anyone running a 350 with 2.1 box?

[Deano]

500lbft/ 400hp turns way way less prop and makes way less thrust than 400lbft/500hp

Ultimately, this statement is a demonstrably true fact without a doubt,
(provided that the definition of "way way less prop" is admittedly a subjective observation).

According to my AC pocket protected fuzzy math excel calculator the engines have equal power and both exceed waterthunder thrust expectations :salute:

I challenge any CM calculators to prove me wrong!!
:stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing

OK, I accept your challenge.
Remember you asked, I didn't set out to beat up your post. :wink:
There are a couple things to be clarified though, so as not to confuse the natives who are new to our little island. :lol:

No need for any calculator. These calculations are suffering from to way to much pocket fuzz to produce a usable result.
There are TWO fundamental problems with lines 7, 8, and 9 that render the displayed results incorrect and of little value.

The first problem being the definition of "power unit" in lines 7 and 8, and then its use a variable in line 9.

While the underlying presumption of a calculated "power unit" MIGHT be usable/applicable in some equation, some where;
it is NOT usable OR applicable to gear ratio calculations such are displayed above.

This is junk math based on a false presumption, and part of what
perpetuates this debate and people's misunderstanding of the subject.

What needs to be understood as basic truths is that:
1) A gear reduction WILL multiply the delivered torque and
2) A gear reduction WILL NOT multiply the produced horse power.
Hence, the above equation implied on lines 7 and 8 are entirely invalid to produce a variable, or for it to be used in line 9.

The second problem is that the equation on line 9 is completely invalid unto itself (even IF the first variable were to be valid).
There is no equation to take any singular unit of measure (let alone torque) and then produce a thrust number.

Even when given a known amount of Horse Power AND Torque, THE PROP is still responsible for producing THRUST.
Bear in mind that EACH PROP will produce a DIFFERENT thrust curve, which will further vary by the amount of power applied.

Hence, an across the board equation could not be derived except for A SINGLE PROP that might be in question.
Even then, it could only happen if all the thrust variables were known and were plotted using the predetermined HP and Torque.

 

[kwanjangnihm]

I have had a lot of PM's today on how impressive/accurate my AC pocket protected fuzzy math calculator is, but many want to see a few more examples for direct drive motors. I grabbed numbers from oneBFC's chart and I threw in a stock 1970 caddy 500 hp/tq numbers so swamp wouldn't feel left out!

Here are the 2 simplest examples. (even CM guys can follow) :lol:



:stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing

 

[Deano]

-- Sigh --

I challenge any CM calculators to prove me wrong!!

You challenged, and I accepted. No more, no less. However, In spite of your fishing expedition, I have already taken the bait so I will persist as my mission is not complete and I'm as stubborn as the next guy 'round here. :stirpot:

It was never my goal to prove you wrong, but rather to increase other's
understanding of what seems to be perpetually confusing subject matter.

Now you are changing horses in mid stream, and attempting to slide the HP vs Torque vs Gear ratio subject
matter into a direct drive discussion where the original erroneous statements are completely omitted. :thumbleft:
You need be very careful when doing this, lest the Demonicrats reading this begin to think have found a new leader! :shock: :lol:

It is not my intent or desire to insult anybody that sent you a PM, but that does show the reasoning behind this statement:

This is junk math based on a false presumption, and part of what
perpetuates this debate and people's misunderstanding of the subject.

To digress, and to stay with your original formula of a 'power unit', it would be more realistic and accurate to show it like this:
500 HP + ( 400 TQ x 2.68 gear ratio ) = 1572 power units
400 HP + ( 500 TQ x 2.68 gear ratio ) = 1740 power units
Shown as such, it should become readily obvious that that formula is bogus because 400 hp will NOT swing more prop than 500 hp.

Now, onward to a little more sillyness before lunchtime.

I have had a lot of PM's today on how impressive/accurate my AC pocket protected fuzzy math calculator is, but many want to see a few more examples for direct drive motors. I grabbed numbers from oneBFC's chart and I threw in a stock 1970 caddy 500 hp/tq numbers so swamp wouldn't feel left out!
Here are the 2 simplest examples. (even CM guys can follow) :lol:

:stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing

While you're due credit for doing some research, you've over looked that the HP number you sighted there is at 4400 rpm, which is arguably a little past balls out WOT. In any case, even the baddest of all stock Caddies will not come near that number at DD RPMs.

