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Discussion Starter #1
I think there is a misunderstanding with the whole testpipe raspy issue. I want to comment based on my experience over the last 2 years. I have had a few different exhaust setups with various results.

Ill start out with a simple list of the setups and the resulting raspiness, etc.. All setups were done on the stock exhaust and only headers/cats/ypipe were changed. (headers and borla were on friends' cars)

Stock headers --- Non-Resonated Test Pipes ---Stock Y-Pipe --- Rasp = Yes

Stock headers --- Resonated Test Pipes --- Stock Y-Pipe --- Rasp = No

Stock headers --- Resonated Test Pipes --- Aftermarket Y-Pipe --- Rasp = Yes

Aftermarket headers welded to test pipes --- Non-Resonated Test Pipes --- Aftermarket Y-Pipe --- Rasp = No

(exception is this setup with the Borla dual)
Stock headers --- Resonated Test Pipes --- Borla Dual --- Rasp = No

If you look over this list carefully it seems that the test pipes are not necessarily the cause of the raspiness. I believe it is a mis-match between pipes bolted together. When i had my exhaust taken apart, I noted that all the pipe inside diameters were of different sizes. I put the resonated test pipes on and had zero rasp. I then added an aftermarket y-pipe and the rasp was there just as bad as if I had non-resonated pipes..

Maybe some others can post their experience. But i think i covered enough variations to show what the problem is..
 

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I've heard DC Headers and Helix Non-resonated test pipes and it was raspy as ****. It was mean sounding, but very raspy.
 

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I have just the Helix test pipes and don't consider it raspy. Some people may say that, but I think they don't go to a track event often enough. It sounds just like any other modded race car...

The little raspiness I get from my system only occurs if I either 'blip' the gas pedal or get on it at 50% throttle. If I mash it and redline each gear, then it sounds like a beast. Then again, I also have the Crawford plenum and JWT intake.
 

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I'm getting my Borla TD and resonated test pipes from intense motorsports around Tuesday of next week can't wait going to install at a friends body shop using his lift.
 

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Discussion Starter #6
I'm getting my Borla TD and resonated test pipes from intense motorsports around Tuesday of next week can't wait going to install at a friends body shop using his lift.
that will sound awesome.. same setup i am doing
 

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I had Stock Headers, Kinetix Resonated Test Pipes with Japtrix Ypipe and Fujitsubo exhaust and did not have rasp.

And the reason I went with resonated was when I heard a Z with Stock Headers, non resonated test pipes and Injen angle tip exhaust and it was just nasty.
 

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arg.. i cannot help much here other than this:

Stock headers, stock cats, stock y pipe and ARC Ti. exhaust = no rasp.

Strup headers, AAM / RT cats, AAM yipe , ARC exhaust = rasp until warm up.. that is why I believe it to be the cats.. But perhaps it's not.

:dunno:
 

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Found this excerpt from this article ... interesting.

Hollowing out a catalytic converter or replacing it with a test pipe or straight section of pipe is a violation of Federal Law punishable by fines in excess of $25,000 and/or jail time for both the vehicle owner and the person doing the work.
Removing a catalytic converter will result, at most, in 5 HP in power improvement. However, hollowing out a catalytic converter will cause resonance problems. The symptom is most often seen as a hesitation, popping, or backfire at or about 3,200-3,500 RPM. Upon hard acceleration, the engine will appear to cut out for a split second as RPMs drop and a split second later recover and continue past 3,200-3,500 RPM. Additional symptoms are a loud and continual popping sound when the vehicle is allowed to decelerate under load and a whooshing sound that is delayed from or following the engine speed. This is due to the open chamber within the hollowed out catalytic converter case. It loads up and releases pressure in the exhaust system that acts almost as a capacitor. The open chamber allows the formation of standing waves within the chamber which reflects back toward the engine and causes the hesitation and miss in the RPM range.
The symptoms become more pronounced as the exhaust system is made freer flowing, meaning that hollowing out a cat with the stock exhaust may cause mild annoyance, while it becomes a serious problem when a header and performance exhaust system are installed, mimicking a ignition miss or backfire. This is probably the best reason not to hollow out a catalytic converter
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that will sound awesome.. same setup i am doing
I had AAM's single exhaust and test pipes added today to my NA car. WAY TOO LOUD imo!!! I've got no back pressure. It sounds mean at idle, but anything above 3,500RPM and it takes on a trumpet note. It's not what I was looking for. I'm going to put the cats back on and see how it sounds (I really like the look of the exhaust).

I'm setting the car up for FI this spring. This setup is perfect for that as the TT's will quiet the exhaust. We ordered the silencer, but I'm going to try putting the cats on first to see if they provide enough back pressure. If not, I might try test pipes with the stock exhaust.

The check engine soon light came on after driving the car from AAM home. I assume that 's because the o2 sensors recognize that the cats aren't doing there job (because they aren't there). I'm new to this, but I assume that this is the case with everyone who has test pipes. Let me know.

Here's a pic of the exhaust:
 

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I had AAM's single exhaust and test pipes added today to my NA car. WAY TOO LOUD imo!!! I've got no back pressure. It sounds mean at idle, but anything above 3,500RPM and it takes on a trumpet note. It's not what I was looking for. I'm going to put the cats back on and see how it sounds (I really like the look of the exhaust).

I'm setting the car up for FI this spring. This setup is perfect for that as the TT's will quiet the exhaust. We ordered the silencer, but I'm going to try putting the cats on first to see if they provide enough back pressure. If not, I might try test pipes with the stock exhaust.

The check engine soon light came on after driving the car from AAM home. I assume that 's because the o2 sensors recognize that the cats aren't doing there job (because they aren't there). I'm new to this, but I assume that this is the case with everyone who has test pipes. Let me know.

Here's a pic of the exhaust:
OK...once again showing how new I am. I'm trying to attach the file, but it's not appearing. I saved it to a smaller file size (198K) and it's still not working. Any advice?
 

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OK...once again showing how new I am. I'm trying to attach the file, but it's not appearing. I saved it to a smaller file size (198K) and it's still not working. Any advice?
I always use ImageShack for hosting, and have never had a problem. It's free and easy to use.
 

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Discussion Starter #20
**UPDATE**

Combination:
APS 2.5" Test Pipes (non resonated)
HKS Hi Power Dual Exhaust

Result:

NO RASP!
 
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