What Should I Be Looking For On A Dynosheet?
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TECH Junkie
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From: Southside Chicago
What Should I Be Looking For On A Dynosheet? can someone explain what exactly should i be looking for on a dyno sheet? certain torq at certain rpms? everyone says "usable power under the curve", but what does that really mean?
thanx
james
thanx
james
to me, usable power is less than 3500 rpms, because when i'm driving around town i rarely get about 3500. you'll notice that cars with cams that have more "usable" power have a flatter looking torque curve, where as cams that are "gutless" down low have less torque at lower rpms but rapidly increase as rpms increase.
also a couple other things to look for are the peak hp, look to see how long it stays at its peak, and how quickly it drops off after the peak.
and i like to look to see if the hp and tq are the same value at about 5200rpms, because the way that hp is calculated they will have the same value at 5252 (if i remember correctly), if they don't have the same value the graph is
also a couple other things to look for are the peak hp, look to see how long it stays at its peak, and how quickly it drops off after the peak.
and i like to look to see if the hp and tq are the same value at about 5200rpms, because the way that hp is calculated they will have the same value at 5252 (if i remember correctly), if they don't have the same value the graph is
Thread Starter
TECH Junkie
iTrader: (32)
Joined: Sep 2005
Posts: 3,179
Likes: 2
From: Southside Chicago
yea, i noticed they run into each other about there, . . but why should i be looking for this? to see if the dyno is accurate? i've seen some dynos like 435/405 lets say, to me that sounds like low torque, but as long as you have over 300 tq at 2500 rpms thats good huh?, . .thanx, .. i don't know why people haven't responded to this easy thread
Along the same lines ..
This has come up on a local board.
For track / street racing purposes, which would be favored .. higher peak numbers or higher under the curve #'s ?
What do smoother fuel charts net you?
This has come up on a local board.
For track / street racing purposes, which would be favored .. higher peak numbers or higher under the curve #'s ?
What do smoother fuel charts net you?
Teching In
Joined: Aug 2005
Posts: 26
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I think it's better to reach max hp and keep it there throughout the powerband while you're shifting. A car that holds 500hp from 5500 to 6500 is going to be faster than the same car that makes 500hp only at about 6500. Each time you shift, you're dropping horsepower. So you want to minimize that. That's what I notice from racing on the highways.
Couple things to note are SAE correction, want to make sure it's normalized so you can compare it properly. Also I find it frustrating that most dyno operators don't start their runs (especially cammed cars it seems) at 2k rpm to get an accurate picture of low rpm power. I guess it's convention that hasn't changed yet.
