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Old 07-25-2005, 01:31 AM   #1
tallicaguitar88
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Default 2.5 RS Borla Headers and Turbo... Power Loss?

So I was talking with a local guy who is super smart about turbo 2.5's and he said that the borla's would make me lose power with my turbo because of the larger and longer piping and how much it is flowing into my turbo. I have a JC sports knock off kit w/ a garrett t28 turbo. I really just want the headers so I can get the boxer sound but if I lose HP then they aren't worth it... So, does anyone know this for certain? I believe the guy but I just want a little more reassurance I suppose.

I searched but couldn't find anything on this topic.
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Old 07-25-2005, 01:49 AM   #2
99subi
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i guess it comes down to how much you like the sound, im sure the loss cant be too drastic
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Old 07-25-2005, 04:21 AM   #3
Aus_RS
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I won't claim to be super smart, but I'll give you my thoughts :-)
Compared with the stock headers, the Borla's are less restrictive; that's the whole idea. Thing is though, with turbos more restriction before the turbo can actually be good. It's less area to pressurise up on tip-in, to a useful pressure for spinning turbine blades, plus for any given flow rate through a smaller pipe the velocity is obviously higher, which imparts more inertia from the exhaust gas onto the turbine blades (simplistic way of thinking : blow on a piece of paper with your lips close together vs mouth wide open).
So being _really_ basic about it: bigger headers = worse spool-up, but possibly better HP once up to full boost. But with 2.5L and low boost, things aren't all that bad in the spool-up department. I'm running Borla gen-4's with a Garrett GT2540, and I hit full boost (0.4 atm) by 2700 revs. I had the Borlas from day one on turbo so I can't tell you a comparison. I like the sound too (though they drove me nuts when I was still N/A).
Hope that helps some.
Mark.
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Old 07-25-2005, 06:20 AM   #4
speed_freak27
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You will lose down low, but gain more top end and your turbo will spool a bit slower.
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Old 07-25-2005, 09:52 AM   #5
IllNastyImpreza
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Default sound vs power

just like they stated, your spool time is going to be further increased, but gains up top will be noticable. typicly a higher redline would be even more favorable cuz your new headers would flow alot more air up top.

They say if you heatwrap the shiat out of them, and use the factory heat shields that they retain much more of thier heat and work much better. *shrug* go figure....

But I guess you will only know if you like them untill you try em
The sound you get from those things is INSANE
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Old 07-25-2005, 10:14 AM   #6
Wedge
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Borlas suck. They will crack, period. And their customer service is the suck also.

Keep the stock intake manifold, gains are minimal up top with the Borlas + boost. Mine are sitting in some landfill somewhere.
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Old 07-25-2005, 10:21 AM   #7
ForesterPerformance
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Borlas are crap. I went thru 2 sets before I added mine to the landfill as well. One set cracked N/A. The stock manifold flows great. Spend that $300 you were gonna waste on the header on something useful... or just send it to me. PM me for paypal address...
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Old 07-25-2005, 02:07 PM   #8
NeaD
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Well, I had a borla header on for the longest time with my turbo... When I took it off, I could tell a difference for the better. Don't waste your money on the borla, if your going to boost your car.
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