It seems to me that the engines cubic inches are getting smaller and smaller as the years come and go. Is it due to trying to improve fuel mileage?

 

I think its because they can get as much power outta a smaller
engine these days verse there bigger brothers of the past.

 

Bigger engines have a lot more internal drag which decreases fuel economy and power per cube. Plus big engines weigh more which also decreases, yadda yadda.

Small engines are great for horsepower and mileage but not necessarily torque.

In my opinion a small engine has a narrower range of efficient operation. As an example I had a 96 Chebby Impala SS, weighing about 4,400#, old American Iron V8 350 putting out 260 HP and 330Ft#s. I now have an 04 Lincoln LS, weighing about 4,000# with a hightech, Variable vale timing 3.9L V8. That is a tiny V8. It puts out about 280HP at some high RPM and I forget what torque but less than the SS.

The SS feels quicker off the line but starts to run out of breath at higher freeway speeds. The LS is a dog off the line but screams once you get it past say 70.

Strangely on street driving, they get almost the same mileage, maybe 14-17 mpg. I figure it is the heavy car with tiny engine for the LS and lots of stop and go. On the freeway the SS got maybe 24, the LS maybe 26, which seems a little strange since I expected far better. But still could be the same littel engine issue.

As a side note, the Mercury Marauder was built and touted as the SS beater. It have the whimpy 4.6L(?) DOHC engine with supposedly 300HP and I forget what torque but high RPM. It was a dog off the line and statistically/practically could not beat the SS in the quarter, heavy car, little engine, High RPM powerband. Where the Marauder should have shined, the freeway, it still could not keep up with the SS. The car never really caught on, I think due to those failings.

Anyway, yes engines are getting smaller due to decreased friction, less exposed surface areas which cause smog, better mileage, lower weight which decreases other needs including more weight, smaller size so it fits in more things etc.

The newer engines are cleaner, perhaps more fun in certain applications, but I still like the rumble of a good old American low tech V8.

When it comes to towing, you still can't beat the cubes.

Just my opinion,

Jim Henderson

 

I think the use of more aluminum, in blocks & heads, has contributed as well. The engines are lighter than the older ones.

 

Two reasons. Fuel economy and emissions. The larger the bore, the harder it is to control emissions. Thus, you have small bore, long stroke engines like the Ford Mod motors. Plus, the smaller the bore, the less the piston weighs, reducing reciprocating mass. Also a smaller piston reduces the sliding friction on the bore. Of course, those last two are negated somewhat by the long stroke. The smaller bore also has another advantage. That is a shorter combustion burn time. This reduces negative torque on the crankshaft by lighting the mixture closer to TDC. This increases fuel economy and reduces emissions. Of course, with a smaller bore, you just cant get the cubes you can with a larger bore. So therefore, smaller displacements.

Also, newer technology had enabled them to get more from less. Variable cam and or valve timing has enabled 10:1 compression engines that will run on 87 octane. They do this by closing the intake valve late at the low rpm's where it would otherwise ping. Sophisticated computer controls also play into this. So you put less fuel in, get more power out.

Dont get me wrong though, there's nothing I would like to see more than a 450hp FE 390, fuel injected and with all the latest technology, in new F150's.

 

That's not completely true. Chevy is putting the second largest production V8 in their 3/4 and 1 tons ever stuffed in a vehicle (8.1L, roughly 495 cubes). The Triton V10 is a 6.8L (410ish), and the Dodge V-10 is 8.3L(500 or so) I think. The hemi is 5.7L, or 350cu. Chevy uses the 6L as well, which is roughly 360cu. So there are still some big ole engines out there.

Trevor

 

The Corvette Z06 now uses a 7.0 liter (427) V8.

 

If you look at the hp / cubic inch of GM's 8.1L V8, it's really sad. I suspect it will be going the way of the dodo bird in short order. Their Duramax diesel has it thoroughly beat, and the more efficient Vortec 6000 is very close. The Ford V10 uses a modular design, again, small bore. They simply add 2 cylinders to get the displacement. The Dodge V10 is simply a Viper engine crammed into a truck.

 

With an EPA of 16 city, 26 hwy. 505hp, no gas guzzler tax. Amazing.

 

I really don't believe any maker *has* to go smaller to get somewhere.

A decent bunch of the engines that came out in the mid 90s have larger successors as it is. I think most Toyota/Lexus engines have gotten larger in displacement, GM has had some get larger, with their 3.5L and 3.9L v6's, the 3.5L will replace the 3.slow and Dtec 3.0 soon, Nissan got a bigger v6 in the Frontier among others, and on and on. Let's not mince words, Ford didn't really have to decrease the displacement on the Tritons, and shouldn't have as underpowered as they were initially. They need some uppage in cubes now, as it is.

While I am not a fan at all of GMs gassers, I don't want a high revving, high hp big block. I want to see the TORQUE. No one I know complains about the 8.1L being slow by any stretch. If someone wants a high revver 6.0 do cruise with, fine by me. Let's see that 345hp 6.0L gasser tow 12,000 lb's. Easy, it won't do it well.

 

Actually the 4.6L is what is commonly refered to as a "Square" design. Its bore and stroke are almost identical to one another. A 302 was an oversquare design, with a large bore but relatively short stroke. 351 Windsors were slightly better in this regard with their extra half an inch of stroke. While stroke length is important to making torque on the bottom end, cam design has more to do where the power band of an engine is.

But it is true that it is harder to control emissions on a larger bore motor without resorting to multiple spark plugs or getting really creative with combustion chamber design which still may lead to a less then desirable solution. Smaller pistons also mean less reciprocating mass which translates into less power expended moving parts around.

 

Well yes, I was referring more to the 5.4L and the V10. But I'd hardly call the 4.6L a large displacement engine either. Both the 4.6L and the 5.4L use the same bore size - 3.55". Small by most standards today.

 

the 8.1 496 ci can only be had in the gmc line not chevy and that motor is due to be joining the dodo bird due to emmission problems from the big poor flame travel bore. the other gm v8's are small blocks
dodge has noy had a full production v10 for many years and the one being used is a full viper motor in limited production at 60k per copy.
the hemi bs motor is 5.7 at 357 ci's
our ford v10 is 415 ci's at 6.8l. putting out a whole lot of smooth clean burning hp and tire twisting power. so what if it's a 5.4 with two extra pistons it runs powerfull and clean when put along the side of a gas guzzing 8.1 gmc .try and get 14.6 mpgs out of that gmc. thats clean emmisssions

 

If they can ever figure out how to make a truck really aerodynamic, we'll be in business

 

Its not aero its wieght, comes in at about 3200lbs.