Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
05-22-2007, 03:41 AM
#1
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Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
OK! Here we go! so I am in the process of rebuilding my 428 CJ motor! the engine had a fairly mean cam in giving it a real nice loppy sound, when you reved it you could hit 6500rpm no problem, great on the top end, torque ok!
So here I am talking with the engine builder, he says that he builds engine more for throw you back in the seat torque! and he recomends going that rout, but, I'm gonna loose some of my top end for that to happen. In other words better out of the hole and acceleration less at the top! engine will make peak at 3500 RPM.
So ok! this sounds great, but, I love the way the engine sounded, is it gonna sound the same? (keep in mind I have headers flowmaster 40s blah blah) According to my engine guy no! it is gonna idle much smoother, and I don't believe it will be able to rev as high???
I am still learning, but I am trying to figure this out, I need to make a desicion on this in the next day or so! I don't mind giving up a little top end for better torque and take off, but I really love the way the car sounded? any advice?
So here I am talking with the engine builder, he says that he builds engine more for throw you back in the seat torque! and he recomends going that rout, but, I'm gonna loose some of my top end for that to happen. In other words better out of the hole and acceleration less at the top! engine will make peak at 3500 RPM.
So ok! this sounds great, but, I love the way the engine sounded, is it gonna sound the same? (keep in mind I have headers flowmaster 40s blah blah) According to my engine guy no! it is gonna idle much smoother, and I don't believe it will be able to rev as high???
I am still learning, but I am trying to figure this out, I need to make a desicion on this in the next day or so! I don't mind giving up a little top end for better torque and take off, but I really love the way the car sounded? any advice?
05-22-2007, 03:51 AM
#2
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
you can have all the torque in the world and if you caint put it to the ground you aint goin no where..
peak at 3500 is ussless if you ask me.. if you were to run it hard shifting at even a reasoanbly low5k or even 4500 next gear would put youjust at 3500 and then you would loose power.. not to mention the stall (assuming its a auto) stock stall around 2300 lets say so thats only 1200 rpm powerbant to work with.. with a 428 its going to make torque butin my opinion you should built is more around a peak of 4500-5k that way you run maybe a 2500 stall and have good torque atound 3k but can pull to 5k giving you about 2500 rpm powerband
if i recall corectly the motor waswnt meant for 7500 rpm runs like the 427 so no need o go anywhere near that but 5kpeak would be very streetable and still have plently of low end grunt..
but it depends on what you are going to do with it... its up to you.. just wanted to throw some info at you
edit/ well i just saw your pictures nd assuming the blue one is yours i see its a stick.. if you plan on racing with that ( drag or track) with lots of low end power your gunna go up in smoke constantly i would build a more mid range engine...
very clean car by the way..
JOSH
peak at 3500 is ussless if you ask me.. if you were to run it hard shifting at even a reasoanbly low5k or even 4500 next gear would put youjust at 3500 and then you would loose power.. not to mention the stall (assuming its a auto) stock stall around 2300 lets say so thats only 1200 rpm powerbant to work with.. with a 428 its going to make torque butin my opinion you should built is more around a peak of 4500-5k that way you run maybe a 2500 stall and have good torque atound 3k but can pull to 5k giving you about 2500 rpm powerband
if i recall corectly the motor waswnt meant for 7500 rpm runs like the 427 so no need o go anywhere near that but 5kpeak would be very streetable and still have plently of low end grunt..
but it depends on what you are going to do with it... its up to you.. just wanted to throw some info at you
edit/ well i just saw your pictures nd assuming the blue one is yours i see its a stick.. if you plan on racing with that ( drag or track) with lots of low end power your gunna go up in smoke constantly i would build a more mid range engine...
very clean car by the way..
JOSH
05-22-2007, 03:55 AM
#3
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
The engine builder should know how to set up an engine right, and for the street you need better bottom end if you wanna perform well. As far as peak hp....it's garbage. All it tells you is what the power is at 1 particular rpm among thousands of rpm's. What matters under full throttle is the average power created across the rpm range you're operating in, to that end a sacrafice in peak hp for a gain in peak torque may result in better average power and faster acceleration and better bottom end for drivability, or if you're not faster or slower, you still get better drivability. And mileage.....not that THAT matters with a 428. As far as peak, 3,500rpm sounds about right for a street 428 for torque, around 5,000-5,500 for peak HP. Don't be afraid to put some power into it as well, since larger engines can suffer a loss in bottom end better than smaller engines. These are all things to talk about with the engine builder, but in the end, if you use it on the street, you need a street engine which means a sacrafice in top end for something that's quick on the street. Don't get hung up on peak hp numbers, it's easy to do
05-22-2007, 04:45 AM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
I am all for a mid range motor more on the "streetable" vs top end side. But do I need to sacrafice the way the car sounds! I mean that cam that's in it now, is a high rpm and has such a nice lopp, sounds mean when I rev it up to 6K. I understand that the loop from the cam comes from causing the engine to misfire, but do cams that make more torque also use that some process, apparently not?? So I'm gonna mis that loppy sound??
