Vag-Com Dynoplot

[S2central.net]

Wonder of wonders - I created my own graphing tool based on the Power = m.a^2.t calculation and it basically works. I should have done it years ago My one works on acceleration data - no need for deceleration as I assume 25% drivetrain losses.

The graph doesn't exactly match what the Ross-Tech one from that GTi Golf sample data, but then I was kinda sceptical of the shape of the power curve on that one with no sign of it tailing off at high rpm ranges.

For the life of me I couldn't understand the Kinetic ENergy calculations in the Ross-Tech sheet - I'm assuming it was to do with the deceleration timing.

I'll have to wait until later in the week to try some runs on my own car so that I can see the difference in stock and some chipped configurations. The main thing on this is not deadly accuracy of any one plot - its the differences measured on the same car of same weight and same weather if possible that will quantify the worthiness of various tweaks.


Cheers,

Paul

[Doug_RS2]

Have you got the spreadsheet there to share?

[S2central.net]

Yes... and no... I can't remember my fooking password to my FTP server

I'll get there in a moment - permutations


Paul

[S2central.net]

Yes... and no... I can't remember my fooking password to my FTP server

I'll get there in a moment - permutations


Paul

Something is up - I can now logon but cannot post new files

I've attached a zip of the rough calcs I did last night...


Paul

[Doug_RS2]

I take it the drop in torque is likely due to the wind resistance increasing as you go faster? How does the original calculations work that out - I didn't know what to enter in the de acceleration column.

[S2central.net]

I take it the drop in torque is likely due to the wind resistance increasing as you go faster? How does the original calculations work that out - I didn't know what to enter in the de acceleration column.

The original calcs just hurt my head - seemingly halfing the weight of the car, then using a fudge factor along with deceleration timings. My own isn't perfect but at least I understand it. I'll go with a drag factor as follows -

0.1bhp per mph in range 1-25 mph
0.2bhp per mph in range 26-50 mph
0.3bhp per mph in range 51-75 mph
0.4bhp per mph in range 76-100mph

As a vague stab at quantifying aero/drag losses. At speeds beyond (on a test track) we'd be looking at least 0.5bhp per mph in my guesstimation.

Primarily I think torque flattens off on that run cos thats what I'd expect the engine to do anyway. Didn't you think the original plots looked odd - especially power with no sign of it tailing off ?


Paul

[Doug_RS2]

yeah it does look odd - I am going to have a look at the plots from my mates AMD'd 1.8T to see what the characteristics of that chipped engine are.

There must be a more accurate fudge factor for losses - I have measurments so can see how the accelaration figures change while slowing down.