Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - What is causing this flat spot in power?
View Single Post
  #15 (permalink)  
Old 03-08-2013, 10:33 AM
painted jester's Avatar
painted jester painted jester is offline
TAKE A KID TO A CAR SHOW
 

Last journal entry: 360 mopar
Last photo:
Join Date: Jan 2011
Location: Central Michigan
Age: 68
Posts: 1,846
Wiki Edits: 0

Thanks: 103
Thanked 293 Times in 241 Posts
Am I the only one that sees the power wave?

Both Dyno sheets show the same problem at about 5100 rpm to 5500 rpm the line graph shows a drop at 5200 to 5600 and the torque on the other sheet shows torque drop at exactly the same 5100 to 5500. The HP gain was about 10 hp for every 100 rpm till it hit about 5000 rpm and it dropped to 4 or 5 hp gain every 100 rpm till it hit 5400 and then made another 10 hp gain fell off again to 4 or 5 hp every 100 rpm at 5500 and then gained at 5800 your sheet does not show a smooth gain in hp it shows a wave! If you make a graph of your hp at every 100 rpm you will see that wave in power gain! The first thing I would check is reversion pulses! Could be harmonics Ive seen this wave when harmonics created a resonance wave that robbed power and created a wave effect like this! If its a harmonic resonance in the engine it will only get worse! Ive also seen it when cold coolant entered the block every time the thermostat opened and a simple change to a hotter thermostat cured it!

What engine are you running and whats your set up?

Maybe I'm too picky and pay too much attention to minor details LOL years ago thet wave would bother me but maybe today thats considered a small thing

Jester



"People who run these chassis dynos like to talk about only 25 percent loss through the chassis and related components, like I wish, it doesn't take many installation sins to double that amount of loss."

Its actually an average of 1/3 or even a little more with air and power steering!

Last edited by painted jester; 03-08-2013 at 10:45 AM.
Reply With Quote