why is running open headers bad for exhaust valves? Ive heard this before and Im just trying to figure it out. No I dont run open headers, nor would I want to. Just curious
srothfuss said:Because once you turn off your motor the much colder ambient air travels up the pipe and cools off the valve seals too fast...? That is my guess
gt40_2003wes said:i always thought it was because with open headers u have no back pressure.
70_Nitrous_Eater said:I don't buy the "valves will cool off too quickly" arguement. 1/4mile cars proove this wrong often as much as 20x a day. They go from red hot to off right away...can't get more extreme than that.
Michael Yount said:Smock - exhaust valve temps even in a 1/4 mile car get at LEAST as high as a street car would see in traffic (that's one of the EASIEST scenarios for an exhaust valve actually) or 'going up a hill'. Besides that, you seem to think all race cars just race the 1/4 mile. In road racing mine routinely cycled from 4500 to 7000 in 3rd, 4th and 5th for 40 minutes to 24 HOURS at a time. We like to think the drag racers are quite easy on their motors.