Horsepower is horsepower?

pnichols wrote:
.... and if one wants to push intake boosting to the extreme ... BRM once produced an engine of only 1.5 liters that put out 550-650 HP using double supercharging and a whole bunch of RPM.

So yes, "boosting" is only the name of a process, with a whole lot of engineering variables going into exactly how and why one does it. I can imagine a small boosted engine being able to put out more HP than a specific large boosted engine.

Ah yes, the mighty BRM V16 Another example of vision exceeding the technological limits of the day.

The 1.5 liter turbo F1 engines of the eighties put out 1200 HP for qualifying and over 900 race HP but neither they or the BRM used pump gas.

For 1014, F1 is going back to 1.6 liter turbo engines with an emphasis on improving fuel economy. Should be interesting.

2014 Renault F1 Engine

.... and if one wants to push intake boosting to the extreme ... BRM once produced an engine of only 1.5 liters that put out 550-650 HP using double supercharging and a whole bunch of RPM.

So yes, "boosting" is only the name of a process, with a whole lot of engineering variables going into exactly how and why one does it. I can imagine a small boosted engine being able to put out more HP than a specific large boosted engine.

transamz9 wrote:

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:
Problem with these threads is they always become gas versus diesel debates instead of boosted versus unboosted. Futile.

Okay,put a boosted eco boost into a HD truck with the same boosted hp diesel. Hook up the max trailer weight to the back of it.

As soon as they put a 6.7 liter turbocharged direct injection gas engine in a HD truck, let's do that. Until then, stop comparing a 3.5L gasser to a 6.7 liter diesel.

LOL! You will never see a 6.7 liter turbo gas in a truck. HAHA, we couldn't afford to keep gas in it. We are comparing hp to hp not liter to liter.

It would likely be a fuel hog but it would be a towing monster. However, as you say we are comparing hp to hp, not fuel economy. If you are comparing hp to hp how can you not compare liter to liter? My ten liter boosted engine is more powerful than your five liter boosted engine. Duh!

The OP was talking about hp v/s hp not liter v/s liter.

Depends on what you consider a towing monster is. It's still going to have to rev very high to be into the hp range.It's hard to get air forced into a gas motor because of the nature of the fuel and how it reacts. A diesel motor is different because of the fuel used. The more fuel and air the more power until you blow it apart. You start blowing holes in pistons in a gas motor from detonation once you start raising cylinder pressures or run fuel that you can't pump from a fuel island.

There have been turbo gas motors around for decades and some were put in small trucks with no tow rating. There are reasons for this. The Chevy cyclone is a good example. Why didn't GM put that motor into a 1/2 ton pick up? I think it was 300/300 back in 1990 and the S10 it was in would out run a Vette stock to stock.

I'm not taking sides in the diesel versus gas debate. I have a turbo direct injection gas engine in a car and a turbo diesel in my truck.

Both have their pros and cons, I think diesels are better suited to towing and clear winners on fuel economy, but when it comes to power output, it is possible for gassers to be superior with today's technology.

Some numbers for you.

Audi 2.0t direct injection turbo on 91 octane. Take some other manufacturer's 2L DI turbo gassers and you will find similar or even better numbers.

HP 220 at 4450 to 6000 RPM. 110 hp per liter displacement
Torque 258 lb ft 1500 to 4300 RPM. 129 lb ft per liter displacement



Cummins HO

HP 385 at 2800 RPM. 57.4 hp per liter displacement
Torque 850 at 1700 RPM. 126 lb ft per liter


When it comes to torque per liter, it is a dead heat but the gasser peaks at a lower RPM and is flat over a 2800 rpm range. So much for the diesel's low RPM torque advantage.

When it comes to HP per liter, it is not even close. But you say, the gasser hits peak HP at a much higher RPM. True, but if you calculate the gassers HP at the diesel's peak of 2800 RPM it comes to 68.5 hp per liter for the gasser vs 57.5 hp per liter for the diesel, the gasser still wins.

Granted the smaller engine will have less HP loss due to friction and there is less mass moving around so it should be a bit more efficient, so lets compare likes with likes when it comes to size.

Audi's own 2.0 Turbo diesel

HP 140 at 4000 RPM. 70 HP per liter
Torque 236 lb ft 1750 to 2500 RPM. 118 lb ft per liter

Again, when it comes to HP and torque, the gasser clearly wins. Fuel economy, that's something else again. Diesel hands down.


That's comparing HP to HP.

A boosted 3.5 is bigger than a boosted 6.7? I don't think so.

You may not think so, but it is.

It's funny the talk was between the 6.7 and the 3.5 because at one atmosphere (14.7 PSI)of boost they flow almost exactly the same amount of air. The EB puts out 14.??? lbs of boost so it will be VERY close to a 6.7 liter to a 7.0 N/A engine.

In fact the 6.7 N/A will be only around 90% VE where the boosted engine will be 100% VE so the boosted 3.5 will flow slightly more air and fuel than the 6.7.

