Uppipe Question
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Uppipe Question
I was wondering what Uppipe i should buy. Do you think i should get an extra Stock uppipe thats gutted for around $40 or $50 or go for an after market uppipe like Turboxs or Perrin for around 220? What are the pros and cons of each one?
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Re: Uppipe Question
Originally posted by Res07
I was wondering what Uppipe i should buy. Do you think i should get an extra Stock uppipe thats gutted for around $40 or $50 or go for an after market uppipe like Turboxs or Perrin for around 220? What are the pros and cons of each one?
I was wondering what Uppipe i should buy. Do you think i should get an extra Stock uppipe thats gutted for around $40 or $50 or go for an after market uppipe like Turboxs or Perrin for around 220? What are the pros and cons of each one?
I went with the PDE uppipe. But in reality, almost all uppipe are the same. The TurboXS is made of Cast Iron, so it will rust a lot faster than say the Perrin. But it's thick, and it won't rust through for years.
Blue
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From: Longing for my ol' white '02 WRX :(
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BTW - I don't think there's an "STi catless uppipe" for $150. If you're talking about the one's like I-Speed got on super-mega-backorder its the WRX JDM, not STi. I could always be wrong, but I believe this is the case.
jason
jason
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Yeah big backorder!
FYI, there is no such thing as an STi up pipe. I believe the 2002 MY did have a change to the pipe specifically aimed at the STi. However, the pipe in question is on regular JDMs and the STi.
Don't be fooled into paying more for an "STi"
FYI, there is no such thing as an STi up pipe. I believe the 2002 MY did have a change to the pipe specifically aimed at the STi. However, the pipe in question is on regular JDMs and the STi.
Don't be fooled into paying more for an "STi"
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Joined: Dec 2002
Posts: 469
From: Pleasant Hill, CA
Car Info: 02 WRB Wagon (Cobb AccessPort, P7's), 2-73 914 2.0, 74 914-2.0
I'm in the same boat. You don't want to gut a stock uppipe. If you are going to spend the time and/or money to change the uppipe, buy one that is already catless. Either the JDM WRX catless or one of the aftermarkets. Thanks for the info Jason. Didn't know that. I set on getting one of the I-speed pipes (yeah, I'm on that long waiting list). Now if they could only get that shipment so I can make the change before the exhaust nuts lock up permanently.
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Joined: Jan 2003
Posts: 29
From: Aurora, CO
Car Info: 2002 White WRX Wagon
I have a gutted stock up-pipe, and like the fact that it's subaru quality, has the flex section, heat shields, is definitely gonna fit with no exhaust leaks and looks totally stock to the dealer! Plus, you can't beat the price!!
And yes, I definitely notice the improvment in smoother spool up and low end torque!! Although it seemed more noticable after a couple of days of driving around with it in. I don't know if the ECU had any leaning to do with the increase air flow!
And yes, I definitely notice the improvment in smoother spool up and low end torque!! Although it seemed more noticable after a couple of days of driving around with it in. I don't know if the ECU had any leaning to do with the increase air flow!
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Again, because the US WRX's uppipe was designed WITH a Cat in it, it does not have the same design as a catless uppipe. It has an uneven flow characteristic, due to the smaller circumference where the CAT was..... It's not the best of ideas to do this. Just spend $150 on the JDM WRX uppipe (Sorry, for some reason thought it was STI) or the TurboXS uppipe for roughly the same price. It's like the old Proverb says: You get what you pay for.
Blue
Blue
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From: Aurora, CO
Car Info: 2002 White WRX Wagon
What some people don't seem to understand, when they order larger diameter up-pipes, is that you want air VELOCITY, not VOLUME. Larger diameter pipes flow more air, but at a slower speed. Narrower pipes force the air to increase in speed and density.
The faster you can get the air flowing, the quicker it spools the turbo. The narrower aperture where the cat used to be is designed to speed up air through the cat and keep the turbo spinning. It works the same way without the cat.
After the turbo (especially with a larger turbo) you want to evacuate a larger VOLUME of air to reduce back pressure against the turbo, that is why larger pipe is often used back there.
