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Old Engines are inefficicent at creating power/torque,WHY?
3

Old Engines are inefficicent at creating power/torque,WHY?

Old Engines are inefficicent at creating power/torque,WHY?

(OP)
Why do old engines produce such little power for their displacement, for example, the 1968 426(7.2L) hemi produced  425HP.The modern 6.1 L hemi produces about 425 HP, the same as the 7.2! Why is this?

RE: Old Engines are inefficicent at creating power/torque,WHY?

Because for the last 40 years engineers haven't just been sitting on their bums playing on the internet.

Notice the rpm at which max power is developed - that's increased due to better materials, and perhaps better structural design.

The torque at max power has increased because you've got 4 valve heads, or better cams, or better porting, or better header tuning.

Every cylinder actually fires every time. That is a big help. Every cylinder has roughly the same mixture in it. That is a huge help. The cams actually open and close when the designer thought they should. That helps.

Also, no cold spots on the cylinder walls, able to run higher cc temps due to materials again.

But basically, 40 years of competition and hard work.

A cynic might ask why with hundreds of millions of dollars spent is the specific output of the new engine only 16% better than the old one?

That's a much funnier question.

 

Cheers

Greg Locock

I rarely exceed 1.79 x 10^12 furlongs per fortnight

RE: Old Engines are inefficicent at creating power/torque,WHY?

and...

Better understanding of the mechanicals (rings, bearings, etc) relaxes self-imposed longevity limits.

- Steve

RE: Old Engines are inefficicent at creating power/torque,WHY?

better oils and fuels also helps as does electronic controls which is what produces the results Greg states re reliable ignition and uniform mixture.

A big gain has been manufacturing technology to greatly improve precision and complexity at lower real cost.  

Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Old Engines are inefficicent at creating power/torque,WHY?

Something else you might consider, are the insurance issues; back 'in the day' the rated horsepower contributed to your insurance payments. The hemis ,the tri power 440's ,the crossbolted Ford 427's, and the Chevy 427's of this era were all under rated.

can't vouch for this link, but it seems reasonable.

http://www.ultimatecarpage.com/forum/general-automotive/33343-actual-horsepower-60s-70s-muscle-cars.html

RE: Old Engines are inefficicent at creating power/torque,WHY?

Compare bike engines.  In the early 90's 100 BHP was considered ample and almost became a legislated limit (in Europe).  Nowadays bikes like the ZZR1400 are doubling that.  Even the ZX10R is putting out 180+ BHP from a litre.

- Steve

RE: Old Engines are inefficicent at creating power/torque,WHY?

Thruthefence--I am having a hard time believing the explanation in the link. I was always of the opinion that the horsepower ratings at the time were SAE gross. If so, the ratings would have been determined by a standard test procedure and there would be no way to "derate" an engine for insurance purposes, as that would conflict with the test results.

RE: Old Engines are inefficicent at creating power/torque,WHY?

swall, there are all sorts of ways to play games with this, both then and now. That was an era of mechanical (points and breaker) ignition timing, mechanical carburetors, etc. Think "production tolerances". To give but one example, the ignition timing on the factory spec sheet, and the ignition timing that the engine shipped with, and the ignition timing that actually gave peak power, can be three different things. Sometimes you can game the test procedure, too. If the official test procedure calls for stopping the test at the manufacturer's specified maximum RPM (remember, that was an era before rev limiters), then you just specify an artificially low maximum RPM.

Modern engines are built to tighter tolerances and have fewer adjustments ... but games can still be played.

The difference between SAE gross "back in the day" and modern SAE net corrected figures makes the difference in specific output from then to now bigger than it first appears.

Improvements in other areas besides peak power are more impressive. Fuel consumption, for one. Back then, anything with 200+ horsepower got 7 mpg. The reduction in emissions is spectacular by comparison. And then there's durability, driveability, cold starting, etc.

As others have noted, engineers have been doing something in the past 40 years.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Agreed that time does not stand still, ESPECIALLY for the engineering professions.  However, it's the huge advancements in electronics that are responsible for much of the gains. That and manufacturing technology advancements, also in part because of modern computers and electronics.

A blanket statement that old engines make so little power...
Take a peek at some of the early 1920's Indy engines.  DOHC, 4 valve, duplex supercharge/turbocharged, methanol fueled, etc.  As for machining complexity...try the Jumo 211, DB 601 or, RR PV-12 Merlin.  I've seen the internals of all three and they do not lack for any deficiencies in machining. Especially the Jumo...it is like a Swiss watch.

Your right, Greg.  WHY aren't we further along the curve?

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

WHY aren't we further along the curve?  Because they limited themselves to a long stroke OHV pushrod port injected configuration.  For a more modern layout, look at the 4.5 l V8 in the new 458 Italia.  570 hp naturally aspirated, 127 hp/l vs 70 for the hemi.

RE: Old Engines are inefficicent at creating power/torque,WHY?

(OP)
Thanks guys, I'm buying a 1968 GTO, my first car. It has the stock 400 engine with the TH400 tranny, it produces about 350hp, is there any way to get more horsepower from it? I know i could buy new parts, but i just mean modifications i could make to the existing engine.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

No problem, mechanicat16...It's a simple formula.  Just remember---Horsepower is directly proportional to $$$ spent.  More $$$, more HP !

As to the OP, the 426 Hemi Superbird that I had the chance to see run up on a chassis dyno made well in excess of 425hp AT THE WHEELS! You need to brush up on the "politics of the era".  Big brother had a BIG influence on published numbers!

