why do modern engines makes so much power from relatively small cubic inches?

the last few years it seem like most engines make great power compared to even the hottest muscle car engines of the 60's and seventies. it's nothing to see a V6 with over 300 sae rated Horsepower and the v8's aint doing bad either,. the LS3 (377 ci) and 5.0 (302 ci) are well over 400 hp and the 6.4 hemi (390 ci) is making 485 hp. is it the cylinder heads? obviously fuel injection helps make that power usable in a daily driver and coil on plug ignition certainly helps but those don't make more power do they? A modern day Honda accord will run right there with a big block muscle cars from the glory days. discuss

 

Heads, variable valve timing, higher compression, more aggressive valve angles, lighter valve train, lighter rotating assembly, transmission gearing etc it all adds up to more potent package.

GM still working with pushrods....

 

Many things are improved.

Less friction and parasitic loss.
Better balancing and less reciprocal mass.
Better fuel/mixing and management. (EFI)
Better breathing.
Better ignition timing curves.
Variable valve timing.
More efficient thermal dynamics.
All of these and more contribute to net horsepower gains.

 

variable valve timing wouldn't affect peak hp would it? it would make for a broader flatter torque curve. I was just thinking with aluminum heads ported and roller cams along with a good fuel system and ignition system shouldn't the classic 400 + or - cubic inch engines be comaparable?

 

With variable valve timing you can have a more aggressive profile for top end power that would normally be a dog on the bottom, so yes, it effectively increases top end without sacrificing bottom end power. Head, intake, exhaust design, overhead cams, etc have all improved with things learned over the last 50 years.....

 

GREAT question. I was just thinking the same thing earlier this week and was wondering whether I should ask the same question on here.

The horsepower of many legendary 1966-1971 cars is indeed laughable compared to that of many turbo-four or turbo-six cars these days, or even just upscale six-cylinder sedans. And as for the smogged V8s of the mid 70s and later....sheesh! I will read with interest

 

cylinder head port design. its not the size of the port but the shape. keeping port speed up is a huge factor. compare Fords Cleveland heads or rectangle port bbc heads to a modern LS head.

also much lighter rotating weights

 

Whats interesting is to watch these new cars at the dragstrip.
Their advertised horsepower does not run near as fast as u would think it should! I guess weight plays a big factor in that. Also gm has torque management holding back the engines

 

Electric is the craziest, fastest thing out there. If they ever crack the range/recharge problem to make it viable for more than the allotted single charge range, it's going to be VERY hard to beat.

But with regard to gas, tighter tolerances, lighter oils, roller cams, lighter rings, better heads, better combustion, better factory exhaust and ideal fuel mixtures contribute a lot. Variable valve timing is somewhat of a crutch. I think the next big thing is going to be camless motors as in electronic or pneumatic valve timing. Idle at 500 RPM and pull to redline with the flattest torque curve you've ever seen.

I just saw some new cars have close ratio 10 speed automatics. Seems like another crutch to find the perfect gearing for the flattest torque curve. If the CVT can ever hold real horsepower, I wonder if they will arrive in time to beat the electric cars?

 

Manual trans clutch protection is electronically limited for a GT 500 and a manual Hellcat but they still run mid 11s at 125-127 mph stock. Nothing from the 60s or 70s could do that. Most real world 60s and 70s stock muscle cars ran 13s,14s and 15s at 100 mph plus or minus and few.

 

Its all in the computers Love it or hate it. Without the computer controlled engine management systems none of the big numbers / fuel milage would be possible. JMO

 

We just got our first zl1 camaro in at work yesterday, and that 10 speed is amazing! Our corvette/camaro guy can't wait for them to put it in the vette. They actually developed it together with Ford, and it'll be in the Mustang, as well. I was skeptical but its about as close to an actually efficient CVT and the shifts happen in the literal blink of an eye. Most amazing car I've been in in a while, and I'm not a Chevy guy, I just play one at work......

 

The answer to your question is simple. For 25 years, the big 3 (and all automakers to some extent) have focused all their engineering effort on one thing.

Fuel Economy.

All of the FI systems, Variable valve timing, reduction in rotating and reciprocating weight, port designs and drivetrain enhancements were done to attain the dreaded CAFE average..

They have now achieved parts that are "just strong enough" to survive, after a whole lot of years of misses on the other side of that line. Remember TH-200 transmissions?