The faster you can get the air flowing, the quicker it spools the turbo. The narrower aperture where the cat used to be is designed to speed up air through the cat and keep the turbo spinning. It works the same way without the cat.
After the turbo (especially with a larger turbo) you want to evacuate a larger VOLUME of air to reduce back pressure against the turbo, that is why larger pipe is often used back there.
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From: Pleasant Hill, CA
Car Info: 02 WRB Wagon (Cobb AccessPort, P7's), 2-73 914 2.0, 74 914-2.0
I'm not sure about this but here goes. Part of what you says makes sense. By going to a narrower uppipe, the air density will increase and since you have the same amount of air going through a smaller diameter, air speed should increase also which is good for faster turbo spool-up.
But, there is a negative aspect to this. If you go from a wider opening to a smaller one, you are also creating a restriction prior to that narrow section which would create backpressure and thus hinder evacuation of gasses from the combustion chamber. So, I would think it is a balance. Of course, with the cat in place, there is plenty of restriction and loss of air velocity.
But, there is a negative aspect to this. If you go from a wider opening to a smaller one, you are also creating a restriction prior to that narrow section which would create backpressure and thus hinder evacuation of gasses from the combustion chamber. So, I would think it is a balance. Of course, with the cat in place, there is plenty of restriction and loss of air velocity.
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Originally posted by Sea Dragon Rex
I'm not sure about this but here goes. Part of what you says makes sense. By going to a narrower uppipe, the air density will increase and since you have the same amount of air going through a smaller diameter, air speed should increase also which is good for faster turbo spool-up.
But, there is a negative aspect to this. If you go from a wider opening to a smaller one, you are also creating a restriction prior to that narrow section which would create backpressure and thus hinder evacuation of gasses from the combustion chamber. So, I would think it is a balance. Of course, with the cat in place, there is plenty of restriction and loss of air velocity.
I'm not sure about this but here goes. Part of what you says makes sense. By going to a narrower uppipe, the air density will increase and since you have the same amount of air going through a smaller diameter, air speed should increase also which is good for faster turbo spool-up.
But, there is a negative aspect to this. If you go from a wider opening to a smaller one, you are also creating a restriction prior to that narrow section which would create backpressure and thus hinder evacuation of gasses from the combustion chamber. So, I would think it is a balance. Of course, with the cat in place, there is plenty of restriction and loss of air velocity.
Spend the money and get yourself a REAL uppipe.
Blue
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Originally posted by christoph1371
Yeah big backorder!
FYI, there is no such thing as an STi up pipe. I believe the 2002 MY did have a change to the pipe specifically aimed at the STi. However, the pipe in question is on regular JDMs and the STi.
Don't be fooled into paying more for an "STi"
Yeah big backorder!
FYI, there is no such thing as an STi up pipe. I believe the 2002 MY did have a change to the pipe specifically aimed at the STi. However, the pipe in question is on regular JDMs and the STi.
Don't be fooled into paying more for an "STi"
I believe that Rallispec sells the actual STI upipe, I have been to there shop and all the STI stuff they sell comes there in FHI boxes with Green labels(that say Sti etc.) I don't think they are selling the used JDM wrx takeoffs that are selling for $150 etc. They are selling an new sti upipe. Whether this item is the same upipe that is used on the non-Sti wrx in Japan I'm not sure, but I wouldn't be surprised if the STI has it's own part number etc.
http://rallispec.com/
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Joined: Jan 2003
Posts: 229
From: Pismo Beach, CA
Car Info: 02 WRX, 06 A3
How much hp can I expect to gain with adding a nice after market uppipe? What are the pros and cons of an uppipe with or WITHOUT a flex section. I noticed some of them are solid. Which would you guys reccommend?
Thanks!
Thanks!
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Joined: Nov 2002
Posts: 152
Re: Re: Uppipe Question
Originally posted by BlueDemon
I went with the PDE uppipe. But in reality, almost all uppipe are the same. The TurboXS is made of Cast Iron, so it will rust a lot faster than say the Perrin. But it's thick, and it won't rust through for years.
Blue
I went with the PDE uppipe. But in reality, almost all uppipe are the same. The TurboXS is made of Cast Iron, so it will rust a lot faster than say the Perrin. But it's thick, and it won't rust through for years.
Blue