Not really "news", but I just saw Hellcat dyno numbers for the first time...

[Ryan Bell]

The "707hp" Hellcat put down 670rwhp and 605rwtq in the Motor Trend test vs a ZL1.

For reference, the ~740hp Ferrari F12 Berlinetta puts down 585rwhp on a Dynojet.

So basically, you have a car that's close to 800hp for $65k with a warranty and an 8-spd auto.

Like the car or not, you have to admit, that's a lot of bang for your buck.

[Stangkiller]

yup an awful lot of bang .


I do agree that's some power with a warranty for the money.

[Nemesis]

Originally Posted by Ryan Bell

The "707hp" Hellcat put down 670rwhp and 605rwtq in the Motor Trend test vs a ZL1.

For reference, the ~740hp Ferrari F12 Berlinetta puts down 585rwhp on a Dynojet.

So basically, you have a car that's close to 800hp for $65k with a warranty and an 8-spd auto.

Like the car or not, you have to admit, that's a lot of bang for your buck.

Where did this number come from?

[Ryan Bell]

Originally Posted by Drew M

Where did this number come from?

From me assuming a 15% driveline loss through the automatic (which probably is way too much now that I think about it...still going off of "average loss" from 20 years ago...lol) and then rounding up. 15% would be 771hp.

It's probably more like 750hp at the crank. Point being it's underrated. Probably should have thought about it a little longer before I posted it.

[Mike Mercury]

Originally Posted by Ryan Bell

Like the car or not, you have to admit, that's a lot of bang for your buck.

I like the car. What I dislike is the comparison to the Corvette/Porsche/Ferarri.

The Hellcat is in the Muscle Car catagory; the others are in a different catagory.

[RedLS1GTO]

Originally Posted by Ryan Bell

From me assuming a 15% driveline loss through the automatic (which probably is way too much now that I think about it...still going off of "average loss" from 20 years ago...lol) and then rounding up. 15% would be 771hp.

It's probably more like 750hp at the crank. Point being it's underrated. Probably should have thought about it a little longer before I posted it.

A decent operator can make a dyno say whatever they want it to say...


Isn't there some regulation that states an engine must be within XX% of claimed power?

[DaveK88]

It's my understanding that each Hellcat engine is dyno'ed before it is installed in the car. So that 707 HP would be at the crank.

[Fastguy]

Originally Posted by Ryan Bell

From me assuming a 15% driveline loss through the automatic (which probably is way too much now that I think about it...still going off of "average loss" from 20 years ago...lol) and then rounding up. 15% would be 771hp.

It's probably more like 750hp at the crank. Point being it's underrated. Probably should have thought about it a little longer before I posted it.

790hp minus 15%= 671.5 hp.
You were right the first time.

[Ryan Bell]

Originally Posted by Fastguy

790hp minus 15%= 671.5 hp.
You were right the first time.

My point was that I probably overestimated how much driveline loss there is in the transmission. Modern autos have quite a bit less percentage loss than 15% in memory serves me correctly.

[C5SilverBullet]

Originally Posted by DaveK88

It's my understanding that each Hellcat engine is dyno'ed before it is installed in the car. So that 707 HP would be at the crank.

According to Jalopnick Chrysler isn't sure where the 707hp number really came from. They also claim Chrysler told them several engines produced over 800hp on their dyno, and one even reached 825hp.

[Mike Mercury]

Originally Posted by Ryan Bell

My point was that I probably overestimated how much driveline loss there is in the transmission. Modern autos have quite a bit less percentage loss than 15% in memory serves me correctly.

I dont' think so; still at 15% for manual tranny... 17% for automatic.

[mike100]

When you get over 400-500 hp, you can't just say the car loses 15%. Rule of thumb is out the window. If a drivetrain takes 70hp to spin at 7000 rpm with a given set of gear ratios, then it's +70 hp at that rotational speed to get pretty close to crank hp.

The parasitic loss of a roots blower is a wildcard, but assuming it wasn't running hot yet...

as an example- a C4 corvette typically takes 65hp to overcome the drivetrain- maybe a little more if you are spinning to 7000 rpm.

[polarbear]

Originally Posted by Mike Mercury

I like the car. What I dislike is the comparison to the Corvette/Porsche/Ferarri.

The Hellcat is in the Muscle Car catagory; the others are in a different catagory.

Where does that put the Charger?

[RedLS1GTO]

Originally Posted by mike100

When you get over 400-500 hp, you can't just say the car loses 15%. Rule of thumb is out the window.