About a dozen years ago, somebody sat down and realized that if we put a blower and more aggressive camshaft timing, along with the proper fuel curves for power in our now super efficient engine, and put that in our car with all of it's lightweight hardware, we would have a pretty fast car.

I chuckled at that article on the Demon that was posted the other day in a different thread. They added just 140 HP over the Hellcat, but had to redesign and strengthen virtually the entire drive train.

For 140 HP..

Consider this:

The vast majority of the hardware in the TH 400 that is out in your garage, are the exact same pieces I used to launch a 3100 lbs GS, with 870 HP, off a trans brake and 5300 rpm, hook it thru 14 inch wide slicks, and cover the first 60 feet in 1.2 seconds.

Our old iron carried a lot of extra strength factor in virtually every part on that car.

And Dodge adds 140HP ,and has to redesign everything.

Some call that progress, I call it building tinker toys.

AS far as the comparison with the older musclecars, lets now talk apples to apples.. what is the fastest Non forced induction car of the last 10 years?

The top dog NA offerings from Detroit over the last number of years, that can be compared with the classics of old, (have to have 4 seats) are the 2015 versions of the Ford GT350, Camaro Z-28, and Dodge Challenger RT Scat Pack.

Guess, what.. all are high 12 to low 13 second cars.

I could take a well tuned totally stock 70 GS, with modern drag radials, and run right with them.

And if I want to update to alum heads, a roller cam and matching components, which is what each of those cars is running..well, Hell, I will give them a head start...

My advice to the new car owners is lock the doors, lest they get sucked off when I come roaring by in my 50 year old Musclecar.



JW

 

I agree with you to a point, Jim. I don't own anything without a carburetor, except my 94 F-250, but the new cars mentioned are all under 400 cubic inches and will get 20+ mpg. You aren't going to see a well tuned 350 GS running the kind of times those new cars can, especially one that'll get near the fuel economy. Maybe a Boss 351 would be the only real small block that could crack low 13s from that era. That said, I am a cubic inches guy myself, the only thing that wouldn't be considered a big block is the Nailhead in my Riv.

Correction: the last z/28 was a 427. Still a small block, though......

 

Electric is insane. If you haven't driven one, the acceleration is phenomenal. The wife has a Nissan Leaf and I can toast anyone off the line.

The new Chevy Bolt has I think 300mi range, more than adequate for most people.
I don't doubt they will come up with more killer technology to increase that many times over.

 

A normally aspirated GT 350R Mustang runs about 12.2 at 119 mph in a quarter out of the box. It will run in the high 11s with drag radials. It has a 315 cubic inch Ford V8 engine with a flat plane crankshaft making 526 hp @ 7,500 rpm and 429 lb-ft @ 4,750 rpm. That is not too shabby for a car built for sports car tracks. By comparison a 1965 427 Shelby Cobra S/C runs a quarter in about 12.5 seconds. http://www.zeroto60times.com/vehicle-make/shelby-0-60-mph-times/

http://www.motortrend.com/cars/ford...l1-vs-2017-ford-mustang-shelby-gt350r-review/

I like classic muscle more but you have to tip your hat to Dodge, Ford and GM.

 

I've always said the 2006+ Z06's are the baddest rides around 122+ mph to the 1/4 bone stock is no joke, I've driven several and put a cam and 150 hit on one few years ago, those cars and that one in particular DEMAND your attention and respect when behind the wheel

 

I recall the similar discussion for air-cooled vs/ liquid-cooled engines...it was all about narrowing the operating temperature range. With a wide range, it is important to keep compression ratios low to prevent pre-ignition. If the range is narrow, then compression ratios can be increased, which improves horsepower.

With the advanced composites used in today's engines, along with the full digital ignition mapping and tuned-port injection for fuel delivery, the operating range of engines can be kept even more stable. Of course, less weight improves the power/weight ratio of the vehicle as well.

Of course, there is a trade-off towards so many electronic systems in which any single one going out-of-tolerance will cause an imbalance which the other systems will attempt to correct...and sometimes it does not happen smoothly.

I like my cast-iron 430 and my air-cooled Kawasakis.

 

Similar. Why does more computer memory power fit on a chip the size of my thumbnail than used to fit in a room? technology moves on.

 

I owned a 2006 Zo6 in black.