Since you specifically ask for advice---From someone who has BTDT---Stick fairly close to the stock setup for your GTO.  The closer to absolutely stock you can make it will pay dividends further down the line.  You can get by with a mild hydraulic cam setup, maybe a set of headers (keep the original stuff)...dual exhaust with the stock exhaust manifolds works just as well on the street, though...and, a good Pertronics or similar electronic ignition.  That's about it.  You will have more power than you can ever use on the street.

"Why aren't we further along the curve"?  Wow, DG.  Perhaps I was being TOO subtle!

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

Then there's materials.  There haven't been too many new ideas in the last 40+ years, just ideas that are now practical.

- Steve

RE: Old Engines are inefficicent at creating power/torque,WHY?

Rod - I always thought horsepower was proportional to dollars cubed.  

And I agree about keeping the 68 Goat close to stock & keep all original parts if mods are made.  Look at the Barrett Jackson auctions, it either has to be a really wild custom or totally original restoration to get top dollar.  Typical backyard hot rodder mods will kill value.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Pontiac made some seriously good cylinder heads and other go-fast parts back then, under their Super Duty label.  These are still around, VERY pricey, but in general will not detract from resale value (to a collector) the way an Edelbrock or Weiand part would.  (Save all your original parts!) A friend with a '66 Goat just picked up a desirable set of 455 heads, and had them freshened by a Pontiac specialist.  He has over $2500 into them, and they won't do much good without the related parts (manifold, cam, etc).  

Do you really need more power anyway?!

RE: Old Engines are inefficicent at creating power/torque,WHY?


I believe back in the 60's that the High Priest of Horsepower, Reverend Mr. (Keith) Black stated that "How fast you go is directly proportional to how much money you spend!"  As we could not afford one of his drag motors we were not quite as fast as others less fiscally challenged.  

Back then, the cost of insurance would go up with the HP rating.  So, many were labeled with lower than actual net and way under the gross HP ratings.  Part of it was to make it more affordable for the typical young, barely insurable (remember assigned risk?), wanna go fast car buyer.  If I recollect, a magic number was 300 HP, which my '69 Z/28 Camaro, with a 290 HP sticker on the air cleaner, just got under.  With a '71 Z/28 I gave my insurance guy the 275 net rating instead of the 330 gross and was able to avoid the factory hot rod insurance penalty again.  

Mechanicat, it has been said already and I will say it again, if it is totally stock, leave it that way or make only reversible modifications, keeping the original bits.

Yosh
   

RE: Old Engines are inefficicent at creating power/torque,WHY?

In the old days gas was cheap, they didn't have to worry about being effcient. And when you say old engines, you need to be more specific, because the automotive world of engines has taken years to catch up to what the aviation world was. Huge difference there too, automotive engines usually only run at 20% of capacity when driving down the road, aircraft is more like 80% or so, kinda like any continuous industrial application like a pump or generator, the HP usage is constant. The only time you need HP in the automotive world is accelerating and passing.
I also agree about those big auto engines of the past being under rated for insurance reasons.
Another reason they would not rate them or make them output more HP is most all manufactures then had a performance parts division, and to sell hot rod parts you don't want to make the stock engine that great, else your performance parts department would not be a needed entity.
And its taken the after market to figure out how to make such things as high flow cylinder heads, that has added greatly to the increase of HP in the auto engines of today.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

To get back to the original question: Cars from the 1960's were carburetter types - a carby must always have some pressure drop across it to draw the fuel in - lowering the VE. (and generally quite a bit of air flow restriction in the carb to make the cars more "driveable"). Modern electronic fuel injection systems don't have this problem. Also most manufacturers have taken advantage of the port injection etc. to use tuned length intake runners which add to the power. The FI use alone probably adds 15% or so to the torque/power.
  Two engine types that make an interesting comparision are the small-block Chevys and the modern LS1-type engines. Both are pushrod, both 2-valve but the LS engines make far more power more easily than the old engines.     

RE: Old Engines are inefficicent at creating power/torque,WHY?


Something that you have to consider is how much influence the bean counters had on what made it to the showroom.  Making more HP out of the same size envelope takes better materials along with more engineering and manufacturing sophistication.  There were people at the Big Three that knew how to make plenty of power with smaller packages.  How to get it made at a required price point was probably an insurmountable challenge.  Now, with fuel economy as a major influnce on design, smaller, lighter engines that can make more power with less fuel are a necessity.  Of course, this ups the cost.  Oh boy, to remember that a '57 Chevy with a fuel injected 283 was about $2000 new, and now??

Yosh  

RE: Old Engines are inefficicent at creating power/torque,WHY?

I always found it ODD that throughout the 60's, the engines were getting larger, the cylinder heads better, the camshafts hotter, the compression higher, but peak HP stayed right at 425hp.  

One exception was the Chevy ZL-1, which allegedly did make an honest 435hp.  Yet, remove the log exhaust manifolds and install headers, and it would jump to 550-575hp.  

Or, how about all of the Quadrajets that had little tabs on them that prevented the secondaries from opening fully?

And then there all of those Japanese market cars that happen to make exactly 276hp, and the same engine in the US makes 300, 320hp.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Improvements in specific power are surely due to the many factors mentioned above, such as materials and technology improvements. In addition, here in the US especially, gas was cheap. It is still cheap compared to much of the world.
So, why should I spend $$$$ on a little motor that makes lots of power, when I can spend only $ or $$ on a bigger motor that does the job? That bigger motor will probably be cheaper to fix, and may even live longer. The initial cost of that nifty 'efficient' motor may totally eat the savings in fuel down the road.
Economic/market competition has given us lots of great choices out there...
cheers
Jay

Jay Maechtlen
http://home.covad.net/~jmaechtlen/

RE: Old Engines are inefficicent at creating power/torque,WHY?

