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Discussion Starter · #1 ·
would i be able to fit an unequal length headers on my 06 sti if i swap out the oil pan to the 04/05 design? would it be a direct replacement? thnx
 

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Im just curious? Why would you need to change year oil pan??? I am running unequal lengths on my 05 and they are just fine....
 

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Dumb question, but if they are unequal lengh, then they wouldn't be headers, right?

Header implies equal length tubes.
Another question, if unequal length, what advantage do they have over stock manifold other than weight?

Don
 

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donmei said:
Dumb question, but if they are unequal lengh, then they wouldn't be headers, right?

Header implies equal length tubes.
Another question, if unequal length, what advantage do they have over stock manifold other than weight?

Don

interested as well...
 

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Most people refer to an aftermarket exhaust manifold as a Header. Not sure if thats correct, but I hear what you are saying.

Besides weight I really dont know of the advantage over stock since the stock retains heat very well because of the cast manifold.
 

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aftermarket unequal lengths flow better by having slightly larger ID on the piping and not having the restrictive 41mm stock crosspipe. Check Rainmaker's thread for more info. The Gruppe-S unequal header outdynoed ported stockers with an injen crosspipe (44mm) and came close to dynoing what the unequal length Perrin did.

Oh, and theyll fit your 06.
 

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this has been debated before in relation to our cars. In a V8 application like a drag setup equal length is very important to exhaust scavaging. But in our boxers the equal legnth does not buy us much because we utilize "forced" induction anyway. The unequal legnth allow you to retain the "boxer" sound vise the "honda" or "highly tuned" exhaust sound of the equal length setups....
 

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do you give up midrange and spoolup since egt reaching the turbine is less ith headers, unequal length or otherwise?

Don
 

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twiSTies, How do you like your Borla XR-1 Cat Back? I just bought one but I wasn't too sure that I am going to like the sound based on previous experience with this brand, albeit with other type of cars. I will be using the Cobb DP.
 

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acrijos said:
twiSTies, How do you like your Borla XR-1 Cat Back? I just bought one but I wasn't too sure that I am going to like the sound based on previous experience with this brand, albeit with other type of cars. I will be using the Cobb DP.
Love it. Deep and brings out the perfect boxer rumble without killing you on the highway:tup:
 

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donmei said:
Dumb question, but if they are unequal lengh, then they wouldn't be headers, right?
Header means it has primaries at all, it does not imply a particular length. Technically the stock manifold is a very basic header, but the primaries are extremely short.

2fas4u said:
In a V8 application like a drag setup equal length is very important to exhaust scavaging.
Where did you hear that? It is extremely rare to find a V8 with equal length headers. The vast majority use unequal shorties. Longtubes are easier to make equal length so it's somewhat more likely, but most people don't run longtubes. The power difference between equal and unequal shorty headers on a V8 is zip. In general, exhaust is not nearly as important on N/A V8's as it seems to be on turbo cars.

donmei said:
do you give up midrange and spoolup since egt reaching the turbine is less ith headers, unequal length or otherwise?
You gain between 30-40 ft-lbs of torque at the wheels from ~3200 to nearly 5000 RPM, and it maintains a noticable advantage over stock until ~6500 RPM (where the turbo is the ultimate limiting factor).

On ice cold startup you give up a couple hundred RPM in spool. Once the car warms up, no difference, although it seems to spool a little bit faster when it's *really* warm (when you're beating on it consistently). This may not be true if you use a bare header. This is my experience with my Perrin EL header w/Thermo-tec wrap.

Dave
 

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Discussion Starter · #17 ·
so... im still unsure of what the actual difference is between the 05 and 06 STIs... i thought everything was the same, but i guess i was wrong [according to rich @ maddad]... i read on a post that it's the oil filter mount that is slightly diffferent? and it can be altered to mount on any unequal length headers, including the maddads' [duh~]... i have heard from couple people that the gruppe-s fits on there no problem, as well as the gt spec... and that is where i totally lose the ball... SO WHY DOESN'T THE MADDAD FIT???
 

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What is your basis for saying equal length is more important for turbo than na? I am not speaking from experience on the turbo side, but that doesnt seem to make sense.

On a na car you can use the reflected and standing waves to assist in scavenging of exhaust gasses. On a turbo car you don't need scavenging because the pressurized intake can be used to blow the cylinder clean. Again, I'm speaking theory, just asking questions.

Don
 

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btw - the hookers on my Impala were definitely equal length. The rear headers curved way forward prior to sweeping back to the collector. Back when I put them on (late 80s) the use of "long tubes" was common. That may be different now.
 

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donmei said:
Dumb question, but if they are unequal lengh, then they wouldn't be headers, right?

Header implies equal length tubes.
Another question, if unequal length, what advantage do they have over stock manifold other than weight?

Don
better flow. doesnt hold a ton of heat but still conducts heat effectively
 
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