Optimal Shift Point?
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Originally Posted by aznboysrfr
the best shift point is redline, not at the point of the peak torque
Originally Posted by nindoo
Is it possible to change the rpm where the torque peaks on our cars? Would it be possible and would it increase HP? If the Torque peaked at 6K instead of 4.8.
HP is just an expression of Torque @ RPM's.... So, in your example, if our cars 115 lb.-ft. of torque Peaked at 6,000 RPM's then at that RPM, you would also have.... 131 HP at that RPM. To really answer this question though, we would need to see the torque cruve to see how quickly the Torque drops after its peak....
Example, if say based on this Theroretical Torque cuve, you also had a Peak HP of 160 HP @ 7,200 RPM's... In order to have that, then you would need 116 lb-Ft of torque at that RPM... But say the engines Peak HP was droped to say 9000 RPM's then you would have to have 93 ft.-LB of torque at that RPM...
not sure if this helps...
Originally Posted by Zzyzx
no, the best shift point is when the Rate of acceleration in the current gear = the rate of acceleration you would have in the next highest gear, based on the Torque curve of the engine.
HP is just an expression of Torque @ RPM's.... So, in your example, if our cars 115 lb.-ft. of torque Peaked at 6,000 RPM's then at that RPM, you would also have.... 131 HP at that RPM. To really answer this question though, we would need to see the torque cruve to see how quickly the Torque drops after its peak....
Example, if say based on this Theroretical Torque cuve, you also had a Peak HP of 160 HP @ 7,200 RPM's... In order to have that, then you would need 116 lb-Ft of torque at that RPM... But say the engines Peak HP was droped to say 9000 RPM's then you would have to have 93 ft.-LB of torque at that RPM...
not sure if this helps...
HP is just an expression of Torque @ RPM's.... So, in your example, if our cars 115 lb.-ft. of torque Peaked at 6,000 RPM's then at that RPM, you would also have.... 131 HP at that RPM. To really answer this question though, we would need to see the torque cruve to see how quickly the Torque drops after its peak....
Example, if say based on this Theroretical Torque cuve, you also had a Peak HP of 160 HP @ 7,200 RPM's... In order to have that, then you would need 116 lb-Ft of torque at that RPM... But say the engines Peak HP was droped to say 9000 RPM's then you would have to have 93 ft.-LB of torque at that RPM...
not sure if this helps...
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Originally Posted by Zzyzx
no, the best shift point is when the Rate of acceleration in the current gear = the rate of acceleration you would have in the next highest gear, based on the Torque curve of the engine.
HP is just an expression of Torque @ RPM's.... So, in your example, if our cars 115 lb.-ft. of torque Peaked at 6,000 RPM's then at that RPM, you would also have.... 131 HP at that RPM. To really answer this question though, we would need to see the torque cruve to see how quickly the Torque drops after its peak....
Example, if say based on this Theroretical Torque cuve, you also had a Peak HP of 160 HP @ 7,200 RPM's... In order to have that, then you would need 116 lb-Ft of torque at that RPM... But say the engines Peak HP was droped to say 9000 RPM's then you would have to have 93 ft.-LB of torque at that RPM...
not sure if this helps...
HP is just an expression of Torque @ RPM's.... So, in your example, if our cars 115 lb.-ft. of torque Peaked at 6,000 RPM's then at that RPM, you would also have.... 131 HP at that RPM. To really answer this question though, we would need to see the torque cruve to see how quickly the Torque drops after its peak....
Example, if say based on this Theroretical Torque cuve, you also had a Peak HP of 160 HP @ 7,200 RPM's... In order to have that, then you would need 116 lb-Ft of torque at that RPM... But say the engines Peak HP was droped to say 9000 RPM's then you would have to have 93 ft.-LB of torque at that RPM...
not sure if this helps...
Here is a diagram for torque and hp from AEM, I'm not sure about its accuracy.
http://www.aempower.com/pdf/dyno/24-...Civic%20Ex.pdf
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Rep Power: 381 Think of it this way, the Redline is just the maximum safe RPM for the engine.. it doesnt determin How much Torque the engine is putting down there, it just stops you from exceeding the engines critical stress point.
The Torque cruve tells you where the best place to shift is, based on Gearing. so, on some cars redline may be the best point to shift (Due to the torque curve and gearing), but on ours, Based on The torque curve and Gearing (For a relitively un modified EX) the best place to shift for Maximum acceleration is about 6500 RPM's for every gear... (a few hundered RPM's below the Redline....)
The Torque cruve tells you where the best place to shift is, based on Gearing. so, on some cars redline may be the best point to shift (Due to the torque curve and gearing), but on ours, Based on The torque curve and Gearing (For a relitively un modified EX) the best place to shift for Maximum acceleration is about 6500 RPM's for every gear... (a few hundered RPM's below the Redline....)
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Rep Power: 305 So to change the torque curve you would have to mess around with the gearing?
The torque curve on the aem pdf file is peaking at 4.8k and it is falling afterwards. How do you determine that it is best to shift at 6.5. You used a formula eariler and calculated the result. I trust the formula and your calculation, but I don't understand a few things. For one why is torque falling after 4.8 k and is it complicated to understand the formula you used to calculate the optimal shift point?
The torque curve on the aem pdf file is peaking at 4.8k and it is falling afterwards. How do you determine that it is best to shift at 6.5. You used a formula eariler and calculated the result. I trust the formula and your calculation, but I don't understand a few things. For one why is torque falling after 4.8 k and is it complicated to understand the formula you used to calculate the optimal shift point?
Last edited by nindoo; Dec 3, 2004 at 03:27 PM.
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Originally Posted by nindoo
So to change the torque curve you would have to mess around with the gearing?
The torque curve on the aem pdf file is peaking at 4.8k and it is falling afterwards. How do you determine that it is best to shift at 6.5. You used a formula eariler and calculated the result. I trust the formula and your calculation, but I don't understand a few things. For one why is torque falling after 4.8 k and is it complicated to understand the formula you used to calculate the optimal shift point?
The torque curve on the aem pdf file is peaking at 4.8k and it is falling afterwards. How do you determine that it is best to shift at 6.5. You used a formula eariler and calculated the result. I trust the formula and your calculation, but I don't understand a few things. For one why is torque falling after 4.8 k and is it complicated to understand the formula you used to calculate the optimal shift point?
That post was in regard to aznboysrfr's post... you just hit post quicker then me... But, if you really want to work this whole thing out....
This may help
http://www.datsuns.com/Tech/whentoshift.htm
your going to need The torque curve, and your going to need the gearing of your car. Have fun.
Originally Posted by nindoo
(I'm just giving an example I don't what the actual curve is on our cars) Lets say the that the torque peaks at 4800 currently and it drops almost vertically on a graph where the data is plotted with torque vs rpm. So like at 4.9k rpm it plumuting. Would that mean anything?
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Rep Power: 400 yeah the short of it is this.
you take the given amount of torque at the given rpm. multiply it by the current gear ratio, and your final drive ratio. that gives you i guess your "effective" torque we'll call it.
now, you'd have to graph it out, but you would shift when your "effective torque" in your current gear is equal to/lower than what your "effective torque" would be in your next gear.
you take the given amount of torque at the given rpm. multiply it by the current gear ratio, and your final drive ratio. that gives you i guess your "effective" torque we'll call it.
now, you'd have to graph it out, but you would shift when your "effective torque" in your current gear is equal to/lower than what your "effective torque" would be in your next gear.
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