PLRX

..About Catalyst Cat-Back Systems

As many of you already know I have the Magnaflow Cat-Back System on both of my Corvettes. You also remember that I mentioned about the Magnaflow resonator having an "X" inside.

WELL, it looks like the both times I looked at the resonators ("rexonators") I looked inside from the front of them and never from the rear. TODAY I DID.

I promised you may not like what you are about to see.


I was having promblems with the passenger side connection, the pipe is bigger than stock and it was ribbing against the hangers.
Removed



This heat wrap, helped on reducing the heat wave I was getting on my legs. Notice the "X" pipe before the resonator.



NOW, notice how the "X" enter the resonator as a DUAL exhaust BUT, the resonator is NOT a dual resonator, from
the X to ONE then out of the resonator as a Dual exhaust again. This reminded me of the L98 system








The tube inside the resonator is not 3" in diameter.

WOW...WTF Magnaflow

vettme

Great! I allready ordered mine, itll be here Thurs. H ow does the stock resonator compare to Magnaflow?

PLRX

the stock was two-in, two-out with glass pack inside.

vettme

Is Magnaflow 2&2 also?

PLRX

ks5shooter

I sent Magnaflow a link to this thread explaining we would like a response.Lets see what happens

pologreen1

RetiredSFC 97

yeah, I sent Corvette Central the thread about how awful their magnaflow, with LT 1 tips fit, and how several of us were unsatisfied.

I have not heard a peep from them and that was over a week ago.

no more CC for me.

joe3906

Thanks for that info. I had a pair of magnaflows, but I took them
off the car and put my OEM mufflers back on. TOO MUCH NOISE,
AND THE DRONE WAS UNBEARABLE. No one would get into my car.
You could here me coming two blocks away.

Joe B.

PLRX

This may be a bomb shell on Magnaflow.

Any problems with Borla, Corsas or Flowmaster? Are they a TRUE-Dual Exhaust System?

I'm thinking of taking the X and the resonator to a muffler shop and have them remove the resonator and replace it with 'two" straight pipes.

Why would they do that? Any engineers in here?

Don't get me wrong I do like the way they sound but, I think the reduction from two inlets to one and back to two outlets could be good for performance. Remember, I'm not a designer or an engineer I could be wrong.

uptown193

I have Corsa cat back and i suppose to be true dual but it is not. I remember seeing a thread on here where some dude took it apart and it was not true dual. I was pissed off after I saw that. I paid $1,000 with install. Why do they say it is dual when its not.

shakedown067

Makes me glad I pieced my magnaflow system together...although I ditched the resonator all together anyway.

PLRX

Shoot, did not know that. I've sen the Corsa mufflers on the C6. They are one in and one out and it then becomes a dual muffler tip.

Any word from our "engineers"?

GREGGPENN

I gotta admit I'm not sure what I'm seeing. Are you saying 2 pipes in to 1, then back to 2 pipes? And, that the center pipe is smaller than you'd expect?

Though I only took a couple of engineering courses, short obstructions induce far less resistance than longer ones. In fact, if you REALLY examine your actual "X" pipe (in front of your resonator), the cross-section of the VERY center is not as big as the two pipes coming in/out. So, in addition to combining pulses, that temporary reduction in size is likely to speed up pulses and keep them moving back out the backside. What you see might not slow things down -- like you would intuitively think.

On the L98, the center 3" section is kinda like an "X" pipe -- but because it's so much longer, there might be a detriment. (I think the CATS are a bigger one though).

By combining an "X" and a resonator, it looks like Magnaflow is allowing fumes out into the can,,,then back in ANYWHERE along that 2==>1==>2 pathway. And, the insides of a muffler aren't always straight-thru and smooth -- like we might hope/anticipate. That's because muffling often involves areas and changes in pressure to accomplish it's goals.

Consider how a "performance" glass-pack, round muffler, or resonator works. Though there's a straight-thru pathway, perforations allow fumes out and back in. Since their's no smooth curve to get gases back out the "out hole", it's the same kind of situation. ANY perforation in a tube will cause resistance. Turbulence and packing are a couple other elements of muffling.

Edit: Consider also that exhaust ports on a head usually flow more thru a pipe than into the open air. Firing thru a narrow hole causes a high-velocity release that actually helps PULL fumes from behind it. That's what I'm eluding to about the center section I think I'm seeing in your resonator.

jaa1992

And this is why I let a muffler shop just put straight pipes from my cats to the LT1 stock mufflers. It was cheap and I have a true dual.

biggrizzly

I just bought the Magnaflow axle back and had the muffler shop install the RT Cats and X pipe. No resonator. Its not that loud as far as I'm concerned.

pologreen1

Cost me $300 for dual stainless, and $90 for dynomax muffs I am happy.

mnstrlt1

I have the magnaflows- I removed the resonator and installed straight pipes before the system even went on the car. The x-pipe looks to be a little "pinched" if you ask me (i.e. not true 3").

Otherwise, the system is fine. It fit well, and i've probably had about a years worth of driving on it. It's a bit loud in the car, but it was much louder with the flow-masters.

I only paid about $550 (shipped) for the kit. I figured at that time that a complete "custom" 3" system would cost much more (if having a shop do the install and labor or fabricating a custom system).

Regardless, I do not believe this is reason enough to NOT purchase the kit. Of course, I am also surprised when I hear from members that they've had trouble with install (fit, finish, quality).

PLRX

good post, so, now I see why the stock LT1/LT4 exhaust system is 2.75 but it narrows before the muffler. It may narrow more after the muffler then the LT1/4 muffler tips. The stock resonator is 2 in, straight inside (with holes) and 2 out. You are saying that this type of exhaust is more effective than a free flow from heads-catalyst, X-pipe to mufflers?


I did have trouble with the install, the passenger side would make the resonator too close to the seat belt bolt. The muffler shop cut the tip off. BUT, I'll try to re-install the system without the bracket (see picture #1) and will get back with you.

vettme

Good luck, Ill be installing mine this week end. I may have questions.