here is a big block thats anything BUT inefficient! if only I could fit this in my MINI!!!!

http://www.autoblog.com/2006/08/24/a...eet-and-track/

 

Umm... That's only 117 hp/liter on pump gas... And 233 hp/liter on race gas... I have yet to be impressed... Like I said innefficient motor.

 

well it makes me smile.

 

Try spining the tires at 90 in a MINI.

 

I can get a good chirp at 60

 

how is that efficient?

 

pretty sick.


This is a twin turbo ford gt vid. great vid check it out:

http://videos.streetfire.net/toprate...3c01421e14.htm

 

Check out a Dodge Viper on a dyno: http://www.supersprintna.com/multime...odge_viper.php

 

And a 1.6l Mini Cooper makes 72hp/liter also, but that doesn't mean it's inefficient or a boat anchor

Chevy is no stranger to DOHC, offering such engines three years before BMW in 1975. But sometimes simpler really is better.

 

That's extremely debatable There is a reason 51% of MINI owners in the US drive an S sitting at 102 HP/Liter. However purists know this should be the N/A number; but hey thats what aerodynamics are for right?

 

Well I was just pointing out that hp/liter is a completely esoteric and useless measure.

The RX-7 turbo made 211hp/l and the normally aspirated RX-8 engine 182hp/l but that doesn't mean every piston engine in the world is suddenly inefficient or unsuitable for use...

 

No, it measures efficiency which is quite important, doing more with less. The Rotary engines would be widely more popular if the patents weren't so well protected.

Smaller blocks are lighter, and getting more power out of them makes it easier to make a light well handling sports car that has the power to hang in with larger less efficient vehicles.

 

More with less of what? Isn't a better measure of efficiency MPG or power to weight itself?

A lot of OHC 4-cyl engines (particularly european ones) weigh a lot more than say, a cast-iron small-block Ford V-8 and even take up more room under the hood (use a tape measure and you will see that pushrod V-8s are far smaller than any DOHC V-8, even tiny displacement ones).

Even if they both put out the same power, the Ford is a lot cheaper to buy and repair, can get better fuel economy on lower grade gas, and the reduced weight can allow better handling. The problem is that American manufacturers tend to be really cheap when building the rest of the car, but there are solutions: German http://www.vorshlag.com/ls1bmw1.php Japanese http://autospeed.drive.com.au/cms/ar...estions&A=0824

Not to mention it's a lot easier for aftermarket parts to produce considerable power gains if the specific output isn't high to begin with, and the high numbers of these engines produced ensure lower prices for them. Efficiency with money, gas, weight and space is more important to me than some arbitrary measure of "efficiency" based on internal displacement. I mean 100hp/l just isn't too impressive when it adds up to 160hp.

 

Efficiency is defined as energy out/energy in. Hp/L doesn't necessarily have anything to do with it. High hp/L helps, but its not the be all end all. A Honda Civic makes FAR less hp/L than a MCS, but its more efficient. MPG is a much better measure of efficiency than hp/L, although it measures the efficiency of the CAR, not just the engine (which brings in a bunch of other factors such as gearing, weight, etc.)

actually, rotaries mostly died b/c of poor fuel economy and emissions due to their very low static compression ratios. I chose these cars b/C they are similar weights (the Corvette actually being heavier, so its even weighted in the RX-8's favor)

2006 Mazda RX-8: 18 mpg city/25 mpg highway
2003 Chevy Corvette (LS1 350): 19 mpg city/28 mpg highway

I'm with you in hating 350's, as I love revs, not really the 350's strong point, but lets be realistic. I also love rotaries b/c of how beautifully simple the design is in principle, but efficiency was never their strong point. Particularly with the introduction of the DoD (displacement on demand), the 350 can now be quite an efficient engine. Would a quad-cam, oversquare V8 of the same displacement make more power and be more efficient, probably, but there aren't a whole lot of people that make them b/c its a lot more expensive of an engine to make. Chevy accepted the pushrod design b/c its cheap and because people who buy Chevy's like V8's at a bargain price. They can't rev that high, but they are an undersquare design, so the bottom end probably couldn't survive revving that high anyways.

They are what they are, cheap low end heavy grunt and hp, but they've come a long ways since the 350's of the 70's. . .

 

hehe, whoops, guess I revived a REALLY dead thread didn't I. . .

 

Well considering the original post was a yes/no question which has been answered already, I doubt anyone really minds the OT tangent

The rotary was dropped by GM in the 1970s because it had worse fuel economy than their other engines of the time and they were uncertain if it could be economically made to pass ever tightening emission controls. Mazda chose to run them rich enough to produce a still-combustible mixture in a thermal reactor, which fixed the emissions but made the inherently poor fuel economy even worse. It is simply amazing how far Mazda has been able to improve the efficiency of the latest engine in the RX-8.

Except for fuel economy and durability (the apex seals are notorious), the rotary has it all: light weight, extremely small package size, few moving parts, high RPM capability and high power output. But the hp/l numbers they produce are distorted because they are fundamentally different in design and operation, as are 2-strokes... demonstrating that hp/l by itself is pretty meaningless.

As for a 4-cam Chevy 350, Chevy did make one from 1990-1995. It was a $31,258 option for the Corvette, so it wasn't cheap to make. And at 375-405hp, it made less hp in stock form than today's pushrod motors. But Geoff Jeal from the Lotus development team that developed the LT5 did report the heads were designed to flow enough air for 150hp/L@8000rpm.

BTW all Chevy V8s both small and big since at least 1955 are oversquare. It's usually 4-valve engines like the MINI that are undersquare.

 

For realy big, lets not forget the Boss 429 OHC

 

Talk about off topic. This thread mght have set a new record. Interesting discussion tho. Maby it needs its own thread ?

 

Ok so for example. Let's take the motor in my car. It has the supercharger removed and a turbo instead. On pump gas it makes 300whp. Thats 187 hp/liter. Not even going to get on the subject of race gas...

Ok what did it take internally to do this? Aftermarket pistons, rod bolts, and head studs. Everything else internally is stock. Now how much modification did it take Nelson race engines? Deffinately a lot more than just pistons.

 

That thing sounds like a lawn mower. Gross.

 

If it takes a turbo to make 100hp/liter... Honda, Ferrari, and several other manufacturers have already done this with NA motors.