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Discussion Starter · #1 ·
So, recently got my intake cleaned out for carbon. I dyno'en the car before and after.
353hp before, 362 hp after. These are flywheel hp on a government approved dyno. (cars are tested here to be approved for registration)
Firstly, I was expecting a bit more from Audi on both numbers, as well as a bigger improvement from the cleaning. It was pretty dirty down there.

Car has 100.000 km on it. What's up with the low numbers?
I'm not going to be hunting anything down here, but I would like to know some thoughts on Audi performing like this.
 

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362 to the wheels is pretty much what you get from a band new R8 V8.. so it's more surprising that you only lost 9 hp from a 100,000km junked up valve port. 15% loss from brake horse power to wheel horse power is pretty standard. Check out all the wheel (or even hub based - maybe a tad higher) based dyno's you can find from the Audi R8 V8 and 362 is right about normal.
 

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362 to the wheels is pretty much what you get from a band new R8 V8.. so it's more surprising that you only lost 9 hp from a 100,000km junked up valve port. 15% loss from brake horse power to wheel horse power is pretty standard. Check out all the wheel (or even hub based - maybe a tad higher) based dyno's you can find from the Audi R8 V8 and 362 is right about normal.
i was gonna say, awd loss is more like 20-25%. i would have been shocked if he was measuring 362 at the wheels!
 

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Discussion Starter · #7 ·
AWD has been removed. RWD only. 360ish at the crank is pretty low. For a healthy car, high octane, no engine mods this is pretty bad. Apparently typical for Audi NA engines. But why? That is the question
 

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In which gear was the test performed? What I find suspicious, offical peak power is rated at 7800rpm but here its reached at 7200rpm and drops of massively? Per chart at ~7800rpm well over 100hp are missing compared to Audi spec?
 

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I honestly don't know much about how dynos work. I thought to measure at the crank, the engine would have to be out of the car, and anything that you put the car on would be measuring at the wheel. How does this work?
 

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I honestly don't know much about how dynos work. I thought to measure at the crank, the engine would have to be out of the car, and anything that you put the car on would be measuring at the wheel. How does this work?
This is true, to measure at the crank you need an engine dyno.
 
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Thanks for the sanity check. I was wondering what I was missing here. I felt I had a basic understanding of how they work, but without first hand experience, I've learned to never say never.
IMHO I think the OP has confused or been confused by the dyno company. It is highly unlikely they removed the engine for a dyno test. Usually only car manufacturers, race teams and or engine builders do this. It is a huge hassle and is usually used for testing components, not gov't registration. It was most likely a rolling dyno and in that case, the HP seems reasonable.
 

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It's good practice for a dyno test to show what is actually measured i.e. torque at the wheels and the calculated power. If they have to back calculate / estimate the power at the crank (for government tests etc), then at least you can see what factor they have used to convert the actual whp to crank hp. Without knowing what assumptions they have made on drivetrain loss it's a bit of a guess as to what is going on.
 

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Discussion Starter · #17 ·
Well, most dynos offer the possibility of measuring the drivetrain loss by simply rolling back down in speed. Probably involve a bit more plus some calculations, but to my knowledge they get close enough to make no difference.
363 is what the Audi engine puts out at crank or very very close to. The dyno is government checked and calibrated a set times a year to make sure, for these people to actually by legally used as a place to measure cars for import and registration. This is required in Denmark depending on circumstances.

Today I put my 997.2 GT3 on the same dyno. 435hp. Spot on factory quoted. This is would also expect. Dyno people let's me know it is quite often the NA audi engines is quite a bit off their mark.

Now, question is; why is this?
 
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