Deep Engine Thoughts

I was watching an episode of Graveyard Carz today where they were doing the dyno runs on an original Daytona and a 2016 Hellcat. Of course the Hellcat blew the Daytona away. The comment was made repeatedly about technology being the reason. So what is the difference? The basic short block is still the basic short block. Technology would have to have effect in head design, fuel delivery (EFI), ignition management, and camshaft design. So....what would prevent all of this technology (minus the supercharger) being applied to a 383 and ending up with a 500 hp 383 that gets 22 mpg on the highway?

Somebody with enough money to adapt variable valve timing, spark timing, EFI and all the needed sensors and management system would need to put it all together to find out. It wouldn't surprise me if there's been a lot of work on reciprocating weight as well.

By Stuart Smalley... It's called engineering. It's really cool at FCA. Computers and their related 3D and "real world" simulations have everything down to the elephant's a$$. In the next 25 years they'll get it down to the zebra's a$$ and so on and so forth. Don't know if I'll be around long enough to see the gnat's a$$...The DEMON makes it all worthwhile. I can't believe they actually sell a car that will do a WHEELIE!!!!

Extra mpg is likely from the transmission (# of gears and ratios) and a little from EFI. I don't think EFI by itself is any sort of huge power gain. It's just less wasteful vs a carburetor.

New engines have pistons with much shorter skirts and cranks and rods that are lighter. If you rebuild an old engine with modern aftermarket parts you'll have the same advantage.

Cylinder heads have come a long way vs the originals.

Old engines have cast iron exhaust manifolds that don't flow well. New performance cars have headers of some sort.

There are numerous ways to get an old engine to have amazing power on the street (even on pump gas), but people play it safe, or do what their old school machinist likes to do, and that is build 9:1 engines using .030 oversized heavy cast replacement pistons, stock connecting rods, etc. Being conservative and sticking with original parts is how you end up with a car that runs about as fast as it did when new, or worse if you put too big of a cam in it. I have seen rebuild 440 powered cars in town that struggle to get out of the high 14 low 15 range and still get crummy mileage.

Neil, so reduce the balancing weight & better heads. Are you thinking more SCR (than 9-1), with quench to help with that?

The architecture of the heads makes all the difference in the world.

Add in the lighter reciprocating assembly, modern coatings, cam technology, and electronics and you're dealing with a whole new beast.

Comparing our B/RB engines to Gen III hemis is akin to comparing a flathead ford to a 5.9 Magnum.

Combustion chamber shape is where a lot of the efficiency comes from. The fast burn shape takes in some cases over 20 degrees less timing which reduces pumping losses considerably. The EFI and VVT is icing on the cake.

Kevin

Yes, I'm no engine or cam selection guru, but if you think about it most of the old stuff had more than 9:1 compression originally and then they get rebuilt at 9:1 or less to survive on todays gas. Once you add an aftermarket cam with a bunch of duration you loose bottom end and gain more up top. Problem is if you use stock heads they nose over just when the cam starts to get going.

You can crutch the too big cam situation by adding steeper gearing and a high stall convertor to get the engine into the upper part of the power range faster, but that can kill streetability as well.

My brother has build several Oldsmobile engines at 10:1 with factory iron heads and a moderate cam and they run fine on 91 octane here. If you listen to the machine shop guys they will tell you not to even try it.

Well let's not forget the elephant in the room....The Hellcat has a supercharger.

Sure, a modern NA GenIII Hemi with all of the other modern gee wizz engine design and support management gadgets would out HP per CID the Daytona's 440, but not by nearly as much as the supercharged version.

Airflow through the intake ports of the cylinder heads has been improved a great deal. That accounts for about 70% of the peak horsepower gains since 1970.

On supercharged engines
intercoolers have made a big difference.
The scientific discovery that air/fuel charge temperature has a far greater effect on detonation
than charge pressure or
time of burn
led to big hp gains.

Fuel efficiency of engines only has not improved at a fast rate:
0.7% per year,
for a measly 7% per decade.

