SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: motormonkey on January 03, 2008, 03:04:26 PM
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Hi everyone. Who has used c or d cut impellars before and what was the launch and top end like. thanks
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in which jet brand?
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berkley housing.
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What are you looking to do? Boat type, etc. etc?
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What are you looking to do? Boat type, etc. etc?
What make of motor and size ?
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You must be plannin on some insane r's. I was told my old panther was like a c cut and at 5900 r's I was 60 mph.
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You must be plannin on some insane r's. I was told my old panther was like a c cut and at 5900 r's I was 60 mph.
those R"S seem's kind of high.
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Does anyone on here even have a "c" or "d" cut. As far as my r's to mph with a panther which I was told is like a c cut. I think Jrork said his was something like 67 at the same r's.
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Hi guys, Not looking for a setup persay but data. Like " You have run a bc cut and tried c cut or d cut" kind of comparisons and data. Also what changes in loading did you see. thanks.
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As far as my r's to mph...
??? ??? ???
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Jetaholic how else would you state it? r's to mph. BTW what cut are you runnin? I'll bet it's not a c or a d. ^-^
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Jetaholic how else would you state it? r's to mph. BTW what cut are you runnin? I'll bet it's not a c or a d. ^-^
Actually I run an A for more thrust at lower RPM and better gas mileage. ;D ;D
Just kidding...I am running an A.
My thing is the whole RPM/MPH ratio that doesn't exist with jet boats. I do understand that under a certain condition a jet boat will run at X mph at x RPM. However, due to changes in the weight of the boat and trim setting this does not always apply. This is why I try to stay away from the RPM/MPH relationship with jet boats and try to get others to do the same.
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Actually I run an A for more thrust at lower RPM and better gas mileage. ;D ;D
Just kidding...I am running an A.
My thing is the whole RPM/MPH ratio that doesn't exist with jet boats. I do understand that under a certain condition a jet boat will run at X mph at x RPM. However, due to changes in the weight of the boat and trim setting this does not always apply. This is why I try to stay away from the RPM/MPH relationship with jet boats and try to get others to do the same.
The HP/RPM/MPH seems to be the presiding rule over impeller choice etc... What do you see as a better alternative?
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... This is why I try to stay away from the RPM/MPH relationship with jet boats and try to get others to do the same.
Sounds like the beginning of a cult. :D
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Alot of Drag jets run impellers smaller like that, but there aren't too many drag jet guys here :-\
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im not new to this site but new name old was fast ass ford i run a small block ford 440 turning a massaged A at 6800 and running 102 the harder u can turn the impeller the faster it will go it takes alot of hp to doit not torque the torque comes with the power its a berkley split bowl with snoot and 2 % wedge and a ss loader and for the bottom a pre loader and bleed valve and alot of NOS if u run a smaller impeller its becouse u dont make the hp to get the speed the drag guys run alot of As and AAs just my input
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I'm no pro but I'd think blower motor or stock camed, aa or a. An n/a motor with a semi nasty to nasty cam b 'ish. I'd say my 02 but it's probably more like .01 O0
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single DOM 1350 BG running 14to1 dont need no pu@#%$y blower
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single DOM 1350 BG running 14to1 dont need no pu@#%$y blower
Them be some racing words son
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I do. (need a blower) :'(
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not torque the torque comes with the power
Actually, power comes with the torque.
Torque is a force applied to a rotating object. Horsepower is a measurement of this force applied over time (RPMs) and is expressed as:
(Torque x RPM)/5252 = Horsepower
You build an engine for torque, not horsepower. Torque governs everything from how fast/slow your hp drops off (the more steady the torque curve, the slower the hp dropoff) to how much hp you have at what RPM. Horsepower is a calculation derived from torque...torque is the source of horsepower. The speed (RPM) the shaft spins at is horsepower...how hard the shaft spins at a given speed is torque.
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Here is a very interesting read that I got from one of my books on big block Chevy's. It was originally written by Ed Staffel.
