Same output but different displacement (Mstng, Cmr, Chllngr)

[stetka2]

Hello,

it's been quite some time that I'be been wondering how come Ford is able to squeeze 460hp output out of its 5.0 litre engine while Chevrolet and Dodge need 6.2 and 6.4 litre engines to get similar output, 455hp and 485hb, respectively?

Also, Dodge's 5.7 litre engine option for Challenger is worse off, it produces only 375hp and lower torque than Mustang with its 5 litres => 410 ft-lb vs 420 ft-lb.

Could someone knowledgable please explain this to me in words of one syllable?

Thanks

[Olas]

air flow through the head, and how long the valves stay open is part of it
compression ratio is part of it
air/fuel ratio is part of it
RPM redline is part of it
the shape of the torque curve is part of it

the way different companies measure HP is a big part of it, at the crank vs at the wheels. with ancilliaries vs. without. Gross vs Net vs DIN HP are all different measuring techniques that give different results.


engine power/torque is meaningless though, it the numbers at the wheels that matter - wheel torque and wheel HP are a function or gear reduction and therefore torque multiplication.

[stetka2]

Could you please elaborate thereon and be a bit more specific as to the individual particularities?

[NMNeil]

The Ford Coyote is essentially a race car engine. All aluminum, DOHC, 32 valve, 12:1 compression.
Yes it's powerful but the trade off is the piss poor reliability, especially with the head gaskets.
The GM engines are OHV (With I think the LT5 as an exception) 16 valve, aluminum block and cast iron heads with a lower compression ration. Very very reliable, but less power.
You can't have it both ways.

[stetka2]

Thank you for this additional information. How would you compare the Ford Coyote engine vs Ford Voodoo 5.2 engine they put in Shelby? I mena, in terms of reliability...

[300bhp/ton]

Olas said:

the way different companies measure HP is a big part of it, at the crank vs at the wheels. with ancilliaries vs. without. Gross vs Net vs DIN HP are all different measuring techniques that give different results.

No car maker rates power at the wheels and none ever have done. Also nothing has been rated "Gross" since 1972!! FFS

Edited by 300bhp/ton on Wednesday 25th March 12:56

[300bhp/ton]

stetka2 said:

Hello,

it's been quite some time that I'be been wondering how come Ford is able to squeeze 460hp output out of its 5.0 litre engine while Chevrolet and Dodge need 6.2 and 6.4 litre engines to get similar output, 455hp and 485hb, respectively?

Also, Dodge's 5.7 litre engine option for Challenger is worse off, it produces only 375hp and lower torque than Mustang with its 5 litres => 410 ft-lb vs 420 ft-lb.

Could someone knowledgable please explain this to me in words of one syllable?

Thanks

Displacement and hp per litre mean little unless you are restricted by silly tax rules on the capacity an engine can be.

The Ford is a DOHC 32v engine. More valves mean more control over air flow at a wider range of revs. So you can typically get more specific displacement from a multivalve engine, while still retaining low rpm emissions and tractability.

The downside is, you usually end up with a taller, longer, wider and heavier engine. Which is more complex and expensive to produce and to maintain.

Also in the modding world, on a DOHV V8, you'll have to replace 4 cams if you want a cam upgrade.

The Chevy and Dodge engines are all OHV 16v engines. They only have one cam. And typically are smaller and lighter. While often being better or just as good on fuel, while meeting current emissions guidelines.

Think of it as being bigger on the inside and smaller on the outside vs the Ford engine. But as said initially. BHP per litre is 100% meaningless if there is no regulatory body limiting displacement.

As for the Dodge 5.7, they don't tout this as their top performer. So they probably peg it back to distance it from the larger displacements.



As an example of size. LS on the left, Coyote on the right:

[NMNeil]

stetka2 said:

Thank you for this additional information. How would you compare the Ford Coyote engine vs Ford Voodoo 5.2 engine they put in Shelby? I mena, in terms of reliability...

I'm just guessing but as they are based on the 4.6 V8 engine, which we had in our police interceptor Crown Vics, they should be reliable.
250,000 miles on the clock was not uncommon, with only the early ones needing the plastic intake manifold replaced with the upgraded version.