Just curious. What better materials are used in the basic auto engine of today?
It seems pretty much the same stuff of the good old days.
The biggest improvement is induction and exhaust systems from and to the cylinder, accurate ignition, tight control of A/F etc.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

I can't think of any 60's engines that used molded plastic intake manifolds, with or without variable runner lengths.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Finite-element design techniques were either nonexistent or in their infancy back then, also. The materials in structural applications (crank, rods, pistons etc) might be the same or very close, but modern designs make better use of the capabilities of those materials.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Piston to bore clearances are a lot tighter now. I presume because of better shape and design re skirt flex, but also due to alloys and heat treatments that reduce expansion.

Surface coatings also aid in this tight clearance technology I think.

The relatively reduced cost of higher precision machining is a major area of improvement

Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

This discussion almost touched on one of the most important, often overlooked, considerations for "street power".  You see enthusiasts, such as the "rice burner" crowd spending thousands of dollars to up the net horsepower of their tiny engines.  Some of these engines make considerable HP at a particular high RPM, without most realizing that the narrow band of torque improvement results in no really practical way to harness, given the transmissions in use.  (i.e. narrow band torque in a wide band transmission...)  

RE: Old Engines are inefficicent at creating power/torque,WHY?

That's more of a matching problem.  Traditional auto boxes work best with lumbering agricultural low-revving engines.  Stick them on a modern, efficient, high revving engine and you end up with an undriveable dog.  Stick them on a slick, 6-speed manual and you have a driving machine.

- Steve

RE: Old Engines are inefficicent at creating power/torque,WHY?

Quote:

WHY aren't we further along the curve?  Because they limited themselves to a long stroke OHV pushrod port injected configuration.  For a more modern layout, look at the 4.5 l V8 in the new 458 Italia.  570 hp naturally aspirated, 127 hp/l vs 70 for the hemi.

We aren't further along the curve because, in my opinion, manufacturers are more interested in meeting fuel economy numbers than having large peak power numbers.

Sure, Ferrari makes some impressive engines. But then I'd expect nothing less with the price their cars cost. However, looking at the numbers doesn't impress me a huge amount. That engine is just built to rev quite high to get the large HP numbers - HP is proportional to T x rpm. I have a few user modified Corvette's with "crappy old school" pushrod engines which would have fun playing with that Ferrari and those Corvettes didn't give up much drivability or fuel economy to get the big power numbers they have.
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

I'd like to point out that the displaced volume is a rather arbitrary means of comparing engines. Personally I thought outright mass or geometric size is a much more relevant comparison. Doesn't sell as well on the paper perhaps, but I for one am extremely impressed with the LS7's mass specific output, at roughly 480lbs, fully dressed with alternator, power steering pump, AC pump, etc, I think outputting 505hp is extremely impressive, and a much more relevant way to compare powerplants.

When picking a prime mover for a project, the power to mass ratio (watts/gram) is a much more relevant concern than the power/cylinder swept volume.

RE: Old Engines are inefficicent at creating power/torque,WHY?

I think an excellent example of this metric (power/mass) is one that totally shocked me;  they are selling kits to put LSx engines in Porsche 911's!  In the rear no less!  The kicker?  The LSx engines weigh LESS than the Porsche turbo engines!

YouTube has plenty of videos of these.

RE: Old Engines are inefficicent at creating power/torque,WHY?

I've seen some of those engines ya. And yes society seems so caught up in the cylinder swept volume that they neglect the more basic metrics. There seems to be an assumption that an engine with a larger swept volume will be massier. Altho you take that little 4 cylinder box 4 turbo, and start laying turbochargers, intercoolers, block braces into it. The mass starts to rise very quickly, not to mention the fact that it's running 4 cams where the GM V8 is running 1. From a power to mass standpoint it's usually "cheaper" to just sweep more volume than it is to add more gizmos. Not to mention you generally get a very favourable power curve as a bonus.

Faye Taylor would be spinning in his grave if he could see the directions we've developed down in the last 10 years.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Junior - engine displacement is at least a rough indicator of potential output.  Whether a given engine design specifically targets up toward the "ultimate" potential or somewhere lower on the scale is an entirely separate question.

Mass specific output is fine for comparing engines "in a vacuum" (figuratively, of course).  But output per unit engine mass indicates little about how any given engine will be perceived when in service.

Ignoring forced induction applications, specific torque (peak) doesn't vary a whole lot either way from a little over 70 ft-lb/liter.  Meaning that a first-cut estimate of acceleration based on torque, gearing, and vehicle mass isn't going to yield comparative results all that different from what you'd get using engine displacement, gearing, and mass instead.  Gearing can be dropped out if the vehicles being compared are reasonably similar in that respect.


Norm

RE: Old Engines are inefficicent at creating power/torque,WHY?

2014 - FIA and NASCAR invite Mars to compete in the earthling Formula 1 and NASCAR series for the 2015 season. The three leading Martian constructors say sure, as long as they can use the 16 liter piston type engines they've developed for their equivalent auto racing series whose rules that stipulate a limit on engine power/engine mass.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Norm: I concur. BMEP and Piston speed is the fast and dirty way of calculating a rough estimate of power output. But even that method shows very clearly that a higher bore:stroke ratio is going to net you a higher amount of power with the same BMEP. Sadly there's a lot more to engine design than just peak power. I mean there's certainly a place in the enthusiast crowd for dyno queens, but general consumers also care about how it feels to drive, whether it gets good fuel mileage (which is generally in good proportion to the mass.)

