stock 350 Chevy engines at 6, 000 RPM

[fltcoils]

Make that "Oldsmobile Turnpike Cruiser"

"Friction loss in a large displacement V-8 engine turning at 3000 rpm actually can consurme more horsepower than it takes to push the car down the highway at 60 mph. lf engine speed can be reduced to 2000 rpm or less, friction is reduced by more than 50%. It doesn't matter that it takes a larger throttle opening to produce the same bhp at lower speed. Reduction in friction loss is far more important. In fact, the larger throttle opening is beneficial in that it reduces manifold vacuum, so pistons have less vacuum to pull against on the induction stroke. The pull against vacuum is known as --"pumpingloss" . It also is an important factor in fuel economy, but is not as important as friction loss."

..."The useful engine range with the test car's gearing is not 2000-5000 rpm as it is with normal high-performance gearing. It is 1000 rpm to not over 3000 rpm. The 3000 rpm figure represents about 65 mph in second gear and nearly 100 in high.

And, the engine is designed for midrange torque, not top-end horsepower."

----------

Like my 2004 Buick Lesabre, which gets 34-36 mpg hy at 60.

http://home.c2i.net/terjekl/carlife.htm

 

[cadman]

Of course there was also that change from gross to net HP ratings in the early 70's that makes a lot of the big engines look bad. It wasn't until the adoption of the cat converter that the US automakers were finally able to retune their designs for good drivability, better power and mileage and still meet emissions req's. A friend of mine use to laugh at the "abysmal" 180HP rating of a carb'd 1976 Cad 500 engine. Of course we all know torque is what these land-yachts thrive on, especially at low-rpms to get things moving. Even with 8.25 compression these designs had torque in spades. Nevermind the fact that they're bullet-proof : )

http://www.geocities.com/MotorCity/Pit/9364/guide/Engineid.html

 

[sudsmaster]

The Chrysler turbine car I saw (must have been in the mid-90's) was beige/gold in color. I recall it was museum-owned, but I don't remember which museum. Might have been a factory museum.

Re: rpm's and big motors. The 218 cu in flathead six in my '50 Plymouth seems happiest (smoothest) running about 30 mph in 3rd gear. I think it turns around 1600 rpm at that speed.

At 60 mph it's turning about 3200 rpm and definitely not that happy. As I recall it redlines at 3600, but my memory is a bit hazy on that. I try to keep it under 55 mph.

 

[qsd-dan]

Wow, Rich. How many vehicles do you have?

I'd have a ton of pre-1973 American cars/trucks if I had the space.

Much envy on my part.

 

[sudsmaster]

Dan,

If you were addressing me, I have seven cars/trucks. All Chrysler products.

 

[rp2813]

Rich, drive one of them down to my house sometime! We sold off everything but the '50 GMC pick-up, which as you know played a big role in our recent move.

 

[sudsmaster]

Ralph,

Well, you saw one of them (the 300M) last month.

Right now only three are driveable and/or registered-insured. The rest are garage/carport/car cover queens. I have plans for most of them, but other projects (a fixer-upper's day is never done) take priority.

 

[dnastrau]

Horsepower after '71: Gross vs. Net ratings

Very interesting thread!

Just a quick note regarding horsepower: In 1972 all US manufacturers switched to SAE net horsepower from the previous gross rating method. The difference was that with the SAE net method, ratings were given with engines as-installed in the car including full exhaust system, air cleaner, belts, etc. Ignition timing was to be set to stock specs as well.

I have read that with the previous "gross" method, manufacturers would tweak the engines by running them with the belts, air cleaner, exhaust manifolds removed and the timing way over-advanced to get those high ratings. AS a result, the net ratings from '72 to the present are much more real-world.

For example, a 1971 Cevy Impala 350 2 barrel 8.5:1 compression motor was rated at 245 gross horsepower. The '72 engine was virtually the same but was rated at 165 net horsepower.

The huge drop on paper between '71 and '72 horsepower ratings had more to do with this change in the rating system than it did with anything else.

Keep the old iron running...

Andrew S.

 

[tbolt25]

1969-72 Chevy trucks@ 6, 000 RPM

I used to hear quite a few 1969-72 350 Chevy trucks at 6, 000 RPM!