It's documented that most DD make 900-1000 Lbs of Thrust on average.

C'mon Man ! (Even AC guys can follow) and see that this is a stand alone, blanket, generic statement that can be made without the preceding two lines and does not require a spreadsheet with complex formulas to be made.

Hey ! Wait a minute ! There are no formulas . . . this doesn't even look like a calculator at all !
Will you admit this is only a fancy format for presenting your propaganda to amuse your pot stirring fishing buddies ? :lol: :lol:

One last question, :scratch: What is this "AC Pocket" to which you keep referring, that is protecting your 'fuzzy math calculator' ?

 

[Slidin Gator]

Really? You know better brother....

500lbft/ 400hp turns way way less prop and makes way less thrust than 400lbft/500hp .

YOU KNOW THIS. Why fight it?

I do know better, but my point is that a flat out statement of "Make More HP" is just as incorrect, it all has to be applied correctly. Torque and HP are interchangeable when compared against RPM, just 2 different curves showing the same thing. The HP curve best shows top end and the Torque curve best shows everything else.

Didn't slidin gator write that his high torque A/C motor would make less thrust than the high HSP and low torque LS I am building? I think we need to put them on the thrust tester and find out.

I certainly did, no doubt higher HP produces higher static thrust. Thrust needed is a function of the hull, friction and the load. I spot you top thrust king on the thrust tester vs. my 500 ft-lb motor. I am interested in the thrust response comparison, time to 90% of max thrust for a given rig. 40 yard dash, climb the hill and follow the leader through the woods, that's what counts. We are gonna have to set up an obstacle course :stirpot:

Anyone running a Chevy 350 (not highly modified) with a 2.1 belt box? If so, what is it on and how does it run>?

I ask the question because I was thinking of getting a spare motor (350) cause of a good deal, but have no idea how it performs on a belt.

I think it will run a hell of a lot better than the 350 DD you are running now and probably the cheapest path for you to upgrade. 350 motors are a cheap way to make reasonable power. A used whatever may or may not last, but less than $2000 to rebuild to last on 2:1. Redline it around 5000 and cam it to match, stock heads will be fine at that RPM, you just need a proper rotating assembly.

 

[OneBFC]

I do know better, but my point is that a flat out statement of "Make More HP" is just as incorrect, it all has to be applied correctly. Torque and HP are interchangeable when compared against RPM, just 2 different curves showing the same thing. The HP curve best shows top end and the Torque curve best shows everything else.

...no doubt higher HP produces higher static thrust. Thrust needed is a function of the hull, friction and the load. I spot you top thrust king on the thrust tester vs. my 500 ft-lb motor. I am interested in the thrust response comparison, time to 90% of max thrust for a given rig. 40 yard dash, climb the hill and follow the leader through the woods, that's what counts. We are gonna have to set up an obstacle course :stirpot:

So, not getting off the hook with that kind of reply either as it's all wrong.

Higher HP produces more thrust, period. Static, Dynamic, etc...all will be HIGHER with higher POWER, not torque.

You want to accelerate faster? Get more HP.

I am pretty sure you didn't read or maybe didn't fully understand the information provided at the previous link or you would not have typed your last reply. Torque is useless unless you rotate a shaft with it . As soon as you rotate the shaft, it then becomes useful and is measured in terms of POWER.

Here's a nice little graph comparing the available prop shaft torque and power between a stock SV 0540 vs LTG 2.0. Both stock mind you. Not cooking any info at all.



You tell me, which engine has more Torque at the prop shaft most of the time? Which engine has more HP at the prop shaft most of the time? Anything below 1000 prop RPM is fairly useless when your talking about the types of airfoils that DD setups turn.

Everything about the Ecotec engine is better....period. And this is comparing it using a really poor reduction choice of 2.0:1 vs the better 2.38:1 (for stock LTG). Nothing is slanted in favor of the Ecotec in this comparison and it still beats the 0540. The very top end, beyond the rated RPM where the SV0540 makes its "official" power, the engine makes a bit more and so, with more power available, edges out the LTG after 2750 RPM.

