Our S650 HP compared to the C8.

[Cz_Ziemniak]

Put a Mustang up against a BMW M series M3 or M4, the Mustang is not as refined.

Not as refined, but also better to drive in a lot of ways.

Atleast for the manuals, the Mustang has a better transmission (both Tremec and MT82), more breathable motor that likes to rev, and better gauge cluster setup.

Its arguable that the Torsen diff is also better in some ways, but worse than others. Those M-Diffs are pretty spectacular.

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[GWink]

why don't we toss a Tesla S Plaid in the mix and see what car smokes what car

The Vette is designed and made to compete against Euro supercars, the only way a Mustang gets equal footing is to get a GTD at $350K vs a $170K ZR1, and against a ZR1X the GTD is not going to stand a chance.

Put a Mustang up against a BMW M series M3 or M4, the Mustang is not as refined.

The best Mustang available to most of us right now, the DH, gets smoked by a lowest trim level Vette almost every day of the week.

We are driving a car that stands alone for the moment (until Chrysler gets back in the game), the last "American made" muscle car available to the masses. Front mounted V8, available with 3 pedals and RWD.

But it is no Vette

I think that we have lost the intent of my original post. It was only meant to compare a 6.2 liter V8 producing 490 HP to a 5.0 one producing 486. I am still impressed with Fords’ engineering in that accomplishment!

 

[robvas]

I think that we have lost the intent of my original post. It was only meant to compare a 6.2 liter V8 producing 490 HP to a 5.0 one producing 486. I am still impressed with Fords’ engineering in that accomplishment!

Different power curves, different goals, they used what they had (from the trucks + corvette)

Let's remember GM does make a 670hp 5.5l DOHC NA V8

 

[GWink]

Different power curves, different goals, they used what they had (from the trucks + corvette)

Let's remember GM does make a 670hp 5.5l DOHC NA V8

What vehicle is that engine in? Sounds supercharged to me.

 

[Cz_Ziemniak]

From what i know and have seen and read, it seems like its just easier to make power out of a smaller DOHC V8 than a larger OHV one.

Its really all to do with air flow. DOHC allows a more controlled air flow at a greater valve angle, along with less losses across the entire pushrod system.

As much as I love pushrods, they're sort of shit at higher rpms. Theres a lot of tricky engineering to make all the components stay sync'd up and correctly tensioned when there's as many joints and as much distance traveled as those rods and buckets. Can't have slop in the system.

Its why you see a lot of pushrod motors typically make greater torque figures down low than DOHC motors. They maximize what they can do well while sacrificing that which they do not. By keeping rpms lower, manufacturers choose to sacrifice higher end power gains and focus on lower end grunt. More stroke typically means more torque, but also means a lower rpm ceiling before the entire rotating assembly decides to eat itself apart. Thats the simplest way I can really think to put it without getting into the wacky world of physics regarding 2 vs 4 valves, etc (much of which I have forgotten, its just so much stuff).

Then once you start getting into flat plane cranks, its a whole different ballgame with airflow and scavenging.

Just looking at the specs, the smaller 5.5 liter LT7 actually has a greater bore size than the 6.2liter LT2, however the stroke is far shorter. Whilst I presumed the LT7's bore would be larger than its stroke (obviously), I didn't expect it to be that much, surpassing the LT2. Its not that going smaller is the reason that the LT7 makes so much power as much as the fact that the smaller size is a biproduct of a different way of extracting/making higher power figures. It seems like the only real reason the 5.5 is 'smaller' is because the stroke is so much shorter. Its just less rotating mass overall, if that makes sense. They could've easily kept the stroke and made the bore bigger, but it would've been adding lots of weight, making it harder to rev higher. Its easier to take the weight away.

LT2 (OHV):
Bore 103.25 mm
Stroke 92 mm

LT7 (DOHC):
Bore 104.25 mm
Stroke 80 mm.

Tl;dr - OHV's add mechanical complexity that is not present in DOHC. The greater simplicity of a DOHC allows it to better exploit higher RPM's, which can negate the need for longer strokes. The lack of a longer stroke, however, typically robs them of low end torque.

Thats my 2 cents, if anyone disagrees, please feel free to correct me. I could be off base for all I know, but I'm very much just spitballing what makes sense to me.

 

[AZ_Ryan]

I think that we have lost the intent of my original post. It was only meant to compare a 6.2 liter V8 producing 490 HP to a 5.0 one producing 486. I am still impressed with Fords’ engineering in that accomplishment!

People fixate too much on HP when comparing cars. There is so much more to it, like torque, weight, and gears. The Camaro was a much more fair comparison.

 

[AZ_Ryan]

What vehicle is that engine in? Sounds supercharged to me.

