| I came across a discussion on tt.net from last November where Ash compared Dee’s car with Sp500’s to Dee’s car with SP600’s and extrude honed manifolds. There was a gloriously nerdy exchange about areas under the curve and polynomial approximations which was great. La-Z-Link I have often thought the best way to characterize spool up is to focus on what it really is... the rate of change. So I took the two sets of data (perfect case study since the spool up rates were being compared) and took a rough derivative of the sets in excel and plotted the results. You can see the major peak occurring at 4400 rpm for the sp600 car and 4350rpm for the sp500 car. That peak is the point where the increase in power per rpm increment was the highest and is also the inflection point. This shows the sp600 didn’t quite spool earlier, but at almost the exact same point. More interesting than that are the artifacts in the data!!! Look at how many of those peaks match up between two different runs. Each one has its story and is likely attributable to some feature such as runner length or depressions in the mapping etc. I would love to rekindle this interest in the mathematical approach to post processing dyno data. Perhaps there should be a real concerted effort to put together some standards for comparison. Instead of saying this or that spools sooner or faster we would say this one has a spool max at xxxx rpm and a full width half maximum (FWHM) of 750 rpm. BB turbos should have smaller FWHM’s and that could be shown quantitatively. 
 
While getting tires mounted for Zcon, I had this doozy of a conversation with the mechanic... Tireguy: [looking at emblem] Is this a Twin Turbo?
Me: Well, yea.
Tireguy: Awesome! How much boost do you run?
Me: 14-15 ish.
Tireguy: Cool. On both? ROFLMFAO "...people often mistake charisma for integrity. Sure, he's a nice guy, but that doesn't necessarily make him honest (or dishonest). They are independent variables." -Kenny |
Attn: data junkies- Dyno graph derivatives! :) - 
