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Old 11-20-2009, 09:59 AM   #1
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Default STD vs SAE correction

I've been trying to google the difference in the 2 and can't really seem to find any formula's or anything except people on forums talking about it which one is accepted.

Can someone shed some light on the subject and tell us exactly what goes into each?

Reason I ask is because I noticed something in the dynojet files that we use in Newark, DE and was wondering if that made a difference in the numbers or not.
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Old 11-20-2009, 10:13 AM   #2
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In for answer.
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Old 11-20-2009, 10:32 AM   #3
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SAE correction "corrects" your dyno numbers to standardized temp, atmospheric pressure, etc in an attempt to make dyno runs from one day comparable to dyno runs on a different day with totally different weather conditions.

it actually works pretty well... for n/a cars. for turbo cars the air actually going into the engine is so far seperated from the actual atmospheric conditions, that SAE corrections tend to wildly overcompensate.

personally i always go by the actual uncorrected numbers...
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Old 11-20-2009, 10:52 AM   #4
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Originally Posted by therieldeal View Post
SAE correction "corrects" your dyno numbers to standardized temp, atmospheric pressure, etc in an attempt to make dyno runs from one day comparable to dyno runs on a different day with totally different weather conditions.

it actually works pretty well... for n/a cars. for turbo cars the air actually going into the engine is so far seperated from the actual atmospheric conditions, that SAE corrections tend to wildly overcompensate.

personally i always go by the actual uncorrected numbers...
This is exactly what is on every other forum which gives almost no info. I'm looking for an actual explanation, not just "it uses etc and it corrects".
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Old 11-20-2009, 10:57 AM   #5
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I just look at the number it gives my run and I can see it'll correct it by 1.02 or .98 I've never seen much more than that.
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Old 11-20-2009, 11:01 AM   #6
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Try this link:
Equations: Dyno Correction Factor and Relative Horsepower

Seems to give some equations and reasoning behind it.
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Old 11-20-2009, 11:05 AM   #7
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hey look at that: exactly what he was lookin for.
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Old 11-20-2009, 11:21 AM   #8
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Originally Posted by harleybutter View Post
Try this link:
Equations: Dyno Correction Factor and Relative Horsepower

Seems to give some equations and reasoning behind it.
That is exactly what I was looking for. Except that it didn't touch on STD correction factors. But I think that's ok.

What I was really looking for is if elevation was part of the equation at all. Because the elevation the dyno has set in WinPEP is wayyyyy off for Newark, DE.

Thanks guys!
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Old 11-20-2009, 11:45 AM   #9
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Changes in elevation should make a difference in:
Pd = the pressure of the dry air, mb.
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Old 11-20-2009, 11:48 AM   #10
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Quote:
Originally Posted by ArtieParty View Post
Because the elevation the dyno has set in WinPEP is wayyyyy off for Newark, DE.
Insert comment about FM corrected dyno numbers here.
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Old 11-20-2009, 11:57 AM   #11
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Quote:
Originally Posted by ArtieParty View Post
What I was really looking for is if elevation was part of the equation at all. Because the elevation the dyno has set in WinPEP is wayyyyy off for Newark, DE.
physical elevation is irrelevant, what's important is density altitude. that could be the number your looking at...
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Old 11-20-2009, 12:40 PM   #12
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just as a point of reference, most plots brain and i post are set to STD correction, smoothing at 5.
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Old 11-20-2009, 12:59 PM   #13
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Quote:
Originally Posted by therieldeal View Post
physical elevation is irrelevant, what's important is density altitude. that could be the number your looking at...
No, I'm looking at physical elevation.



If it's a field there, I'm going under the assumption that it may be part of the correction. It says elevation 4500ft, but if you actually google Newark, DE it says average 75 ft.
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Old 11-20-2009, 01:00 PM   #14
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Originally Posted by y8s View Post
just as a point of reference, most plots brain and i post are set to STD correction, smoothing at 5.
Yup, that's what Paul and I do too.
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Old 11-20-2009, 01:09 PM   #15
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weird my runs show 0ft. my SAE correction is .98. yours is the same correction.
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