Smokin 1000HP Twin Turbo Club
Join Date: Oct 2009
Location: Bethesda MD
The LS2 intake system is restrictive. There is a good gain on 2005 - 2007 vettes from both a cold air system and an intake manifold swap. The LS3 intake, filter, and manifold are much better designed.
Most of the advantage from aftermarket cold air intakes on the LS3 come from the fact that engine bay air gets warm when the car is sitting still at the drag strip. Warm air causes the timing to be retarded which kills power. Bottom feeders like the Vararam pull in air from outside the engine bay and result in the car not pulling timing. The stock LS3 tune is very aggressive at pulling timing starting at ~86* air temp (3* at WOT). Most tuners raise the temp and reduce the initial amount of timing pulled. I don't pull any timing until 104* and only 1* which is still more conservative than some tuners. Point being is that most tuned LS3's are less sensitive to the engine air temp off the line than stock. On the road, the stock system temps generally drop down within a couple degrees of aftermarket, negating most of the value.
As much as I want to believe in the ram air effect, even at 100 MPH, guys tacking manifold kPa are not seeing any changes in pressure according to the car's MAP sensor. If you're not going to tune the car and do race from a stop, a bottom feeder will make the car quicker. Even on a tune car there can be some gain if the car sits still at a long light as engine bay air temps will climb. Point is the gain is coming from colder air rather than removing a restriction.
2008 Atomic Orange Coupe 3LT, CC3, Z51 M6
LG Pros with cats, Vararam, 160 T-stat, DTE 3.90s, Elite tunnel plate, catch can, LG Wheels with 275 / 325 Invos, MGW Shifter, EPS 226/230 115 cam, HPT. Pfadt JOC suspension, Peak ported TB & IM.
Gone but not forgotten:
2002 Camaro SS Droptop. cam, gears, etc.
11 sec 99 Z28 Vert, RIP.
Last edited by Ragtop 99; 06-27-2012 at 03:41 PM.