellcat engines would benefit from the same.

There is so much heat coming off these things it is no surprise they become saturated and feel soft. However, it is also how the power is delivered - a pre-2018 car may run harder in ideal conditions (single pass, long cool down) than a post-2017 car, but the post-2017 car may not become as fatigued once certain thresholds are exceeded and be more repeatable.
 

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The torque is high and the power keeps climbing right until it slams face-first into the rev limiter. The limitation is the reciprotating assemblies.
Let's run with that at bit. That whomppin' big intake valve doesn't like to change direction, and the valve train (rockers, followers, etc.) looks heavier than on an LSx but I've never weighed it. Here's the Modern Hemi...with stabilizers installed...



...and here's the LSx...



So the LSx design sure LOOKS a lot lighter, and our angled actuator mech isn't helping mass either.

Short of a full redesign, the only other option would seem to be increasingly exotic lightweight materials, which usually come with cubic cost increases. 🤑

Maybe a different tack? What about fiddling with the cam phasing rather than the ignition timing? Gotta watch that PTV clearance though...
 

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My ‘20 RE feels much more agressive than my ‘16 Hellcat lol. Is it faster? Who knows but the seat of the pants feel is much more beast. The thing just wants to go. 3.09’s have a lot to do with it I’m sure.
 
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Let's run with that at bit. That whomppin' big intake valve doesn't like to change direction, and the valve train (rockers, followers, etc.) looks heavier than on an LSx but I've never weighed it. Here's the Modern Hemi...with stabilizers installed...



...and here's the LSx...



So the LSx design sure LOOKS a lot lighter, and our angled actuator mech isn't helping mass either.

Short of a full redesign, the only other option would seem to be increasingly exotic lightweight materials, which usually come with cubic cost increases. 🤑

Maybe a different tack? What about fiddling with the cam phasing rather than the ignition timing? Gotta watch that PTV clearance though...
I am predominately an LS-guy and I can attest to how simple the engine is and how with pretty basic valve train upgrades it will do 7000-7500rpm all day long (especially the 4.8L variant). Dodge knew the limitations of the HC engine when it upgraded parts of the Demon/RE iteration. A small increase in RPM netted huge gains, but longevity and warranty issues capped that number rather conservatively.

Cam phasing helps promote air flow - duration more than lift is what fills cylinders (especially with boost); cam specs are here: Hellcat cam vs demon cam We know that a Demon cam can be used in a HC engine without issue - because @hpindy -things. How the cam is adjusted in the tune remains to be discussed.

The thing is this, while the early cars may be more aggressively tuned, they may run up against a ceiling (timing) on a stock tune with something like 3.17" pulley or an Incognito depending on the fuel that is run. It is a thin margin for error. Heat management may also be a wise investment for the newer cars (blankets, spacers, heat wrap, ventilation, etc)

Stock for stock on the same crappy day the pre-2018 car may take the cake; but the 2018+ cars may shine in ideal conditions due to total air flow. May.
 

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Let's run with that at bit. That whomppin' big intake valve doesn't like to change direction, and the valve train (rockers, followers, etc.) looks heavier than on an LSx but I've never weighed it. Here's the Modern Hemi...with stabilizers installed...



...and here's the LSx...



So the LSx design sure LOOKS a lot lighter, and our angled actuator mech isn't helping mass either.

Short of a full redesign, the only other option would seem to be increasingly exotic lightweight materials, which usually come with cubic cost increases. 🤑

Maybe a different tack? What about fiddling with the cam phasing rather than the ignition timing? Gotta watch that PTV clearance though...
561045
It's not optimal that the rib over the valve does not extend directly to the area over the pushrod. A weak point in the rockers is going to be where the ribs get close, but do not blend into each other.
 

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In short, good air and good fuel is what the 2018+ cars need for top performance.
What is air charge G? I'm familiar with timing, WOT timing, KR, A/F Ratios, and retard tables....attack rate, recovery rate etc...

What is the 3rd table representing?
 

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A few months back I traded in my 2017 Hellcat Challenger automatic for 2019 Hellcat Challenger automatic 17 at the drag strip would always run anywhere from 127- 129 11 teens to high tens in the quarter stock with drag radials
My 2019 best time so far 11:18 at only 124 it is like it 2 to 4 miles an hour slower in the 1/8 through the 1/4 with 305/45/ 18 MT drag radials
127-129 mph is very high for a pure stock HC. You had to have exceptional track conditions. 124-126 is more the norm with even lower mph when you have bad DA. We really need more information but it may be a little slower? Everything being equal, it is not unusual for some motors to run better than others.
 

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What is air charge G? I'm familiar with timing, WOT timing, KR, A/F Ratios, and retard tables....attack rate, recovery rate etc...

What is the 3rd table representing?
Timing pulled due to IAT.
 

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My ‘20 RE feels much more agressive than my ‘16 Hellcat lol. Is it faster? Who knows but the seat of the pants feel is much more beast. The thing just wants to go. 3.09’s have a lot to do with it I’m sure.
I’ve gotta get the 3.09’s then. Even with the 2.62’s my ‘20 redeye goes like mad too. Nothing pulls harder from 65-70 mph at WOT than it does already. Can’t wait to get the rear gear swapped out!
 

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My 2018 traps at 127-128 stock. Probably a DA issue. Air quality all across the North American continent is bad right now for the most part.
 

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Sorry my reply was inadvertently posted before I finished:

"Lots of great technical information explaining the 2015-2017
vs the 2019-2020"

What's puzzling is why the SAE J1349 test measured: 714 HP for the 2015-2017 ----- and ----- 745 HP for 2019-2020 ?

Based on that measurement theoretically the 2019-2020 (717) should be stronger ??????
 

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Sorry my reply was inadvertently posted before I finished:

"Lots of great technical information explaining the 2015-2017
vs the 2019-2020"

What's puzzling is why the SAE J1349 test measured: 714 HP for the 2015-2017 ----- and ----- 745 HP for 2019-2020 ?

Based on that measurement theoretically the 2019-2020 (717) should be stronger ??????
It’s capable of being stronger at SAE standard conditions. However, more timing is removed as conditions worsen, which results in less power.

That being said, I’d rather have my 2019 regardless. Further, this shows that if you don’t want to tune, and run higher octane/lower temps, the newer cars will make more power on the factory calibration.
 
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