At What Rpm Am I At Peck Power

[bobert]

I was looking through my dyno run papers the other day and I had 325 BHP @ 6500 RPM. what happens to my BHP figure from 6500RPM to the rev limiter.

So when I am driving hard should I be changing gear @ 6500RPM?
when I am driving hard I normaly change gear at around 7500RPM.

[John Yorke]

Holding the revs past peak power will gain you nothing, to get the best out of the car [acceleration] you should be up shifting a couple of hundred rpm prior to peak power [about 6250 in your case] If your dyno man did his job you should see the power dropping away after 6500. Is the 325 FW or RWHP?

[MikeLMR]

depends on the situation, reving past peak power can help no end if it saves you a gear change. Quite often taken the rally car a little past it\'s redline on short straights bad habit I know but it\'s got a tough engine and a "new" one costs a couple of hundred at the most LoL

[bobert]

Holding the revs past peak power will gain you nothing, to get the best out of the car [acceleration] you should be up shifting a couple of hundred rpm prior to peak power [about 6250 in your case] If your dyno man did his job you should see the power dropping away after 6500. Is the 325 FW or RWHP?

it is 325 fwhp

[ianelvar]

Hi Bobert

Are you asking why the power drops off after 6500 RPM?

[Adriansturgess]

Don\'t think he\'s asking WHY it drops off.

I know myself when you are under full acceleration you just don\'t want to change gear, it kind of interupts the flow and feels so good that you end up red lining it in each gear....It takes a real effort of will to engage brain and think rationally about whether you are gaining anything or whether you should change gear at 6500 rather than 7500rpm.

[oldone]

Don\'t think he\'s asking WHY it drops off.

I know myself when you are under full acceleration you just don\'t want to change gear, it kind of interupts the flow and feels so good that you end up red lining it in each gear....It takes a real effort of will to engage brain and think rationally about whether you are gaining anything or whether you should change gear at 6500 rather than 7500rpm.

Old man like you racing\\redlining ?:evillaugh

[oldone]

I found in racing situations,that you have to change at the \'right\' moment so that the motor is always in its \'power band\' i.e. if your peak power is made at 6000 rpm then you must try to be in that \'zone\' in every gear.....:Typing

[Adriansturgess]

Well, I just have a vivid imagination....Normally change gear at 3000rpm, don\'t like the turbo\'s too much, so change gear well before they kick in. Sorry to have been caught out as a complete fraudster....:god

Edit....Hey Era, making a second post like that you caught me out, how inconsiderate!!!!!!!!

[iaint]

To get the most out of your engine\'s grunt you need to keep it within it\'s \'power band\'.  This will generally fall between the peak torque and peak power.  It\'s high torque that gives acceleration so driving round that part of the graph is a good indication.

As Mike said though - if you can avoid a gearchange you\'ll save a lot more time than lots of changes.

Most of our cars, when tweaked a bit, tend to have peak power quite late ~7-7.5k rpm so it\'s a moot point really!  My peak power is at ~7200 (pretty much flat from 6300-7500 rpm) and torque is at 5500rpm.  I find that I tend to run between 5000 and 7500 when really booting it...

[stylus350]

Gear ratios will also be a factor. The difference between gears will dictate the rev drop. If you change at peak hosepower and this then puts you into a  flat area of the rev range where the torque/horsepower is less than that which your engine produces above peak then holding onto that gear longer will be beneficial.

[Adriansturgess]

Yes, so the moral of this thread is just red line it in every gear...Its safer that way.....:Thumbs-up

[stylus350]

Yes, so the moral of this thread is just red line it in every gear...Its safer that way.....:Thumbs-up

And a whole lot more fun :Thumbs-up

[oldone]

Yes, so the moral of this thread is just red line it in every gear...Its safer that way.....:Thumbs-up

No the moral of the story is.........drive it like you stole it !!!!!!!!!:eek

[Adriansturgess]

Well you don\'t think I actually bought mine do you....:rollin