10-14 bar BMEP is the rule of thumb I use. The 70ft*lbs gets tricky, I've dealt with 2-stroke motocross engines that when set-up properly make nearly 4 times that.

RE: Old Engines are inefficicent at creating power/torque,WHY?

The 426 hemi was ADVERTISED at 425 hp for insurance/liability reasons.  Ever had one on a dyno?  My brother, who is the Mopar authority in the upper midwest, has seen a bone-stock hemi dyno at over 800 hp.  This motor is insane!

RE: Old Engines are inefficicent at creating power/torque,WHY?

I've seen plenty of dyno runs on the MoPars with 426 hemi's back in the day, freshly broken in, none of them approached 2 HP/c.i. This kind of test was a monthly feature in Hot Rod, Car Craft, et al every month back then. ('69 - '72) They were "conservatively rated" but I've never heard of it being anywhere near 1/2 actual. 454 Chevies of the period were routinely reported in the mid-400's at the crank (stock, absorption dyno, corrected, etc.), hemi's were not that much better.

I'd be curious to see what a decent modern DIS system by itself would do to those dyno figures!

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

To add to Greg's post:   
Imaginary or computer?

I'm with you, Ross.  I saw a crate motor 426 run up and, while impressive, it only made a bit over 500 hp. At the time everyone was jumping for joy...Most did not do that well.

Did get to see an 800 plus on a dyno...looong time ago.  One of the Pitman bros. 390 blown Chrysler's.

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

I ran 800 HP on an absorption dyno 30 years ago but it was a 1000 in3 turbo diesel V8.

RE: Old Engines are inefficicent at creating power/torque,WHY?

I'll have to pry some more info out of him.  I know the 426 was derated by the factory to keep it under 1hp/cu in.  The Hotrod and Car Craft editorials are not exactly white papers, either.

Just as an interesting side note, the 8000 hp mark has been breached by an aftermarket hemi (496 cubes) running nitromethane, and obviously tweaked a bit more than what you would have gotten in '64 or '65.  I'll see if I can dig up my references on it.

But anyway, 2 hp/in3 is not rocket science, and easily obtainable in a streetable motor.

RE: Old Engines are inefficicent at creating power/torque,WHY?

"But anyway, 2 hp/in3 is not rocket science"

True, that's on the wimpy end of rocket science. ;)

RE: Old Engines are inefficicent at creating power/torque,WHY?

Quote:

But anyway, 2 hp/in3 is not rocket science

On pump gas?  Totally stock in the late '60's/early '70's, with (single or dual?) carbs, and point ignition?  Factory exhaust manifolds?  "Totally stock" I take to mean "as delivered to Joe Average by the corner Plymouth/Dodge dealer".  Not some skunk works factory blueprinted and tweaked drag engine.  Totally stock as I've described, 2 HP/ci was indeed rocket science back then for a normally aspirated OHV engine with pushrods a foot long.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Not talking about 2hp/in3 as a stock delivered motor.  As streetable, I mean one that you or I could build in our garage with available aftermarket parts, and actually be able to drive it with commonly available fuels.  I'm on a different train of thought here than my first post in this thread.

RE: Old Engines are inefficicent at creating power/torque,WHY?

IIRC, the late 60's Trans-Am 5 liter engines eventually put out 475-ish HP.

It was a big deal when HRM ran an article on a small-journal SBC build-up that made 572 HP (early 1970's).  Around 5.4 liters.

I think there was one tiny V8 (OHC) that claimed 240 HP from 2 liters at some time in the 1960's.  In the context that Italian dynos of the time were commonly suspected of being calibrated using small horses.

None of those engines would be considered daily-driveable, and the pushrod ones still fell short of 1.75 HP/in^3.


Norm

RE: Old Engines are inefficicent at creating power/torque,WHY?

We're getting 600+ hp out of Mopar small block 360's, no blower, carbureted, pump gas (maybe a little avgas to help retard detonation). No NO3 or anything tricky.  Mind you, Grandma isn't going to be using it for thursday bingo or picking up kitty food at Walmart, but it is street driveable.  Yes, we do need to put TALL valve covers on them.  You don't do this kind of thing with a small block chevy and expect things to last very long.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Okay...I have a couple problems with confirmed readings of ~8000 hp from > 500 cu. in....To start, where is the engine dyno that reads that high? Or is it just "guesswork"?
Largest dyno I have seen was testing a RR Merlin race engine for a P-51, about 4000 hp.  I don't recall anyone publishing data on fuel diggers.  I know that the claims are all in the big numbers and, I agree with some...I just don't agree with 8000 unless I see some supporting data.

Two...On pump gas?  91 octane pump gas?  600hp from 360 cu.in.?  Several 600+ hp street cars out there, I agree.  However, NOT 360's.  Most are 500+ cubic inch monsters.

Perhaps I have been on the left coast too long and have missed out on the automotive revolution back east.

Rod

 

RE: Old Engines are inefficicent at creating power/torque,WHY?


The 475 number is about what Traco was supposed to have been getting out of their Trans-Am 302 CSB according to what I remember.  A well tuned in-the-car stock Z/28 would  be around 375, sometimes a bit more.  The Penske cars were another matter.  A combination of motor, drivetrain, chassis, body and mystery(??) modifications.

Could be that those Italian dynos were calibrated with a team of AGIP, Ferrari's fuel sponsor before Shell, six-legged dog from their logo.