...and outside of internet dickswinging, talking about peak dyno numbers is absolutely pointless.

How much power does it make? A shitload. Want to know what that gets you? Take it to the track and find out.


Out of curiosity, I pulled up the article. Some parts are rather amusing...

The ZL1 lapped the figure eight in 24.0 seconds ...the Chevy for the most part just sticks and goes...


While the Camaro behaves like a sports car, the Challenger pretends to be nothing else than a straight-line dragster, and when you toss a corner its way it can be a handful. As associate editor Scott Evans put it, the Hellcat handles "just like a Challenger. Understeer into the corner, oversteer out." The quickest way around the figure eight ultimately was the old tried and true racing mantra of "slow in, fast out" as you lap the boat-like car. The result is still pretty impressive, even if it doesn't feel it, with a 24.7-second figure-eight time with a 0.85 average g, and a 0.94 lateral g average skidpad performance. The Hellcat may not inspire confidence in the corners, but it'll do the most glorious drifts you can possibly imagine as it shreds through its rear tires.

The Hellcat is a hell of an impressive engine stuffed into an otherwise underwhelming car.

You want to know why it shouldn't be compared to a Corvette? Because even a Camaro makes it feel like a boat.

I the Hellcats. I'm not knocking them. While I have no use for a 2 door Challenger, I may consider a Charger when they come out. With that said, call a spade a spade. They aren't some amazing sports car ready to take on the exotics. They are a straight line warrior. Nothing more, nothing less.

[vetteman9368]

Originally Posted by mike100

When you get over 400-500 hp, you can't just say the car loses 15%. Rule of thumb is out the window. If a drivetrain takes 70hp to spin at 7000 rpm with a given set of gear ratios, then it's +70 hp at that rotational speed to get pretty close to crank hp.

The parasitic loss of a roots blower is a wildcard, but assuming it wasn't running hot yet...

as an example- a C4 corvette typically takes 65hp to overcome the drivetrain- maybe a little more if you are spinning to 7000 rpm.

Actually an automatic with a converter will definitely have a percentage loss relative to the engine when not locked up (which it's not at WOT)

[Mike Mercury]

Originally Posted by mike100

When you get over 400-500 hp, you can't just say the car loses 15%. Rule of thumb is out the window.

that's why it's called a "rule-of-thumb".

If a drivetrain takes 70hp to spin at 7000 rpm with a given set of gear ratios, then it's +70 hp at that rotational speed to get pretty close to crank hp.

what's left after the tranny... does still create additional loss based on the speed things are turning (rear diff, axles, ...). So loss it not a "set amount"; as frictional losses are variable. Granted; it does start to even-out at some point.

as mentioned earlier, automatics loss is not a set amount either. WOT runs - the TC is not locked. The more load added (comparing first gear to second gear - for example) the higher the loss.

Originally Posted by RedLS1GTO

How much power does it make... Take it to the track and find out.

[racer313g]

Originally Posted by RedLS1GTO

...and outside of internet dickswinging, talking about peak dyno numbers is absolutely pointless.

How much power does it make? A shitload. Want to know what that gets you? Take it to the track and find out.


Out of curiosity, I pulled up the article. Some parts are rather amusing...



The Hellcat is a hell of an impressive engine stuffed into an otherwise underwhelming car.

You want to know why it shouldn't be compared to a Corvette? Because even a Camaro makes it feel like a boat.

I the Hellcats. I'm not knocking them. While I have no use for a 2 door Challenger, I may consider a Charger when they come out. With that said, call a spade a spade. They aren't some amazing sports car ready to take on the exotics. They are a straight line warrior. Nothing more, nothing less.

Don't be such a Mopar hater......

[Mike Mercury]

Originally Posted by polarbear

Where does that put the Charger?

good question.

the rule-of-thumb for muscle cars is that they are 2 door versions. Todays Charger is 4 door; which would typically lable it as a "sedan".



What are fast & powerful sedans called?

and then, this:

[RedLS1GTO]

Originally Posted by racer313g

Don't be such a Mopar hater......

Just like the trucks, the Mopar mentality is simple. Take a great engine... and wrap it in shit.

[Ryan Bell]

Originally Posted by RedLS1GTO

...and outside of internet dickswinging, talking about peak dyno numbers is absolutely pointless.

If you're an OWNER bragging about your own car's numbers, then yeah, maybe so.

Talking about how much power something makes isn't pointless. It's interesting. That's why we have forums.