Dynolicious

[Y2008]

Just wondering how many people from the Polo community have or use dynolicious? If yes, what is everyone using for their vehicle info for weight and drivetrain loss?

[leasaunce]

dirvetrain loss i think you put 12 or 15%. vehicle weight is around 1150kg. best way to go to a truck weighing depot.

[RhysQ]

dirvetrain loss i think you put 12 or 15%. vehicle weight is around 1150kg. best way to go to a truck weighing depot.

drive train loss on 4 cyl FWD drive cars is about 20%, close to 25% for RWD and close to 30% for AWD.

claimed weight on a Polo GTI is 1190kg, but add fuel, passengers, brake fluid, washer fluid etc etc etc and it comes to about 1350kg.

[RoSonic]

On my registration certificate is mentioned 1298kg.

[pologti18t]

Drivetrain losses are not as simple as 20-30%.

Dyno of GTR (AWD remember) with driveline loss shown. It never ever gets to 30%.



At moderate RPM driveline losses are < 10%!

Driveline losses increase (absolute and %) as RPM/speed increased.

[JCM308]

I gave it a go the other night (but wasn't calibrated properly). I got 88kW and 0-100 in 10sec (just normal take off not launched). That was with a full tank and 2 people in the car. Am going to calibrate it properly and put in correct weight figures on the weekend and give it another go. So far have found that it takes 1-2 seconds to start regestering properly, I'm hoping that's because of the calibration.

[RhysQ]

Drivetrain losses are not as simple as 20-30%.

Dyno of GTR (AWD remember) with driveline loss shown. It never ever gets to 30%.

At moderate RPM driveline losses are < 10%!

Driveline losses increase (absolute and %) as RPM/speed increased.

Thats a VERY big call. Trent had a dyno run with us in Brisane in his MKIV R32. On that day I managed 122.2kW atw (APR quoted 152kW at the fly) and he managed 122.1kW atw (VW quoted 177kW at the fly). Is that not a 31% loss for Trent. And hey, mine works out spot on 20%.

[Timbo]

FWIW, my S3 dynos 150Kwatw, against a rated engine output of 188Kw

Best to look at some of the dyno results in the UK/European forums, as they always calculate back to the fly from the wheel when producing dyno results, and their sheets nearly always include a drag factor (drivetrain loss).

(Personally, I think it makes dyno results, in terms of comparing the output of specific cars rather than the effect of tuning, even more mumbo-jumbo than the arguments we have here over simple measured wheel output )

[madglf3]

Drivetrain losses are not as simple as 20-30%.

Dyno of GTR (AWD remember) with driveline loss shown. It never ever gets to 30%.



At moderate RPM driveline losses are < 10%!

Driveline losses increase (absolute and %) as RPM/speed increased.

I think Attesa in the GTR uses mostly RWD until the rear wheels lose traction, hence it would mostly read as a RWD if it has traction (although I'm not too sure how much traction a near-500hp GTR has on a dyno).

[Spec83]

I think Attesa in the GTR uses mostly RWD until the rear wheels lose traction, hence it would mostly read as a RWD if it has traction (although I'm not too sure how much traction a near-500hp GTR has on a dyno).

Depends how many fat bastards / sand bags they can fit in the boot

I was standing in front of a 400+hp 808 on a dyno and they way it lurched forward half scared the crap out of me

[pologti18t]

Thats a VERY big call. Trent had a dyno run with us in Brisane in his MKIV R32. On that day I managed 122.2kW atw (APR quoted 152kW at the fly) and he managed 122.1kW atw (VW quoted 177kW at the fly). Is that not a 31% loss for Trent. And hey, mine works out spot on 20%.

You are assuming that dynos give an accurate readouts.

They are meant to be used to measure increases/decreases in power due to modifications. They shouldn't be used to say "my car has 175.5kw at the wheels" as you could go to another dyno and get a figure of 160kw.

[RhysQ]

You are assuming that dynos give an accurate readouts.

They are meant to be used to measure increases/decreases in power due to modifications. They shouldn't be used to say "my car has 175.5kw at the wheels" as you could go to another dyno and get a figure of 160kw.

Who told you that crap, they CAN BE/ARE used for that purpose, but are MADE to measure power output at the wheels (or engine depending on the type of dyno).

Used to measure an increase of power......an increase of what power? Stock power? How was that stock power measured? Oh....a dyno

We've done the testing and our stock Polo GTI's showed a very close reading (within a few %) to the claimed VW 110kW at the fly output for the Polo GTI.

I would have thought most people assume dyno's give an accurate read-out, that's why people use them and what they are made for aren't they. If someone wants to know how much power their car has, what do they test it on? When car manufacturers test their new product for power output, what do they test it on? Please answer that?

I know there are discrepanicies with each dyno but me and Trent were there on the same day and were tested within a few hours of each other. On that same day a stock Polo GTI got within a few % of the 110kW at the fly. So really, it's all we've got to run off, and what we've got to run off seems pretty solid to me.

[Timbo]

Oh dear

No, if you really, accurately want to measure power "at the wheels" and compare it with another car, you need to use a hub dyno. There's too many variables with a roller dyno, although they're fine for measuring tuning deltas.

Manufacturers use engine dynos to give flywheel power. Again, there's less issues about friction, drivetrain loss etc.

Of course, regardless of the method, dynos are an excellent source of "lies, damned lies...and statistics"

[RhysQ]

Of course, regardless of the method, dynos are an excellent source of "lies, damned lies...and statistics"

and possibly the best fuel for argument, as we've all seen.

Regarding the dyno, I was referring to all dynos, not just a roller dyno (hence my section on engine dyno). I was just shocked at him implying that dyno's are not made to accurately measure power output, which they are! It's just that too many variable get in the way when tested.

[Y2008]

I thought 1190 was the curb weight of the car not the dry weight. And do you guys think it would be a good idea for us to pick some set figures for drivetrain loss and curb weight to minimize the variables? Does anyone have some recommendations? It would make it easier to compare figures or come up with conclusions? Maybe a set weight and leave the drivetrain loss at 0%