A lot of people don't understand turbo's and what they do to air flow. My turbocharged 5.7 SBC at 15 lbs of boost will flow more air than a 11.4 liter N/A engine. And that is only at 15 lbs of boost. 30 psi is not uncommon at the strip now days. :E

Unfortunately a lot of people don't understand what that does to fuel flow either. A 5.7 liter engine at 30 lbs of boost will use 4 times the amount of fuel as a N/A 5.7 liter engine at wide open throttle. :E :E :E

transamz9 wrote:
The Chevy cyclone is a good example. Why didn't GM put that motor into a 1/2 ton pick up? I think it was 300/300 back in 1990 and the S10 it was in would out run a Vette stock to stock.

Well ... it probably had something to do with that 300/300 not holding up very long (as built on production lines back then) ... unlike a modern Ford truck V10.

Even way back in the 1990's diesel would hold up for 100K's of 100K's miles due to all the iron in them needed to keep the lid on that compression ratio and low RPM thump, thumping. Now, of course, V10's (for instance) as built on computer controlled production lines and with such refinements as OHV cams will last that long too -> even with their high RPM whirring.

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:
Problem with these threads is they always become gas versus diesel debates instead of boosted versus unboosted. Futile.

Okay,put a boosted eco boost into a HD truck with the same boosted hp diesel. Hook up the max trailer weight to the back of it.

As soon as they put a 6.7 liter turbocharged direct injection gas engine in a HD truck, let's do that. Until then, stop comparing a 3.5L gasser to a 6.7 liter diesel.

LOL! You will never see a 6.7 liter turbo gas in a truck. HAHA, we couldn't afford to keep gas in it. We are comparing hp to hp not liter to liter.

It would likely be a fuel hog but it would be a towing monster. However, as you say we are comparing hp to hp, not fuel economy. If you are comparing hp to hp how can you not compare liter to liter? My ten liter boosted engine is more powerful than your five liter boosted engine. Duh!

The OP was talking about hp v/s hp not liter v/s liter.

Depends on what you consider a towing monster is. It's still going to have to rev very high to be into the hp range.It's hard to get air forced into a gas motor because of the nature of the fuel and how it reacts. A diesel motor is different because of the fuel used. The more fuel and air the more power until you blow it apart. You start blowing holes in pistons in a gas motor from detonation once you start raising cylinder pressures or run fuel that you can't pump from a fuel island.

There have been turbo gas motors around for decades and some were put in small trucks with no tow rating. There are reasons for this. The Chevy cyclone is a good example. Why didn't GM put that motor into a 1/2 ton pick up? I think it was 300/300 back in 1990 and the S10 it was in would out run a Vette stock to stock.

transamz9 wrote:

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:
Problem with these threads is they always become gas versus diesel debates instead of boosted versus unboosted. Futile.

Okay,put a boosted eco boost into a HD truck with the same boosted hp diesel. Hook up the max trailer weight to the back of it.

As soon as they put a 6.7 liter turbocharged direct injection gas engine in a HD truck, let's do that. Until then, stop comparing a 3.5L gasser to a 6.7 liter diesel.

LOL! You will never see a 6.7 liter turbo gas in a truck. HAHA, we couldn't afford to keep gas in it. We are comparing hp to hp not liter to liter.

It would likely be a fuel hog but it would be a towing monster. However, as you say we are comparing hp to hp, not fuel economy. If you are comparing hp to hp how can you not compare liter to liter? My ten liter boosted engine is more powerful than your five liter boosted engine. Duh!

Turtle n Peeps wrote:

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:
Problem with these threads is they always become gas versus diesel debates instead of boosted versus unboosted. Futile.

Okay,put a boosted eco boost into a HD truck with the same boosted hp diesel. Hook up the max trailer weight to the back of it.

As soon as they put a 6.7 liter turbocharged direct injection gas engine in a HD truck, let's do that. Until then, stop comparing a 3.5L gasser to a 6.7 liter diesel.

That 3.5 is a bigger engine than a 6.7 at full boost. :E

A boosted 3.5 is bigger than a boosted 6.7? I don't think so.

Hannibal wrote:

ib516 wrote:
IIRC, the last Cummins Hannibal had was a 5.9L Cummins with only 250hp/460tq. If that was the latest diesel he has driven/owned, it doesn't surprise me that he doesn't recall diesels as "powerhouses" when compared to modern gassers.

Heck, the 2014 RAM HD will have a 410hp/429tq 6.4L Hemi available.

They've come a long way since 2003.

That's why you've never seen me post ridiculous statements like "any this will out tow any that". I only post "my" experiences with vehicles that I've owned and towed with. I've made it perfectly clear that my '03 Cummins was a SO and not a HO. I've also stated many times that if we towed much in the mountains, I would own my 5th Cummins powered Ram. There are no surprises. I've always been straight up with my experiences. None of the trucks I've owned have been powerhouses. Especially my current F250. But, it's quiet, reliable, issue free and makes me a lot of money as it doubles as my daily work truck.:B

...and THAT, my friend, is the important part :)

wilber1 wrote:

transamz9 wrote:

wilber1 wrote:
Problem with these threads is they always become gas versus diesel debates instead of boosted versus unboosted. Futile.

Okay,put a boosted eco boost into a HD truck with the same boosted hp diesel. Hook up the max trailer weight to the back of it.

As soon as they put a 6.7 liter turbocharged direct injection gas engine in a HD truck, let's do that. Until then, stop comparing a 3.5L gasser to a 6.7 liter diesel.

That 3.5 is a bigger engine than a 6.7 at full boost. :E