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Re: torque per cube?
[Re: MuscleMike]
#578467
01/12/10 07:30 PM
01/12/10 07:30 PM
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Joined: Sep 2008
Posts: 2,840
Flint, Michigan
B1Fish540
master
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master
Joined: Sep 2008
Posts: 2,840
Flint, Michigan
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Quote:
Thats why 440's were always perceived as torquey engines. A good amount of cubic inches with a head better suited for 350-370" engine.
Class over
Mike @MM
I think we all have taken head flow 101, Mike. What needs to be talked about more is specifics.
btw, all OEM heads back in the day were small valve, small port, except for the Hemi and the BB chev(well, the boss ford also). Take the 455 Buick, it had even smaller valves than the 440. These things made huge TQ for propelling the big Buicks down the road.
Why a big motor responds this way, tho, is still a little murkey. Is the small valve producing a faster/richer charge earlier in the RPM range resulting in more power? And is that alone producing more torque? My question i guess is: Does intake velocity account for the low RPM torque in these engines, along with the longer stroke/displacement?
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Re: torque per cube?
[Re: gregsdart]
#578469
01/12/10 11:46 PM
01/12/10 11:46 PM
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Joined: Sep 2003
Posts: 2,966
Wendy, I'm home.
dstryr
master
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master
Joined: Sep 2003
Posts: 2,966
Wendy, I'm home.
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Quote:
I am curious what some of the best packages produce for torque per cube. I and I think a lot of other guys would like to see how the various heads work, and what is possible. Non mopar combos wellcome for comparison.
Please give head type, induction, cam type (specs also), usage. Thanks, Greg
Greg,
This is my 505" street car engine that was finished up in November:
Here are the basics:
1966 440 block +.030"
440 Source 512" kit
440 Source heads, valve job, back-cut valves
Porting: 254cfm initial, 283 after porting on the intake side
.044" ROL head gasket
Squared and decked, pistons -.004"
10.2:1 compr. approx.
Comp Cams XS290S
Comp Cams EDM lifters
Smith Bros Pushrods
Harland Sharp 1.5 roller rockers S70015K
'69 6 bbl induction system with Promax outboard metering plates, center metering block, and rear adj. base
Stock dist. with Pertronix Ignitor conversion and Flamethrower coil
Doug's D452 2" headers
598hp, 651 lbs/ft torque on 91 octane pump gas.
1.29 lbs/ft tq/cubic inch
dstryr, since 1986.
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Re: torque per cube?
[Re: MuscleMike]
#578470
01/13/10 01:55 AM
01/13/10 01:55 AM
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Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11
super stock
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super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
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Quote:
The converse is true if you have a small head on a big engine, it will make gobbs of torque but the small head will not allow the engine to breath at higher RPM to make more HP.
I agree in theory Mike, but if you have a good head on the big motor it may not make the amount of torque at low rpm that the small head will but it will produce more torque overall than the smaller head can possibly produce. Which I am sure you know.
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Re: torque per cube?
[Re: MuscleMike]
#578472
01/13/10 08:45 AM
01/13/10 08:45 AM
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Joined: Jan 2008
Posts: 1,213
Minn
SportF
pro stock
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pro stock
Joined: Jan 2008
Posts: 1,213
Minn
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This has turned into a very interesting discussion. Let me step back and propose this. Say you have a lawn mower engine, and you go full throttle and they go up to about 4K in revs, no load. It can't rev faster because the air in and out just won't let it go any faster, that’s as fast as it can rev. At that "no load" 4K rpm, you can rub a stick on the shaft and slow it down because it has virtually no torque there as it is running at max rpm without a load. Now, change that engine however you want and now this same engine will rev "no load" to 5K. Now there won't be any torque at that 5K, but what now happens at 4K. You got torque there now! So doesn't the ability to run higher revs move the whole torque curve up? I think it has to. This lawn mower engine that now goes to 5K has more power than that engine that only went to 4K. And if everything is reasonably efficient, I bet with this motor too, the HP and TQ are within 10% of each other, same as all the motors listed this topic.
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Re: torque per cube?
[Re: SportF]
#578473
01/13/10 07:32 PM
01/13/10 07:32 PM
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Joined: Dec 2005
Posts: 293
Kansas City Metro
mbogina
enthusiast
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enthusiast
Joined: Dec 2005
Posts: 293
Kansas City Metro
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SportF- Your logic is that spinning the motor higher will make more HP, but this is not true. Once the TQ curve drops faster than the math converts to bigger HP due to the increase of RPM, the motor has reached its peak HP and turning more RPM will not make more HP. On my SS Hemi, if I happen to make peak HP at 8000 RPM, turning it up to 9000 will definitely NOT produce more HP, the TQ curve is simply falling too fast. A motor under no load makes very little TQ. Most Dyno's are "water brakes", pretty hard to compress that water, and the "water always wins", loading the motor to its "stall point" prior to the operater "releasing" the water in a controlled manner to allow the motor to accelerate. In your previous post, you stated that most motors peak TQ production will be within 10% of peak HP, I have not found that to be true. My SS motor is closer to 40%, the last 572 I dyno'ed was around 15%, a stock 1970 rated 440-4V from the factory was 31%, a stock GS 455 motor was around 50%, the last 505 Hemi I dyno'ed was 20%.........
Be a Rebel- Break the Laws of Physics!
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Re: torque per cube?
[Re: B1Fish540]
#578475
01/14/10 01:28 AM
01/14/10 01:28 AM
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Joined: Jan 2003
Posts: 31,050
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,050
Oregon
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Quote:
Quote:
Thats why 440's were always perceived as torquey engines. A good amount of cubic inches with a head better suited for 350-370" engine.
Class over
Mike @MM
I think we all have taken head flow 101, Mike. What needs to be talked about more is specifics.
btw, all OEM heads back in the day were small valve, small port, except for the Hemi and the BB chev(well, the boss ford also). Take the 455 Buick, it had even smaller valves than the 440. These things made huge TQ for propelling the big Buicks down the road.
Why a big motor responds this way, tho, is still a little murkey. Is the small valve producing a faster/richer charge earlier in the RPM range resulting in more power? And is that alone producing more torque? My question i guess is: Does intake velocity account for the low RPM torque in these engines, along with the longer stroke/displacement?
Yes, the key is intake velocity. Low velocity kills the torque and so does velocity that is too high. There is a direct relationship between the CID, CSA and the RPM of the torque peak called the McFarland formula.
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Re: torque per cube?
[Re: AndyF]
#578478
01/14/10 12:55 PM
01/14/10 12:55 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Quote:
Yes, the key is intake velocity. Low velocity kills the torque and so does velocity that is too high. There is a direct relationship between the CID, CSA and the RPM of the torque peak called the McFarland formula.
I believe this is one of the key elements in PipeMax's calculations too. The problem with those formulas is they give a specific number for a specific rpm. Not a range. An rpm point. IMO, fo the rpms that Greg is curious about intake pulse/wave tuning could become an effective boost too. The smallest, straightest port with the largest intake valve that isnt shrouded will make the most torque provided it's volume is correctly matched to the stroke an rpm point of the desired result.
Mike (MM), I can't recall what the constant in the HP formula represents... Can anyone answer that one?
PS - FINALLY A REAL TECH DISCUSSION!!! UN would be so happy 
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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