Thread:

HP or TQ ?

You guys keep wanting to veer off course of the topic
When building for max hp you usually end up with an engine that does it at a high rpm so you end up cutting the impellar to get there. With an engine that make 1800+ ftlb tq you end up with the largest imp. you can get usually. But the impellars are selected from a HP chart.
Take this engine for example, you probably couldnt use it to its potential without some form of gear box so it could turn 10,000rpms, and it was built for every last hp. 1432hp but only 840ftlb tq

Okay. Now take this engine, put it through a gear reduction box to where the HP is usable in a jet. Then put the engine and gear reduction box back on the dyno and refigure the torque. You will then start to see the answer to the original question here.

Duane HTP

So, on the HP vs TQ question none of the big players had anything to say(except Duane and he didnt add much). I believe this is a very misunderstood part of impellar selection.

Originally Posted by Sleeper CP

Haas,


Power under the curve.......the engine that's making 2,100 at 7,000 will out perform Mark's engine( 1,809hp at 5,800) even though it's making less trq. It also depends on where in the rpm range the trq is being made. you can make 2,100 lbs ft, but if it's at 3,500 rpm it's not going to help you all that much without a gear box.

Trq is "work" but hp is work over time. To accuratley answer your question you'd need to have a graph of the impeller in mind, but the engine that is doing more work over time will out perform the other engine............ at least in this rpm range.


S CP

Not sure I agree with this. If both had a 9.5" AAA Hi-Helix I believe Marks would out perform Steve's. The perimters I gave for the question were if both engines were put in front of a very large imp. in a well loaded pump.
But if the imp. was cut and dialed in to put Steves engine in the sweet spot -rpm wise then i would agree. (but that wasnt the question, Same large imp.)

Originally Posted by cyclone

You are handicapping the schmidt motor by not putting the correct impeller behind it.

Kind of like people wanting to race a boat set up to run Nitrous by telling them to un-hook the bottle.

Haas has stacked the deck against against the 1 engine.

S CP

Originally Posted by cyclone

You are handicapping the schmidt motor by not putting the correct impeller behind it.

Originally Posted by Sleeper CP

Kind of like people wanting to race a boat set up to run Nitrous by telling them to un-hook the bottle.

Hass has stacked the deck against against the 1 engine.

S CP

Corrected your spelling of my name John.

Boys I dont care one ounce about the engines in question. I was comparing the tq output of the two and just how you could fall short with an engine that has huge hp and not so great in the tq department as compared to a properly setup engine that makes as much or more tq as it does hp.
I could just see this senario happening, Joe-shmoe has paid to have this 1800hp monster built and it wont turn this AA Hi-helix impellar past 6600rpms when his friend-Don-Won has a 1600hp & tq setup that will crank the same pump up to 7200.

Joe has to have his Imp cut to get to 7200rpm because Don keeps spanking his azz with the 1600hp setup. (after the cut job Don continues to spank that azz)

Now they are both turning 7200 but the man turning the larger imp. is processing more water, biting harder from the launch. What does all that translate to?

Originally Posted by Here Comes Whitey

We run a B- in Whitey. Pretty sure it leaves hard, not to many jet boats spanking its azz especially for the first 660ft!

It gearing terms ....the B- would be like turning 4.30 gears and an A would be like turning 3.70's ? So the taller gears will accelerate quicker?


S CP

Originally Posted by Sleeper CP

It gearing terms ....the B- would be like turning 4.30 gears and an A would be like turning 3.70's ? So the taller gears will accelerate quicker?


S CP

Do you think a top fuel car runs 4.30's to run over 325mph ? Most of your really fast turbo-nos guys today are running taller gears too.

Originally Posted by Here Comes Whitey

We run a B- in Whitey. Pretty sure it leaves hard, not to many jet boats spanking its azz especially for the first 660ft!

And thats one way to do it, doesnt mean thats the only way to skin the cat. Pretty sure John D isnt running a B-cut.

Originally Posted by Hass828

And thats one way to do it, doesnt mean thats the only way to skin the cat. Pretty sure John D isnt running a B-cut.

I'm pretty sure John D is making more hp than Morgan....... I'd also bet Morgan has the better 660' times.

But I'm just guessing cause I don't know crap about this.........................

S CP