MPG of vehicles has improved more than the snails pace of engine efficiency
due to low rolling resistance tires and
aerodynamic Cd going from 0.6 to as little as 0.26
and taller gearing approaching a ratio of 40 mph for every 1000 rpm.

14 mpg cars have been around since the 1920s.
The 1937 model year VW bug was a 40 mpg vehicle at 50 mph.
Todays 30 -ish MPG five passenger cars at 75 mph are not really that much better.

Gasoline "real prices" are also more constant than first appears.

32 cent per gallon gasoline
when vending machine Coca-Colas were a dime,
and a Troy ounce of Gold sold for $36
or a Troy ounce of Silver for $3

Is not too far off

240 cent per gallon gasoline
when vending machine Coca-Colas are $1.25
and an ounce of Gold sells for $1280
or a Troy ounce of Silver sells for $17

Two other items not mentioned are the low emissions and the longevity of modern engines.

Lots of little things plus some big ones add up maybe?

A stock'ish 383 bottom end can carry 500 HP so OK there. Cylinder head flow matters. The G3 Hemi has more. Compression and chamber design matters, the Hemi has better. For MPG, transmission and torque curve matters. 6 or 8 gears vs 3 or 4. Also variable valve timing and variable intake to help low RPM performance. MDS also helps when "loafing". Also aerodynamics helps a lot. Also EFI which handles different gas blends well and allows close tuning for WOT and cruise.

A BB can make the power and with some of the tricks above get OK mileage. Mine does!

Still hard to get both the power and efficiency combined of a newer design engine.

Thanks guys. I was hoping I would get some thoughtful responses.

Gas real prices are off quite a bit. Going by 360view's example,
modern coke price should be 75 cents, or gas should be 4.00 going the other way.
Gold should be $204/oz at the same silver to gold price ratio. Either gold is way overpriced (my opinion), or silver is way under priced (I believe it's a more accurate indicator).

Lets not forget the lower tension and thinner piston rings which reduce the friction considerably. Also I am sure engine oil technology plays a small part.

Reduced ignition timing reduces negative work, not pumping losses. Using more power to push down the piston in the right direction increases efficiency.
Nobody has mentioned cylinder deactivation, this made quite a difference when adapted to the Hemi.

Computer optimization of systems has greatly affected mileage. One example is the automatic transmission with 8 speeds which selects the right gear to go with load to keep the engine in the right area of the efficiency map. This takes a lot of design time, plus the supersmart computer sitting behind the glovebox. Electric power steering eliminates the drag of the PS pump and averages the load caused by the steering assist through the battery. Better bearings in the wheels, along with disk brake systems that retract the pads when not braking, are advances that happened years ago.

What I find impressive is the performance and fuel economy that we get from cars that are physically larger and at least 500lb heavier than those of 1970. Look at the 4500 lb Hellcat vs the 3900lb Challenger R/T. Same for the Z28, the 1970 version at curb weight 3340lb, the 2014 curb weight at 3862. Yet the porky 2014 outperforms the 1970 in every category, same as the Hellcat vs R/T.

Amazing!

R.

On gas mileage you have to remember the new cars with computers and EFI can control fuel mixture and timing so closely to get about 14 to 1 ratio at all times for good mileage and great eng power through all rpm ranges. Its unreal how fast the new technology works on the computers of todays cars. And the engines are built to take more power then the older muscle car era engines. I mean the Hellcat bottom end can handle well over 700 hp with stock parts. And the technology of the turbo and superchargers of today are so much better then the 70's that they can sell supercharged engines with great power that stay together. But as was said the biggest power maker of today is the boosting of engines. Supercharging adds so much more power its unreal. Take a SRT-8 Challenger or Scat Pack Challenger today and it should run mid to high 12's all stock with a good tire. Add the supercharger and run high 10's on a good tire. I remember some years back Mopar Muscle dyno'd a crate 360 eng at 359 hp. They added a supercharger to it and still used a carb and with 8 lbs of boost were over 600 hp as it nearly doubled the eng hp ! But I still love building the older engines with some newer parts like aluminum heads and making some good hp N/A. Ron

Probably best to compare the 6.4 apatche

Also one thing at a time strting at the bottom

Much Lighter crank with smaller journals.
Much lighter rods with a narrow smaller diameter bearing.
Much lighter pistons, much shorter compression height has less friction, also has less friction from teflon coating. Much thinner rings for less friction(this one may be harder to retrofit more on that in a second). Smaller wrist pin is much lighter and smaller for less friction and I think the 6.4 is a floating pin.
All that adds up to a rotating assembly probably slightly over 1/2 the weight.

Much better oil control (this is why the thin rings work so good), the new hemi has all the oil from the head diverted outside the block down through big passages cast on the outside and they dont drain freely into the pan till they are below the windage tray witch also is much better at scavenging oil from the rotating assembly. Another thing is the much tighter tollerances in the bearings and piston fit, much less oil flows through them and they are much more round and less taper.
This all adds up to a lot less oil flinging around on the cylinder walls and crank. If the rings are not drowning in oil they can keep it out of the chamber easier with a thinner lower tension ring. It also has a dykes style second ring for even more efficent rings.

The cam is larger diameter to make it more rigid and it is higher up in the deck to give a lot shorter lighter stiffer pushrod. Also the VVT helps a bunch, it eliminates the need to a EGR valve to keep cylinder temps down, it just retards the cam timing to bleed off cylinder pressure, this retarded cam timing allows the cylinder pressure to also push on the piston a few degrees longer to make a little more use of the fuel that was burned. Thease aspects of the cam are all gonna be a challenge to retrofit into your 383.

Onto the valve train, the pushrods I mentioned already are very light, the valves are small diameter stems and also very light, the small guide also reduces friction and increases air flow. The behive springs have a very light retainer and keepers. All this light weight stuff means less spring pressure is needed to control the valve and that also reduces friction. Also those behive springs tend to be better at reducing valvetrain harmonics again meaning less pressure needed. With some money thrown at your 383 you could greatly reduce the valve train weight.

The combustion chamber is insanely better, 2 spark plugs nearly centrally located instead of one at the very edge of the chamber. Dual squish pads. Valves that moves away from the cylinder wall as it opens instead of staying right next to it. Also they are aluminum. You could buy some trickflow heads to improve on the metal choice, squish/swirl part of the chamber and offset the head location to improve valve location over the piston but it gets complicated to do much here but at least air flow would be much better than your 906 heads.

The intake is much better than anything out there for a 383, long, equal length, high flowing, gently curved runners, plastic to keep the heat out of the air, MPI for perfect air/fuel distribution... maybe you could get a 3d printed plastic one made for your 383?

The MDS would be nearly impossible to incorperate.

Crank driven oil pump is nice, it means less load on the timing chain and no drive gear train to wear (less moving parts is always nice and makes things quieter).

The block is much more rigid so less flexing of the cylinder walls for better sealing and less friction on the crank from distortion of the bearing housing.

COP is better than a distributor because there is going to be less flex and vibration in the cam and timing set as timing is measured directly from the crank. Coil on plugs could be done, they allow more precise timing and lots hotter spark because you don't have to worry about arcing in the distributor cap and each coil can recharge longer before it discharges and the shorter path from coil to plug means less resistance.

Then you add in the sealing improvements like one piece rear main seal, awesome steel core flat pan gasket, rubber o ring type valve cover gaskets, o ring intake gaskets, no open oil under the intake (also helps keep heat out of the intake). O ring style timing cover gasket. O ring water pimp gasket...

Many of the improvements work together to allow a much higher compression ratio that also improves HP TQ and MPG.

You could add a bunch of the improvements to your 383 but they will cost a fortune and some are just not reasonable to bother trying.

The awesome MPG comes from the modern engies ability to make TQ very smoothly and effortly at a very low RPM and the modern drivetrains ability of keeping the RPM low when power is not in demand and then it can switch to lots of TQ multiplication at a moments notice.