We all know that both engines are possible to have in the 300+ power range as well and the comparison doesn't change one bit.

Facts are facts man.... Still waiting for some proof here based in real world physics (or any physics for that matter). The torque is king myth needs to die once and for all!

 

[Slidin Gator]

So the argument for killing the torque myth is the perfect torque curve? I guess it's just arguing for the sake of making noise.

I'm just gonna scratch the Ecotec of my list of future engines. There are many factors to consider when buying, #1 in this case is the salesman.

 

[OneBFC]

I am sure the ecotec sales person will or would be devastated? LS engine comparison is far and away even more obvious which is better from a performance perspective.

I am not selling anything but knowledge.

Use it how you wish. Not meant any other way.

 

[brlcLA]

Torque is nothing but cylinder pressure x cylinder area x crank lobe offset

It is absolutely useless number w/o rpm being involved and torque x rpm = HP

If you want to run your engine at high torque which equals high cylinder pressure and lug the motor all the time... by all means let it blow!

That's my $0.02

 

[SWAMPHUNTER45]

Torque equals usable power, horsepower is great...luv it... but... don't need the noise and don't like to wait for my snap!

 

[kwanjangnihm]

 

[Keeth1123]

Always make me laugh with these memes

 

[Deano]

 

[Slidin Gator]

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
About busted a gut on that one :thumbleft:

I guess no one else has any actual useful input for Keeth? Consensus is get another 350 motor with a 2:1 for cheap and get on with it?

 

[OneBFC]

Consensus is get another 350 motor with a 2:1 for cheap and get on with it?

Yep, I agree. No messing with rigging or any other cans of worms when you go changing stuff.

Done and back to sliding.

 

[SWAMPHUNTER45]

I would be looking for a 383 or 400 since they make more TORQUE!

 

[Slidin Gator]

See Keeth, consensus is to gear that 350 and turn it. Sure, you gotta change all the rigging to turn a bigger prop (gotta buy that after all), move the motor stand forward to make room for the belt drive. Probably change the seating and rigging to make room for the engine, now moved forward. Yep, throw some gear at the problem and make some damn Hp! Hp is free and all.

Wait, my right hand man is talking, damn Torque Devil. What's that Swamp, uh, I mean Devil?

I would be looking for a 383 or 400 since they make more TORQUE!

Keeth, Unbelievable as it sounds, there is another option. It turns out for a bit more money vs. a stock reman you can build a 383 stroker and wake your rig right up! Seriously, Keeth can keep all your stuff the same, just rebuild the bottom end with a stroker package and find some throw away 305 heads to make compression? Turns out that this will make more Torque and I now understand that higher torque at 2,850 RPM actually equals increased Hp! What a trip, I learn something new every day :violent1:

Keeth, time to pick a team, :stirpot:

Just like Smokey the Bear said about preventing Forest fires:

 

[SWAMPHUNTER45]

I have seen a 13ft glass boat running around with a junk yard sbc take out that ran very well.

1973 Chevy 400 with a 2 barrel Rochester carburetor, it came out of a 4 dr Caprice Classic. Had long tube headers and a HEI upgrade with good curve.

Ran dry with 2 adults like it was no trouble at all

 

[Keeth1123]

Well I currently run a 400 with a belt box. Does really well for me. I only started this thread because I had to do some fixing. Had to replace the head gaskets because I think the steam holes worked one loose.

. Put in some high dollar gaskets, aluminum locking rockers, new rods and lifters. Running great again. I just like to read the posts lol

 

[SWAMPHUNTER45]

They don't like a lot of rpm but they are a great engine

 

[flcracker9]

500lbft/ 400hp turns way way less prop and makes way less thrust than 400lbft/500hp

according to my AC pocket protected fuzzy math excel calculator the engines have equal power and both exceed waterthunder thrust expectations :salute:

I challenge any CM calculators to prove me wrong!!

:stirpot: :fishing :stirpot: :fishing :stirpot: :fishing :stirpot: :fishing

thrust.PNG

Looks like we may have attended the same schools :lol: