Winter Project: Fun with Numbers – Airflow - Free HP???

[2ndAmend]

Looking for way to make the cars faster without significant mods. One idea I had was to open up the right hood scoop. As most of you know, the right scoop on the 2019+ is mostly or fully blocked off, mine is completely blocked by what appears to be urethane foam. The reason it is blocked is a mystery but some have theories.

I ran some very elementary calculations and hope you guys might be my peer review.

THE ENGINE

The 6.2L at 6000 is demanding 657cfm. At sea level and with 14.5psi boost, the engine is looking for 1305cfm of atmospheric air.

HOOD SCOOP

I estimated the area of a single scoop to be 10.64sqin. At 200, this area captures 260cfm ignoring any losses or gains, assuming my calculations are correct.

HEADLIGHT SCOOP

Based on the approx. 5.5” ID of the bezel, that area will capture 635cfm (same assumptions).

TOTALS

Based on the above, 1 scoop plus the headlight capture 895cfm for an engine looking for 1305, so the engine is still working to get air.

BUT…. If we add in the 2nd scoop, the total captured air is 1155cfm, getting very close to the 1305 demand.

I have to wonder if the headlight plus 2 scoop was designed to meet the air demands of the car….

CONCLUSION

Based on this, I am seriously considering opening up the right scoop before Land Speed Trials next year.

As always, I welcome comments, constructive comments are even more welcome! 😉

 

[Decay]

How would you direct it to the intake?

 

[2ndAmend]

How would you direct it to the intake?

They appear to be connected, but blocked. Take a look.

 

[2ndAmend]

Initial calculations considered the opening of the scoop near the rear. The scoop bezel is tapered and if I consider the full area of the leading edge, the cfm of each increases from 260 to 385. Based on that, 2 scoops and the headlight capture 1405cfm for an engine demanding 1305.

Unless I find a good reason not to, I have to give this a try next summer.

 

[DGatzby]

Just trying to save you some trouble.

Where is the flow from the most substantial air input to the system? The open area in the air box supported by the lower opening?

Comes in here…
View attachment IMG_2060.jpeg
Flows into and up the area under the filter…

I have also seen a description that if you attempt to open the right side of the hood the airflow will become turbulent and not work well within the SMALL air scoop hood system.

 

[EricG]

@DGatzby you beat me to that reply!

 

[2ndAmend]

Just trying to save you some trouble.

Where is the flow from the most substantial air input to the system? The open area in the air box supported by the lower opening?

Comes in here…
View attachment 172853
Flows into and up the area under the filter…
View attachment 172855
I have also seen a description that if you attempt to open the right side of the hood the airflow will become turbulent and not work well within the SMALL air scoop hood system.

I have heard about the turbulence also, we "hear" a lot of things. If anyone comes across documentation please post it, thanks.

Underhood air is warmer, and yes, according to the numbers, a lot of air is sucked in from under the air box.

But, as we all know, cool air is king. I figure forcing in more cool air will lessen how much warm air is sucked in.

What got me on to this is it surprises me how strong the car pulls right up to the speed limiter. My guess is that at extreme speeds the car is really enjoying the high quantites of fresh air. I was thinking about what might happen if I could improve on it.

 

[DGatzby]

It sure appears that the opening(s) from under with the primary feed of air not only thru the 20 square inch duct opening pictured above but also is open for flow from the larger center area, probably is where lots of air enters the intake box. These other holes are minuscule by comparison. Moving good on the highway for a while, look at your intake temps. Mine are not that bad. Yours?

Keep in mind the right side 20 sq-in hole alone is enough to cool the oil cooler in this design.

 

[EricG]

Interesting thought as I remember for the OG Hellcat, the SRT engineers say it was the headlight duct and extra airflow that allowed them to call it 707hp instead of 700, and they said the '18 Demon's massive air duct helped with it's 808 hp rating, and they said the smaller left snorkel air hole on the redeye on was the reason they had to dial the rating back down to 797 hp. I always thought that was a bunch of crap, especially then when they came out with the super stock and redeye jailbreaks(same dual snorkel hood) and rated them at 807 saying they re-calibrated the tune - but really it's the extra 100 rpm that the hp is rated at that probably make the 10hp difference. Is the air filter or the access to air really the limiting factor in hp development? I'd be surprised if it is, I mean take off the filter then and let it breathe all it wants! @2ndAmend you may be on to something, who knows? Will be interesting to follow what you do.

