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OK, why no correction factor? Without a correction factor for the observed atmospheric conditions in the test cell, you don't have any relate-able data. Sure you made that torque and horsepower right at that moment in the real world, but the next time you dyno or someone else's QV dyno run will be under different conditions, and correction factors that correct to SAE J-607 or SAE J-1349 allow you to have data that is more meaningful outside of your singular test event.

I'm an engineer in the automotive aftermarket, and while I don't use chassis dynos, a large part of my job consists of testing my projects on a Superflow SF902 engine dyno. Bad dyno testing is just throwing money away, because you won't get anything meaningful out of it.
 

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Discussion Starter · #3 ·
To be honest I probably couldn't give the best answer. Maybe @[email protected] can give a better one. Here are my thoughts: No need for correction factors as elevation and atmospheric test conditions won't vary too much as we don't live in a place like Colorado. Also all cars are tested with out any correction I believe this is due to it loading the front wheels properly, rather than just letting them roll along so long as they don't put down power this is more equivalent to real world scenario of a car driving on a real surface.
 

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To my mind, the best dyno test results might be doing it at the same time along with some buddies C63s and M3. At least that will provide a meaningful spread versus the manufacturers claims. Dynos of a single car seem pointless because if you go on the AMG and M3 Forums, they always believe their cars are highly under-rated from the factory, and in actuality make over 1,000hp, and "they have the dyno results to prove it!" Those guys take fanboydom to an entirely new level. Every dyno test is flawed...unless you have an engine dyno as the other poster stated.

Anyway, thanks for setting a baseline, but hopefully, we'll get some same day AMG, M3, QV dyno shootouts. Will be really interesting to see that type of comparo.
 

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To be honest I probably couldn't give the best answer. Maybe @[email protected] can give a better one. Here are my thoughts: No need for correction factors as elevation and atmospheric test conditions won't vary too much as we don't live in a place like Colorado. Also all cars are tested with out any correction I believe this is due to it loading the front wheels properly, rather than just letting them roll along so long as they don't put down power this is more equivalent to real world scenario of a car driving on a real surface.
First and foremost I appreciate you taking the time to do this. This gives us a raw look at what the car is doing.

I am certain "Nannies" are interrupting and even though you are on a 4wd dyno the car is not happy and operating at peak output. Further more these cars operate on multiple mappings that jump constantly during driving conditions. All dependent on various temps, throttle inputs, load cycles etc.

Using an SAE correction factor would be helpful BUT is not the end all be all. The SAE correction factors are good in laboratory conditions such as engine dynos where you can eliminate a lot of factors.

SAE correction factors are essentially a way to normalize different dyno results under different conditions. So in theory someone in Colorado with much different ambient conditions can directly compare those results with someone from lets say California or NY.

Going to keep it simple at this point.
 
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Discussion Starter · #6 ·
First and foremost I appreciate you taking the time to do this. This gives us a raw look at what the car is doing.

I am certain "Nannies" are interrupting and even though you are on a 4wd dyno the car is not happy and operating at peak output. Further more these cars operate on multiple mappings that jump constantly during driving conditions. All dependent on various temps, throttle inputs, load cycles etc.
You have no idea! haha. After each dyno run the car had to be unstrapped and taken for a drive to get ECU back to normal again. Thanks for your Thanks. It took a while but finally got close results lol.
 

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You have no idea! haha. After each dyno run the car had to be unstrapped and taken for a drive to get ECU back to normal again. Thanks for your Thanks. It took a while but finally got close results lol.
There's our proof that it wasn't putting out peak power/torque. The nannie system thought something was wrong and cut power.
 

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Discussion Starter · #8 ·
There's our proof that it wasn't putting out peak power/torque. The nannie system thought something was wrong and cut power.
Not really. It cut power on the wind down not wind up. So after the dyno run was completed and the car was coming down from speed it started to freak out haha.

I am providing a Stock GTR (2016) on the same dyno results for comparison.
 

