Previous vs New:






ID = Inside Diameter
OD = Outside Diameter

Old APR DPs:
ID=2"
OD=2 1/8" (2.175")

New APR DPs:
ID=2 3/8" (2.375")
OD=2 1/2" (2.5")



The old bottleneck was 2". It's now 2 3/8". This is a 41% increase in cross sectional area*

* Inside diameter of 2" versus 2 3/8":
Cross sectional area = Pi * (Diameter/2)^2

Old/stock = Pi * (2/2)^2 = 3.14
New = Pi * (2.375/2)^2 = 4.43

% increase = (4.43-3.14)/3.14 = 41%
(actually, the previous version had a bottleneck in the flex joints less than 2", so this new version is actually a bigger improvement)

Mark P


Dyno: 469wHP / 451wTQ
93 oct - best 60':1.734 | best 1/4ET:12.239 | best 1/4mph:116.58
100+oct - best 60':1.698 | best 1/4ET:11.762 | best 1/4mph:121.72



ECUx template version 11.16 (3/12/07)
AWD Dynos by State - Race Gas in New England - B5S4 100k+ mile post

Current:
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - imolavant website - 186k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, GT28R, EPL-tuned - 14.8 | 101mph - 198k miles
Previous:
'00 Audi A4 1.8T, Silver - Quattrobonium website