shift points for best power

[WWJD]

I read the best shift point is right at the top of the power band, not past it or near the rev limiter. Is that right and if so where exactly is that for each gear? I'm talking about hammering down for a fun back road chalenge or on the drag strip. Where should you shift for the best power? If you're like me, you aren't watching the RMP but see it fly toward the RED and shift then.
Feedback?

 

[fstbusa]

brock davidson recommends 10650 rpm which supposedly is the peak of the powerband.

 

[Ssilkyslim_3rd]

Well I read that it's good to shift at 80% of the engines redline. In the case of the Busa that would be about 8700 rpms. Because consider that your max torque is at 7,000 rpms. There is also a point where power and torque peak and then begin to fall. Get a print out of a dyno run. It has the graph of engine speed, torque, and power. my 2 cents

 

[Got-Busa?]

Well I read that it's good to shift at 80% of the engines redline. In the case of the Busa that would be about 8700 rpms. Because consider that your max torque is at 7,000 rpms. There is also a point where power and torque peak and then begin to fall. Get a print out of a dyno run. It has the graph of engine speed, torque, and power. my 2 cents

Uh....that's fine and dandy if your in a 5.0-liter mustang but in the BUSA world, that doesn't mean/do anything but make you run slower!

10,600RPM is optimal but most factory tach's are off so you will have to take it to RED-LINE to find out what yours reads. FUEL cut off is 10,800 so you want to get as close to that as possible.

My tach indicates 11,200 before fuel cut off so......I take it as high as possible without hitting the limiter. I usually shift around 11,000-11,100!

If you don't believe me, take it to the track and watch your times drop and MPH go up the higher you shift!

Josh

 

[WWJD]

yeah, I remember seeing the slope DOWN after a certain point on dyno sheets. that is exactly what I was talking about. then the rev liimit drops it after that. I guess I'm doing it right - driving her right up next to the red but before the limiter [sometimes I hit it - ooh I hate that!] its seems quicke enough. thanks for the replys!

 

[WWJD]

this

 

[scottybusa]

Good topic WWJD!!! Thanks!!!

 

[Ssilkyslim_3rd]

Well I read that it's good to shift at 80% of the engines redline. In the case of the Busa that would be about 8700 rpms. Because consider that your max torque is at 7,000 rpms. There is also a point where power and torque peak and then begin to fall. Get a print out of a dyno run. It has the graph of engine speed, torque, and power. my 2 cents

Uh....that's fine and dandy if your in a 5.0-liter mustang but in the BUSA world, that doesn't mean/do anything but make you run slower!

10,600RPM is optimal but most factory tach's are off so you will have to take it to RED-LINE to find out what yours reads.  FUEL cut off is 10,800 so you want to get as close to that as possible.  

My tach indicates 11,200 before fuel cut off so......I take it as high as possible without hitting the limiter.  I usually shift around 11,000-11,100!

If you don't believe me, take it to the track and watch your times drop and MPH go up the higher you shift!

Josh

But running that close to the redline can't be good for the life of the engine right?

 

[Ssilkyslim_3rd]

I read the best shift point is right at the top of the power band, not past it or near the rev limiter.  Is that right and if so where exactly is that for each gear?  I'm talking about hammering down for a fun back road chalenge or on the drag strip.  Where should you shift for the best power?  If you're like me, you aren't watching the RMP but see it fly toward the RED and shift then.
Feedback?

I should have asked first. Are you running it at the track or are you talking about everyday riding?

 

[Ssilkyslim_3rd]

Forgive me WWJD, but Got Busa is right. I reread your post and realized that you are talking about a race application. I was thinking about something totally different. Again forgive me.

 

[WWJD]

well, I am talking about everyday riding, but riding hard and fast. seems to me most power is 8k and up, but that might just be the sound adding to the overall preception of speed. shifting right when the horsepower starts to dip seems to be the ticket 10,600 or nearby. thanks!

 

[Mikey D]

My .02...

Your RPM is goning to drop about 1500 during each shift.  You want the meat of the power to be in that 1500 RPM range.

You should shift just before peak power so you get as much of the HP in that 1500 rpm range as possible.  If you shift at redline, according to your graph, your power will be dropping off all the time, and by the time you shift the bike is only making HP in the 140 range.

In my humble opinion, shift it at 9k to get the most HP to the ground possible. This way the RPM range that you will be in throughout the gears, is the peak of your power curve.

 

[stkr00]

WWJD:

Looking at the dyno sheet, Mikey D is on track, as are the others, but what you're looking for is not so much the HP, but the Torque.

When you shift near redline as stated, the resultant rpm drop puts you right near your peak "Torque". Shifting around 9K rpm will put your closer to the actual peak, but the resulting loss is speed will be counter-productive to a quick time. The difference in torque is only about 5 ft-lbf, so it's not that big of a change.....UNLESS you're at the dragstrip racing for money.

The higher gearing in the low gears helps make up for the drop off in HP and Torque when shifting close to redline. The sooner you shift, the sooner you lose that mechanical advantage.

This is the simplest explaination I've ever heard:
Torque gets you there, and HP keeps you there[/QUOTE]


That's my $0.01 worth.

 

[srmbusa]

xxx



<!--EDIT|srmbusa
Reason for Edit: None given...|1084929291 -->

 

[Got-Busa?]

I was talking about a race only condition. On the street in normal everyday riding, I shift around 2,500--3,000 when I am just dinking along!

As stkr00 stated for the most drive you will still need to REV the bike pretty high. Of course if you have a passenger, there is no need to go that high. Let the Busa's torque get you where you want to go. It won't jerk the passenger around as much!

As far as reving the motor up to 10,800 every time!?!? You aren't going to hurt the BUSA in the stock configuration. You can do just about anything to it without hurting anything. It's when you start modding it and hitting it with the N20 that you have to be careful not to over-rev it.

Josh