Yosh
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Hi Evelrod,

I've been trying to find a link on the web for you, no luck just yet.  The 8000 hp monster I mentioned is being measured/extrapolated with torque sensors, and I don't know that the data has been certified third party yet.  I have just bits and pieces myself, but I've heard that they're running in the neighborhood of 50+ psi of boost from a roots blower, force feeding a gallon per second of fuel (injectors in the blower hat, intake runners, and cylinders) at some over 8000 rpm.

In regard to the 600 hp 360's.  We have twisted driveshafts, snapped u-joints, and exploded transmissions with these things.  We had a 72 Satellite (big and heavy) that would toast anything less than a fueller from a dead start.  The hardware is all mostly straightforward, it's the timing, mixture and ignition that is critical.  Can't do it every day either, the weather plays a huge factor.  There are days when we're down 50 hp or more.

RE: Old Engines are inefficicent at creating power/torque,WHY?

My own website?  Hmmmm. You give me more credit than I deserve.  It has taken me nine years here on ET to figure out how to post a photo.  ;O)

I can make an engine from an idea...I cannot make this infernal machine do anything without help.

Rod

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

800hp factory stock Hemi? I don't think anyone here, besides you, believes that one.

A bolt together in your garage parts kit to get a 600hp 360 that runs on pump gas? This could be possible but it would be very difficult. Even "new school" engine technology does not make this a easy feat for a naturally aspirated engine.

Can I borrow your dyno to do some testing?  Or do you only allow the "big HP" Chrysler products....
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

My son is up in NorCal at this moment picking up one of our Lotus/Cosworth DOHC, two valve engines.  It made 197hp @ 8500 rpm from 1594cc!  I have had a hand in a Cosworth BDA 1600 that made 240hp, but its a FOUR valve DOHC and injected. Those numbers certainly would have been suspect 40 years ago (I was able to get 165hp from this very same engine in 1967) when those engines were fairly new. (Supercharged 2 litre versions of this engine have been in the 1000 hp range for several years...yeah, time marches on)

So...   Agreed that time marches on and things change. However,I'm sorry, but 1.7hp/cu.in. in a NA, two valve, pushrod domestic V8 running on 91 octane gasoline is just more than I can accept without some REAL numbers from a reputable, believable source.  I'm sure you are convinced in your belief...So be it.  I choose to remain skeptical until proven otherwise.

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

I think some of the most impressive racing engine figures are from the Oz V-8 Supercars. 5 litre Fords and Chevies, 2-valve pushrod etc. - limited by regulation to 10:1 CR and 7,500RPM limit - and the best ones make 650HP.    

RE: Old Engines are inefficicent at creating power/torque,WHY?

No one needs 600 hp on the street nowadays. Whats the sense? Well maybe a class 8 truck, for sure a car does not.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

They may not need it. But they want it, and they're willing to pay for it.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Some are certainly pleased and prepared to pay for being told they have it. They generally are not nearly so pleased if they actually get it as they find it unmanageable for road work and it generally greatly overpowers their chassis and tyres.

I was involved in one build of a 351 CI Ford Cleveland for a street/race car that was a weekend driver and street class race car.

The guy asked us to build a dual purpose engine and gave us a budget that in the day, allowed stock head and block casting, considerable head work, big SS valves, roller cam, forged pistons, stock crank casting and stock rod forgings with good prep and good bolts etc, after market inlet, big single carby, MSD ignition, avgas 115/145 fuel and a good tubular 4 into 1 exhaust.

It dynoed at 400hp at somewhere around 6500rpm.

The owner was furious at only 400hp, said he already had over 500hp from his back yard built current engine and would not even consider installing the engine.
About 6 months later he blew his old engine and needed to make a race meet next day and make a pass to qualify for some prize money, so he reluctantly fitted it as it was the only possibility to be there with a running engine.

He ran at 1/2 second under his previous best ever time with the worthless 400hp POS.

Moral of the story. There are dynos and there are dynos. There are dyno operators and there dyno operators and there are salesman and there are spin doctors and there are plain BS artists.

Magazines tend to quote numbers from the most self serving BS artists around.

In the day and age, 400 real fair dinkum hp was a very stout street/race American push rod V8 that could regularly beat engines claimed to be 50% more powerful.

 

Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?

Do you doubt the V-8 Supercars claimed 650HP? You can never say for certain - but I am inclined to believe it.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

I never said I doubted the V8 Supercar claim.

I said that for amateur part time racers, big power numbers are often unrealistic or even fraudulent.

I said that for a street drivable Ford Cleveland with stock castings back when, that 400hp was a lot.

V8 Supercars are not street driven and do not use stock castings, do not use a cast iron crank nor stock rod forgings and certainly do not use a single carby for fuel metering.

650hp is quite believable for them.

Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?

I had a 1970 Olds 442 (L69 option) with a 455 4 BBL and turbo 400 automatic.  No ram-air, no eotic parts, but it was well maintained and tuned to factory specs with quality parts.  I have no idea how much horsepower it made, but I suspect it was more than the 365 at 4600 Olds claimed.  I outran more guys with big dollar engines on the street that were carboned up, backfiring, missing at high rpm than I can count.  It would also start and run at temperatures below zero (F) in Buffalo NY winters.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Quote:

So...   Agreed that time marches on and things change. However,I'm sorry, but 1.7hp/cu.in. in a NA, two valve, pushrod domestic V8 running on 91 octane gasoline is just more than I can accept without some REAL numbers from a reputable, believable source.  I'm sure you are convinced in your belief...So be it.  I choose to remain skeptical until proven otherwise.

