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      03-02-2010, 06:22 PM   #1
EagleEye CA
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Can someone explain Gintani dyno's

I am confused now looking at dyno's done at Gintani. Why are the axis point where tq meets hp differ from run to run? Why are they not intersecting at 5252 rpm? If they have dyno'd many different M3s why can't they have a consistent scale to use all the time?



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Bone stock run, notice how its at 5252


Rpi Scoops, Fully catless Stock exhaust, Powerchip Stage 1, RD Sport Pulley


Rpi Scoops, Macht Schnell Air Filter, No cat stock X-pipe, RD SPort Pulley ,Gintani Rear section.


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Stock run Axis point is at approx 5700


After envy intake, note that after they leaned it out the axis point is shifting back from 6100 to 5800


Original post

Finally this one, notice this was on the same exact day but couple hours apart yet the axis point is way off.

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      03-02-2010, 06:35 PM   #2
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Why don't you just call and ask Gintani ?
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      03-02-2010, 07:03 PM   #3
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Its due to the HP And TQ Scale being different. That will move the RPM cross point. The unexpainable ones are the graphs that have the same scale and different cross points. It is either photoshop or something in the dyno dynamics software. I have never seen anything like that.
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      03-02-2010, 07:19 PM   #4
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Quote:
Originally Posted by powertrip View Post
Why don't you just call and ask Gintani ?
+1
I really don't see the point of this thread unless you are trying to be a troll and start a bashing thread. Really you should either PM them or give them a call before posting next time.
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      03-02-2010, 07:19 PM   #5
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Originally Posted by PencilGeek View Post
I can tell you exactly why this happens and and assure you this is totally normal. You are correct that HP and TQ should always intersect at 5252 RPMs. But notice that in each of these graphs HP and TQ are on separate scales. For example in the first graph, HP is on a 0-400 scale, but TQ is on a 0-450 scale. If you put them both HP and TQ on the same exact scale then they would perfectly intersect at 5252. But because HP and TQ are on different scales, that means you can't even think of the two lines intersecting -- because it's like two different graphs being overlayed onto the same screen.

For example, if TQ scaled from 0-5000, then the TQ curve would be crunched at the bottom of the screen and wouldn't even intersect HP at all. This isn't unique to the Gintani dyno results -- this would be true of any dyno that puts HP and TQ on separate scales. Dynojet does the same thing, as does Dynapack. To avoid this confusion, when I print my own dyno graphs, I makes sure that HP and TQ have the same scale, then the lines intersect on the screen exactly where you expect to see them.

I hope this helps explain the confusion.
Thanks for clarifying all this. Why wouldn't you use the same scale everytime? Any advantage to scaling differently?
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      03-02-2010, 07:40 PM   #6
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Originally Posted by PencilGeek View Post
Dyno software does it automatically so you can actually see some shape in the TQ curve. If it didn't auto scale, then sometimes the TQ curve would have no visual shape to it and you'd never be able to tell where your peak was.

It's a real pain-in-the-butt for a dyno operator to change it. They may need to override the system defaults every time they do a dyno run. That's not practical for a shop trying to make a profit. I do it on my own graphs, just because I'm not a shop and I have too much time on my hands.

When I first saw this more than a year ago with my own dyno results, it confused me too. That's when I noticed that the two numbers were on different scales. As soon as I corrected the scales, the lines intersected exactly where I expected.
it all makes sense now, thank you.
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      03-02-2010, 08:09 PM   #7
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This was one of the more informative posts I've seen on this board in a while. Thank you to EagleEye and PG for sharing this information.
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      03-02-2010, 10:15 PM   #8
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It is not just as simple as the scaling. Why do curves laid over each other on the same graph with the same scale have 2 different intersection points.

Look at this one the blue run crosses @ 5800 and the red @ 6000. How can this be if both runs are in the same scale?

Can you scale scale two runs on the same graph differently? Is this a Dyno dynamics thing?
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Last edited by masitr; 03-02-2010 at 10:21 PM.
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