Just comparing some numbers here..

1988 V6 Camry = 152/2.5 = 60.8 hp/liter
2000 ES 300 = 210/3.0 = 70
2005 LS430 = 290/4.3 = 67.4
LS460 = 380/4.6 = 82.6

I'd have expected a little more for the LS430 (maybe something in the 70s), but I ain't complaining. Just saying.

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Not sure if it's still true, but for a while Honda's S2000 had the honors of highest hp per liter on a naturally aspirated engine. It was something like 120hp per liter, depending on which year it was. So a 2.0 litre engine had just a little under 240hp.

I think Lexus could easily bump that number up higher, but usually luxury car owners don't want an engine that you need to scream to 10,000rpm to get high horsepower. They want a nice cruiser with good power down low and decent fuel economy.

 

Well, yeah. I couldn't care less about hp/liter. I love that I can cut and thrust through LA traffic, melting through the gears without barely going over 2100 RPM. This imparts a serious feel of luxury. But when you do stomp it, there's a marvelous ripping silk sound and a great high rpm horsepower rush.

I came from a high strung Acura TL 6 speed with virtually no torque below 3000. It took just a little while to get used to, the difference in power delivery. After about a day or two I was smitten with the 4.3L.

 

The 460 accomplished this mostly with the addition of direct injection. To me, that ruined the car. The ticking noise, which is more noticeable in some cars than other, drove me absolutely nuts. Sounded like spark knock. I would have rather had less hp and the smoothness/silence of the 430.

 

pretty sure the strongest per liter is the Mercedes-Benz CLA45 AMG's twin turbo 4 cylinder, 2.0 liter. 355 hp.

 

Agera 1, 5.0 liter = 1,341 HP: 268.2 Horse/liter

It's called the 1:1 because every kilogram it weighs has 1 horse carrying that weight. Amazing car, Bugatti slayer.

 

I was talking about naturally aspirated, forced induction is a whole new ballgame.

 

A lot of good info in this thread.

Now why do certain engines report hp at 5200 RPM, while others report it at 6000 RPM ?
How is that RPM determined for a particular engine?

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It is just what the engine is designed to peak at.

For example, the LS430 peaks at 3000 rpm I believe, that is where the engine meets the the perfect spot to spit out most hp. Just the way the engine is designed.

 

The LS430's peak power is at 5,600 and peak torque is at 3,400 rpm, both of which are among the lowest RPMs for any Japanese engine from Toyota/Honda/Yamaha/Suzuki/Kawasaki I've ever seen.

I don't know why you'd expect more hp/liter from the LS430. It makes 290 horsepower and displaces 4.3 liters. How could it make any other hp/liter than 67?

HP/liter favors forced induction, high redline engines, and 2 stroke/rotary engines. Horsepower is basically 'how often a given amount of torque is made'.

I own motorcycles and they've got all the hp/liter I need (I got one in my garage with >300 hp/liter normally aspirated).

There's another metric one that I think is better than Hp/liter to describe an engine, and its called Brake Mean Effective Pressure. Basically it describes the pressure inside the combustion chamber at a given power level. The higher the pressure, the more torque the engine is making at a higher RPM. The LS430 has a BMEP of 163 PSI at HP Peak. That puts it in class with the Rolls Royce Phantom V12 (163 psi at hp peak), and above the Audi 4.2 v8 that makes 330 horsepower (158 psi at peak) and way above the VR6 GTI (150 psi).

I don't know about the LFA, but I think the Lotus Elise / Toyota inline 4 (2ZZ-GE maybe? ) has the highest BMEP of any production Toyota engine with a BMEP of 176 psi, which actually is just on par with the fast Honda K series (the 2l 200hp ones are in the neighborhood).

Most sport bike engines were in the mid-170s in the 2000s. I haven't ran the numbers for the new S1000RR, but given the RPM, I'd be surprised if it broke 180.

The king of BMEP is the S2000, of course, at 188 PSI for the American F20B and 193 PSI for the JDM Spec F20B.

The best race engines get about 200-220 PSI which is incredible. Especially since the 220 PSI motors are from NASCAR. Although NASCAR engines use an out dated architechture, it's amazing that they get those push rod, 2 valve head V8s to run at 9,400 + rpm. And I've heard that we'd see 10k rpm engines if the rules didn't specify gear ratios.

So what do we know about the LS430? It has a modern (but not state-of-the-art) engine. It makes good power, it's supremely reliable, quiet, and efficient. It moves the car around smartly and pretty rapidly when need be.

The engine makes a ton of torque and has minimal vibration at moderate to high engine loads.

I think Lexus made all the trade offs I'd want them to make on an engine.

Consider that the 3UZ is 15 years old now. And the basic engine goes back to the 80s.

Personally, I think its great. And frankly, I wish there were a V6 LS. I'd enjoy the milage, but I don't begrudge the V8 at all.

When the recession hit, Lexus considered a Lexus LS350, with a 3.5l v6. That'd be an excellent car.

 

Great info. My favorite part of the LS is the 4.3 V8. Smooth as silk, and loads of power when needed. I just did a 2k road trip and passing other cars on high speed two lane roads in Florida with the LS430 is actually fun and safe because the power is right there when you need it. Step on the gas and the LS goes from 65 to 90mph so fast and smooth it is a just amazing. Cars I passed probably surprised at the XXL sized barge passing them at 85+mph in the wink of an eye with no noise and no drama.

 

Feb 2015 issue (page 59) of Consumer Reports has an article on direct injection engines, and how some manufacturers' vehicles are running into related problems as they age.

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The benefit of going from 300lb-ft @4000rpm in my 99' to 320lb-ft @3400rpm in the 4.3L has me forgetting the fact that they both produce the same horsepower. It's a massive difference when driving steep hills daily.

Anyone know what numbers a stock motor puts down on the dyno?

 

Yes, some engines with D.I have carbon build up issues. The 2GR (2.5 liter V6 in the IS250) has issues. But a majority of Lexii with direct injection actually use a combination of port and direct injection and don't suffer the carbon build up issues of poorly configured direct injected motors.

And some D.I motors don't have carbon build up issues. I don't think Honda has any issues with the earth dream engines (but it's too soon to tell), and Hyundai/Kia have some engines that run really well on D.I.