Ya, I've a few dyno numbers for Vette's with around 450 to 500 crank hp from stock displacment LS1's (350 cu-in) that would still run on Sunoco 94, but I don't recall ever seeing anything at 600hp without a displacement increase.

I see a lot of people who go "I remember back in the day..." and describe how awesome the old American muscle cars were. It's mostly looking back at those times with rose colored glasses. For the most part, the muscle cars from the 60's and 70's had poor chassis and suspension technology and crappy tire technology with engines that needed high octane fuel and badly polluted and constantly went out of tune and tended to quickly wear out, typically needing a rebuild before the 100k mile mark.

To compare, many of todays engines will easily run 200k miles plus with only oil changes and a couple of spark plug changes.

At a car show last summer, I saw a old Charger (probably about 69-70 vintage) that had the whole floor cut out and then the body was welded over a new Charger chassis. That's certainly one way to make an old muscle car perform as well as many people remember they do.

As already stated, every aspect of building a new engine from design to finished product has been improved. Time does march on and better does happen. It'd be naive to think an old engine design will perform as well as a new design. The old design can be updated using the new technology but that's a different arguement.
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Well said Pat.  Mind you, I am known for an ample supply of BS . . . and absolutely, dynos do vary.  But, that said, a fearful amount of horsepower can be wrung from an engine when all the factors are in harmony with one another.   

RE: Old Engines are inefficicent at creating power/torque,WHY?

"Do you doubt the V8 Supercars claimed 650HP?"

No sir, I do not doubt that the numbers they quote are actually numbers they may have seen on their dynos.  Mainly because I recently watched a NASCAR 358 Ford running at 750hp on a Superflow...it was totally strung out, too.

Was what I saw accurate?  Is what the Supercar guys claim accurate?  Are the numbers I just got today on our Lotus/Cosworth accurate?  Probably NOT.  Leave the high hp numbers to the salesmen and the dorks that believe all this crap.  A dyno is only good for comparison.  Anything else is subject to interpretation.

Does all this change my mind about an old school domestic iron block 360 @ 600hp on 91 octane?  Nope.

Rod
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

2
"Why do old engines produce such little power for their displacement, for example, the 1968 426(7.2L) hemi produced  425HP.The modern 6.1 L hemi produces about 425 HP, the same as the 7.2! Why is this? "

I've been involved in the development and homologation of some high performance modern engines. I've recently moved to the USA and have been getting into old American Muscle- looking really deeply into the engines- trying to build GT power simulation models of my 440 R/T DOdge and a 426 Hemi, I also know the new twin plug Hemi very well.

For starters the homologation back then when the 440 6 pack was rated at 390 Bhp and the Hemi at 425 bhp- was optimistic. It's true that the 425 Bhp Hemi was 'under rated' by contemporary standards but if it were re-homologated by todays SAE J1349 or DIN standards it would still be lower than the rated 425 Bhp. (My colleague worked at Chrsyler and has the VE and fueling figures to hand- this is what I'm basing my GT power model on).

back to topic- the reason why things have progressed:

First of- engines breath alot better. 4 valve heads is an obvious one- but even if you compare a modern 2 valver with an older one- the flow for a given port size is alot better so the port mean gas velocity/flow compromise is better optimised.
The next is runner lengths- alot of these cars were running carburetteurs- with an intake manifold compromised for fuel flow distribution AND air flow distribution and no room for tuning. Even in the 80s Chevy ran fuel injected cars with no tuned intake lengths for the normal engine operating range.
Back pressures for alot of the more mundane Buicks and Oldmobiles were high compared to modern high performance machinary. The Aston Martin Vantage V8 has a peak power back pressure of only 350 mbar, an E39 BMW M5 has a back pressure of 250 mbar, looking at an LT1 engined 1996 camaro- I've measured the back pressure at 600 mbar. I know people WITHIN the big three that think that's a Good figure. The intake losses were high on many american domestic cars- the same Checvy LT1 engines thing has an intake losses of 80 mbar. A Jaguar XJ8 has an intake loss of around 33 mbar.

Sophisticated engine management systems have allowed higher compression ratios to be specified with fine knock control.
Cam profile design has come a long way- even staying with the pushrod configurartion- the new LS7 engine has a light valve system mass- a very high rocker arm ratio (1.8:1)- compare that with a 440 RB big block of 1.5:1, allowing a peak valve lift of 15 mm!! Piston masses have gone down- which in league with valve train design improvements--sees peak power speeds on V8s going up from the norm of 4800-5200 rpm to 5800- over 6500 rpm. If we start looking at Hondas and BMW M engines- MUCH much higher!
In cylinder charge motion has finely developed tumble motion optimisation which allows more ignition advance FOR A FAST BURN  before the onset of knock.
Engine bearing friction has come down- if you look at the size of the bearings of an old Mopar- they're way oversized for the IMEP the engines made. The "RB" big block especially so- the 'B" Big block Mopar sizes would have been just fine.
So we've covered port flow, manifold design, CR, combustion, friction and ECU control of it all.
And that about sums it all up

www.auto-scape.com

RE: Old Engines are inefficicent at creating power/torque,WHY?

Our engine designers used to get narky if the backpressure reached 6 psi, that's 400 millibar in the new money.

Now with Euro V coming our way I imagine that number has increased, just due to the extra cats, but I don't do engines or noise any more, so that may be misleading.

Cheers

Greg Locock


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RE: Old Engines are inefficicent at creating power/torque,WHY?

I'd like to point out that the person who originally mentioned 360s did not sepcify displacement. The mopar small blocks can be built into some very large(~472ci) and very stout strokers.

