[formare]

So hear me our before you judge the title.

The 3.7 liter engine makes 90.5hp per liter. Its efficient and reliable. So why is the LT1 so far behind in development. By my math, a 6.2 liter engine should make 561hp. That's a metric crap tone of HP.

Suppose you could make the argument that with the GM performance cam and heads IE "hot cam" kit it could get close to the 561hp. But why not include it from the factory. Why so much evolution difference between the platforms?

[Mr. Wyndham]

HP doesn't work that way.

It's fairly common to assume HP is directly proportional to displacement...but it's not. HP is directly related to torque x rpms. That's why a Porsche 4.0L six (for example) can produce 500 hp: It revs to 9000 rpms. Then factor in the "other" stuff...like frictional & thermal losses.

[formare]

HP per liter is a measure of engineering prowess. Agree with all your points. The best builders aim for maximum torque with the broadest area under the curve. We still have the issue of the LT1 being far behind in efficiency.

[vtirocz]

Originally Posted by formare

HP per liter is a measure of engineering prowess. Agree with all your points. The best builders aim for maximum torque with the broadest area under the curve. We still have the issue of the LT1 being far behind in efficiency.

Power/internal displacement is a useless metric and not a measure of engineering prowess.

These are useful:
Power / fuel economy
Power / physical external size
Power / engine weight

Who cares if you make a ton of power our of a relatively small internal displacement if the fuel economy sucks, engine is heavy, engine is physically huge, etc?

Let's look at the MY18 Mustang's 5.0 with 460hp. It gets worse fuel economy, not lighter, and external size is larger than the LT1.

Tell me: What's that smaller internal displacement buying me, from an engineering standpoint?

Regarding being "far behind in efficiency": Please list off other 455hp/455lb-ft engines with better fuel economy ratings than the Corvette and Camaro.

[Mr. Wyndham]

Originally Posted by formare

HP per liter is a measure of engineering prowess.

I don't know that I agree with that. IMO, it's a single metric that was made up to apologize for a lack of displacement in modern engines, and appease those who expected a "big" engine.

I believe engineering prowess is demonstrated by reliable HP produced for the least amount of $$. I'd even go so far as to bring in the actual weight of the engine vs. HP to the conversation, because that'll have more bearing on overall performance of the vehicle than HP/L.

EDIT: what vtirocz said.

[KingLT1]

Exactly...while the 5.0 technically is smaller on paper via cubic inches...it's physically a much larger engine then you would think due to the DOHC and 4 valve heads. The heads are the size of BBC. So it's not apples to apples to compare a OHV push rod motor to a DOHC motor. The LT1 is actually very efficient for a 2v pushrod engine. The Coyote is 444lbs undressed, the LT1 is 465lbs dressed.

[formare]

Fuel economy has a lot to do with the body style and overall weight. Kind of a strange request in this conversation, but here is two off the top of my head:

2006 Mercedes-Benz E55 AMG
Mercedes-Benz s600


By "efficiency" I was referring to the ability to efficiently utilize displacement to produce torque and subsequently HP.

"I believe engineering prowess is demonstrated by reliable HP produced for the least amount of $$. I'd even go so far as to bring in the actual weight of the engine vs. HP to the conversation, because that'll have more bearing on overall performance of the vehicle than HP/L. " ---- Interesting viewpoint, so the V6 is better engineered? (it does produce more HP per pound.)

[ULTRAZLS1]

For its engine design it’s doing just fine.

You are comparing a 4 valve head high revving dohc design to a 2 valve head pushrod motor.

An engine is an air pump and can’t be compared by displacement alone in producing power.

It’s actually amazing what they are able to do with it. It’s physical size, power and efficiency is great. Hp/l is ricer talk and means nothing. Just a pointless figure for people to brag about that don’t understand engines

[vtirocz]

Originally Posted by formare

Fuel economy has a lot to do with the body style and overall weight. Kind of a strange request in this conversation, but here is two off the top of my head:

2006 Mercedes-Benz E55 AMG
Mercedes-Benz s600


By "efficiency" I was referring to the ability to efficiently utilize displacement to produce torque and subsequently HP.

