roygts

What is the best RPM shift point for best 0-60 times. I have read that the shift point should be 500 RPM beyond the point where the torque curve crosses the hp curve on a graph. Is this valid?
Roy

Jean-Marc

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by roygts:
<strong>What is the best RPM shift point for best 0-60 times. I have read that the shift point should be 500 RPM beyond the point where the torque curve crosses the hp curve on a graph. Is this valid?
Roy</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">It's not really valid. It all depends on the speed at which you are able to shift. With the rpm drop, you want when your **** is complete to be at the top of the torque curve. for most cars, this means redlining 1st and going right before the safety cut off
JM

axhoaxho

Quote "you want when your ""****"" is complete to be at the top of the torque curve. "

Ha ha ha, lol! I know it is a typo (you meant shift, right?) but it makes my day...

ettsn

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by roygts:
<strong>What is the best RPM shift point for best 0-60 times. I have read that the shift point should be 500 RPM beyond the point where the torque curve crosses the hp curve on a graph. Is this valid?
Roy</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">No. The torque curve and the HP curve always intersect at exactly 5252 rpm. It's a mathematical relationship that doesn't change. Therefore, what you've heard is a gross generalization that wouldn't be right for 90% of the cars out there.

The best place to shift is slightly after the peak horsepower, but where the next gear engages close to the torque peak. For many cars, that shift point is close to redline.

-Paul

cmoss

<a href="http://auto.howstuffworks.com/question622.htm" target="_blank">http://auto.howstuffworks.com/question622.htm</a>

Here is a great explanation.

autobahnNY

For the Boxster "S" i find 7000 RPM is the best point to shift.

Jean-Marc

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by axhoaxho:
<strong>Quote "you want when your ""****"" is complete to be at the top of the torque curve. "

Ha ha ha, lol! I know it is a typo (you meant shift, right?) but it makes my day... </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">That's actually pretty embarassing... <img border="0" title="" alt="[Eek!]" src="eek.gif" />

roygts

Actually I think the **** POINT is around 8500 RPM....
Roy

Alan Herod

Autobahn is right about 7000. Porsche is still very thorough and puts that in the back of the owner's manual, on the 02 5 speed, they are shifting from 1st at 7000-- and it looks like 7000 on the six speed S as well. You could probably learn more from the graphs by doing a better job interpolating then I just did.

special tool

So, Lets assume yOu Want to improve eConomy, cAn you shift slightly loweR??

<img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" /> <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />

JohnM

For maximum acceleration you should not change up until you reach the point where the torque at the wheels in the gear you change up to would match/exceed the torque at the wheels from the gear you are in. For most petrol-engined cars you reach the rev limit before this happens in at least the first 4 gears, so shift just before you hit the limiter. About the only times it is faster to change below the rev limit is if gearing is tall and the ratio change to the next gear is small, or in diesels where peak torque is much lower down the rev range and drops off dramatically at higher engine speeds.

adrial

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by JohnM:
<strong>For maximum acceleration you should not change up until you reach the point where the torque at the wheels in the gear you change up to would match/exceed the torque at the wheels from the gear you are in. For most petrol-engined cars you reach the rev limit before this happens in at least the first 4 gears, so shift just before you hit the limiter. About the only times it is faster to change below the rev limit is if gearing is tall and the ratio change to the next gear is small, or in diesels where peak torque is much lower down the rev range and drops off dramatically at higher engine speeds.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Bingo