BTW: Thanks Josh, yes it's the blue one and it has a 4 speed.
BTW: Thanks Josh, yes it's the blue one and it has a 4 speed.
05-22-2007, 06:26 AM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
actually that lope that you are talking about is because the engine is choking on its own exhaust because of all the overlap ya its fun on the highway but i would get a more streetable grind take it from me i got 72 degrees of overlap on my cam its fun on the highway but around town not so much but atleast i do alot of highway driving but if you want the best of both worlds then see if there is a roller cam available for your engine because that will give you the best of both
05-22-2007, 10:31 AM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
Will it spin the wheels in 2nd gear from a roll the way it is now (without playing with the clutch)? If yes, then you don't need more torque from a performance standpoint unless you're also going to go to taller gears in the axle. But even without a gear swap, you probably would pick up a slight gain in mpg, if that matters. Engines are usually most efficient in terms of BSFC around the rpm's where peak torque is developed.
Put your own number on it. How much useable torque are you willing to give up for the sound (or how much more torque would it take for you to give up at least part ofthe sound)? 10 ft-lbs? 25? more? Bring that to the next conversation with your engine builder.
About the roller cam - a shorter roller grind will give you nearly the same high rpm power as your current flat tappet cam while giving you better low end torque.
Norm
Put your own number on it. How much useable torque are you willing to give up for the sound (or how much more torque would it take for you to give up at least part ofthe sound)? 10 ft-lbs? 25? more? Bring that to the next conversation with your engine builder.
About the roller cam - a shorter roller grind will give you nearly the same high rpm power as your current flat tappet cam while giving you better low end torque.
Norm
05-22-2007, 11:53 AM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
I don't understand. Why are you having the engine rebuilt to different specs if you like it the way it is? Tell the builder to make it just like it is now with new parts. If he refuses, then take your engine elsewhere.
05-22-2007, 01:28 PM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
ORIGINAL: Norm Peterson
Will it spin the wheels in 2nd gear from a roll the way it is now (without playing with the clutch)? If yes, then you don't need more torque from a performance standpoint unless you're also going to go to taller gears in the axle. But even without a gear swap, you probably would pick up a slight gain in mpg, if that matters. Engines are usually most efficient in terms of BSFC around the rpm's where peak torque is developed.
Put your own number on it. How much useable torque are you willing to give up for the sound (or how much more torque would it take for you to give up at least part ofthe sound)? 10 ft-lbs? 25? more? Bring that to the next conversation with your engine builder.
About the roller cam - a shorter roller grind will give you nearly the same high rpm power as your current flat tappet cam while giving you better low end torque.
Norm
Will it spin the wheels in 2nd gear from a roll the way it is now (without playing with the clutch)? If yes, then you don't need more torque from a performance standpoint unless you're also going to go to taller gears in the axle. But even without a gear swap, you probably would pick up a slight gain in mpg, if that matters. Engines are usually most efficient in terms of BSFC around the rpm's where peak torque is developed.
Put your own number on it. How much useable torque are you willing to give up for the sound (or how much more torque would it take for you to give up at least part ofthe sound)? 10 ft-lbs? 25? more? Bring that to the next conversation with your engine builder.
About the roller cam - a shorter roller grind will give you nearly the same high rpm power as your current flat tappet cam while giving you better low end torque.
Norm
Car has reasonablytall gears 3.50! I can do 60ft burnouts in 1st gear (albiet 245 rear tires) I can chirp second slamming through the gears, I never tried a rolling start to burout in second? not sure if it would do it.
Top End is great, but it's not like there is no torque! It is after all a 428! I may look into a different roller setup, or maybe even stroke it??
05-22-2007, 03:18 PM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
As I understand it, the lop you hear from your cam is what allows you to move the peak torque up thetorque curve to a higher rpm. This gives you more horsepower, which is just torque at a given rpm (i.e. moves your peak torque from 3200rpm to 4400rpm thus increasing your horsepower). The formula for horespower is ((Torque * RPM) / 5252). As you can see, if you move your peak torque to a high rpm, you get more horsepower. Now this is not always good. That is why many people look at the peak torque and torque curve to determine the quality of a motor.
