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why are open headers bad for our cars

  • Thread starter Thread starter er22bball0302
  • Start date Start date Jan 14, 2007
E

er22bball0302

New Member
Oct 23, 2005
26
0
0
el reno, ok
Jan 14, 2007
#1
  • Jan 14, 2007
  • #1
why are open headers bad for our cars. i have heard that you will lose torque and or possibly ruin your valves? a friend of mine wants to install some exhaust cutouts
 
C

Cobracide

Founding Member
Nov 8, 2001
111
0
0
Charlotte, NC
Jan 15, 2007
#2
  • Jan 15, 2007
  • #2
Backpressure on the exhaust provides vacuum on the other cylinders, making your engine more efficient.
 

larrendeuce

Member
Sep 13, 2003
649
1
19
Southern NJ
Jan 16, 2007
#3
  • Jan 16, 2007
  • #3
er22bball0302 said:
why are open headers bad for our cars. i have heard that you will lose torque and or possibly ruin your valves? a friend of mine wants to install some exhaust cutouts
Click to expand...

If the primaries are too short the valves can cool too quickly, and warp. I don't know of anyone having problems with open longtubes, but open manifolds wouldn't be good.
 
E

er22bball0302

New Member
Oct 23, 2005
26
0
0
el reno, ok
Jan 20, 2007
#4
  • Jan 20, 2007
  • #4
Cobracide said:
Backpressure on the exhaust provides vacuum on the other cylinders, making your engine more efficient.
Click to expand...
wouldn;t back preasure in the exhaust be a postive preasure not a vacum? i could see how a vacume in the exhaust could benefit. the high preasure from combustion would move to the area of lower preasure(exhuast if there was a vacum), but i dont see how you would get a vacum?
 
C

Cobracide

Founding Member
Nov 8, 2001
111
0
0
Charlotte, NC
Jan 22, 2007
#5
  • Jan 22, 2007
  • #5
er22bball0302 said:
wouldn;t back preasure in the exhaust be a postive preasure not a vacum? i could see how a vacume in the exhaust could benefit. the high preasure from combustion would move to the area of lower preasure(exhuast if there was a vacum), but i dont see how you would get a vacum?
Click to expand...

When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.
 

SVT98Snake

New Member
Apr 15, 2005
258
0
0
OK, USA
Jan 22, 2007
#6
  • Jan 22, 2007
  • #6
backpressure creates a vacuum....and wha tI have heard about open headers allow heat to travel back into the ports which can ruin the valves...now whether or not that is true, I don't know....but it's better than chancing it.
 
E

er22bball0302

New Member
Oct 23, 2005
26
0
0
el reno, ok
Jan 22, 2007
#7
  • Jan 22, 2007
  • #7
Cobracide said:
When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.
Click to expand...
oh ok i see where your coming from now.
 
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