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2012...Magnaflow good choice?

7K views 32 replies 16 participants last post by  TheDriver916 
#1 ·
I need quick feedback as I may have a Magnaflow put on this morning. Please...what do you folks think about it?
 
#2 ·
Cat back or just a muffler?

I'm trying to figure out if the 2.5" catback from an ST, modded to fit, would be a better choice than the standard 2.25" model for the N/A cars currently...
 
#3 ·
The 2.5" would have a lower restriction than the 2.25" tubing, however if you go too large you reduce the backpressure too far and start to hurt performance.

Its been discussed that the 2.5" might be a better plan if you are planning on adding additional power adders down the line. If the limit of your modding is an intake and exhaust and nothing else a 2.25" exhaust may work better.
 
#4 ·
Soooo if a 5.0L pushrod made 225hp from the factory with 2.25" dual pipes... Why does it gain power moving to a 2.5" system? I daresay that a 2.0L making 160hp from the factory is moving much more air volume than that weezy 2.5L per bank engine.

I honestly don't give much credit to the backpressure theories on modern cars where multiple cats are retained. The cats are a blockage, and force backpressure to be retained for the engine side of things, cancelling out most if not all pulsation in the exhaust flow, and anything post-cat system is made better by open pipes.
 
#5 ·
Pv=nRT, which is the ideal gas law will explain the principle of how the exhaust gasses flow at a very basic level.

The stock system on the 5.0 L was quite restrictive at the time.

Modern catylasts don't pose nearly the restriction on flow or increase in back pressure as the earlier systems did as well.

Only the PZEV models have two catalysts though for the 2012+ 2.0 L GDI Ti-VCT, the regular models only have the integrated exhaust manifold catalyst.
 
#7 ·
If the aftermarket offers a 2.5'' over a 2.25'', I'd get the 2.5 system. I'd bet most of the aftermarket kits are geared towards the 2.5'' systems.
 
#11 ·
Modern Street bikes have valves in the exhaust to increase back pressure at low rpms. With this valve the low end torque is reduced.

I don't think I've read anyone complain about the magnaflow, other than preferance to something else, so good luck and tell us what you think
 
#12 ·
Magnaflows sound great with this engine... It's a shame they didn't go 2.5" but if you're not looking to mod everything, the 2.25" should do ya fine
 
#13 ·
I have the 2.25 as well and it will be fine for now. honestly there isn't enough mods out yet for the 2.25 to hold you back. And at the shop where I had my exhaust installed, they told me that the stock piping was 2 1/8th.

[scratch][???:)]
 
#15 ·
I have had the Magnaflow system on for about 3 weeks now. Overall it is not too loud. No drone at highway speeds. When you accelerate there is an RPM range that it sounds the loudest. I heard it from the outside the other day when the wife took the car to run an errand. It was not loud at all as she drove away. Sounded good. Overall I'm happy.[cool]
 
#16 ·
DO IT!!! I've had mine on since August. Sounds great, looks great, no drone, well built.
 
#17 ·
I got 'er done. Got the Magnaflow installed and I really do like it. Sounds good...and the car does indeed have a little more zip. Accelerates well and is just loud enough to let you know it's there.

I was planning on seeing mileage increase and initially I thought I had...but I can't keep my foot out of it long enough to say for certain.

Overall...a great addition to the car.
 
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