I was doing some testing yesterday at an airport a few of us rented and noticed in the rear mirror a large cloud of white smoke at 140 mph in sixth gear. So i tried it again and at about 100 the smoke starts. I did some other tests and then tried it in forth gear and got no smoke. Anyone got an idea what the hecks going on? My tips definitely had some water coming out. Drove home 50 miles with no smoke and tips were totally dry?
White smoke is never a good sign, means water is coming into the motor somehow. My guess is that in sixth gear, the load is heavier on the motor and therefore causing the issue. I wouldn't drive it until you had it checked out by a pro shop....
Condensation? Yesterday morning i backed my ZR1 out of the garage. The tthe temp was about 47 deg here in Michigan. I let it warm up while i was locking up and observed water dripping from the exhaust tips which turned into white smoke in a few minutes. I didn't pay attention behind the car as i drove but only got up to 45 mph. I can tell you it takes 10 miles for the oil to get to 190 degrees at these speeds. If you are not loseing coolant or there is not coolant in the oil, power loss or running rough i think that condensation is what you saw. After some hard running for a good period of time all of the moisture should burn out. When the hot exhaust system cools it will happen again.
At WOT and triple digit speeds I'd definitely be concerned. Let us know what your GM friends come back with.
GM has contacted me they are happy to have a look. Their planning to take it to the test facality at their proving grounds. They wanted me to know they would be checking EVERYTHING I told them have at it.
There's an electric pump in the system that circulates the fluid from the radiator through the intercooler, and you need a Tech 2 to command the electric pump to run to properly purge the system when servicing it.
Gm going to have to figure it out.