Torque is an expression of physical force acting on a lever over time and distance. Horsepower is not a force, it is a method of measurement that is arrived at by comparing the force of torque and in our case, its relationship to the RPMs an engine turns. The classic formula for measuring torque and RPM and then expressing this measurement as horsepower is HP = (Torque x RPM) / 5252. The number 5252 is a constant in the formula that relates to time and distance and so horsepower and torque measurements will always be equal at 5252 RPMs. Look at the plot curves on a dyno sheet and the two plot lines showing horsepower and torque will always cross each other at 5252 RPM and be equal at that point. When an engine is on the dyno, the dyno actually determines how much torque is being made and then a calculation is done to determine horsepower at that given RPM.
It happens that when an engine reaches its peak torque and then starts to fall off to a lower torque figure, horsepower can continue to climb upwards because the RPMs can continue to go up. On a motor this multiplying effect of the RPMs can still act positively on the horsepower side of the equation depending on how quickly or the rate at which the torque curve falls lower after peak torque.
So what, you say? You already know all of this. My point is when you build the motor, what you are trying most to attain is torque and large amounts of torque over the broadest, flattest range you can achieve in your circumstances. If you can do this, horsepower will take care of itself. Remember that most motors do not spend all of their time at peak torque or peak horsepower. It is possible to keep a motor close to peak power through the proper selection of transmission and rear gear ratios or if you have a boat. At the low end and middle of the engine's operating RPM range, keeping cylinder pressures as high as possible will accelerate the vehicle quickly. At the high end of the engine's operating range if you can keep the torque from dropping off too quickly after torque peak and help the engine to hang on longer in terms of torque production, horsepower will continue to climb even though torque is declining. This is generally due to better breathing heads, valve sizes, induction systems and longer duration camshafts that operate well at higher RPMs.
Let me give you an example. We have two engines and at peak torque they are both making 600ft lbs at 4500 RPM. At this point both motors are putting out 514 horsepower. As the RPMs continue to climb and torque begins to fall lower, we find that at 5500 RPM motor "A" is now putting out 580ft lbs and is making 607 horsepower. The other "B" has dropped lower and is making 520ft lbs, which means at 5500 RPM it is making 544 horsepower.
We then take both motors to 6500 RPM. Torque is still falling off and motor "A" is now making 540ft lbs which at 6500 RPM comes out to 668 horsepower. Motor "B" has fallen to 475ft lbs and is making 588 hp. At 7500 RPM torque has fallen further still. The "A" engine is making 480ft lbs and 685 horsepower. "B" is down to 400ft lbs, and horsepower has fallen to 571 horsepower and is headed down, not up.
Motor "A" Motor "B"
RPM Torque/HP Torque/HP
4500 600 514 600 514
5500 580 607 520 544
6500 540 668 475 588
7500 480 685 400 571
At 7500 RPMs motor "A" is making 114 more horsepower than motor "B", but it didn't do this because of horsepower. Motor "A" did this because the torque curve dropped off at a slower rate than motor "B". At all RPM points above 4500 RPM motor "A" had more torque than motor "B".
It's TORQUE that you should be looking for when you build an engine. Horsepower is an interesting afterthought.
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that is way to much to read this early but i know what your talking about but i would rather build a hi reving big block then a low reving one get on the rs quick and dont look back alot of people will disagree but when it comes to boats HP is king torque will only get so far you need the HP to do 95% of the rest the harder u can spin that A the faster the boat will go the A is the best cut but it takes both TQ HP to do it :)
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I think you just missed the head of the nail completely.
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Actually, power comes with the torque.
Torque is a force applied to a rotating object. Horsepower is a measurement of this force applied over time (RPMs) and is expressed as:
(Torque x RPM)/5252 = Horsepower
You build an engine for torque, not horsepower. Torque governs everything from how fast/slow your hp drops off (the more steady the torque curve, the slower the hp dropoff) to how much hp you have at what RPM. Horsepower is a calculation derived from torque...torque is the source of horsepower. The speed (RPM) the shaft spins at is horsepower...how hard the shaft spins at a given speed is torque.
Where did yah copy and paste that from? Hmmm, could you tell me where they get the 5252 oh so knowledgeable
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Where did yah copy and paste that from? Hmmm, could you tell me where they get the 5252 oh so knowledgeable
From my understanding 5,252 is the RPM at which torque and horsepower equal each other...why they do at that RPM I have no idea.