I had some personal expereicne wiwth a pump gas 425" 360 that made ~540hp NA. That motor had a conservative cam choice as it was slated for EFI use. 600 is certaintly not out the question for an NA mopar small block on pump gas. 600hp with 360 cubes- I have not heard of, but I wouldn't mind being wrong.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

Engines have always been under rated from the factory if they were in performance models.

In Japan the 276HP LAW was inacted because there government thought that the 300ZX Twin Turbo was fast enough and governed that no car in Japan could be rated at any more so skylines, Supras, and NSXs all got down rated in japan though they were capable of much more, stock skylines and supras are capable of over 400 HP with a twist of a boost controller.

In America they underrated from the factory for insurance but the way they measure HP is different from how it used to be. What we think of as 505 from the new corvette would be much higher to them back then, a stock Z06 2010 vette would smoke any old stock muscle car.

This sorta relates to OP's question as to power, Cars have made huge leaps and bounds in technology and people are working on it more and more everyday, the next BIG tech to hit cars will be solenoids for there valves, the valve train sucks up to 25% of the engines true power output just to turn. But before that we will have DISI injection (direct injection similar to a diesel but much lower pressure). DISI allows for much leaner mixtures to be used at higher boost/compression to lower knock and increase fuel mileage.

So to answer the question: Humans got smarter and built better machines.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Not every computery/electronic new idea is an improvement (a lot are though). I doubt if we will ever see any production use of solenoid (or hydraulic) valve gear.  DI is a possibility but I have heard that Commodore (GM) DI is no useful improvement over ordinary EFI.  

RE: Old Engines are inefficicent at creating power/torque,WHY?

Yves, direct-injection is already in production: VW FSI/TSI, Hyundai GDI (2011 Elantra), Mitsubishi GDI (many models), and several others.

And, Fiat's Multiair system appears to be a practical way of getting almost infinitely variable valve timing and lift. It still uses a camshaft, but uses a solenoid to regulate a hydraulic circuit between the cam and the valve. It's in production.

Direct solenoid actuation of the valves is not likely to see mass production in the foreseeable future. Multiair and other similar systems achieve the majority of the benefit at a fraction of the cost and electrical power demand.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Yep, GDI is becoming fairly common ... at least in Europe and Japan.  But direct solenoid actuation of valves is likely to be limited to use on research engines, where full flexibility is desired.

- Steve

RE: Old Engines are inefficicent at creating power/torque,WHY?

That engine is probably optimized for power and the transmission optimized for smoothness. Initial impressions of the new direct-injection 2011 Hyundai Sonata were favorable regarding its fuel consumption, and the VW 1.4 TSI is another good example.

RE: Old Engines are inefficicent at creating power/torque,WHY?

All of Ford's EcoBoost models, I believe all GM engines 2.4L and above (not in trucks) are DI.

RE: Old Engines are inefficicent at creating power/torque,WHY?

Brian - the Ford's engine is a full litre bigger than the Holden (4l against 3l), and the Ford is  more than a second faster to 60mph - and yet the Ford uses less fuel - where is the SIDI Holden better? Unless there was something terribly wrong with the Holden this cannot be seen as a victory for SIDI.   

RE: Old Engines are inefficicent at creating power/torque,WHY?

All it means is that particular engine, in that particular drivetrain, in that particular vehicle, under those operating conditions, isn't all that great (and this isn't the first time I've heard that about the 3.0 litre version of the GM HFV6).

It shouldn't be considered a blanket condemnation of that engine concept. Your comments on the 2011 Hyundai Sonata, please.

- Best in class power output
- Best in class (gasoline non-hybrid) fuel consumption, and it was possible without too much difficulty for road testers to beat the US EPA estimates.

No doubt some is due to good aerodynamics and attention paid to weight reduction, but it's also the only direct-injection engine in its class in the North American market.

RE: Old Engines are inefficicent at creating power/torque,WHY?

My guess is that the SIDI engine would have reasonable fuel economy IF they changed the trans schedule. The problem then is that the car would feel gutless and fail in the important tests, standing 1/4 and 0-100.

Fitting rather untorquey engines into fat cars is always going to be a bit of a gamble. 40 years of experience says you won't be particularly happy with the result, but the pimply faced youth managers will know better. Although of course the front-line engineers will get the blame when it only achieves two out of three program goals.





 

Cheers

Greg Locock


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RE: Old Engines are inefficicent at creating power/torque,WHY?

Which car is heavier, the Holden or the Falcon? They were driving around a road course presumably accelerating and decelerating a fair bit. This should give the ligher car the advantage.

They was also some comment about never going more than 60kph during the testing.

Take both out on a freeway and set the cruise at say 80kph or 100kph for a good run and see where the economy is.
 

RE: Old Engines are inefficicent at creating power/torque,WHY?

I own a '69 Torino Talladega clone with a 428SCJ. The entire car is brand new. The engine was carefully rebuilt with attention to the heads & the entire valve train. I also own a '05 GTO W/LS2, 6speed. This engine has very minimal mods. They both have the same tires/width. They have similar gearing.The GTO is faster, much faster. It turns in 18mpg in spirited driving. Don't ask what the Torino turns in. I'm considering installing an Edelbrock fuel injection system & a 6 speed trans in hopes of being able to use is more. Why is the newer car faster? Any ideas?

RE: Old Engines are inefficicent at creating power/torque,WHY?

It's already been said, but for those of you not paying attention---The engineers in the automotive field have not been asleep for the last forty years!

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

Quote:

Any ideas?

Learn to read...

RE: Old Engines are inefficicent at creating power/torque,WHY?

