I've been reading a most excellent book Formula 1 Technology by Peter Wright, published 2001. He points out that volumetric efficiency hasn't increased much since the 1960s. Instead, the huge power increases have come almost solely from RPM increase. For example:

___1965: 120 bhp/liter @ 8,000 rpm
___2001: 275 bhp/liter @ 18,000 rpm

This indicates how revving any engine higher (even our A-series motors) will give more HP -- assuming the carbs, intake, valves and extractors can handle higher air flow.

Valve Spring Limitations
The first problem with increasing RPM was the valve springs. This was eliminated in 1986 by Renault's air spring system (pneumatic springs). Now the RPM limitation is not in the valvetrain, it's solely in the strength of the bottom end. Piston design is a top secret in F1 today.

The problem with high RPM
The problem with increasing RPM is that the resulting increased friction tends to cancel out any HP gains made from increased air flow. In other words, more air=more HP, but then that HP is used up in turning the crank (bearing friction) pumping air losses in the crankcase (below the pistons), etc. This problem was resolved in various ways including:

-- Pumping losses: The engine crankcase is divided into sealed compartments for pairs of cylinders. That's 5 compartments for the V-10 engines. The pairs help cancel out pumping losses.

-- Windage: The crankcase is run at high vaccuum by using scavenger pumps so there is no air for the rotating parts to stir up. That's up to 30 pumps per engine! This is an extension of the standard dry sump system used to prevent the crank from hitting drops of oil and wasting HP.

-- Friction: high tech coatings are used for all friction surfaces. Low friction oils are used. Parts are designed for minimal friction surfaces, for example, smallest bearings practical.

-- Accessories: careful design of water pump, oil pump, alternator, etc.

Notes on stroke vs. RPM
The piston stroke has dropped over the last 30 years (as we would expect) from about 70mm to 45mm to help with higher RPM, but ring speeds have still risen 30%. . The bore is increased to keep similar liter capacity (currently 3.0 liters). HOWEVER, a lot of the advantage gained is by making the engine block correspondingly shorter for increase Center of Gravity (handling advantages).

Horsepower, schmorshpower!
I wish the almost totally useless concept of horsepower had never been thrust upon us!
TORQUE! That is what we are all really looking for. Horsepower, and kilowatts too I believe, is just a convenient way of getting big numbers from small ones. An S2000 engine makes 200 horsepower at 9000 rpm, that sounds much better than 116 foot pounds of torque. As they say in the car biz, "horsepower sells cars, torque wins races" or alternately "you buy horsepower but you drive torque."
I'm not trying to put down F1 engine technology, on the contrary I think 18,000 RPM engines are just about the coolest thing around. It's just the horsepower figures really don't apply in the real world. That same "275 HP per liter at 18,000 rpm" engine is only making 240 foot pounds of torque. Not so impressive, eh?
My point is, big HP figures at stratospheric RPM's should be taken with a grain of salt.
Sorry about the rant.

Okay, so what if the torque doesn't double when they double the rev's?
If you rev the engine twice as many times, the torque is applied twice as many times.
That is what makes new F1 cars faster than old ones.

I agree with you. F1 and most forms of racing are limited by class rules. For the street we have more freedom to do it the "best" way (meaning the way we like best). With extra torque, you just go faster. No need to fine-tune gearing and driving style or spend megabucks. A high revving engine cost big bucks. A high torque engine can be very inexpensive.

There are two straightforward ways to make a lot of extra torque:

...Bigger engine
...Supercharging

Club members have spoken in favor of "big" engines like the CA18, SR20 and L20, but rarely anything bigger. I wonder how the Nissan 2.5 four would fit in - is it a light engine?

Since not many of the club members are fans of V6 or V8 powered 1200s - or in Australia, not even allowed to use big engines - that leaves supercharging (either using a supercharger or a turbocharger). The advantage of a turbo over a supercharger is you can just "turn up the boost".

If ya wanna keep an A-series motor, you're not going to make a lot of torque. So to get a lot more performance ya gotta rev it higher or used forced induction (and even turboed, it's not a lot of torque). To make it go faster with higher revs, gearing becomes really important.

Err..hey guys...

But isn't torque just good for towing...?

Cheers

ddgonzal,
Actually, gears are something I lack. I'd like to build up a serious revving engine, but cost prohibits.
A close ratio trannie and all the treatment to the engine required is too much to justify.
P.S... I'm looking for some trim bits.
I tried to contact you on P.M., but I think it failed.
E-mail me at slkearney74@hotmail.com

ahh, the age old debate! filled with so many myths and over-simplified definitions and generalisations that all have one thing in common; they completely miss the point. It is really only simple high-school physics, but then I guess most people didn't really understand much of that either - especially the ones that ended up being interested in cars!

here are a couple of simple facts to get you started:
* torque is the (only) force an engine produces. It is the only useful thing an engine makes, everything else is a by-product.
* horsepower is not a force. It is not something you can directly measure from an engine or car. It is simply a measure of an engine's ability to do work with the amount of torque it generates. In real world terms, that rate of work is accelleration.

I won't try to explain it all, it's been done many times in a much better way than I can. Have a look at this article on torque and horsepower

there's not much accurate info on the internet and most stuff you read has to be taken with a big grain of salt, if not totally disregarded, but this article is an exception. Read it and think about what it is saying. Trust me, it is correct.

Quote:
So, aside from the humorous remark about towing, is there anything in this thread that is incorrectly stated?

yep. a few, but it's still early days yet

here's a couple of examples of some generalisations and myths:

"With extra torque, you just go faster"

"A high revving engine cost big bucks. A high torque engine can be very inexpensive."

"horsepower sells cars, torque wins races" or alternately "you buy horsepower but you drive torque."

But it's all relative and so we need to be clear what we are talking about. We can't compare an F1 engine to a street A series engine. The objectives are just too different. They are tuning for absolute maximum effort peak bhp that will last for the duration of a race, wheras you are looking for something that makes your car a bit quicker without:
-being a pig to drive,
-running hot at lights,
-using stupid amounts of fuel,
-requiring the most exotic and expensive materials in the world, and
-being 'lifed' at about 2.5 hours!

starting to get the idea of exactly who has more limitations? and I haven't even mentioned the big one yet...

Quote:

Thank you! Thank you! Thank you!

That is what I was trying to say with my rant. That "horsepower" is really a myth. Well ok, not a myth but it isn't what people are really talking about when discussing engines.

By the way, what are we doing every time we try to get our cars moving but "towing" them up to speed? Just a thought.