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that is way to much to read this early but i know what your talking about but i would rather build a hi reving big block then a low reving one get on the rs quick and dont look back alot of people will disagree but when it comes to boats HP is king torque will only get so far you need the HP to do 95% of the rest the harder u can spin that A the faster the boat will go the A is the best cut but it takes both TQ HP to do it :)
Maybe when it comes to prop boats you would be right. But with Jet boats, you're dead wrong. And dead in the water.
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From my understanding 5,252 is the RPM at which torque and horsepower equal each other...why they do at that RPM I have no idea.
How how much more power do you need to spin 5352 rpms ?
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Maybe when it comes to prop boats you would be right. But with Jet boats, you're dead wrong. And dead in the water.
if you talk to any drag jet boat guy he will tell u that hes probley spinning that motor up around 6500 7000 if not more and with an AA cut more than likly true it does take tq to get the boat moving but normally your tq curve falls of around half track and hp takes over thats why i said build for hp rather than tq becouse the tq comes with the hp theres not a jet boat on here running triple digits thats only turning 5200 it takes the hp to push u to those numbers . wiht a vdrive u can take a low hp motor and run 100mph and only turn 5200 becouse of the gearing pitch of the prop size of the prop and so on . i have been around this for years thats why i said some will disagree but im not wrong just a different op but if its still not enough proof be in blythe this summer and ill show u a 440 ford that spins 6500 with and A cut and runs over 100mph :)
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You're mistaken. torque makes HP. You have it backwards. That is a matter of fact, something you cannot argue. You don't have to believe me, I'll scrounge up a list of reputable engine builders for you to call and ask. Hell I'll give you the number for my great uncle Tyler Alexander who was McClaren's Formula 1 race team manager for many years. He was also an engineer for the firm and in fact was the man who invented the "spoiler" along with the air powered "jack" system made to lift cars off the ground for speedy repairs/tire changes. In car racing my family is second to none. In jet boat racing my best friends grandfather owns the most renowned Jet manufacturing company (especially in the Drag boat segment).
I work in a manufacturing shop that is home to over 100 machinists who have all been building engines for years. One of which was a mechanic for a Top Fuel team in the early 80's.
Ever heard the name Dean Moon? As in MoonSpeed equipment? Who was one of the biggest names in offshore racing before his death? His family lives across the street.
Lil' John Lombardo? Held top speed records in the '80s driving funny cars. He's been at my last 21 birthday parties.
All of these people have always told me one thing in common. TORQUE MAKES HORSEPOWER.
This obviously does not mean I know everything, however I do have access to a wealth of information in these particular areas. Need parts? I am only 21 but the life I live has led me to a vast network within the many facets of the racing world.
http://www.grandprix.com/gpe/cref-aletyl.html
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You can do the same with a jet boat. The whole idea behind the 'hi-helix' impellers is to make more thrust at a lower RPM. Of course, you need lots more torque and horsepower to pull that off with a jet boat, but as Jim has said before RPM doesn't always mean MPH. Also the efficiency of the pump comes into play. Some pumps you tighten 'em up and you may lose RPM, but gain MPH. This happens because you have made the pump more efficient by tightening it up. True, lots of drag boats may be spinning insanely high RPMs, but that doesn't mean that you HAVE to spin that fast to get that kind of speed out of them. It all depends on your pump/motor combo.
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You're mistaken. torque makes HP. You have it backwards. That is a matter of fact, something you cannot argue. You don't have to believe me, I'll scrounge up a list of reputable engine builders for you to call and ask. Hell I'll give you the number for my great uncle Tyler Alexander who was McClaren's Formula 1 race team manager for many years. He was also an engineer for the firm and in fact was the man who invented the "spoiler" along with the air powered "jack" system made to lift cars off the ground for speedy repairs/tire changes. In car racing my family is second to none. In jet boat racing my best friends grandfather owns the most renowned Jet manufacturing company (especially in the Drag boat segment).
I work in a manufacturing shop that is home to over 100 machinists who have all been building engines for years. One of which was a mechanic for a Top Fuel team in the early 80's.
Ever heard the name Dean Moon? As in MoonSpeed equipment? Who was one of the biggest names in offshore racing before his death? His family lives across the street.
Lil' John Lombardo? Held top speed records in the '80s driving funny cars. He's been at my last 21 birthday parties.
All of these people have always told me one thing in common. TORQUE MAKES HORSEPOWER.
