Old Cars VS New Cars

[tanner892]

I've got a question that ive never been able to get my head around and it relates to old cars vs new cars, here it goes
EG:

Holden Torana LH L34 SL/R 5000 (1974-76)
308ci
240hp@ 4800rpm
315 lb. ft of torque at 3000 rpm (not sure what it is in NM but its quite high)
***1230kg***

1/4 mile 15.9 seconds

Now if you get a modern day car with the same kind of numbers i.e. 180kw and even add 300kg i find that they achieve better performance than a car from the 1970s who has equal power or even in some cases more power and at a lighter weight..

So why is this? obviously technological change, computerisation, efficiency, are my guesses, but what is it EXACTLY that makes a modern car able to achieve better performance over a car from the 70s when they have the exact same power output at the flywheel? is there more power lost in the transfer to the wheels in older cars?
for example my vz sv6 (190kw, 340nm) almost 1600kg would beat an old slr5000 on the 1/4 (all stock of course)

Why is this???

[Astranomical]

Newer cars have better, stronger drivetrain components that do a better job of transferring the power to the wheels, as you said, not to mention they're often also lighter.

[dimsim]

So if you beefed up the drivetrain components you might have a good chance?

[ryno_vrx]

i kinda figured it came down to the chassis and the ability to get the power down but i know FA about it. this is something i've wondered about as well

[stocky]

it all depends on gearbox ratios, number of gears, diff ratios too

[levymetal]

power curves would be very different... most old cars made their power lower down, newer cars can rev their tits off. i'm guessing revving higher would equate to quicker acceleration in the long run (think about F1s etc... they don't rev that high for no reason). old cars would take longer to actually rev up to their peak as well, engines aren't as responsive.

[stocky]

also, better fuel, better ECUs, EFI vs carby

[VrWagz1]

efi was by far the best revolution in engines, they run a whole lot more efficient because of evenly distributed air/fuel mixs. Also alot more is known about manifolds now and their effects are harnessed well these days. Better oils, better bearings, better machines to make more accuratly toleranced motors ect..., theres a million reasons why todays seemingly equivilant engines do alot better now days.

[calais_304]

it all depends on gearbox ratios, number of gears, diff ratios too

that would make sence, old bloody 4spd's and big ratios arn't good for getting numbers :P that along with injection, better delivery and good ol technology get the newer cars moving quicker.

pretty much what stocky has said and others...

...was just pondering how good it would be to get an old slr or monaro and re vap all the running gear to lighter stronger modern stuff...would cost a bit but, that and a 5spd box.

[commsirac]

Quarter mile times with manual gearboxes of the day suffer(they can only be changed so fast), but no there was no more loss through the drivetrains of yesteryear than today.
Most likely factor is aerodynamics. The top speed of these vehicles is also very much limited by this, whereas, correct me if Im wrong, even a stock v6 would have a higher top speed than the v8 torana you mention.

[Calaber]

The level of efficiency of modern engines is far greater than those of the old cars. The need for modern engines to use less fuel yet still produce decent performance means that the whole car has to be engineered for greater efficiency. As Stocky and others have said, fuel injection and computerised engine and transmission management were probably the greatest innovations in achieving the sort of improvements we have today.

In 1970, 250-300 BHP V8's were matched to only four speed manuals or three speed autos. Diff ratios were lower to aid accelleration. Aerodynamically, the older cars were like a brick wall compared to the cars of today. Tyres had greater rolling resistance - hell, they were still cross plies until the early seventies, or bias belted rubbish from the States.

Horsepower outputs were often exaggerated too.

Bodywise, the metals used were low tech steels, heavier in guage and body weights were affected adversely. There was very little use of lightweight materials such as alloys. Modern steels, plastics and alloys have reduced the body weights so much that increased equipment can be added to the cars without increasing the weight dramatically. Accesories such as air conditioning draw far less power from the engine than the old monster compressors used to. I can remember a 253 HZ I had that died on hills when the air cut in.

When people say they don't make them like they used to, be thankful for the fact that they don't.

[Not_An_Abba_Fan]

Available torque in the rev range you need it is the problem. The older engines as already mentioned only produced decent torque down lower where as newer engines had torque available across a larger rev range. The new engine will accelerate faster and longer than the old engine with similar figures.

Drive train ratios play a big part as well.

[Reaper]

I've got a question that ive never been able to get my head around and it relates to old cars vs new cars, here it goes
EG:

Holden Torana LH L34 SL/R 5000 (1974-76)
308ci
240hp@ 4800rpm
315 lb. ft of torque at 3000 rpm (not sure what it is in NM but its quite high)
***1230kg***

1/4 mile 15.9 seconds

Now if you get a modern day car with the same kind of numbers i.e. 180kw and even add 300kg i find that they achieve better performance than a car from the 1970s who has equal power or even in some cases more power and at a lighter weight..

So why is this? obviously technological change, computerisation, efficiency, are my guesses, but what is it EXACTLY that makes a modern car able to achieve better performance over a car from the 70s when they have the exact same power output at the flywheel? is there more power lost in the transfer to the wheels in older cars?
for example my vz sv6 (190kw, 340nm) almost 1600kg would beat an old slr5000 on the 1/4 (all stock of course)

Why is this???

Any number of reasons as indicated in the posts above. Another thing that has changed is the way HP/KW/Torque has been measured. It changed in the late 70's/mid 80's where engine outputs were measured as net figures. Till then a "gross" hp was quoted. This is a figure where the motor was run with no accessories or exhausts to tax any hp. These days all the standard accessories are bolted on.

Reaper

[commsirac]

Tanner, further to what I offered ^, it would be good to get some splits on the 1/4mile times, I suppose there are still people that drag toranas and the like.
Compare the splits times for modern more streamlined cars with that of the older toranas etc, the acceleration of the modern car should decrease less in the 2nd half of the quarter. Any differences would be attributed more to aerodynamics than mechanicals given the sameness of the power plants and drivetrains that are currently in use at the strip, though possibly two foot of supercharger sitting above the bonnet may make those measurements meaningless!

[Dayvo]

The level of efficiency of modern engines is far greater than those of the old cars. The need for modern engines to use less fuel yet still produce decent performance means that the whole car has to be engineered for greater efficiency. As Stocky and others have said, fuel injection and computerised engine and transmission management were probably the greatest innovations in achieving the sort of improvements we have today.

In 1970, 250-300 BHP V8's were matched to only four speed manuals or three speed autos. Diff ratios were lower to aid accelleration. Aerodynamically, the older cars were like a brick wall compared to the cars of today. Tyres had greater rolling resistance - hell, they were still cross plies until the early seventies, or bias belted rubbish from the States.

Horsepower outputs were often exaggerated too.

Bodywise, the metals used were low tech steels, heavier in guage and body weights were affected adversely. There was very little use of lightweight materials such as alloys. Modern steels, plastics and alloys have reduced the body weights so much that increased equipment can be added to the cars without increasing the weight dramatically. Accesories such as air conditioning draw far less power from the engine than the old monster compressors used to. I can remember a 253 HZ I had that died on hills when the air cut in.

When people say they don't make them like they used to, be thankful for the fact that they don't.

I was actually working at G.M.H when production went from the Torana to the Commodore. All the MIG welders had to have the heat turned down as they were just burning holes in the metal due to it being thinner.
I can simpathise with you with the air con thingy .Also we all used to run sports air cleaners on V8's ,They were big chrome jobbies that sucked in all the hot under bonnet air back into the motor