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Discussion Starter · #9 ·
On another note Pogea Racing is giving me so much **** on youtube hahaha. Apparently they measure their cars using DYNO MODE (that is only available with the original Fiat Witech),

ALL of them have had more than 510PS and all of them had more than 600Nm of torque.

I find it a bit odd that all of their cars on their dyno in dyno mode had factory rated HP and TQ to the wheel? LOL. I think there is a language barrier.
 

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In Germany you show the power at the crank, that is what they are claiming.

Its like mc3456 has said, you gotta compare your car with others on the same dyno at the same day.

Regarding pogea - I believe they are quite good at what they do, but they are showing of too much and they can't beat physics either...
 

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In Germany you show the power at the crank, that is what they are claiming.

Its like mc3456 has said, you gotta compare your car with others on the same dyno at the same day.

Regarding pogea - I believe they are quite good at what they do, but they are showing of too much and they can't beat physics either...
power at the crank is what manufacturers do here as well, not at the rear wheel as you lose HP due to physics....
you will always have 2 camps when it comes to HP numbers....measured at the crank and rwhp.....I left out the guys that @mc mentioned who use the ever popular butt dyno:grin2:
M
 

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This might be a stupid question now but does the QV have to be run on a AWD dyno only in AWD mode and not just the rear tires spinning? I know my 4C freaked out after a RWD dyno runs only.
 

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Discussion Starter · #16 ·
This might be a stupid question now but does the QV have to be run on a AWD dyno only in AWD mode and not just the rear tires spinning? I know my 4C freaked out after a RWD dyno runs only.

Not just a AWD Dyno but a AWD Link. I tried a AWD Unlinked the it freaked out lol. Though I didn't try the car in Line Lock Mode (maybe worth a shot). @[email protected] what do you think about Line Lock Dyno Mode?
 

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How do you enable line lock then? I've never seen an option like it anywhere.
 

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On another note Pogea Racing is giving me so much ****
Pogea is not wrong on some of their points they're making.

Telling people that all Mustang chassis dynos read low is like telling me that a Home Depot tape measure gives different readings than a Lowes tape measure. You'll get some variation between dynos, but ultimately, if there is a major discrepancy, something is wrong with one of them (or how they're being utilized).

The aftermarket is full of firms do not understand the science behind what they're doing, and thus don't do things properly. Most shops rely on the fact that customers are even less informed/knowledgable than they are, so they never get called out on their BS! You absolutely should have used a correction factor for the environmental variables. Both temperature and humidity changes have a sizable influence on the measurements you'll get. After they took your car off of the dyno rollers after every run, when they strapped it down for the next run, did they keep a log of the safety strap load? There are SO MANY variables you need to account for to do chassis dyno testing accurately. How were they exhausting the dyno cell? If they didn't have any containment leading right up to your exhaust pipes, they better have had a massive CFM puller fan behind the car. It wouldn't be hard to come up with a half dozen things these guys did wrong that invalidate your tests.

Just so it is known, I am not in the Alfa tuning scene. I don't do anything Fiats, Alfas or BMWs for that matter. I have no desire to see any specific outcome here, other than to see things done right. Because it drives me crazy to see people spend money for test results, then post erroneous data/results, and know that it was a waste of time.
 

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Discussion Starter · #20 ·
I know what you are saying how ever we don't drive air cooled porsches at 4000+ feet elevation. Most modern cars these days have computers adjusting for all factors and getting a baseline is simply that a baseline. Yes I know factors come into play but you are talking 20whp here or there max with the most severe of factors (mainly temp as elevation is not a factor in our area).

I take argue with the fact that they claim they have 498whp on the same dyno I have in "dyno" mode. Either Pogea is saying they have 1% drivetrain loss or its severely under rated from the factory.

In terms of the video things you dont see are

Huge Fan + 2 Blower Fans
Exhaust gas removal hooked up in the back removing exhaust gasses from the rear.
 
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