"I believe engineering prowess is demonstrated by reliable HP produced for the least amount of $$. I'd even go so far as to bring in the actual weight of the engine vs. HP to the conversation, because that'll have more bearing on overall performance of the vehicle than HP/L. " ---- Interesting viewpoint, so the V6 is better engineered? (it does produce more HP per pound.)

The body style and weight are very similar between the Mustang and Camaro. It's also similar to it's Alpha twin, the ATS-V.

The LT1 in the Camaro gets better fuel economy than both the 5.0 in the Mustang (rated at 460hp) and the 3.6TT in the ATS-V (rated at 464hp).

Two questions:

1. Do you consider the ATS-V's LF4 twin turbo V6 to be "more efficient" due to it making the same power with smaller INTERNAL displacement? (I'm not sure it's any lighter when considering the intercoolers(+dedicated cooling system and pump for that)/turbos/plumbing)
2. IF the LT1 had an internal displacement of 4.0 liters, would you consider it to be more efficient than it is today even if the fuel economy, power, weight, external size were all identical?

Also, the 2006 Mercedes-Benz E55 AMG has a supercharged 5.4L V8, that while it does make 469hp also is EPA rated at 13city/19highway. That kind of fuel economy does not sound very "efficient" to me compared to the Camaro's fuel economy.

Again, what's that smaller internal displacement buying me? Show me an example of an engine with a similar power curve that has better trade-offs on weight, cost, external size, and fuel economy. Those are all things that actually matter. Internal displacement does not, unless it affects those things I've listed.

[JamesNoBrakes]

"MOAR" will mean you need better materials, higher flow injectors, all sorts of things that will add up to more cost for the car. Lots of stuff is possible, but that doesn't make it practical. I can blow 40 grand on a Subaru WRX for the same as a SS, the WRX makes far more hp/liter, but it costs the same and is less HP/tq overall. If we wanted the same hp/tq per liter in the 6.2, which would ultimately give you a lot more, it's going to have to cost more.

[nicktechla]

Originally Posted by vtirocz

Power/internal displacement is a useless metric and not a measure of engineering prowess.

These are useful:
Power / fuel economy
Power / physical external size
Power / engine weight

Who cares if you make a ton of power our of a relatively small internal displacement if the fuel economy sucks, engine is heavy, engine is physically huge, etc?

Let's look at the MY18 Mustang's 5.0 with 460hp. It gets worse fuel economy, not lighter, and external size is larger than the LT1.

Tell me: What's that smaller internal displacement buying me, from an engineering standpoint?

Regarding being "far behind in efficiency": Please list off other 455hp/455lb-ft engines with better fuel economy ratings than the Corvette and Camaro.

for sure... My LT4 gets better MPG than my Whipple'd coyote.. or even before it was supercharged.

[georgez32]

Hp/l is an indication of engineering competence but at the same time an engineering limitation. Horsepower is simply a function of torque and rpm smaller displacement means for the most part shorter stroke which means lower piston velocity which is one of the major limitations as displacement goes up

Hell literbikes get 200hp/liter, by that logic the 3.6 should be getting 720hp.....so yes, (hp/l)/l is not linear(well it is linear in theory if you want to rev that lt1 to 12000rpm but we all know that’s never going to happen)

[formare]

Two questions:

1. Do you consider the ATS-V's LF4 twin turbo V6 to be "more efficient" due to it making the same power with smaller INTERNAL displacement? (I'm not sure it's any lighter when considering the intercoolers(+dedicated cooling system and pump for that)/turbos/plumbing)
   
   No sir - its forced induction.
   
   
2. IF the LT1 had an internal displacement of 4.0 liters, would you consider it to be more efficient than it is today even if the fuel economy, power, weight, external size were all identical?
   
   Same HP and Torque? If yes, then absolutely.
   

Also, the 2006 Mercedes-Benz E55 AMG has a supercharged 5.4L V8, that while it does make 469hp also is EPA rated at 13city/19highway. That kind of fuel economy does not sound very "efficient" to me compared to the Camaro's fuel economy.

I did not realize the E55 was using forced induction.

[enzia35]

There's that ricer math again.