[Spoolin]

Hey guys,

So, my buddy is a tuner and has his own dynojet. We dyno'd my stock 2019 Hellcat on a hot and humid day last summer, making 670 whp. Moving on to yesterday....He posted up a stock 2021 Redeye that he just dyno'd and it made 700 whp on a nice and cool 40 degree day. Dodge claims 717 for the Hellcat and 797 for the Redeye, why only a 30 whp difference? And to top that off, the Hellcat has the 2.4 SC at 11 psi of boost and the Redeye 2.7 SC at 14 psi of boost.

I find this very interesting and reminds me of some comments I have heard that the 2.7 SC isn't as efficient as the 2.4. Just thought you guys would find this interesting as well.

 

[ArchGE]

I have a friend who went from a Cat to Redeye. He mentioned he felt like the Redeye wasn’t quite as responsive as the Cat. It was also ordered it with the 3.09 rear end. Dyno’s are pretty finicky things though. I take what they show with a grain of salt. That’s why they should just be a tuning tool and not necessarly a true power indicator. Put ‘em both on a Mustang dyno (the Heartbreaker) for an eye opener .

 

[saagz87]

I have a friend who went from a Cat to Redeye. He mentioned he felt like the Redeye wasn’t quite as responsive as the Cat. It was also ordered it with the 3.09 rear end. Dyno’s are pretty finicky things though. I take what they show with a grain of salt. That’s why they should just be a tuning tool and not necessarly a true power indicator. Put ‘em both on a Mustang dyno (the Heartbreaker) for an eye opener .

Totally agree. See what they both trap on same day. You will see

 

[Blkout]

Hey guys,

So, my buddy is a tuner and has his own dynojet. We dyno'd my stock 2019 Hellcat on a hot and humid day last summer, making 670 whp. Movign on to yesterday....He posted up a stock 2021 Redeye that he just dyno'd and it made 700 whp on a nice and cool 40 degree day. Dodge claims 717 for the Hellcat and 797 for the Redeye, why only a 30 whp difference? And to top that off, the Hellcat has the 2.4 SC at 11 psi of boost and the Redeye 2.7 SC at 14 psi of boost.

I find this very interesting and reminds me of some comments I have heard that the 2.7 SC isn't as efficient as the 2.4. Just thought you guys would find this interesting as well.

There are other factors at play besides the larger supercharger, the Redeye also redlines higher and shifts a few hundred RPMs higher which also makes more power. If you were to dyno both of those cars on the exact same day under the same conditions, the delta would be greater than 30whp.

 

[Xylander]

WHP is a fickle thing. For example, the cars with the highest whp are going to be standard body cars with 275s on the rear. The 9.5" wheels weigh less than the 305s on the widebody. More unsprung weight directly drags down final whp.

So, in the original example, if your car is an NB and the Redeye is a WB, you'll get the disparity there. If both cars are even with the same body style and trans, then I will be like others and say the dyno isn't exactly precision science. The only way you can get an honest to goodness power rating is with an engine bench dyno. Chassis dynos can measure estimated horsepower, but they cannot provide actual horsepower. They're good for comparing before and after results for things like tuning and mods. I always tend to get a chuckle out of YouTubers who post dyno battles between two different cars. There are a lot of factors that go into a chassis dyno and how the car is configured will affect the outcome. Most dynos will vary in spread between 20-30hp on the same car. They're good for gross comparisons... like if you added 50hp, it should show up as an increase on an average number of pulls. But, dynos aren't going to be able to show much variance on minor upgrades if they fall within the dyno's margin of error.

 

[Ross61]

Totally agree. See what they both trap on same day. You will see

My first thought too

 

[Dennis H]

Redeye is a Hellcat with a Demon Motor.

 

[JeffL]

a dyno is a tool used for tuning.

 

[Spoolin]

I have a friend who went from a Cat to Redeye. He mentioned he felt like the Redeye wasn’t quite as responsive as the Cat. It was also ordered it with the 3.09 rear end. Dyno’s are pretty finicky things though. I take what they show with a grain of salt. That’s why they should just be a tuning tool and not necessarly a true power indicator. Put ‘em both on a Mustang dyno (the Heartbreaker) for an eye opener .

I get what you're saying and agree, but Mustang dyno's can be manipulated (not necessarily nefariously but just because all the data that has to be input for each day and vehicle before the run), unlike a Dynojet that is inertia driven. That's why the numbers are always all over the place with the Mustangs. Also, a Dynojet is supposed to be the most accurate reading chassis dyno you can use.

 

[Spoolin]

There are other factors at play besides the larger supercharger, the Redeye also redlines higher and shifts a few hundred RPMs higher which also makes more power. If you were to dyno both of those cars on the exact same day under the same conditions, the delta would be greater than 30whp.

That's not my point......on a hot day (85 degree and humid), my Hellcat made 670 whp on the exact same dynojet and yesterday on a very cool and low humidity day, the Redeye made 700 whp. That Redeye should have made easily 80 whp more than mine.

 

[Spoolin]

WHP is a fickle thing. For example, the cars with the highest whp are going to be standard body cars with 275s on the rear. The 9.5" wheels weigh less than the 305s on the widebody. More unsprung weight directly drags down final whp.

So, in the original example, if your car is an NB and the Redeye is a WB, you'll get the disparity there. If both cars are even with the same body style and trans, then I will be like others and say the dyno isn't exactly precision science. The only way you can get an honest to goodness power rating is with an engine bench dyno. Chassis dynos can measure estimated horsepower, but they cannot provide actual horsepower. They're good for comparing before and after results for things like tuning and mods. I always tend to get a chuckle out of YouTubers who post dyno battles between two different cars. There are a lot of factors that go into a chassis dyno and how the car is configured will affect the outcome. Most dynos will vary in spread between 20-30hp on the same car. They're good for gross comparisons... like if you added 50hp, it should show up as an increase on an average number of pulls. But, dynos aren't going to be able to show much variance on minor upgrades if they fall within the dyno's margin of error.

