Good Cam Choice?

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273 said:
Power is real, that's a false statement you can say hp standard is kind of made up, it's very loosely based off what a horse can do, but that don't matter we don't use the number to compare what horses vs engines can do but what amount of work an engine can do. Power is real and we use hp as the measurement, you can use different types of power measurements if you like, but all convert to one another.

It like saying speed ain't real cause distance and time measurements are based of arbitrary units miles and hours.

Torque and rpm combined is what moves and accelerates your car but we need someway to rate that combined effort which is power and here we use hp to do that can use watts or some other power rating if you like.

I feel people don't quite grasp rpm is just important as torque. Eg.. Take an electric motor (flat tq curve) that makes, 500 lbs-ft from 0-6000 rpms, without a factoring the power at each of those rpms looks the the motor ability is equal across the rpms. But rpm multiplies the torques abilities, eg... About 19% every 1000 rpms, so @1000rpm hp is 19% of 500lbs-ft = 95hp, @2000rpm 38% of 500lbs-ft = 190 hp, @6000rpm hp is 114% of 500lbs-ft = 570 hp. So with out figuring out the motors power we'd be in the dark about calculating it's capabilities eg.. 0-60, et/mph, top speed etc.. Making it hard to match the required engine to the job.
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TBH I don't really feel like engaging in this argument. It's nonsense anyway bro. We will think what we think. It really doesn't matter either way.

For the record I would love to have a nice 650 hp BB.
 
273 said:
Sorry I miss read this didn't see the 1st "isn't" so guess were on the same page then :)
( this subject is a pet peeve of mine )
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We're not really on the same page but it's not important enough for me to spend time on. Nobody's mind is being changed anyway.
 
Mean416 said:
My point isn't that power isn't real. It's that horsepower isn't real. It's a calculation. It was derived for marketing purposes in the old days.

An engine that makes big torque at low rpm but the torque curve falls off with rpm. That's your stock engine.

We alter cam timing and other aspects and now we're making peak torque higher. It's a more powerful engine. It's still torque production. It's just capable of it at higher rpm, which helps the vehicle accelerate faster.

Put another way: when you look at the horsepower curve, you ARE looking at the torque curve. The power curve rises and falls in proportion with rpm and a random *** constant, 5252.
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Yet no one EVER said I need to make more torque to go faster.

You don’t have a clue how a dyno works or what the numbers mean.
 
siuauto said:
I am building a stroker 340 with a set of trick flow heads. It's a Molner 3.79 stroke with their H beam rods and Wisco forged pistons. The compression ratio is going to be 10.6:1. OTB Trick Flow Heads with Hughes 1.6 rocker arm. I have an Edelbrock air gap and Victor Jr for intakes (Any input there, too?), and a Holley super stealth sniper. Its going into a duster with a 4 speed and 3.91 gear with a 29" tall tire. Headers are TTI 1 3/4" primary
The car is not a race car but a hot street car that will go down the track a couple of times a year.
The cam in question is a Comp Cams solid roller with .288 duration (.243 @ .050) and .550 lift. Its on a 110 lobe separation.

Any thoughts on this cam? Too small? Too Big? etc...

Thanks,
Jeff
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What is the intake valve size. Using 2.05" in the 128 formula indicates a 102 LSA. Pretty tight so I would order the cam ground on a 108° LSA.
For the intake manifold it depends on what you expect for street manners. The Performer AirGap will provide a little better off idle torque, but with the 3.91 gearing the Victor should work well as the revs will pick up quickly.
 
TT5.9mag said:
What’s the goal for the car? Do you have a number (hp or track time) in mind? Without a goal in mind anyone suggesting a cam profile or manifold choice is kinda pissin in the wind. What’s the car weigh?
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HOT STREET WITH A TRIP TO THE STRIP A COUPLE OF TIMES A YEAR.
 
siuauto said:
Could you elabrate on this? I didnt know a throttle body injection would affect it? Not sure if it's easily explainable, but if so, I would love to hear it.
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With an exhaust O2 sensor the tighter LSA increases overlap which can allow unburned fuel to get out the exhaust during the overlap period. The O2 sensor sees this as a rich condition and tries to lean it out. Throttle body injection is more difficult. With multiport the beginning of injection can be tuned to reduce that.
 
Newbomb Turk said:
Yet no one EVER said I need to make more torque to go faster.

You don’t have a clue how a dyno works or what the numbers mean.
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Cause People don't seem to realize when talking about torque their generally talking about power indirectly. Cause your generally referencing it's against Rpm if your conscience of it or not Eg.. My engine got a strong tq curve from 3000-5000 rpm which is also more power at those rpms, or I got a tq engine would
generally mean it makes its hp at low rpm etc..
 
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273 said:
Cause People don't seem to realize when talking about torque their generally talking about power indirectly. Cause your generally referencing it's against Rpm if your conscience of it or not Eg.. My engine got a strong tq curve from 3000-5000 rpm which is also more power at those rpms, or I got a tq engine would
generally mean it makes its hp at low rpm etc..
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Torque without RPM means nothing. Like torquing a bolt. You can’t measure torque without RPM. And RPM is what moves the car with horsepower.
 
