DIY Turbo Discussion greddy on a 1.8? homebrew kit?

straight pipe or High flow cat?

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Old 03-22-2007, 01:27 PM
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Default straight pipe or High flow cat?

I have a 2.5" Racing Mazda DP and 2.5" Enthuza turbo exhaust with a crappy stock cat. I think changing out the stock, 17 year old, 1.5" cat would give me a significant loss of backpressure. Im wondering which of the two, test pipe or high flow cat would give me more power? I dont care about legal issues because i dont mind switching out either before an emissions test every 2 years. Also, an increase in noise wouldnt bother me.
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Old 03-22-2007, 01:38 PM
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then, it's the whatever's cheaper thing.
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Old 03-22-2007, 01:40 PM
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so a jr high flow has the same effect as a test pipe:?
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Old 03-22-2007, 01:49 PM
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most high flows should flow enough CFMs that's it not going to be a big effect vs. a test pipe.

with that said, i'd i wouldn't buy the JR unit. Give turbo tony a buzz and have him make you a 2.5" one for under $100.
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Old 03-22-2007, 02:08 PM
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I have the Bossfrog test pipe.
The price was cheap compared to a cat and it's made out of stainless steel.
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Old 03-22-2007, 02:19 PM
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I got a SS one off ebay that bulges out so it even kinda looks like a cat. It was like $60 delivered.
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Old 03-22-2007, 02:28 PM
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With the threat of global warming caused by greenhouse gasses and o2 emissions, it's now more than ever each and every human's responsibility to spool up as fast as possible while spending as little as possible, so I say test pipe that bish.
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Old 03-22-2007, 02:39 PM
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i hate following 60s era cars. they stink.
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Old 03-22-2007, 02:41 PM
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Originally Posted by SloS13
With the threat of global warming caused by greenhouse gasses and o2 emissions, it's now more than ever each and every human's responsibility to spool up as fast as possible while spending as little as possible, so I say test pipe that bish.

i was about to e-slap you :gay:
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Old 03-22-2007, 03:15 PM
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turbo+testpipe=flames.
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Old 03-26-2007, 08:15 AM
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Originally Posted by spike
turbo+testpipe=flames.


IDK why, but I don't shoot any flames. I might occasionally but pretty rare. I have a test pipe and no muffler....lol seems like it would.
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Old 03-26-2007, 10:41 AM
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wow, I imagine your car is a tad loud there bravo... I just replaced my magnaflow cat with a test pipe, and I think it may have made it breathe a bit easier. The test pipe is going to be cheaper.. its just a piece of pipe with 2 flanges, i.e. should be like $20 or so.
-Michael-
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Old 03-26-2007, 11:40 AM
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+1 on the test pipe. I had to put a cat in for emissions as they also do a visual inspection, I noticed a significant difference in spool with a test pipe vs. HF cat. I know that the tests have shown very little difference in final HP between the two, but I don't think that they looked at the difference in power curve/spool with boosted applications.

Just another note, on club drives people will NOT want to drive behind you.
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Old 03-26-2007, 12:29 PM
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Test pipe all the way, screw the cat.
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Old 03-26-2007, 12:30 PM
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High performance cats may flow well (at least compared to regular cats) but they will never flow as well as a straight pipe.

Test pipe ftw.
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Old 03-26-2007, 12:57 PM
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Yeah, the power might be better with the test pipe, but if you run on tours with groups, you'll be at the back. Trust me, it sucks. I had a hollowed cat for a while.... and I hated it. The stick was rough.... (of course this was with a motor burnin' oil too. <G>)

Not worth it IMHO......

Dave,
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Old 03-26-2007, 01:14 PM
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Originally Posted by ak47bravo
IDK why, but I don't shoot any flames. I might occasionally but pretty rare. I have a test pipe and no muffler....lol seems like it would.
Just turn the fuel decel cut to "off" on the LINK and you will shoot fames all the time.
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Old 03-26-2007, 02:13 PM
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Originally Posted by steelrat
Yeah, the power might be better with the test pipe, but if you run on tours with groups, you'll be at the back. Trust me, it sucks. I had a hollowed cat for a while.... and I hated it. The stick was rough.... (of course this was with a motor burnin' oil too. <G>)

Not worth it IMHO......

Dave,

I like the smell of raw exhaust fumes from a car w/ no cat. It is well worth not having a CAT. The cat robs power and spoolup, why would I want it at all?
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Old 03-26-2007, 04:50 PM
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Originally Posted by that7guy
I dont care about legal issues because i dont mind switching out either before an emissions test every 2 years.
Even thought the inspection is biennial, you can still be cited by the police during a roadside stop. Not very likely, but something to keep in mind.


Originally Posted by that7guy
Also, an increase in noise wouldnt bother me.
I've been surprised at how little a convertor dampens exhaust noise. They quite things a bit, but not much.
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Old 03-26-2007, 05:23 PM
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Originally Posted by AndyFloyd
I like the smell of raw exhaust fumes from a car w/ no cat. It is well worth not having a CAT. The cat robs power and spoolup, why would I want it at all?
Andy, I agree it does give you the powa.... but for me, I am just high on life...... Just like Clinton..... Don't inhale. <VBG>

Dave,
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