 

[2ndAmend]

Interesting thought as I remember for the OG Hellcat, the SRT engineers say it was the headlight duct and extra airflow that allowed them to call it 707hp instead of 700, and they said the '18 Demon's massive air duct helped with it's 808 hp rating, and they said the smaller left snorkel air hole on the redeye on was the reason they had to dial the rating back down to 797 hp. I always thought that was a bunch of crap, especially then when they came out with the super stock and redeye jailbreaks(same dual snorkel hood) and rated them at 807 saying they re-calibrated the tune - but really it's the extra 100 rpm that the hp is rated at that probably make the 10hp difference. Is the air filter or the access to air really the limiting factor in hp development? I'd be surprised if it is, I mean take off the filter then and let it breathe all it wants! @2ndAmend you may be on to something, who knows? Will be interesting to follow what you do.

I have thought about pulling the filter but the runway can get dusty.

I don't know how they rate hp, but air intakes work very differently on a dyno than they do at high speed.

The way I figure, the more O2 you can get in, the more fuel it will provide, within the limits of the tune.

Watch how this stock REWBJB just keeps pulling, add 9mph for the S2. Hell, what do I have to lose trying this?

https://www.facebook.com/video.php?v=1532694434751358

 

[2ndAmend]

Ever since Bull first pointed out the hood lifting at speed I have been looking to reduce underhood pressure. That pressure not only lifts the hood, it also forces more warm air in through the bottom drain hole in the airbox. This summer I removed the master cylinder access cover and the cowl weatherstrip hoping to relieve underhood pressure. It seems to help, and the car sure seems to run better at speed. I had 6 runs over 200 this summer, set 14 records. (Had a good year, maybe I should retire??? )

I like the intake idea because it is zero cost and virtually no risk. But I’m always open to new ideas!

 

[DGatzby]

I have thought about pulling the filter but the runway can get dusty.

I don't know how they rate hp, but air intakes work very differently on a dyno than they do at high speed.

The way I figure, the more O2 you can get in, the more fuel it will provide, within the limits of the tune.

Watch how this stock REWBJB just keeps pulling, add 9mph for the S2. Hell, what do I have to lose trying this?

https://www.facebook.com/video.php?v=1532694434751358

The engine was rated on a dyno in accordance with SAE Standards. You can look around to determine how or what is used for intake air.

What you may lose is nothing. Even if you negate the small amount of air in the hood, it has plenty from below. I agree with Eric, other items may be more beneficial. Realize you may be a at a point the drag racers and others reach, fairly easy to get to this point, further improvements are expensive and small. Here is your enginedyno. Your welcome.


Want more? Eric is all over it, the power btw the models are in the RPM’s. My tune allows 6500😉 and 6000-6500 is where it gets serious (if I want it).

Courtesy of Ray. Thanks buddy!

 

[2ndAmend]

The engine was rated on a dyno in accordance with SAE Standards. You can look around to determine how or what is used for intake air.

What you may lose is nothing. Even if you negate the small amount of air in the hood, it has plenty from below. I agree with Eric, other items may be more beneficial. Realize you may be a at a point the drag racers and others reach, fairly easy to get to this point, further improvements are expensive and small. Here is your enginedyno. Your welcome.

View attachment 172867 View attachment 172868
Want more? Eric is all over it, the power btw the models are in the RPM’s. My tune allows 6500😉 and 6000-6500 is where it gets serious (if I want it).

Courtesy of Ray. Thanks buddy!
View attachment 172869

Are you saying that adding more free fresh air is a waste of time?

 

[DGatzby]

Are you saying that adding more free fresh air is a waste of time?

IDK😁

 

[DGatzby]

You think the engineers left a simple amount of power on the table with the air box design?

 

[Report CPO Super stock]

You think the engineers left a simple amount of power on the table with the air box design?

most likely maybe.