I just don't get it. Why is hp/l so touted? What does it show you about an engine besides horsepower if you know the displacement or displacement if you know the horsepower?

It just seems like a useless number to me. Can anyone shed some light on it's uses for me?

 

Hp/L shows both efficiancy and the level of tuning on that specific engine. For example: 5L putting out only 100hp vs 1L@100hp. This yeilds 25Hp/l vs 100hp/l. This rating doesn't take into account of torque, but it does show that the 1L has much more tuning and is putting out a higher specific output.

 

So the B16 in the Del Sol with 160 hp is higher tuned than the B18 in the GSX with 170 hp? Does this make the 1.6 better for anything? I just don't get it I guess.

And how is it more efficient, I also do not understand that. I mean, the S2000 gets worse fuel milage than the Corvette, and aren't they both ULEV rated?

That is one of the better answers I have gotten, but it just doesn't seem to help much. Why is a higher level of tuning better than a lower one? Wouldn't it be better to have a lower tuned engine, making it easier to add hp?

Thank you for responding.

 

It refers to the quality and precision involved in producing a performane motor.

 

Yes, in theory, a lower tuned engine is easier to mod up for more power, but the trade off is that you can start with something already worked up and then add biger and badder extras like a turbo and not have to do the more minor stuff like cams or intake manifold, etc. Efficiancy and fuel economy are not always related. The difference between the HP of the Vet and s2000 is apples and oranges, one has a huge motor (ie: vet) that is undertuned to produce easy hp and gobs of torque while the s2k is highly tuned and must be pushed harder to produce bigger numbers. I don't know if that makes any sense, I'm not quite sure how to word this, maybe one of the smarter people on this board will step in and take over where I left off...

 

So did more precision and quality go into the Del Sol VTEC or old S800 motor than into the new V6 Accord motor?

What about differing designs? Can hp/l only be used to determine the quality and precision of engines with the same configuration, DOHC, SOHC, OHV, Rotary, Turbo, Supercharged. Surely you can't throw those into that classification can you?

Rotaries tend to get much higher hp/l than other types. Same with FI setups. OHV is lower due to the fact that it moves more air per cycle rather than more cycles per minute. SOHC seems to be about the same but more of an in-between for the OHV and DOHC.

 

But if you could get a 3 liter motor with 300 hp and a 5.7 liter motor with 300 hp, wouldn't the 5.7 give you more room for modifications and cost less to make more powerful? Assume they are the same size and everything, like the Nissan VQ30DE and LS1, which are about the same size and weight. I would use a Honda engine, but I do not know the 3 liter V6s dimensions.

I agree that on two engines with the same displacement, higher hp/l is better, but wouldn't it be better just to say more hp is better in that case? It seems that using more hp/l on two engines of the same displacement is just getting wordy.

I really am trying to learn. I don't want you guys to think I am on a crusade to show that hp/l is useless or something. It just doesn't make sense to me.

Again, thanks for the replies!

 

The problem is your not factoring in the torque you get from displacement and I don't know how to do that either. But, one would assume the LT1 puts out more low end torque than the VQ series simply because its bigger.

 

Does that mean that the LS1 is engineered better, worse, or does more torque have no bearing on engineering?

 

yeah but you have to take into account that accords werent really made for high performance, thats why you could have a 3.0 putting out the same hp as the b18c5 just about, the b18c5 was made for performance, not practical driving habits.