Specific Output (a.k.a. hp/L)

An engine alone doesn't really produce fuel mileage, that's also a product of how heavy the car is, how aerodynamic it is, and what the transmission is like... in the Corvette's case, it's got a long sixth gear and, as far as i know, it locks out second and thrid gear when not driven hard.

I'd agree that hp/l isn't all that useful of a measurement, but then again neither is horsepower, torque, displacement... none of them mean much by themselves.

I think Firebird's point is that hp/L tells you nothing new...it is simple a way of rejiggering numbers so that they might look better. A Z06's 71 hp/L looks terrible next to a S2000's 120 hp/L, but in reality both the 405 hp small-block and 2.0 L S2000 engines are excellent, each in their own way.

Heck, a 3.75 hp Briggs and Stratton makes 21 hp/l. Is it lousy? No, it's good for what it does.

well if were talking about track racing, (this stuf isn't so important in drag racing) perhaps the power to weight ratio of the engine would be a better measurement.

inferno

...on a broad scale an engines displacement is reflective of its actual size. A big engine is a heavy engine, and a heavy engine is bad....

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I call the BS flag on that. That is nearly 100% crap. The GM 305 was considerably heavier than a 350. A 355 (bored) is a bit lighter than a 350. Using Ford's 4.6L (281cid) is a good example as the iron block versions are heavy engines, though it's much smaller in displacement than a Chevy 350. In fact it weighs in about the same as a Ford 351 or Chevy LT1 if I remember correctly. The real main factors in weight of a motor are materials used and initial block weight.

And thanks for posting up that table Firebird, that is some pretty good information! 👍

^^ very true. The 500 ci cadillac engine weighs in in between small- and big- block Chevys. And they are all iron blocks.

Drifting Thunda

I call the BS flag on that. That is nearly 100% crap. The GM 305 was considerably heavier than a 350. A 355 (bored) is a bit lighter than a 350. Using Ford's 4.6L (281cid) is a good example as the iron block versions are heavy engines, though it's much smaller in displacement than a Chevy 350. In fact it weighs in about the same as a Ford 351 or Chevy LT1 if I remember correctly. The real main factors in weight of a motor are materials used and initial block weight.

And thanks for posting up that table Firebird, that is some pretty good information! 👍

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You say that like dual overhead cams and stuff dont weigh anything.

ShobThaBob

You say that like dual overhead cams and stuff dont weigh anything.

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No, I say that like that doesn't change anything. The SOHC version of the 4.6L is nearly just as heavy anyways, it's the bulky block that weighs the motor down. Also, the 305, 350, etc. are all cam-in-block, OHV designs. The 305 is still heavier than the 350.

Heres an interesting pic of the 4.6 dohc sitting next to the 302W.

Drifting Thunda

No, I say that like that doesn't change anything. The SOHC version of the 4.6L is nearly just as heavy anyways, it's the bulky block that weighs the motor down. Also, the 305, 350, etc. are all cam-in-block, OHV designs. The 305 is still heavier than the 350.

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You are aware that the 5.7l LS1 weighs about as much as the 3.5l engine that nissan uses so much nowadays? What difference does HP/l matter there? Face it, HP/l doesnt matter at all. It doesn't win races, and it doesn't give advantages.

///M-Spec

But outside of racing, power/liter is over emphisized by too many people, IMO. Especially young people in the 'tuning community'.

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Heresy! Flagellate thyself! The American pushrod V8 is an obsolete dinosaur that the modern Japanese mammal has rendered extinct. Those who hold any other false creeds are infidels who must be flamed by the True Believers!

Modern Japanese, Ha!

I get 116bhp/litre from my 40y.o. carb 4pot!!

ShobThaBob

You are aware that the 5.7l LS1 weighs about as much as the 3.5l engine that nissan uses so much nowadays? What difference does HP/l matter there? Face it, HP/l doesnt matter at all. It doesn't win races, and it doesn't give advantages.

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Umm... Dude... THAT'S WHAT I'M TRYING TO SAY!!!!!!!

The LS1 is light because it's alluminum block and heads, which further proves my point.

neon_duke

Heresy! Flagellate thyself! The American pushrod V8 is an obsolete dinosaur that the modern Japanese mammal has rendered extinct. Those who hold any other false creeds are infidels who must be flamed by the True Believers!

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If this guy's serious he needs to have one of those moron signs.

Big displacement American motors aren't any better nor worse than small displacement Japanese motors that RELY ON higher compression, DOHC, etc etc...

Besides, I can gaurantee you 100% that Chevy will continue using a pushrod design in their new engines for years to come and they'll still be right there with Japanese motors. The pushrod LS1 already puts all that technology crap to rest for the most part. And in Ford's scenario the OHC design 4.6L is often liked LESS than the pushrod 5.0L anyways.

Specific output is crap.

Drifting Thunda

If this guy's serious he needs to have one of those moron signs.

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That'd be a no. He is being very facetious, I assure you.


M

Okay... whew, just checkin. Take no offense from what I say haha!