Magnaflow catback very raspy

[Roadcone]

I'm using a borrowed magnaflow catback on my car while my other exhaust gets repaired from being drug across speedbumps and the road from when we crest a hill a bit faster than expected and this thing sounds pretty awesome as long as I keep it under about 1/3 throttle and 3krpm. Above that it gets this real funky rasp. Is this normal? Has this exhaust had an internal failure?

the mods that have affected engine noise/sound are as follows:
TRD airbox w/ snorkle mod
JDL 4-2-1 header
ISR 2.5" Overpipe
Megan Racing 2.5" resonated front pipe

Loaner Magnaflow 2.5" catback.

[RayRay88]

If I had to guess I'd bet on the front pipe not doing its job. Most cat less front pipes usually need at least two resonators to keep rasp at a minimum and even then aren't enough to get rid of it 100%
Which cat back did you have originally?

[Roadcone]

Originally Posted by RayRay88

If I had to guess I'd bet on the front pipe not doing its job. Most cat less front pipes usually need at least two resonators to keep rasp at a minimum and even then aren't enough to get rid of it 100%
Which cat back did you have originally?

Dezod v1. It was never raspy with that catback. This magnflow catback has a 14x4 muffler in place of a typical resonator so it's not from a lack of devices.

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[RayRay88]

Originally Posted by Roadcone

Dezod v1. It was never raspy with that catback. This magnflow catback has a 14x4 muffler in place of a typical resonator so it's not from a lack of devices.

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The dezod has a resonator and a muffler per side, so if I had to lay blame it's going to be on the catback. I've had a 2.5 inch magnaflow exhaust on another vehicle, and even with a cat it was super raspy. Just the nature of their mufflers. On a vehicle like ours which is known to be rasp city with out cats, I wouldn't be surprised with your results.

[Roadcone]

The V1 dezod has a single resonator and a pair of mufflers. The Magnaflow has a similar sized muffler in place of the resonator and i would say the one muffler matches the combined muffler sizes of the dezod. The dezod is WAYYYYY louder but lacks any rasp in my mind.

Also magnaflow mufflers are far from raspy on any other car I've heard them on.

I guess i'm curious if these are known to have an internal failure or if the design of them causes the rasp. i'm not a fan of the stamped steel 180* turn into the rear muffler

[RayRay88]

Originally Posted by Roadcone

The V1 dezod has a single resonator and a pair of mufflers. The Magnaflow has a similar sized muffler in place of the resonator and i would say the one muffler matches the combined muffler sizes of the dezod. The dezod is WAYYYYY louder but lacks any rasp in my mind.

Also magnaflow mufflers are far from raspy on any other car I've heard them on.

I guess i'm curious if these are known to have an internal failure or if the design of them causes the rasp. i'm not a fan of the stamped steel 180* turn into the rear muffler

It's possible, I did blow out the magnaflow after about 90,000 km's. But that car was running stupid rich,



Also size =/ equivalent suppression. Magnaflow is known for their straight through mufflers and although they suppress noise they won't change tone or suppress certain frequencies like a well designed resonator.

[Roadcone]

Originally Posted by RayRay88

It's possible, I did blow out the magnaflow after about 90,000 km's. But that car was running stupid rich,



Also size =/ equivalent suppression. Magnaflow is known for their straight through mufflers and although they suppress noise they won't change tone or suppress certain frequencies like a well designed resonator.

This one was used on an eforce equiped car for a while so I wonder if that's what happened here.

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[Summerwolf]

"The nature of their mufflers...."

That's the first time I've heard of magnaflow and rasp being synonymous. Normally the only complaint is they're too quiet. They're not known to be super raspy, normally just a good, smooth tone.

[RayRay88]

Originally Posted by Summerwolf

"The nature of their mufflers...."

That's the first time I've heard of magnaflow and rasp being synonymous. Normally the only complaint is they're too quiet. They're not known to be super raspy, normally just a good, smooth tone.

Maybe it's just my limited experience but all the magnaflow exhausts I've heard on civics and domestic 4 cylinders have been raspy. I find they've been the quietest and smoothest on V8's.

[Roadcone]

Originally Posted by RayRay88

Maybe it's just my limited experience but all the magnaflow exhausts I've heard on civics and domestic 4 cylinders have been raspy. I find they've been the quietest and smoothest on V8's.

Well the rear muffler used on our cars is the same as a 3rd and 4th gen Camaro/fbody.

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[RFB]

Originally Posted by Summerwolf

"The nature of their mufflers...."

That's the first time I've heard of magnaflow and rasp being synonymous. Normally the only complaint is they're too quiet. They're not known to be super raspy, normally just a good, smooth tone.

I have gone through 3 sets of Magnaflows in 140,000 kms. of heavy tracking (built motor) since June of 2012.

They all have been fine, no rasp even without a cat In the header.
However, excessive throttle, especially with a supercharger, dissolves the muffler packing eventually, and the catback sounds like sh!t.

I keep buying them cause I love the uneven moaning banshee roar

[RayRay88]

Originally Posted by Roadcone

Well the rear muffler used on our cars is the same as a 3rd and 4th gen Camaro/fbody.

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F Body's/V8s sound so much smoother and less raspy than any 4cylinder. Having the same muffler doesn't mean much when the two engines put out drastically different frequencies and resonances. Have you tried combing through youtube for clips of other cat less Magnaflow exhausts to compare to yours?

[Summerwolf]

Originally Posted by RFB

I have gone through 3 sets of Magnaflows in 140,000 kms. of heavy tracking (built motor) since June of 2012.

They all have been fine, no rasp even without a cat In the header.
However, excessive throttle, especially with a supercharger, dissolves the muffler packing eventually, and the catback sounds like sh!t.

I keep buying them cause I love the uneven moaning banshee roar

That's true for any packed, straight through design muffler.

[Roadcone]

Originally Posted by RayRay88

F Body's/V8s sound so much smoother and less raspy than any 4cylinder. Having the same muffler doesn't mean much when the two engines put out drastically different frequencies and resonances. Have you tried combing through youtube for clips of other cat less Magnaflow exhausts to compare to yours?

It's near impossible to find anything that would be comparable to what I have since I've got one of the very few JDL 4-2-1 headers that are out in the world now. It sounded great with the dezod and I plan to go back to that when my buddy patches the holes I've put in it.

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