Just a thought,,, I know you guys are talking engines here,But,,what if you think this thing from the other END.. I'll call it impellor limted,,, does the
boat with a AA and a 540 @ 6000rpm go as quick as a boat with a FF impellor and a 283 cid @1200rpm ???
hi steve. that's easy; the boat with the aa/540 at 6k, rather than a pocket engine revving to 12k, if they're the same hulls with the same weighti thought we settled this a long time ago?
you have the size and mass in your arm and body to lift that 100lb dumbell, but how many times can you curl it in a minute?
a pump requires power to perform work (work being the curls). if you don't have enough power, you're only going to curl that 100lbs 1 or 2 times in a minute. if you have lots of power, you can curl it 20-30 times in a minute. if you reduce the amount of weight, you might be able to curl it more times in a minute, but did you really do the same amount of work? (you'd have to curl 50lbs 40-60 times to be equal).
the larger impeller is more efficient because, for one thing, it can pump more water (more work/thrust) with fewer revolutions. the ff will struggle to provide the same type/amount of work, even with the same hp applied (at a much higher rpm).
to get more work/thrust out of the larger (a or b) impeller, you need more power.
Geeeeze,,, What up Steele, just wanted to see whos up. been a while.
I'd call all this the 124 million doller Q. Thats why where here!! hows it
going. Good look on the boat!!!What up Brule'. Guess I missed this lastnight. Been a year...almost exactly. Thanks for the good luck. Should be interesting.
Hope to see ya.
Ok!!!!! I Am Going Threw The Same Problem. I Put 8000.00 And Stroked My Sbc And Still 3500, Went To A Ab Cut Impeller Also. I Am Doing A Cam Change At The Moment Ill Get Back With You To See If This Solved My Problem.
T
If you are gonna stick with the small block I would recommend stroking the motor you have to make it a 383. There are a lot of places like Powerhouse that have some pretty good deals on stroker kits with everything you need for a pretty good price and it doesn't really cost all that much. I don't know what heads you are running but if they aren't a quality piece there are still some good easy to find factory small block heads that work well and are very economical such as the iron vortec heads or even a set of slightly messaged 882s. Making your deal a 383 with some decent iron heads, a good properly selected hydraulic cam, a good intake like an Edelbrock Performer RPM Air-Gap #edl-7501, and a nice carb would probably wake it up nicely and put you where you want to be with that pump.
What heads are on your motor and what are it's internals?
Agreed.
Taking another angle on this answer: Stroking the motor gives you more cubic inches and more torque (more horsepower at a lower rpm) where you need it.
It does a jet little good to develop hp at 8,000 rpm.
I've seen engines with more dyno HP get out- accelerated by engines with less comparative power. Why?
Gearing. Setup efficiency. Weight.
If the hp numbers are normalized so it's apples to apples and the work being done is the same, more horsepower always wins... by definition.
One thing about tight t-shirts is the sleeves give me a place to keep my smokes.
hi steve. that's easy; the boat with the aa/540 at 6k, rather than a pocket engine revving to 12k, if they're the same hulls with the same weight
If it was settled in favor of the larger displacement engine, then it was settled wrong.
There is no advantage to a slower turning, larger displacement engine, as compared to a faster turning, lower displacement engine. If there are performance differences at the same power levels, then something else in the setup is different causing the performance deviation.
It does a jet little good to develop hp at 8,000 rpm.
It does if you're turning the jet 8,000 rpm as well.
Ok!!!!! I Am Going Threw The Same Problem. I Put 8000.00 And Stroked My Sbc And Still 3500, Went To A Ab Cut Impeller Also. I Am Doing A Cam Change At The Moment Ill Get Back With You To See If This Solved My Problem.
T
The Berkeley chart I have doesn't even go that low. Must be in the neighborhood of 130hp to spin a stock pump with an AB to 3500 rpm.
Good guess.
According to JPCalc, 126.5 is an AB @ 3500RPM.
If it was settled in favor of the larger displacement engine, then it was settled wrong.
There is no advantage to a slower turning, larger displacement engine, as compared to a faster turning, lower displacement engine. If there are performance differences at the same power levels, then something else in the setup is different causing the performance deviation.
There are HUGE advantages to a slower turning, bigger motor, but that's not the whole picture. You're not ocnsidering impeller efficiency. Bigger impeller turning slower will stay more within it's efficiency range than a smaller impeller turning faster. As impellers get smaller, so does theier window of efficiency, ultimately to a point of no return. It may be favorable to turn an engine to 7500 to make the good power, but not necessarily the impeller. It's always favorable to build power at the lowest RPM you can, and still make the power you need. High RPM = broken parts = DNF = you lose.
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