[Shotimes] Running moving car without y-pipe attached?

[George Fourchy]

On Mon, 27 Sep 2004 17:47:57 -0400, Bruce Malachuk wrote:

>Will a SHO start and run without an Y-pipe attached?

I wouldn't drive it down the street very far, but in the driveway you will have no
problem.  It is VERY loud, but has plenty of power....the power loss due to no
backpressure shows up most at high RPM and high load.  

The O2 sensor lights won't show up until the PCM says they should start sensing,
after the engine warms a bit.  I moved my black Lowrider replacement around the back
yard plenty without the Y-pipe on it, and got no lights.  I didn't run it more than
a couple of minutes, but there is no difference in operation or indication before it
warms up.

The biggest theoretical worry, though probably not much of one with these engines
(especially if the heads never warm up), is the exhaust valves warping because there
is too much of a change in temperature too fast in an exhaust manifold open to
ambient air.  I haven't heard of this happening in decades..... rumors of this
problem ran around in the '60s with big block engines running open headers or
straight pipes on drag strips.  I never did figure out exactly why this was supposed
to happen, but it was what everyone warned about....."don't run your headers
open....you'll warp your valves!!!".

Bottom line.....move it around as much as you want, but don't run it too long at one
time.

George