If you are planning on driving your car at high rpms like acircle track cardoes, then the lop is what you want. They want torque at high rpms. If you are going to drive your car at street level rpms, you want something more mild. There is a program called desktop dyno that works great for figuring this all out. Changing the bore and stroke (i.e. stroker) will also affect the torque curve and thus the horsepower. I love the lopping sound, but for many applications, it sucks for street driving because you have to run the engine at 4k to get any power. This will hurt both your gas mileage and your lowend rpm power (off the line put you in your seat power burn the tires power).
Like Norm said, it come down to what you want. Do you want power in low or high rpms? Do you want lopping sound or good streetability? Do you want to burn down tires and pin your girl into the seat or do you want to run the car at 160mph?
If you are planning on driving your car at high rpms like acircle track cardoes, then the lop is what you want. They want torque at high rpms. If you are going to drive your car at street level rpms, you want something more mild. There is a program called desktop dyno that works great for figuring this all out. Changing the bore and stroke (i.e. stroker) will also affect the torque curve and thus the horsepower. I love the lopping sound, but for many applications, it sucks for street driving because you have to run the engine at 4k to get any power. This will hurt both your gas mileage and your lowend rpm power (off the line put you in your seat power burn the tires power).
Like Norm said, it come down to what you want. Do you want power in low or high rpms? Do you want lopping sound or good streetability? Do you want to burn down tires and pin your girl into the seat or do you want to run the car at 160mph?
05-22-2007, 03:47 PM
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RE: Torque Vs Horsepower Stock sound Vs Mean Loppy Sound??
ORIGINAL: urban_cowboy
As I understand it, the lop you hear from your cam is what allows you to move the peak torque up thetorque curve to a higher rpm. This gives you more horsepower, which is just torque at a given rpm (i.e. moves your peak torque from 3200rpm to 4400rpm thus increasing your horsepower). The formula for horespower is ((Torque * RPM) / 5252). As you can see, if you move your peak torque to a high rpm, you get more horsepower. Now this is not always good. That is why many people look at the peak torque and torque curve to determine the quality of a motor.
If you are planning on driving your car at high rpms like acircle track cardoes, then the lop is what you want. They want torque at high rpms. If you are going to drive your car at street level rpms, you want something more mild. There is a program called desktop dyno that works great for figuring this all out. Changing the bore and stroke (i.e. stroker) will also affect the torque curve and thus the horsepower. I love the lopping sound, but for many applications, it sucks for street driving because you have to run the engine at 4k to get any power. This will hurt both your gas mileage and your lowend rpm power (off the line put you in your seat power burn the tires power).
Like Norm said, it come down to what you want. Do you want power in low or high rpms? Do you want lopping sound or good streetability? Do you want to burn down tires and pin your girl into the seat or do you want to run the car at 160mph?
As I understand it, the lop you hear from your cam is what allows you to move the peak torque up thetorque curve to a higher rpm. This gives you more horsepower, which is just torque at a given rpm (i.e. moves your peak torque from 3200rpm to 4400rpm thus increasing your horsepower). The formula for horespower is ((Torque * RPM) / 5252). As you can see, if you move your peak torque to a high rpm, you get more horsepower. Now this is not always good. That is why many people look at the peak torque and torque curve to determine the quality of a motor.
If you are planning on driving your car at high rpms like acircle track cardoes, then the lop is what you want. They want torque at high rpms. If you are going to drive your car at street level rpms, you want something more mild. There is a program called desktop dyno that works great for figuring this all out. Changing the bore and stroke (i.e. stroker) will also affect the torque curve and thus the horsepower. I love the lopping sound, but for many applications, it sucks for street driving because you have to run the engine at 4k to get any power. This will hurt both your gas mileage and your lowend rpm power (off the line put you in your seat power burn the tires power).
Like Norm said, it come down to what you want. Do you want power in low or high rpms? Do you want lopping sound or good streetability? Do you want to burn down tires and pin your girl into the seat or do you want to run the car at 160mph?
Well said, this is more or less what my engine guy explained to me. Now using a comp 110 cam, gonna switch it out to a 112 cam, he said I will gain about 50ft of torque and a little hp, but it will make that torque at 3500rpm vs 4500, I guess this is a better solution for the street.