This obviously does not mean I know everything, however I do have access to a wealth of information in these particular areas. Need parts? I am only 21 but the life I live has led me to a vast network within the many facets of the racing world.
http://www.grandprix.com/gpe/cref-aletyl.html
I don't ever claim to know everything either (although some people would beg to differ with that) but I do know for a fact that you are 100% correct on this. As has been said countless times before...Horsepower is a calculation derived from Torque and RPM.
Engines are built for torque. Horsepower is just an interesting afterthought.
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thats verry nice my father ran a alcohol funny car in the 70s and 80s then went to TFH thats the one in my pics i used to be fast ass ford my dad and me are also good freinds with Larry Minor who ran top fuel funny cars and top fuel dragsters and my uncle works for Don Phurdome thats why i said this is nothing new also greg shoemaker is a good freind of mine along with jonh west of ultra boats . greg did some test last year on a hallet jet with an A blown 468 nice 800 hp it ran an honest 112 mph they took the same boat with a single carbed small block making a little more power that would rev to the moon and it ran 3 1/2 mph slower and it was not a tq motor it all depends on real world ap and by the way ray at dogouns will beg to differ you can build a motor for hp and one for tq he would know he has built many of championship drag boat motors and they all are built to make hp but im shure the people i have named dont come close to yours but like i said just my op and would love to show you how fast a NON TQ motor runs ;D
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great your still wrong. call a dyno shop before you make yourself look more like an ass hole.
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great your still wrong. call a dyno shop before you make yourself look more like an ass hole.
Keep this discussion clean, no more name calling.
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great your still wrong. call a dyno shop before you make yourself look more like an ass hole.
i dont c were im wrong i agree that tq and hp work together and are built alike but when u go down to and engine shop and tell them u want to tow your boat at 50 all day they set it up that way cam carb ect. u tell them u want to tow your boat at 50 smoking the tires all the way they change those things thats what i was try ing to say and by the way its all in good fun so dont get your pantys in a bunch oh sinse were name droping on here i can give u donnys # who is chet herberts mech on his fuel car
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I think all this is is that you're wording what you're trying to say wrong.
For a "grunt" motor or "building for torque" as you call it, the motor makes all its power in the lower range of RPM and not much in the mid-range.
On a motor "built for horsepower" as you call it, the motor is making its power in the mid-high RPM range.
This is not the correct way to word what you're trying to say.
A motor that is "built for horsepower" in your terms is nothing more than a motor that is built with a much more steady torque curve. In other words, the torque curve does not drop off as quickly and because of this, horsepower continues to rise even though torque is dropping off. It's just dropping off at a much slower rate than a "built for torque" motor. It is because of the fact that there is still much torque to be had that your horsepower at higher RPMs continues to rise.
On a "built for torque" motor as you call it...actually nothing could be further from the truth. Yes there is plenty of torque at the lower range of RPMs, however the torque curve on these motors drops off a lot faster, causing your peak horsepower to happen at a lower RPM. And due to the fact that peak HP is at a lower RPM, the amount of peak HP is also less.
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exactly thats what happens after a few drinks.with a jet you want it to keep climing to go faster and faster im not at the river boating all day i sit on a sand bar with my freinds and familly and look for races it fun for me thanks for clarifying? ;)
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Right. This is what we've been trying to tell you. The less the torque curve drops off, the more the horsepower will keep climbing after peak torque. The torque curve controls everything related to horsepower.
However, how much horsepower and at what RPM you want it at is governed by what impeller cut you run. You want the horsepower curve of the engine to match the horsepower demand of the impeller. As far as MPH, not just pump RPM control that. The weight of the boat and the amount of thrust produced @ what RPM (which is controlled by the efficiency of the pump) will control MPH. You may have two pumps running the same impeller spinning the same RPM yet one pump makes less thrust than the other. This would mean that that pump is less efficient than the other. The other pump is getting more work done with the same impeller spinning the same RPM.
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I think all this is is that you're wording what you're trying to say wrong.
For a "grunt" motor or "building for torque" as you call it, the motor makes all its power in the lower range of RPM and not much in the mid-range.
On a motor "built for horsepower" as you call it, the motor is making its power in the mid-high RPM range.
