When people talk of cams as not making any power past a certain rpm point is there actually no power? Or does the power just drop off/lower?

 

Stock b16 cams quit making power around 7600-8000, depending on the motor. The tq falls dramatically past that point.

 

considering it redlines at 8,200/8,300 those numbers have to be off

 

How so? The stock Civic Si is rated at 160hp at the flywheel at around 7,200-7,700. Somewhere in that region. Off as in to high or to low?

 

those numbers arnt off... when people say cams stop making power at a certain rpm they dont mean you wont make any power at all they mean power starts to drop off... on stock b16 cams power will start to fall after about 7800

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by miksew &raquo;</TD></TR><TR><TD CLASS="quote">considering it redlines at 8,200/8,300 those numbers have to be off</TD></TR></TABLE>

redline does not = max power

kthxbye.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chris@allmotor.net &raquo;</TD></TR><TR><TD CLASS="quote">

redline does not = max power

kthxbye.</TD></TR></TABLE>
not for the most part, but redline usually is the part where the torque curve starts to fall so significantly that revving any more isn't worth it. Shifting at redline is ususally fastest though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realfasthonda &raquo;</TD></TR><TR><TD CLASS="quote">those numbers arnt off... when people say cams stop making power at a certain rpm they dont mean you wont make any power at all they mean power starts to drop off... on stock b16 cams power will start to fall after about 7800 </TD></TR></TABLE>

but still rev it to 8200, though.

 

yeah i know im just sayin power will start to dip off some around 7800

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -KangaRod- &raquo;</TD></TR><TR><TD CLASS="quote">
not for the most part, but redline usually is the part where the torque curve starts to fall so significantly that revving any more isn't worth it. Shifting at redline is ususally fastest though.</TD></TR></TABLE>


If the max HP of a b16a is 7800 RPM then that is the ideal shift point. Torque starts to fall off at about 7K RPM, making 7K the peak torque of the engine, in stock form. You want to shift at the RPM where the engine is making maximum HP which is around 7800 RPM in the b16a.


Taking the RPM to the redline means you will be losing power because the peak power of the engine is 7800 RPM and after that RPM torque drops significantly. An engine does not make peak torque and HP at the same RPM, the torque will peak before the HP will peak.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WAFFLES &raquo;</TD></TR><TR><TD CLASS="quote">Stock b16 cams quit making power around 7600-8000, depending on the motor. The tq falls dramatically past that point.</TD></TR></TABLE>

I can subscribe to that..Just check my latest dyno:



Torque drops like right down just above 8100 or so...Need to get my stage 2s in

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiRWanabe &raquo;</TD></TR><TR><TD CLASS="quote">


If the max HP of a b16a is 7800 RPM then that is the ideal shift point. Torque starts to fall off at about 7K RPM, making 7K the peak torque of the engine, in stock form. You want to shift at the RPM where the engine is making maximum HP which is around 7800 RPM in the b16a.


Taking the RPM to the redline means you will be losing power because the peak power of the engine is 7800 RPM and after that RPM torque drops significantly. An engine does not make peak torque and HP at the same RPM, the torque will peak before the HP will peak.</TD></TR></TABLE>

Not right..'Cause you forgot one factor..Gearing...It's better to stay longer in the lower gear before shifting..if one knows the gear ratios and how much the rpms will drop after shifting it can be precisely (sp ?) calculated where the optimum shift point is..And it is above the peak hp..By a few hundred rpms or so but it all depends on the power curve and gearing.,..

 

The B16A2 cams make power to 7800rpm or so, at that point, the torque dies off therefore the horsepower does.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ce &raquo;</TD></TR><TR><TD CLASS="quote">

Not right..'Cause you forgot one factor..Gearing...It's better to stay longer in the lower gear before shifting..if one knows the gear ratios and how much the rpms will drop after shifting it can be precisely (sp ?) calculated where the optimum shift point is..And it is above the peak hp..By a few hundred rpms or so but it all depends on the power curve and gearing.,..


</TD></TR></TABLE>


About the gearing you are right; I am going on my particular engine, the tranny I have in there is super short (J1), and if I shift at 7800 the RPM won't fall out of VTEC.


Modified by SiRWanabe at 3:06 PM 9/17/2003

 

i **** exactly at 8k rpm but never felt the rev limiter to kick in maybe my tach is off... and never felt the power loss i'm talking higher gears 4th and 5th around 8k rpm but the tach is off is there anyway i can check this except the dyno or a 5" tach...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiRWanabe &raquo;</TD></TR><TR><TD CLASS="quote">


About the gearing you are right; I am going on my particular engine, the tranny I have in there is super short (J1), and if I shift at 7800 the RPM won't fall out of VTEC.


Modified by SiRWanabe at 3:06 PM 9/17/2003</TD></TR></TABLE>


u might not fall out of VTEC but ur still at a lower rpm u would be after shifting at 8200. only about 400 rpm lower but that could be 5 to 8 hp difference. the different shift point probaly wouldn't make too much difference in a street race unless its really close. go to the track and make a couple runs shifting at 7800 then make a couple runs shiting at 8200. see which average is lower. of course this will only be affective if your a consistant driver.