Average HP rather than Max HP:

Why we do not see reference to Average HP (Total Area below the curve) in Dynos?

Better still why not having a new Matrix HP.rpm or lb.ft.rpm?

In this is way a mod can be judged by the avergae HP gained and 2 engined can be compared by comparing HP.rpm or lb.ft.rpm?

What do you think?

 

I would agree 100% with this! Unforunately calculating the area b/w two curves requires calculus and I never was a big fan of integration and derivatives.

 

No biggie, a simple DSP integrating function from Numerical Analysis can do the trick :P

 

If you did work up something like that, then I would also weigh the gearing of each particular car as well to know what rpm range is pertinent for your calculations. I kno my car never goes below 4000 on an full acceleration run for example.

 

Did anyone ever computed the "low-rpm" at 1-2, 2-3, 3-4, 4-5 shifts at WOT?

Pull_T,

I agree, the gearing is important.

Any gains in HP at any rpm would be refelected in 1st gear.

However,

At WOT on 2nd, 3rd, and 4th, 5th gears:
low-rpm of 1-2 shift to Redine would be used for the 2nd.
low-rpm of 2-3 shift to Redine would be used for the 3rd.
low-rpm of 3-4 shift to Redine would be used for the 4th.
low-rpm of 4-5 shift to Redine would be used for the 5th.

Let us compute:

low-rpm of 1-2 shift = ( 1.551 / 2.563 ) * 6900 = 4175 rpm
low-rpm of 2-3 shift = ( 1.021 / 1.551 ) * 6900 = 4542 rpm
low-rpm of 3-4 shift = ( 0.653 / 1.021 ) * 6900 = 4413 rpm
low-rpm of 4-5 shift = ( 0.470 / 0.653 ) * 6900 = 4966 rpm

Note that all the above shifts ( except the 4-5) would drop below VTEC hot-cam engagement set at 4800 rpm!

So the best mod is the one that would max HP/Torque starting from 4000 rpm. Unfortunately , Comptech Headers does its trick starting at 5500 rpm. So, If any other headers that has better average gains from 4000 rpm up to 6900 rpm it would be superior.

 

That's exactly what I had in mind. Good analysis Nash...

 

That's wierd... on the V6 Accord we are in VTEC (3,500+ RPMS) after every gear change.

1-2 leaves us around 4,200 (give or take a few hundred RPM's)
2-3 leaves us around 3,800 (same disclaimer)
3-4 doesn't really count since 3rd tops out at 115mph and 4th is strictly over drive in our car and VTEC dis-engages after about 120-125mph anyway. (I can't prove this but I can hear the difference in my intake level when accelerating past 120mph)

 

I don't have the ratios handy, but it certainly seems odd that the rpm reduction would increase between the 1-2 and 2-3... Can someone confirm the ratios here?

 

Not only that, but if I recalled correctly, the Dyno charts of various members showed a drop in HP/Torque at the switch point of the secondary plenum opening up, ~ 3800-4000 rpm. So, not only do we drop out of VTEC, but we also temporarily lose HP/TQ with each gear change!

 

They’re a few things to look for... One curve is not always above the other. IN the case of one curve always above the other, a simple trapezoidal approximation can be used to give a close enough approximation for the area gain.

When one curve is not always above the other one (common with lots of mods), it is possible (and probable) to have the dyno curve crossover points in between the x sample points (RPM sample points). This requires a calc to find the x-location (and associated y) where the graph lines cross. The line crossings are then used to determine “positive” and “negative” areas of HP and/or torque gain.

The other option is to generate an equivalent equation for the two curves (take your curve fit method) and just use a popular numerical integration method (the function of y is now well defined as a function of x at all points)…

-- end integration diatribe --


One of the factors that would be rather important for knowing just what area is important would be to include a set of horizontal lines that showed the starting point of interest based on a car's gearing. The area that is below a shift point would only be of interest in 1st gear...

Want to write some WinPep post processing software. The data should be availabe as x,y data!

 

Boy, you guys are faaaast.... My shift point blurb is already stale...

 

lol, let me know if you need help writing the interface to the winpep.

 

Maybe we should talk some time.

From what I understand the DynoJet is available in x,y data (ascii?). The tool could probably just "supplant" WinPep for doing averaging/integration and for entering "gear ratio profiles and into the tool".

New tool.... I wonder how many people would be interested?

(Just get the disk with the "raw" data from the Dynojet operator and run the data into WinPep OR into the "enhanced" version...

(perhaps a poll tommorow....)

 

Oh HELL YEA! That would kick so much azz! Just protect yourself so that DynoJet doesn't turn around and steal your idea and incorporate it into their software.