Turbocharger Heaven
Last week with the help of a friend I made some changes to the way the turbocharger on my car (2007 Pontiac Solstice GXP) is managed by the engine computer. It involved some slicing of rubber tubes and such. The GXP turbo is really fast -- very little lag even in stock condition. But there are certain situations where there is a tangible delay while the engine computer checked the pressure in the unit to make sure that it's not going to stall (what jet airplane types call "compressor surge", which is really bad if your compressor is holding 250 passengers aloft at 36,000 feet, but in in an automobile it just means a few seconds with less power). The practical upshot of the mod is that the turbo is now available much sooner in the throttle's travel. I can still accelerate without the turbocharger if I want to, just by not pressing down on the pedal as hard, but by having it available sooner it means that the power spools up more quickly, and is also more quickly returned after changing gears.
Fun stuff. Anyway, here are a couple of pics. I actually wrote up a full set of instructions and about twenty images for a discussion board for fellow Solstice owners, and if you're really curious you can see that whole thread here.
My friend Hector pulling off the engine cover:
A shot of the engine with all the relevent parts labelled:
Modern engines sure are complicated, aren't they?