Request for gents with a data logger:

[P_G]

Come fella, you can do better than that Let's really home in on this data so we can all decide whether it's worth partaking in, or that it has no universal value (perhaps, a big perhaps, limited value on an individual basis as P-G suggested).

& this one

The 'Limited value' suggestion was attributed to dyno results, not the 3k-8k rpm test which I believe is what the Excel spreadsheet and this thread were about?

So yes it appears you have misquoted me as you appear to be implying I suggested that the 3k-8k rpm test had limited value which i did not say?

[Sims]

Come fella, you can do better than that Let's really home in on this data so we can all decide whether it's worth partaking in, or that it has no universal value (perhaps, a big perhaps, limited value on an individual basis as P-G suggested).

& this one

The 'Limited value' suggestion was attributed to dyno results, not the 3k-8k rpm test which I believe is what the Excel spreadsheet and this thread were about?

So yes it appears you have misquoted me as you appear to be implying I suggested that the 3k-8k rpm test had limited value which i did not say?

I have re-read and can see where the misunderstanding arose, as you have alluded to in this post. Apologies.

So you are saying that the 3-8k test is a worthy test of checking power. Is that right?

Are you suggesting it has greater validity than a RR?

Do you accept that both have a lot of variables, one more than the other?

Hopefully arthur will restrain himself giving you the opportunity to respond.

[SR71]

I have something better than that
designed by a physicist and Cal Tech, iirc
you put in the torque curve, gearing, weight, etc.
and it will do a curve for any speed/gear range...
pretty accurate, but can't compete with real world numbers

That is what it does...

There are 38 specifications to define the car and 54 parameters to play with.

I've written to the author requesting a carbon deposition variable be included. He says it'll be ready by tea-time.

You can define your torque/hp curve in 500rpm increments to 20000rpm...

Great fun.

[ArthurPE]

[ArthurPE]

...

So you are saying that the 3-8k test is a worthy test of checking power. Is that right?

Are you suggesting it has greater validity than a RR?

Do you accept that both have a lot of variables, one more than the other?

Hopefully arthur will restrain himself giving you the opportunity to respond.

I'll respond anyways despite your underhanded personal attack...
since it was I who derived the test, tabulated the results, and have been a proponent of such...

but this does not preclude P_G (or anyone else from chiming in)...
not sure why you think I'm not allowed to...
my responding prohibits P_G from doing so? really?
if he agrees, you'll personally attack him again as a 'follower', etc., so perhaps he chooses not to give you the opportunity?

yes, power relative to the stock rating and as impacted by deposits (or other changes)

yes, far less variables than a rolling road
it is an actual time measurment of a car doing what it is supposed to do...drive on a road under full load, wind resistance, tire friction, etc.

yes, the RR has more variables...set-up alone has dozens, that can be manipulted...all RR's are different...a car on a road, pretty much consistent and repeatable...

[HYFR]

here's my train of thought

you have two cars....one pulls 414 on a RR, one pulls 371 on a RR

put them on rear road, side and by side, ask them to do a 3k-8k rpm race....

they are neck and neck to the human eye/dyno

do I therefore believe there is a power deficit.....no

[scaghead]

here's my train of thought

you have two cars....one pulls 414 on a RR, one pulls 371 on a RR

put them on rear road, side and by side, ask them to do a 3k-8k rpm race....

they are neck and neck to the human eye/dyno

do I therefore believe there is a power deficit.....no

dave you are spot on, we did this test after the rr day at paramount april 2009 one car dynoed 385 another 310..... in the real world on the road you guessed it, 310 was pulling away slightly in a 3rd gear drag

[Sims]

... dave you are spot on, we did this test after the rr day at paramount april 2009 one car dynoed 385 another 310..... in the real world on the road you guessed it, 310 was pulling away slightly in a 3rd gear drag

That is odd, is it not? Of course there are many variables that have been discussed often, including driver reaction time. But why do you think the 310 car faster on the road?

This is a serious question for this is about results, that needs explanations and reasons .