Both my car and the Redeye are wide bodies. I just find it odd that the Redeye has a larger blower, 3 psi more boost, dyno'd on a lot cooler day on the same dyno that gets calibrated regularly, and only made 30 whp more than a standard Hellcat. My buddy said this was the first Redeye he has dyno'd on it, but also said the 20+ Hellcats he has dyno'd on his dyno over the past 5 years or so are all in the 660-670 whp range stock.

BTW, mine traps 104 in the 1/8 but it is now tuned.

 

[Ron b]

My stock 2019 Hellcat ran consistent 10.70s with best of 10.71, my stock Red-eye runs consistent 10.30s with a best of 10.31 (best time was 10.16 but printer was down so no slip, so don't count).

Except for the skinnies on the Hellcat all things are exactly equal, same track, same conditions (as much as conditions can be, ie same temps, time of year, ect) stock rear seat delete and same rear drag wheels and tires.

The Red-eye is much quicker than the Hellcat, even though Hellcat had skinnies (which is worth a tenth at the minimum), and in summer conditions the spread is even bigger with the aid of the Power Chiller.

No way that big a difference comes from an extra 30hp, tuner must have had a bad day or the Red-eye is malfunctioning.

 

[Spoolin]

My stock 2019 Hellcat ran consistent 10.70s with best of 10.71, my stock Red-eye runs consistent 10.30s with a best of 10.31 (best time was 10.16 but printer was down so no slip, so don't count).

Except for the skinnies on the Hellcat all things are exactly equal, same track, same conditions (as much as conditions can be, ie same temps, time of year, ect) stock rear seat delete and same rear drag wheels and tires.

The Red-eye is much quicker than the Hellcat, even though Hellcat had skinnies (which is worth a tenth at the minimum), and in summer conditions the spread is even bigger with the aid of the Power Chiller.

No way that big a difference comes from an extra 30hp, tuner must have had a bad day or the Red-eye is malfunctioning.

He wasn't tuning it, just dynoing it. Maybe something is just up with that Redeye.

 

[Germansheperd]

Hey guys,

So, my buddy is a tuner and has his own dynojet. We dyno'd my stock 2019 Hellcat on a hot and humid day last summer, making 670 whp. Moving on to yesterday....He posted up a stock 2021 Redeye that he just dyno'd and it made 700 whp on a nice and cool 40 degree day. Dodge claims 717 for the Hellcat and 797 for the Redeye, why only a 30 whp difference? And to top that off, the Hellcat has the 2.4 SC at 11 psi of boost and the Redeye 2.7 SC at 14 psi of boost.

I find this very interesting and reminds me of some comments I have heard that the 2.7 SC isn't as efficient as the 2.4. Just thought you guys would find this interesting as well.

This is null and void. If you didn't compare the same cars, same dyno, same day within an hour each other or put them on the drag strip with the SAME tires to check MPH all you have is theories and bench racing.
Not defending either car it's the way it is. When I built my last Mustang I could get different numbers higher and lower with the identical combo on different days.

 

[turbodaniel]

Good info here, as I am considering selling the hellcat and going red-eye!

 

[VancityCat]

This is null and void. If you didn't compare the same cars, same dyno, same day within an hour each other or put them on the drag strip with the SAME tires to check MPH all you have is theories and bench racing.
Not defending either car it's the way it is. When I built my last Mustang I could get different numbers higher and lower with the identical combo on different days.

Furthermore - fuel can make a huge difference . Old fuel, a bad tank, not using fuel from a dedicated pump, a million factors

 

[Germansheperd]

Furthermore - fuel can make a huge difference . Old fuel, a bad tank, not using fuel from a dedicated pump, a million factors

Absolutely some old/bad fuel will pull timing.

 

[Bored Panduh]

The reason I'd sell my hellcat for a redeye is the after market capabilities. The hellcat is great but duel fuel pumps and everything else the redeye comes with internally, aluminum block etc is what I'd be willing to pay for in price difference. Regardless what they make stock unless you have solid tires on a prep track you won't really notice any difference between the two. IMO it isn't until you start adding aftermarket parts is when the redeye will start walking away from the hellcat. Just look at the stage packages dodge is pushing. The redeye power potential is far beyond the hellcat. Regardless of what the dyno says I'm not buying a redeye for the stock HP alone I'm buying it for what it's capable of putting out. Although I would like to see a redeye and hellcat on the dyno with identical conditions juuuuuuuust to see what happens lol

 

[saagz87]

The reason I'd sell my hellcat for a redeye is the after market capabilities. The hellcat is great but duel fuel pumps and everything else the redeye comes with internally, aluminum block etc is what I'd be willing to pay for in price difference. Regardless what they make stock unless you have solid tires on a prep track you won't really notice any difference between the two. IMO it isn't until you start adding aftermarket parts is when the redeye will start walking away from the hellcat. Just look at the stage packages dodge is pushing. The redeye power potential is far beyond the hellcat. Regardless of what the dyno says I'm not buying a redeye for the stock HP alone I'm buying it for what it's capable of putting out. Although I would like to see a redeye and hellcat on the dyno with identical conditions juuuuuuuust to see what happens lol

Redeye has very nice upgrades over Hellcat, but it doesn’t offer an aluminum block

 

[RB185AFM]

Expert from another thread.