This is not the correct way to word what you're trying to say.
A motor that is "built for horsepower" in your terms is nothing more than a motor that is built with a much more steady torque curve. In other words, the torque curve does not drop off as quickly and because of this, horsepower continues to rise even though torque is dropping off. It's just dropping off at a much slower rate than a "built for torque" motor. It is because of the fact that there is still much torque to be had that your horsepower at higher RPMs continues to rise.
On a "built for torque" motor as you call it...actually nothing could be further from the truth. Yes there is plenty of torque at the lower range of RPMs, however the torque curve on these motors drops off a lot faster, causing your peak horsepower to happen at a lower RPM. And due to the fact that peak HP is at a lower RPM, the amount of peak HP is also less.
A little confusion here, doesn't a toque engine have a flat curve and keep climbing and a HP engine drop the torque when the HP takes over and pulls it all the way to the moon ?
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Not exactly. You guys are all talking too vague. Shit a 1200 Gsxr makes 40lbs of torque, but it holds it all the way to 12,000rpm that's why it makes so much horsepower, because of it's flat torque curve.
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You guys are getting a little worked up over this ain't ya? BTW the formula for HP is torque times RPM so you can't have HP with out having good torque numbers . But from my seat you both are some what correct . I,m just an old mech and I don't know anybody important ,but I did stay in a Holiday Inn Express last nite if that counts . Peace Jimbo.
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You guys are getting a little worked up over this ain't ya? BTW the formula for HP is torque times RPM so you can't have HP with out having good torque numbers . But from my seat you both are some what correct . I,m just an old mech and I don't know anybody important ,but I did stay in a Holiday Inn Express last nite if that counts . Peace Jimbo.
....and i saved a ton on my car insurance by switching to gieco.
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that sh t is funny but watch out he might call u and a$$ H :oLE
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So, let me see if i'm understanding things right.....
I need to multiply horsepower x torque x $1000.00 to get my overloaded Hondo to run over 60 mph >:D
OK, I think I got it know ;D
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So, let me see if i'm understanding things right.....
I need to multiply horsepower x torque x $1000.00 to get my overloaded Hondo to run over 60 mph >:D
OK, I think I got it know ;D
Dont wory about your Hondo Keith. Your boat runs GREAT!. It was fast enough for me anyways!
Bob
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Thanks Bob.
Maybe I can convince the wife I need nitrous :o
Not likely :'(
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Thanks Bob.
Maybe I can convince the wife I need nitrous :o
Not likely :'(
Take her to a show and let her see those big shinny things on top of the engine. If she likes you might end up with a 6-71 GMC Blower.
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Jetboy here is what I was trying to remember;
With RPM reduced to 70% of maximum, fuel needed is reduced to only 32% of maximum, while speed is maintained at 66% of maximum.
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Take her to a show and let her see those big shinny things on top of the engine. If she likes you might end up with a 6-71 GMC Blower.
Doesn't work, her dad use to be a crew member on a top fuel dragster.
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Same story with my ex. She knew more about shit than I did. In fact she built the engine in her dad's HTM that's doing 132MPH with single engine...
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try to build as much freakin' power as you can over 5,000 rpm and below 7,000rpm, then match your impeller cut near the peak hp/rpm level and your jet boat will haul ass.
forget the debate about torque/hp...forget about torque getting you to half track and hp taking over from there because that's nonsense. its a jet boat. you mash the pedal and the motor zings to wide open throttle and full power instantly.
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Same story with my ex. She knew more about shit than I did. In fact she built the engine in her dad's HTM that's doing 132MPH with single engine...
exactly why would you split with a women that could build motors like that? ::)
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try to build as much freakin' power as you can over 5,000 rpm and below 7,000rpm, then match your impeller cut near the peak hp/rpm level and your jet boat will haul ass.
forget the debate about torque/hp...forget about torque getting you to half track and hp taking over from there because that's nonsense. its a jet boat. you mash the pedal and the motor zings to wide open throttle and full power instantly.
Very well put!
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Cyclone has his A game on.
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after much thought im was going to freshen up my ford for this season and continue to make a dyno tested 825 hp at 7100 rpm and continue to run a 250 shot of nos to push my boat into triple digets but after reading these posts i found a 496 that makes around 350 hp at 4500 and about 400 of tq so that should push my boat just as fast if not fast becouse it makes its power down low thanks u guys saved alot of money ;)
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haha.