"The engine was carefully rebuilt with attention to the heads & the entire valve train."

Seems like for lots of projects The focus is on measureable hard parts.  Rod bearing clearances controlled within 0.0002 inch, etc.

My old twostroke dirt bikes have patiently explained to me several times there is exciting HP and excellent throttle response still hidden in the small suitcase full of brass jets and aluminum needles.
When Bill "Grumpy" Jenkins first achieved prominence in drag racing it was as a tuner.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Tmoose, I'm a "tuner" by that definition.  
I can read plugs, tailpipes...
I can hear what the "heartbeat" is telling me.  
I can "sense" what the engine is doing.  
Yes sir, I CAN do all these things.  I've always been able to do all these things.  I have NOT been able to teach others how I do it, not for not trying.  
My oldest boy, the painter/artist/mechanic is fair, but misses the little stuff.  
My youngest son is a "reader".  If it's in a book, he knows all about it.  He is, however a very talented race car driver.  
My daughter loves cars.  She also loves computers, Ipods, cell phones and, is for the most part very intelligent...she is also a space cadet when it comes to cars.
Even my wife, just after we were married enrolled in a basic automotive maintenance course after she graduated high school.
If you want to follow me around, maybe it will rub off a bit. The last of the "black arts"?

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

Here's a not old, relatively "new" 1500 Cee-Cee ( 90 cubic inch ) engine that wheezes out a mere 75.231 lb-feet.

http://www.electrifyingtimes.com/priustechspecs.html

This, despite benefit of such proven power boosting brochure bullet points as:
- 13.5-1 compression ratio
- Fuel injection
- 4 valves per cylinder
- DOHC
- cHaIn DrIveN cams
- Variable valve timing

And, the popular torque enhancing "long stoke."

Might have >>something<< to do with those interesting valve timings.

Pretty good BSFC though.

 

RE: Old Engines are inefficicent at creating power/torque,WHY?

Hi Greg,

Yeah, I was just being contrary, providing a new, high tech sounding example of "crumby" HP and torque. Probably cause  I'm pretty old and inefficient myself.

I wonder what operating condition triggers The intake closing at 120 ABDC. 50 degrees BTDC.  Start compressing when the glass is  nearly empty. Just take a quick sip of air.

I used to have some info on Crower's "more complete expansion" kit for Chevy V8s.  High compression, skewed valve events. That had to function with a carburetor though.

Dan T

RE: Old Engines are inefficicent at creating power/torque,WHY?

SIDI on its own gives no major fuel economy benefit. It must be carried out with other changes in mind. It's nothing like the huge step change in efficiency you get when going from a pre chamber diesel to a DI diesel.

SIDI or GDi delays the onset of knock at high loads- which means a higher compression ratio can be specified. May be 1-2 ratios higher than a conventional SI engine. For every ratio increase- assume about 3% fuel economy benefit. When you're already at 10:1 it may be less- say 2.5 %. This is a benefit in terms of BMEP and BSFC. GDi alone gives between 3-5 % benefit in terms of Volumetric efficiency and therefore torque. However some of the fuel economy benefit of GDi alone is lost due to the pump drive torque required to inject at 200 bar or so. So the net gain is about the benefit of the CR change alone with a handy BMEP benefit- due to charge cooling and due to the CR change itself.
If the engine is down sized to compensate for the power/torque increase- - while targeting a certain torque/power curve you can get a further slight benefit in fuel efficiency due to lower pumping losses.
The biggest gain with GDi comes when you boost the engine in league with variable cam phasing. You can specify BIG valve overlaps at low engine speeds- for great scavenging- and boost the engine hard, and not worry about short circuting of the injected fuel because being DI you can inject whenever you want in the cycle and thus avoid short circuiting. This gives a HUGE wall of torque at low speeds- and you can therefore, in theory down size your engine further to chase slightly better fuel efficiency.

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RE: Old Engines are inefficicent at creating power/torque,WHY?

Evelrod said:"My daughter loves cars.  She also loves computers, Ipods, cell phones and, is for the most part very intelligent...she is also a space cadet when it comes to cars."

is she looking for a husband? winky smile

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RE: Old Engines are inefficicent at creating power/torque,WHY?

I sure hope so.

Rod

RE: Old Engines are inefficicent at creating power/torque,WHY?

Who said arranged marriages don't work !!!  

RE: Old Engines are inefficicent at creating power/torque,WHY?


Rod -

Practioner of a Black Art indeed.  There have always been lots of parts selector/assemblers out there.  Some working to very precise tolerances and clean to a fault.  But, not many have been able to make every motor they touch the one to beat.  

I thought that I was OK at tuning, but would have my partner touch it up before we made a run.  Not just to make sure as a lot of times he would make a minor adjustment which made a real difference.  Typically, it would be me in the seat fired up and ready to stage, he would nod his head when it felt and sounded right to him.  Found it was best not to ask him to explain how he knew what to adjust, just drive the car.

Yosh   

RE: Old Engines are inefficicent at creating power/torque,WHY?

If you want to keep the GTO original and up the HP and torque then I recommend balancing and blueprinting the motor, change the pistons to a dish or dome and a thinner head gasket for higher compression, and have the heads fully (re)ported using 21st century tech :).  These with the original cam spec ought to get you well into into the 400's hp, perhaps into the low 500's with a mild mod on the cam (newer tech again in a place that you can't see looking under the hood).  I recommend you go to Comp Cams and download CamQuest 6.0 (it's free on their site) and play with the figures some.  Your motor with a carb ought to generate a considerable number of cam options.  Then you pick the one you want to live with.

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