Torque and HP are separate but related e
Newbomb Turk said:
Torque without RPM means nothing. Like torquing a bolt. You can’t measure torque without RPM. And RPM is what moves the car with horsepower.
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Newbomb Turk said:
Torque without RPM means nothing. Like torquing a bolt. You can’t measure torque without RPM. And RPM is what moves the car with horsepower.
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Without torque you get no RPM.
 
Newbomb Turk said:
Torque without RPM means nothing. Like torquing a bolt. You can’t measure torque without RPM. And RPM is what moves the car with horsepower.
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True, but You automatically increase Hp when You increase torque at the same rpm, You have no choice in the matter. And per My example above, the torque can remain the same, but raising the rpm increases the Hp...again, You have no choice in the matter, because the two are inexorably tied together....this Tq vs Hp thing is pointless....
 
RRR,
Toilet is working well. Sorry, you are wrong. Hp is NOT measured, it is calculated from the tq, which IS measured.
 
Dan the man said:
Then why is torque king on the street? I'm not saying that it's true, it's just about everywhere I've read about rv torque cams that's what they always say
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Because it's easier & more reliable to go big for the avg. leadfoot, if the package & tune are in the ballpark, unless one F's up the basics really badly.
 
Bewy said:
RRR,
Toilet is working well. Sorry, you are wrong. Hp is NOT measured, it is calculated from the tq, which IS measured.
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In the example that I gave it is measured.
 
Killer6 said:
True, but You automatically increase Hp when You increase torque at the same rpm, You have no choice in the matter. And per My example above, the torque can remain the same, but raising the rpm increases the Hp...again, You have no choice in the matter, because the two are inexorably tied together....this Tq vs Hp thing is pointless....
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What happens AFTER peak torque? RPM goes up and so does horsepower. All while torque is going down.

The ability to increase power is limited. You increase cylinder pressure, increase RPM or both. Thats it.

The torque verses horsepower thing isn’t pointless. It matters.
 
Dan the man said:
Then why is torque king on the street? I'm not saying that it's true, it's just about everywhere I've read about rv torque cams that's what they always say
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Who says that? Guys who think smoking the tires is cool?

The problem as I see it Dan is you want to carve out one point and live and die by it. Like saying torque is king on the street. There is far more to it than that. You can’t take one thing in isolation.
 
Newbomb Turk said:
What happens AFTER peak torque? RPM goes up and so does horsepower. All while torque is going down.

The ability to increase power is limited. You increase cylinder pressure, increase RPM or both. Thats it.

The torque verses horsepower thing isn’t pointless. It matters.
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It's pointless in that, unless You increase the level of torque past-peak or raise it, You will not see an improvement in Hp...it is mathematics...hence the flatter the curve, the faster the car..
 
Newbomb Turk said:
Who says that? Guys who think smoking the tires is cool?

The problem as I see it Dan is you want to carve out one point and live and die by it. Like saying torque is king on the street. There is far more to it than that. You can’t take one thing in isolation.
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I don't know if it's true or not
 
Dan, for street you want a torquey engine to get you rolling off street lights and stop signs. Some of the commenators here live with HP up their hoop. Fine for them. A big HP engine will have a cam that provides higher RPM torque. That with higher RPM gives a higher HP figure, and that high HP allows you to drive at 150 to 200MPH. Not exactly street.
Then the arguement goes to a torquey engine making you smoke the tires every time you step on the throttle. Well maybe if you have no filter, but judiscious application of the loud pedal controls that. A torquey engine allows use of taller rear gears which enables better fuel economy. A torquey engine in a truck allows pulling a trailer with less throttle opening again giving better fuel economy.
If you go to show and shines and to the strip a couple of times a year, more gear can be tollerated.
The "RV" cam designation came about as the design gave slightly more duration and lift than the OEM cams, which allowed easier hill climbing in motor homes and trucks pulling a holiday trailer. Then motor homes and trailers got bigger and that market moved to diesel engines, and diesels provide great low RPM torque for those working applications.
 
Dan the man said:
I don't know if it's true or not
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It's simple, people are making more complex then it needs to be, power (hp) is what moves and accelerates your car from idle/stall until you run out of power, power is equal to torque x rpm. The only way to increase power is to increase torque and or rpm. In a street engine acceptable rpm range is somewhat limited eg. Idle to 5000+rpm, leaving a little room to increase power by moving torque up the rpm range eg.. 4500 vs 5000 peak hp rpm but generally leaving torque the main way to increase power through street rpm range.

Any time you hear torque vs hp or torque does x and hp does y is gonna be a wrong statement.

Bottom line is..
Hp moves your car and hp is a combination of torque and rpm.
 
273 said:
It's simple, people are making more complex then it needs to be, power (hp) is what moves and accelerates your car from idle/stall until you run out of power, power is equal to torque x rpm. The only way to increase power is to increase torque and or rpm. In a street engine acceptable rpm range is somewhat limited eg. Idle to 5000+rpm, leaving a little room to increase power by moving torque up the rpm range eg.. 4500 vs 5000 peak hp rpm but generally leaving torque the main way to increase power through street rpm range.

Any time you hear torque vs hp or torque does x and hp does y is gonna be a wrong statement.

Bottom line is..
Hp moves your car and hp is a combination of torque and rpm.
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Kinda so. But HP is the result of torque, and torque does the acceleratiing.
 
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