doubleoh

Any dyno testing of cat backs? Does anyone make a bolt on high flow cat for 2014 GT?

09GT/CS

I doubt anyone has paid dyno fees for only a catback because dyno time is expensive. I'd be inclined to say no not on a modern car as they are tuned well from the factory. However there are dozens of write-ups on hi flow cats. Most make no difference at all and some are downright dangerous to the motor if you have mods like nitrous or forced induction. It's not uncommon for aftermarket cats to clog or melt under boost/ nitrous and destroy a motor. Ford did a really good job on engineering the cats unless your running crazy numbers I doubt you'll even notice the difference.

P51C

Stock cats melt too, when you subject them to boost for extended periods.

...and cat backs do just make sounds....

proeagles

According to Magnaflow's dyno results on one of their aggressive cat back systems, they show 25+hp gain. Most of the gains come from removing the resonator which you can do with a X-pipe.

fourdegrees11

Some cat backs come with an x-pipe (true cat back), wouldnt those make some power? Assuming someone wants to keep the factory cats in place and use shorty headers that would be the best choice right?

Anyone know what kind of power is made from shorties + X pipe cat back?

P51C

Full exhaust does make power but, that means getting the cats out and tuning for the exhaust. Full exhaust adds between 3-10 mph at the track, based upon my observations.

Dino Dino Bambino

Shorty headers (retains stock cats) ~5hp
X-pipe resonator delete (retains stock cats) ~5hp
Catbacks/axlebacks (retains stock cats) ~0-5hp
Complete system from manifolds back with LT headers, midpipe, catbacks, and tune ~20-25hp

pascal

Those are BS numbers with a BS Dyno and they put them there to sell the product.
A cat back system alone ain't giving you 25 ponies, period.

Dino Dino Bambino

Agree.

Agree again. Only a full headers-to-tailpipe system plus a tune will yield that sort of gain.

proeagles

Just the messenger here. Also why I use Borla/Ford Racing instead of Magnaflow