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Alloytec Exhaust Rasp Sovled! Its Goooone! :)

bludeck

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After many hours spent researching and talking to many different people, I thought I’d share my experience with my rasping VZ.
Being there is no definitive answer to the rasp issue.
Personally I can’t stand the rasp I know some people like it although this is for people who would like it gone.


To start with I have a 175 wagon.

Started with a stock exhaust, I then installed pacemakers with high flow cats and a custom tune.
Very happy with the power and drivability although rasped straight away around 2500 rpm.

Personally I couldn't stand it.

I then had a custom 2.5" cat back fitted, which gives a nice note although the rasp is still there. It is less noticeable only because it is muffled by the louder tone. When outside the car and listening to it take off is ear piercing.

Determined to get rid of it I then installed standard 5.7L V8 cats off an SS model.

Bingo rasp is gone, it’s the high flow cats!

I always had an inkling and am now very chuffed to get rid of it!

Hope this can help and solve others issues with Alloytec Exhausts.
 

Not_An_Abba_Fan

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Actually, the rasp is because the resonators are removed when fitting high flow cats. The cats on the VZ are up close to the manifold, the ones under the car that look like cats are actually resonators. WHen fitting extractors and high flow cats, these are removed and the cats put there. Removing these resonators induces that rasp that Alloytecs are renowned for.

Alternatively, you could have fitted a different cat back. The Manta that I do does not have the raspy note.
 

bludeck

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The cat back I had installed also included a 3" resonator after the Y collector, rasp was still there.

The cat back was never the problem even rasped with the standard item.

By removing the Hi Flow cats the rasp is gone, I personally see this as the fix in my case.
 

Not_An_Abba_Fan

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The rasp was there after you removed the resonators, that is what induced the rasp, not the high flow cats.
 

Not_An_Abba_Fan

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You removed the resonators. Replacing the high flows with standard cats may have eliminated the rasp, but that's not what caused it in the first place.
 

bludeck

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You removed the resonators. Replacing the high flows with standard cats may have eliminated the rasp, but that's not what caused it in the first place.
Exactly, the thread is my personal experience in eliminating the rasp. Not why or where it came from.
You clearly know more about the subject then myself, im not interested in a slinging match.
Im just sharing my experience to help others, in this case by replacing the cats the rasp is no longer there.
 

Kiddo

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You will have to keep in mind that the aftermarket cats/resonator you installed wouldn't have muffled the rasp as well as the OEM equiment
 

Not_An_Abba_Fan

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After many hours spent researching and talking to many different people, I thought I’d share my experience with my rasping VZ.
Being there is no definitive answer to the rasp issue.
Personally I can’t stand the rasp I know some people like it although this is for people who would like it gone.


To start with I have a 175 wagon.

Started with a stock exhaust, I then installed pacemakers with high flow cats and a custom tune.
Very happy with the power and drivability although rasped straight away around 2500 rpm.

Personally I couldn't stand it.

I then had a custom 2.5" cat back fitted, which gives a nice note although the rasp is still there. It is less noticeable only because it is muffled by the louder tone. When outside the car and listening to it take off is ear piercing.

Determined to get rid of it I then installed standard 5.7L V8 cats off an SS model.

Bingo rasp is gone, it’s the high flow cats!
I always had an inkling and am now very chuffed to get rid of it!

Hope this can help and solve others issues with Alloytec Exhausts.
You said there where it came from. That's not the case at all.

I'm not trying to argue, I'm telling you what caused the rasp. You said it was the cats, it's not.
 
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