The guys at Graveyard are not engine builders so don't put too much stock in what they say. I have a 514 engine sitting in my shop that makes 900 hp. It has EFI and 8 coils so I can adjust fuel and ignition for each cylinder. If that engine was in a car with a 6 speed transmission it would probably get decent mileage going down the road. With EFI you can just lean it out and advance the timing and get the engine super happy at cruise.

Modern engines have a lot of work put into them to make them efficient. Most of those tricks can be applied to older engines. Tighter clearances, lighter weight oil, better head design, computer controls, etc. About the only thing you can't do with the older engines is retrofit variable cam timing. The variable cam timing really opens up the door to building an engine that idles like a sewing machine but really rips at WOT. With fixed cam you have to just live with a compromise for the overlap and it hurts you either top end or bottom end.

Here is the engine in the Duster that I'm building for a series in Car Craft. This engine makes 700 hp on the dyno but it should run down the road just fine. The idle might be a little aggressive since I don't have variable cam timing but it won't be bad. It will idle better than 90% of the hot rods out there that have a carb and it will get better fuel economy. Very, very few guys know how to tune an engine better than the feedback loop on an EFI computer.

It will get about 4 mpg. DOUBLE what I get in my Dart with a 4150. The old cars were great because they were topped off daily with cheap primo before going home from work. The gas stations were always full of bull, especially when you drove in to the isle, driving a striped, muscle car with high impact paint. At night, under the lights, was even cooler. Stopping for a cold beverage wasn't unheard of. So my take on this is that if you are going to daily drive an old car, with any "performance" mods at all, get ready to pay the piper. Even the newer, high powered cars burn GAS! Big time! You might get 20 idling down the road in overdrive in a new Corvette. Only because I think it would be the lightest of the bunch. I know nothing about foreign cars and their engines.

This thread and its posts touches on another important question:

How much are EPA regulations on automobiles alone actually costing the typical citizen?

How much $ would be saved by the typical citizen if their vehicle's engine was optimized for fuel economy?

Another related question:

How much UP
would NOx, CO, and HC go
if all engines were optimized for fuel economy?

It might be a small percentage increase like 10% to 20%
and that might be only for NOx..

Hidden things are bad for Democracy.
This is a general principle.
( there can be exceptions for Military Security)

When you buy fuel it is hidden from you how much extra you had to buy due to the EPA.

When you buy a product or service it is hidden from you how much of the price was due to the 35% Corporate Income Tax.

I think the variable valve timing, efi, variable tuned length intake runners and overdrive transmissions all help keep the modern engine near it's peak efficiency during normal driving and peak power production at full throttle. Newer engines have a less internal drag, are smaller displacement and make less power in the bottom end that our old big blocks. But the gearing and transmissions in the newer cars do a lot to keep the rpm up when you put your foot into it.

Well, efficiency is relative. Here are two heavy hitters.

My father has a 99' K2500 4x4 Suburban. Gen VI 454 BBC. It's rated at 290hp @ 4,000 RPM & 410 lb/ft @ 3,200 RPM. Vehicle weight - 5,600#. 4.10 gears with 31" tires. 4l80e transmission (4 speed).

I have my 15' Ram Power Wagon. 6.4/392 Hemi. It's rated at 410hp @ 5,600 RPM & 429 lb/ft @ 4,000 RPM. Vehicle weight - 7,000#. 4.10 gears with 35" tires. 66rfe transmission (6 speed).

BOTH of these trucks get 10mpg around town. Both get nearly identical fuel economy on the interstate. One weighs 1,400# more than the other, and makes 120 more HP and 19 lb/ft of TQ. Cylinder deactivation rarely if ever occurs, as I leave my truck in tow-haul mode. This shows how efficient newer drive lines truly are, even a watered down 392 Hemi with eagle heads (not Apache) is relatively efficient, for the most part, due to having 6-gears versus 4-gears.