comparison of FATS vs CAPS times...

[ModifiedA4]

(CAPS is the FATS for the 1.8t A4)

this is some interesting stuff for cross forum performance comparison.

I took a stock FATS log data from this post, which was 6.06 seconds.

the FATS calculator uses a shorter RPM range than the CAPS calculator, so I recalculated the data with my online CAPS calculator. the CAPS calculator also takes into account of the 6-speed manual tranny's gearing relative to the 5-speed manual. The equivalent CAPS time for a 6.06 FATS is 6.81 seconds.

6.81 seconds puts a stock S4 as an equivalent with an A4 with a k04-15 turbo.

any thoughts?

(here's a link to the CAPS database for comparison)

[nyet]

but i need cD, FA, rpm/mph, weight, and dtl.

[ModifiedA4]

the way i look at these numbers is that as long as the gearing is equivalent, the MarkP style calculation holds.

wouldnt you only need dtl & cd if you were to make an assumption on HP?

[nyet]

specifically, area under the curve, which is what FATS attempts to measure.

[ModifiedA4]

im using this simple calculator (see below).

for comparison's sake, car to car, HP is irrelavent. Including it makes a comparison less accurate I think. dont get me wrong, its nice to estimate HP, but a time is a time. a quicker time is a "faster" car by definition.

of course many things can skew the time so a car with less HP can get a faster time. wieght, rim size, temperature, humidity...a stiff breeze. but theorectically if the two cars to be compared were to line up and do a 3rd gear pull, the car with the quicker time would be the faster car. in that way, the "simple" calculation has merit.

im interested in how you are able to derive HP from a datalog.

[nyet]

time vs rpm, add in dtl and drag, viola, hp.

the perl script is in my sig if you are interested in specifics.

i thought you were already familiar with the tool..

[nyet]

i can't believe you think this is true.

[Ochlockonee]

Many of the homebrew guys with great fats times for K04s are using an EBC that can beef up the boost in the bottom end where it's safer for the turbos, then taper as redline approaches.
Coming from a guy with a relatively low fats time to horsepower ratio, I'm pretty interested in looking at horsepower.
He gets HP from measuring acceleration over time for each data point, to put it simply. Good accel in the high rpm range=higher horsepower than the same acceleration in the lower rpm range.

[ModifiedA4]

i knew about your fats calculator, i didnt know it predicted hp.

how accurate have you found your HP prediction to be? obviously people have done dyno pulls for comparison.

[JMS-Four]