Header info, right or wrong ?
#1
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Year: 1997
Model: Cherokee
Engine: 4.0
Header info, right or wrong ?
My 2cents from a newbie that only has research on his side
From what I have read the best set up is a header that flows from 3 to 2 to 1 like this one http://rustysoffroad.com/mm5/merchan...y_Code=headers
As far as going to a larger than 2.5 diameter pipe it has been stated that all is good with longer pipes to improve exhuasting the spent combustion chamber gasses thus allowing more fresh air into the combustion chamber giving a better explosion, BUT the larger than 2.5 diameter pipes are said to effect the back pressure of the system ( I`m guessing it has something to do with the compression like a vaccum cleaner going to big will only cause a tornato affect instead of a straight flow ) and rob the engine of it`s good gass mileage due to the combustion chamber still being full of gasses from the last explosion...
This is just what I can gather from what I have read, Myself I have decided not to go with a header as my stock manifold is still in good condition and my 96 cherokee is only a stock engine and the only noticable gain I would get is a louder growl... I have up graded my exhuast system to a 2.5 high flow from the bottom of the stock manifold to the tail pipe and this setup will help my engine breath better and improve my gas mileage a little, My next upgrade is a cold air intake and larger throttle body to better improve the fresh air flow into the combustion chamber, of course after I has researched the crap out of everything I hate waisting time and money
From what I have read the best set up is a header that flows from 3 to 2 to 1 like this one http://rustysoffroad.com/mm5/merchan...y_Code=headers
As far as going to a larger than 2.5 diameter pipe it has been stated that all is good with longer pipes to improve exhuasting the spent combustion chamber gasses thus allowing more fresh air into the combustion chamber giving a better explosion, BUT the larger than 2.5 diameter pipes are said to effect the back pressure of the system ( I`m guessing it has something to do with the compression like a vaccum cleaner going to big will only cause a tornato affect instead of a straight flow ) and rob the engine of it`s good gass mileage due to the combustion chamber still being full of gasses from the last explosion...
This is just what I can gather from what I have read, Myself I have decided not to go with a header as my stock manifold is still in good condition and my 96 cherokee is only a stock engine and the only noticable gain I would get is a louder growl... I have up graded my exhuast system to a 2.5 high flow from the bottom of the stock manifold to the tail pipe and this setup will help my engine breath better and improve my gas mileage a little, My next upgrade is a cold air intake and larger throttle body to better improve the fresh air flow into the combustion chamber, of course after I has researched the crap out of everything I hate waisting time and money
#3
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Year: 1997
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J just
E enough
E essential
P parts
#5
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Year: 1998
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Engine: 4.0 i6
i call bulls#$% back pressure is very important i went from 4 into 1 headers to a set of zoomies (4 individual pipes) on my rail and lost .8 of a second in the 1/4..to much exhaust WILL rob power and can heat up exhaust valves
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Year: 1998
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and going from the "tubular manifold" like on my 98 to a long tube header is kind of pointless ... i swapped out a cast manifold on a buddies 95 for a stock "header" i had and it picked up noticibly
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#9
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Year: 1991
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Engine: I-6 4.0 HO
Want my source?
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
I have more if you want them.
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Year: 1998
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Engine: 4.0 i6
i tell ya what bring your jeep to the track or a dyno.....run it full exhaust,run it with a proper performance exhaust, then rip the whole thing off....bet you lose power wide open...too much exhaust WILL LOSE POWER!!! for that matter ANY stock motor will produce more power with the proper exhaust over a super free flowing system or open headers
#12
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Year: 92
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Call BS all you want. Back Pressure is NOT neccesary on an engine that can modify its air/fuel ratio like our XJ's and every other fuel injected vehicle can.
Want my source?
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
I have more if you want them.
Want my source?
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
I have more if you want them.
even with the modifying of the AFR's , the motor will still result in less power because of the spent gasses that are ALSO in the cylinder during combustion
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Year: 1991
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Engine: I-6 4.0 HO
i tell ya what bring your jeep to the track or a dyno.....run it full exhaust,run it with a proper performance exhaust, then rip the whole thing off....bet you lose power wide open...too much exhaust WILL LOSE POWER!!! for that matter ANY stock motor will produce more power with the proper exhaust over a super free flowing system or open headers
#14
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Year: 1991
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Engine: I-6 4.0 HO
What? The only spent gas left in the cylinder is that with which was not able to flow to the lower pressure zone in the exhaust system with the rest of the expelled gases. I'm not understanding what you're saying here.