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Lotta talk about Dyno Runs... (Fake Runs)

ProChargerTECH

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Guys,

There seems to be a lot of talk about dynos and power numbers. So figured it was worthy to share a video that I made a while back after a customer of mine showed me a dyno graph that was clearly fake... (or shall we say false)

The dyno graph sent to me was a P1SC car making 1004hp! And as cool as that sounds, I know that is well above the CFM flow limits of that compressor (no matter how fast it was spun), cleaning indicating that something was up...

I asked if he could send me another graph that showed the dyno run data. (Climate, and Correction factor used)
And it was then discovered that his run had a CF of 36%... yes 36% So take away the correction,you have a very legit power number for a P1SC blower. Obviously there should have been SOME percentage of CF, but clearly, the 36% was in error because it produced a power number not physically possible.

So to show this customer how this may have happened, I borrowed a CTSV from a friend and made a little video...


Also: If you guys have any more tech videos you'd like to see, let me know!

Oh and: If you click "subscribe" that makes baby kittens/puppies smile. (just sayin)



NOTE: This is a personal video I made, at my friend's shop and NOT at ProCharger.

ProCharger has (2) climate controlled dyno cells (one with a DynoJet brand, the other a Mustang brand), that maintain about 72 degrees and very low humidity. So our correction factors are usually 0-5% with an average of around 3%. So when a car makes 1,071 with a 2% correction, you know she is making some HP!

We like to use "percentage power gains" in our ads. Because although the "number" might vary from dyno to dyno. The overall "gain" our customers get mimic what we get here in our dyno rooms. (as long as the car was dyno'ed on the same dyno, in similar conditions).
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lxh89

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This goes back to the old saying, "You can't race a dyno." For SAE, if the correction factor is greater than 3%, it's outside specification for trusted numbers.

Tony
 

3beeps

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This goes back to the old saying, "You can't race a dyno." For SAE, if the correction factor is greater than 3%, it's outside specification for trusted numbers.

Tony
I completely agree about these wild correction factors, but do you have a source for the "greater than 3%" part?
 

lxh89

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I completely agree about these wild correction factors, but do you have a source for the "greater than 3%" part?
Absolutely. The SAE J1349 specification, section 5.5.3: The magnitude of the power correction for tests run at non-standard conditions should not exceed 3% for inlet air or 3% for inlet fuel corrections. If the correction factor exceeds these values, it shall be noted as a nonstandard test in accordance with 8.1.

Reference inlet pressure is 100 kPa or 1 Atm or Sea Level air pressure. Exceed that by 3% and the numbers aren't valid for comparison.

That's why its comical to see vendors playing games with dyno numbers that clearly exceed the tolerances for the specification. To the point by ProchargerTech, dyno numbers with less than 3% correction factor are the real deal and can be properly compared with other cars within the same correction factor tolerance. The more that tolerance is exceeded, the less reliable the number.

Tony
 

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ramirj2

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Horsepower = weight x (velocity / 234 ) ^ 3
 

80FoxCoupe

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This goes back to the old saying, "You can't race a dyno." For SAE, if the correction factor is greater than 3%, it's outside specification for trusted numbers.

Tony
Yep, take it to the track. That will tell the tale.
 
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ProChargerTECH

ProChargerTECH

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This goes back to the old saying, "You can't race a dyno." For SAE, if the correction factor is greater than 3%, it's outside specification for trusted numbers.

Tony
I been doing this a long time, and even I didn't know that.
I just always thought I was lucky when using climate controlled dyno cells. LOL.

Thanks for the knowledge bomb drop of the day. :)
 

tsloms

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Thanks so much for the clear cut and straight forward video showing the dramatic variation. Nice to see some truth out there.
 
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ProChargerTECH

ProChargerTECH

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Thanks so much for the clear cut and straight forward video showing the dramatic variation. Nice to see some truth out there.

I think my next one will be for the "LS" guys, and how a tune effects camshaft idle "sound"
AKA: I can make a cam smooth as silk, or chop chop chop like its 5 times bigger then it is. LOL
 

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80FoxCoupe

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I think my next one will be for the "LS" guys, and how a tune effects camshaft idle "sound"
AKA: I can make a cam smooth as silk, or chop chop chop like its 5 times bigger then it is. LOL
Is there a follow up to the intercooler pressure drop vid?
 

Jay-rod427

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Is there a follow up to the intercooler pressure drop vid?
Haven't seen the vid, but something to think about with intercooler drop is that reducing the temperature alone increases the density of the air and loses pressure. Any gas that is cooled drops volume/pressure. Everyone thinks it's restriction. Our F2 BBC race car lost about 4 lbs of boost going to air to water intercooler from nothing. 300° to about 90°. A cheap gearset later and boost is back where it belongs:) 25 lbs on a 588ci BBC and not even max rpm yet!

EDIT: With a GOOD intercooler expect some pressure drop relative to no intercooler, or a substandard intercooler.
 
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80FoxCoupe

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Haven't seen the vid, but something to think about with intercooler drop is that reducing the temperature alone increases the density of the air and loses pressure. Any gas that is cooled drops volume/pressure. Everyone thinks it's restriction. Our F2 BBC race car lost about 4 lbs of boost going to air to water intercooler from nothing. 300° to about 90°. A cheap gearset later and boost is back where it belongs:) 25 lbs on a 588ci BBC and not even max rpm yet!

EDIT: With a GOOD intercooler expect some pressure drop relative to no intercooler, or a substandard intercooler.
Watch the video.
 

80FoxCoupe

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Ah yes, the psi drop is excessive in that case.
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