Hey folks got my car rr'ed - need a little help

[PaulJC84]

Hey i got my car rolling roaded at Star on the 20th of Aug.

However i have a query about my figures.

On the 20th of Aug got these.

Norm power 220.0 bhp
Engine Power 223.0 bhp
Wheel output 162.5 bhp
Drag output 60.5 bhp

Max Power at 96 or 5340 rpm

Torque 220 lbf-ft


I thought fair enough but then when i got home i had a look at my previous figures from the 10th of Jan.

As on the 10th of Jan i got these figs.

Norm power 223.5bhp
Engine Power 218.5 bhp
Wheel output 136.5 bhp
Drag output 82.0 bhp

Max Power at 103 or 5710 rpm

Torque 233 lbf-ft

So looking at the figures the power normal and engine have swaped over as which is higher.

However the wheel output is now 26 bhp higher. I do not know how this could be when the engine output has not changed much at all!!

So since the engine output is normally calculated i wonder if the computer calculated my figures for a FWD car???

I dont understand how the power figures can be similar as before because since fitting a slightly larger turbo i can now keep up with a mates imprezza which was RR at Star and got 245bhp. Also on the way to Star i had a race with a BM 330ci and there was next to nothing in it and it will only be rear wheel drive so i think my figures could be wrong. Maybe not though as i say i am not 100% sure.

I have a had a good think about this and doing a little further investigation my %age lost through the drive is similar to a MK2 1.8T.

Which my car being quattro can not be right at all!!

And going by a 40% loss for a 4x4 car my power figure should have been just over 250bhp.

Sorry for the long story but i just thought i would ask.

And for those wondering how i would expect more power, i expected a little more because i have a K04 fitted however it is not setup though.

If anyone wishes i will post the graphs up.

Thanks for reading.

 

[Ryanc]

Is your car haldex or torsen?
haldex = roughly 60bhp loss
torsen=roughly 90bhp loss.

 

[dummi]

that aggrees with soupies research that his was measured as a haldex rather than torsen, interesting that! i didn't realise there was as much as 30hp at the wheels different, makes sense though

 

[Ess_Three]

[ QUOTE ]
that aggrees with soupies research that his was measured as a haldex rather than torsen, interesting that! i didn't realise there was as much as 30hp at the wheels different, makes sense though

[/ QUOTE ]

A rolling road can't decide whether a car is Haldex or Torsen...it simply measures the torque at the wheels, works out the power from that and the revs, and then measures the drag with the clutch pressed.

It CAN'T know whether it's one type of 4wd system or another...it doesn't care either. Drag is drag.

There are factors that effect the drag reading:
2 or 3 wheels being driven
Torsen type or Haldex type couplings
Tyre pressures
Tie down strap tension
Camber / toe settings

But not whether it's Torsen or Haldex. Nor can a RR know whether tyhe car is to be measured is FWD or 4wd...the operator has to know how many wheels are being driven...all the RR then does is is measure the resultant torque at each driven wheel - and then the drag at the same driven wheels...be there 2 driven or 4.

Too many factors influence RR graphs...I have an odd set that dagnosed sticking front brake callipers (power at the flywheel was way up after fitting cams...but WHP was the same...the result - 15BHP lost to sticking brakes!)

Unless you keep a very close eye on ambient tremperature, and keep all other parameters as close as possible - suspension angles & settings, tie down strap tightness, tyre type, diameter, width, pressure etc, diff type (LSD or open diff), gearbox oil weight etc, etc...you will have differences in dyno runs from different days.

What will not change however, is that the rolling road will not - and can not - measure the car as FWD if it's 4WD...nor can it calculate losses for a Haldex type car on a Torsen type car...it's a piece on metal...a simple measuring instrument that takes information in, and gives other information out.
4 wheels driven...4 wheels worth of drag. Simple...

It doesn't care about Haldex vs Torsen.

It's us who make the differentiation based upon the losses...not the RR or it's operator.

 

[Ess_Three]

[ QUOTE ]

haldex = roughly 60bhp loss
torsen=roughly 90bhp loss.

[/ QUOTE ]

I think these are just a little on the low side for Star's rollers.

My FWD GTI gives losses = 50BHP ish on Star's rollers
Haldex Audi = 60-70 BHP
Torsen Audi = 90-100 BHP
Subaru = 100-120 BHP. Gulp!

 

[Ryanc]

owen developments rollers gave me crack on 60bhp loss.

 

[Ryanc]

Just as a bit of interest a evo 6 had roughly 80bhp loss

 

[mac1403]

I am a bit confused with all this rr stuff. I had mine remapped at AMD with a claimed 220 ish BHP. 3 months later I took it to Westtec performance for a power run and they said the car was running as it should....ie standard (180BHP) I can't understand how this could be as according to the boost gauge I am running 15-16PSI. Last wek it went back to AMD and rr again at 220BHP. Anyone else had similar probs

 

[Ryanc]

If you 100% want to know the power try owen developments,get them to dyno it and log boost for you.
http://www.owendevelopments.co.uk/

 

[dickys3]

[ QUOTE ]
I am a bit confused with all this rr stuff. I had mine remapped at AMD with a claimed 220 ish BHP. 3 months later I took it to Westtec performance for a power run and they said the car was running as it should....ie standard (180BHP) I can't understand how this could be as according to the boost gauge I am running 15-16PSI. Last wek it went back to AMD and rr again at 220BHP. Anyone else had similar probs

[/ QUOTE ]

I hear that Westec are having some problems with their RR mate.. All cars are reading very very low....

Have a look on the seat forums for more info...

 

[dummi]

cool.