[ArthurPE]

here's my train of thought

you have two cars....one pulls 414 on a RR, one pulls 371 on a RR

put them on rear road, side and by side, ask them to do a 3k-8k rpm race....

they are neck and neck to the human eye/dyno

do I therefore believe there is a power deficit.....no

dave you are spot on, we did this test after the rr day at paramount april 2009 one car dynoed 385 another 310..... in the real world on the road you guessed it, 310 was pulling away slightly in a 3rd gear drag

very interesting, but not really surprising...
a ramp dyno run is an extremely inaccurate measurment...
I would expect at best 10% accuracy, but more like 20% in a real world scenario...

if those 2 cars had been run steady state, variable load (increase load until car bogs/stalls at ~7800 power peak, then hold steady, stabilize, and record), power would have been ~ the same...

a car with 75 more real HP (25%) would have pulled dramatically on the lower power car...

I sound like a broken record, but power means nothing, it's torque, and more so, the area under the torque curve...
that's why low power electic cars are so fast, electric motors are almost constant torque once running, so long flat curve, a lot of area...
an 100 HP motor makes 440 lb ft at 1200 rpm...

[scaghead]

sims my car was the one that dynoed 310 at paramount and to confuse you more i went to the same rr day in november 2009 my car dynoed 390 i had done nothing to it in the seven months in between except a service.

[ArthurPE]

sims my car was the one that dynoed 310 at paramount and to confuse you more i went to the same rr day in november 2009 my car dynoed 390 i had done nothing to it in the seven months in between except a service.

I remember those threads

how in the name of all that is good and holy they could claim your car made 310 crank HP is beyond me...and after 1 year and an oil change, 390...
that's some damn good oil

any error codes either time?
I don't have the database at work, any 3k-8k runs (pretty sure you did)
remember what they were?

[scaghead]

the boys at paramount vag commed it first time around and no fault codes, obviously did not bother in november as it was the highest barring raudiguys beauty of a motor.. sims the rr days at paramount are threads on here fella.. arthur it was not even a year only seven months

[ArthurPE]

so, if yours was reading that low, does that mean ALL were reading low?
if yours went from 310 to 390 (I don't believe either figure as absolute)
will the cars that made say 350 go to 420?
or the ones that made 370 go to 420+?

SR71 raised a very interesting question
how does the quattro system respond to a awd dyno
if front/rear wheel speeds differ, what happens? is this interpreted as slip and timing/torque reduced?
it's a mechanical diff so it can't be adjusted electronically, so the computer systems would only see an 'out of control' scenario and cut/limit power...
it's a default 40/60 split, so would the front drum be driven/accelerate slower since it has less force?

I'm going to contact a few dyno suppliers I work with and see if I can get some info

[P_G]

I have re-read and can see where the misunderstanding arose, as you have alluded to in this post. Apologies.

So you are saying that the 3-8k test is a worthy test of checking power. Is that right?

Are you suggesting it has greater validity than a RR?

Do you accept that both have a lot of variables, one more than the other?

Hopefully arthur will restrain himself giving you the opportunity to respond.

Sims, I would suggest there are less variables in the 3k-8krpm test than on a dyno. Although cars do not use the same stretch of road and there is no account for incline this is offset against an r/r for slip and what I suggest is the biggest fault of r/r, torque vectoring and a r/r ability to measure that (particularly Dyno Dynamics roads) However what is constant is air flow rate and exhaust flow rate because you are travelling through air. r/r all rely on fans. I was one of Paramounts biggest critics because they used two small capacity fans and opened their fire exit to vent exhaust gas.

Compared to a number of other places I have visited the air flow and ventilation were not on a par. The rest of the variable are probably on a par. Yes there is human error in timing but again a r/r software's ability to translate its data.....

I also subscribe as someone else suggested that if you have delay error in judging start then usually there is delay error in stopping.

[SR71]

I'm going to contact a few dyno suppliers I work with and see if I can get some info

That'd be helpful Art.

I see that some dyno manufacturers claim they measure individual torque but I can't see how that would work unless you tell the machine the torque split in the first place?

Or else, like you say, things would spin at different rates...

They don't appear to so I'm thinking the diff is constantly trying to shift 10% of the torque to the front wheels to bring it back to 50:50?

I'm obviously missing something...