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thought u would like that thats whats cool all the different op good sh t now if that were only true i would be money ahead :P
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Gee I wish I would have joined this thread earlier - I could have cleared it up by saying that the torque measurement tells how much a weight can be moved (400 foot pounds - or how much effort it takes to lift 400 pounds one foot) and horsepower (how long it takes to lift that 400 lbs one foot in the air).
(Torque x Engine speed) / 5,252 = Horsepower
5252 is the result of many formulas, including rpm's to rps, foot pound to pound feet, etc - basically take all of those conversions, and you get 5252. Because of this, the torque and hosepower lines will cross at these two points. If someone really wants me to post the real formula - I suggest you do a google search, I'm sure something will come up.
All engines make torque, all engines make horsepower.
The faster you spin an engine, with everything else equaled, the more HP it makes because the work is happening faster.
What we call a torque engine is just some term humans use to catagorize things. If the engine makes max power below 5252, the printed out dyno curve is going to make the torque curve higher than the HP curve - and humans will say it is a torque engine. Conversely if the max HP happens above the 5252 line, the HP number will look bigger - hence a HP engine.
You can run the same 1/4 mile number with a "torque" engine as with a "horsepower" engine (assuming you could make the raw average numbers the same).
This is why we can have cummins diesels in 4x4 trucks running low 10's in the quarter mile with only 300 peek HP.
The torque number is mostly dictated by the cubic inches, compression, and fuel - without too much you can do to change it (other than turning up the boost or adding nitrous to make the engine seem larger) - hence the reason why spinning it faster is really the only thing to do. You can't make more torque than the ci allows without boost, but you can spin it faster to make more horsepower.
Oh well, I thought this would be quick...
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Awesome post speedymopars, cleared a lot of things up for me. Thanks.
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Could you be more specific? j/k
Well put.
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Gee I wish I would have joined this thread earlier - I could have cleared it up by saying that the torque measurement tells how much a weight can be moved (400 foot pounds - or how much effort it takes to lift 400 pounds one foot) and horsepower (how long it takes to lift that 400 lbs one foot in the air).
This is also why you have torque wrenches and not horsepower wrenches :)
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OK - here is what I did to illistrate my point.
Same engine, heads, carb CFM, small tube headers.
I "put" a small hyd cam with a dual plane in one of the engines, while I put a solid roller with a tunnel ram in the other.
hyd is .425 lift, 206 duration while the roller is .606 lift with 246 duration. I didn't go too radical because then you need to worry about changing exhaust, etc. and I'm trying to keep it the same.
Assuming the stuff you need to change for the roller, $300 cam, $300 lifters, $240 pushrods, $300 roller rockers, $500 in valvesprings, keepers, retainers - well I'm into it for $1700 just in the valvetrain.
Look at the graph - I only gained ~30 ft/lbs of torque for all that effort - and I know I could get that 30 ft lbs by optimizing the combo without changing the cam.
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Now I put in an even bigger 292 duration .690 lift cam vs the hyd. Now I changed the exhaust and optimized the combo somewhat. I have to run all of the good hardware, better rods, pistons, studs, etc etc - added lots of $$ to the engine. I have the same raw torque number, but at a different RPM.
Look at the torque (green line vs green line).
What is changing? The RPM it is happening at, not the number itself.
If you were to look at the torque number only, you wouldn'y pay the money to modify your engine, that's for sure.
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Now use that and say, OK, if I'm pumping out 600 ft lbs of torque at 2000-3000 RPM, but my HP peeks out at 4000 RPM, then you want the impeller that takes the most force down low, not one that allows the engine to spin 5000 RPM. Max water flow at the lowest RPM that matches. AA, A2-4, etc.
Now if you are running that larger cam, you need to take advantage of the higher rpm power, so you need to let the impeller "slip" to take advantage of that higher RPM - otherwise because of the lower power output at the lower RPM's - you may never get there.
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I knew this guy was smart just cuz he likes Mopars. Welcome Professor Speedy ;D
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heh heh :)
At your service O0
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Great explanition Speedy !!! [attachimg=1] Thanks for shareing. ;D ;D