Thread: mods for the gxp

I've been posting over at LS1 tech since my intake manifold swap generated a lot of questions, and I think that we've figured out that the stock transmission calibration doesn't like the extra power. It's not that the transmission is too weak per say, it's just that the LS4 is already near the limits of the transmission for longevity and the stock calibration assumes a stock engine (shocking I know) and let's you get the most out of the engine (there's a lot of torque management when shifting, but you can scorch the tires and use tapshift to get to the redline). You should expect to have to recalibrate your transmission if you add power, and you probably should add a shift kit for longevity even with a few bolt ons. Trannyman95 can hook you up if you want to get serious. That said, at 303HP a stock LS4 will run with a GTP with basic mods.