That's the naturally aspirated Z06 engine.

The 490 HP 6.2L is the base engine.

 

[Eli GT]

I'm not a drag racer so my Mustang GT, although not as fast as a C8, is more comfortable and driveable, IMO. A friend has a new C8 and getting into it is like riding in a go-kart. I do like the looks of the C8, very cool but I'm happy with my GT.

 

[GWink]

That's the naturally aspirated Z06 engine.

The 490 HP 6.2L is the base engine.

That IS impressive from an NA engine!!!

 

[Junkyard Dog]

People fixate too much on HP when comparing cars. There is so much more to it, like torque, weight, and gears. The Camaro was a much more fair comparison.

The Camaro no longer being manufactured makes it not really competition anymore.

 

[GWink]

People fixate too much on HP when comparing cars. There is so much more to it, like torque, weight, and gears. The Camaro was a much more fair comparison.

What is it they say? HP is how fast you hit the wall, torque is how far you push it afterwards?……LOL…..

 

[robvas]

I'll bite

Its really all to do with air flow. DOHC allows a more controlled air flow at a greater valve angle, along with less losses across the entire pushrod system.

One big thing with DOHC is you can fit more valve in the bore. Two (four, actually) smaller valves instead of one big one. Coyote and LT1 engines have similar surface area in the intake valves (and the LT1 has much smaller exhaust valve surface area) even though the LT1 has a much larger bore/cylinder.

The LT6 in the Z06 has a slightly larger bore than the LT1 and has 25% more valve than the Coyote

Its why you see a lot of pushrod motors typically make greater torque figures down low than DOHC motors.

It has nothing to do with the DOHC, but it has to do with the fact that pushrod engines are generally larger displacement. Displacement = power (especially low end torque)

More stroke typically means more torque

Stroke doesn't affect torque any differently than bore. It's a common myth. All that matters is cubic inches.

It seems like the only real reason the 5.5 is 'smaller' is because the stroke is so much shorter. Its just less rotating mass overall, if that makes sense.

A lower stroke also lets you have lower piston speed (longer stroke means the piston travels further each revolution of the crank)

The lack of a longer stroke, however, typically robs them of low end torque.

Again, bore/stroke doesn't matter. Rod angle blah blah. It's all just displacement.

Look at a stock Z06 dyno vs a stock 2024 Mustang GT, the Z06 makes about 75 more lb-ft of torque, even though it has a 3.150 stroke vs the coyotes 3.65 stroke. Because it has 4.104 bore vs the tiny 3.63 bore of the Coyote

And it would make even more if they only spun it to 7200rpm instead of 8500rpm or whatever.

 

[GWink]

I'll bite


One big thing with DOHC is you can fit more valve in the bore. Two (four, actually) smaller valves instead of one big one. Coyote and LT1 engines have similar surface area in the intake valves (and the LT1 has much smaller exhaust valve surface area) even though the LT1 has a much larger bore/cylinder.

The LT6 in the Z06 has a slightly larger bore than the LT1 and has 25% more valve than the Coyote


It has nothing to do with the DOHC, but it has to do with the fact that puhrod engines are generally larger displacement. Displacement = power (especially low end torque)



Stroke doesn't affect torque any differently than bore. It's a common myth. All that matters is cubic inches.


A lower stroke also lets you have lower piston speed (longer stroke means the piston travels further each revolution of the crank)



Again, bore/stroke doesn't matter. Rod angle blah blah. It's all just displacement.

Look at a stock Z06 dyno vs a stock 2024 Mustang GT, the Z06 makes about 75 more lb-ft of torque, even though it has a 3.150 stroke vs the coyotes 3.65 stroke. Because it has 4.104 bore vs the tiny 3.63 bore of the Coyote

And it would make even more if they only spun it to 7200rpm instead of 8500rpm or whatever.

Well said!

 

[Cz_Ziemniak]

StRoke doesn't affect torque any differently than bore. It's a common myth. All that matters is cubic inches.
A lower stroke also lets you have lower piston speed (longer stroke means the piston travels further each revolution of the crank)
Again, bore/stroke doesn't matter. Rod angle blah blah. It's all just displacement.

How does stroke not effect torque? It makes perfect sense to me that it would, and I've never seen anything refuting it. There is simply more leverage on the crankshaft with a longer stroke.

 

[robvas]

How does stroke not effect torque? It makes perfect sense to me that it would, and I've never seen anything refuting it. There is simply more leverage on the crankshaft with a longer stroke.

It doesn't really matter if it's stroke or bore. It's cubes. As I said the rod angle blah blah doesn't make enough of a difference to matter.

You can make a similar cubic inch engine, one with more stroke and one with more bore and it will make the same power.

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