duration vs torque
duration vs torque I know that bigger duration means the power band shifts up. Is there a more specific rule to this? Does the torque peak move up alot? Lets say one has a 200 duration cam and 4000 peak torque. Now one puts in a 230 duration cam, what is the peak torque? Does it really matter though? Isn't horsepower all that's important at high rpm? So if one has a 4400 stall the torque is really not as important and big duration can only help? Basically is there a rule of thumb that says for a certain duration you'll need this stall to get the best results? Please enlighten me.
TECH Senior Member
Joined: Nov 2001
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From: Troy, AL
Re: duration vs torque Yes, with more duration the TQ peak moves upward much like the HP peak.
There's ALOT of difference between a 200 and a 230 cam. I can't say exactly how much it would shift the HP peak but it would be quite a bit. More than 1200 RPM I'd say.
HP v/s TQ will be debated 'till the cows come home but yes, HP is what wins races SO LONG AS it's properly channeled (this means proper gearing and converter.) Of course, there is a direct relation between HP and TQ. You can't have HP without TQ. HP (in this case) is simply a measure of TQ at a paticular RPM. In other words, X amount of TQ at a given RPM equals X amount of HP, ALWAYS. You could say that EITHER HP or TQ is all that's important at ANY RPM since TQ at RPM is the same thing as HP.
If you have a true 4400 stall then what is important is what power you have at 4400 or higher. You should also note that anytime you change the amount of TQ coming into a converter you change the stall speed. Take a 4400 stall and add a 150 HP shot of nitrous. What happens? You may now have a 5400 RPM stall! Make it a 300 shot and it goes up even more. No nitrous? Back to 4400.
I know of no rule of thumb that dictates what stall speed for a given duration. Other people's experiences, educated guesses, and especially, dyno sheets will make the choice as accurate as it can be.
<small>[ July 14, 2002, 11:14 AM: Message edited by: Colonel ]</small>
There's ALOT of difference between a 200 and a 230 cam. I can't say exactly how much it would shift the HP peak but it would be quite a bit. More than 1200 RPM I'd say.
HP v/s TQ will be debated 'till the cows come home but yes, HP is what wins races SO LONG AS it's properly channeled (this means proper gearing and converter.) Of course, there is a direct relation between HP and TQ. You can't have HP without TQ. HP (in this case) is simply a measure of TQ at a paticular RPM. In other words, X amount of TQ at a given RPM equals X amount of HP, ALWAYS. You could say that EITHER HP or TQ is all that's important at ANY RPM since TQ at RPM is the same thing as HP.
If you have a true 4400 stall then what is important is what power you have at 4400 or higher. You should also note that anytime you change the amount of TQ coming into a converter you change the stall speed. Take a 4400 stall and add a 150 HP shot of nitrous. What happens? You may now have a 5400 RPM stall! Make it a 300 shot and it goes up even more. No nitrous? Back to 4400.
I know of no rule of thumb that dictates what stall speed for a given duration. Other people's experiences, educated guesses, and especially, dyno sheets will make the choice as accurate as it can be.
<small>[ July 14, 2002, 11:14 AM: Message edited by: Colonel ]</small>
