Originally Posted by Tony Mamo @ AFR

Would like to see this engine on a different dyno....

Essentially the results are physically impossible....or more specifically the TQ output represented here is physically impossible which leads us to question all the data.

Not wanting to rain on anyones parade I have been waiting for someone else to kind of lend a "sobering" post to this thread and was surprised it hasn't happened yet.

A 346 CID inch engine.....and I don't car how much static CR it has.....simply couldn't generate 560 ft/lbs and Im talking about on an engine dyno, never mind a chassis dyno losing even more to the tires.

A 350 CID NASCAR engine might see 1.45 - 1.50 ft/lbs per cubic inch (once again discussing numbers generated at the crankshaft....not the tire).

560 TQ to the wheel assumes at least 600 ft/lbs at the crank.....do the math fellas (that's 1.73 per cube).

You know why practically all of the highest 346 dyno graphs you see are usually in the 435 - 445 range? Because that's all that size engine is capable of producing physically limited by its displacment (of course a "generous" dyno might show a little more). By the way my former 346 laid down 435 - 440 RWTQ.....and on the engine dyno peaked around 480 ft/lbs (generating 552 HP as well).....very stout for a 346 CID combo at almost 1.39 ft/bs per cube.

Now HP is a different story though.....there is far more variance there. If you have enough intake and exhaust flow to generate 400 ft/lbs at say 7800 RPM you just generated 594 HP. Essentially there is no limit to how much HP you can produce (within reason) if you keep improving an engines breathing ability which allows the engine to continue to fill the cylinders at higher and higher RPM but torque output per cube is a much more "finite" figure.

The Engine Masters contest is getting ridiculously competitive of late.....some of the smartest engine builders in the country are testing and swapping parts 6 months in advance. The winning motors a few years ago were generating 1.4 ft/lbs per cube....a very stout figure all things equal on pump gas (note these engines are usually 12.5 - 13.0 to one and only have to live three pulls). Recently that number has been pushed up even more.....now in the mid 1.40's....an even more impressive achievement and these engines are designed to make big torque output and lots of "average power"....they aren't just hunting for big high RPM HP figures.

Also, last I heard Pro Stock engines.....the pinnacle of naturally aspirated engines, were producing in the low 1.5 range (torque output per cube), BUT.....slightly over 3X their displacement in horsepower!!

Also, another situation which makes me scratch my head is the peak torque shows to be in the 3000 RPM range with a 346 CID engine?? That makes zero sense....

Anyway....I don't know what to make of this power curve and/or the numbers. Some strange issue with the converter perhaps?

I dont know....I just felt I had to say my peace in an effort to help educate some of you, especially those that think any type of numbers are attainable and dont realize that sometimes the laws of physics (as it relates to internal combustion engines) sometimes get in the way.

Rolling this car on a different dyno would prove to be very interesting....its certainly cheap enough to do these days. That would be an interesting comparison IMO.



Cheers,
Tony

Originally Posted by boostdoctor

Let me clear some things up for you. We couldn't get a clean tach signal, so we calculated the rpm using roll speed. This works well on stick cars but It's not as accurate on a unlocked auto. The dyno's rpms were about 6-700rpm down from what the bs3 was reading. That's where the high torque numbers are coming from. The tach signal is only needed for torque, so trust and believe that the hp is correct.

Originally Posted by THADD

Maybe I took what he was saying completely the wrong way, if so then Im sorry for that. Also maybe he should throw a bad *** set of AFR's my way and see how much more power it can make over factory heads, lol