How restrictive is are the cats on stock SC exhaust?

MustangJake88

Registered User
I am looking to free up my exhaust before I throw my 15% OD pulley on and I have heard that eliminating the resonator is a bad thing, and I have heard it's not bad if you leave on the cats. How restrictive are these cats if I am planning on throwing more boost at my car? My plan was just to delete the resonator and replace it with a dual in/single out Magnaflow. Will this hurt my boost?
 
They've covered that quite a bit on here, do a search. Basically, if there is less restriction going out, there is less restriction (boost) going in. That's not a bad thing, though. if your boost goes down as a result of freed up exhaust, that means the air is being pushed in easier, meaning you have more breathing room for the od pulley. But be sure to get the air going in cooler, like getting one of kenewagner's double ic's. Now you're talking power.:cool:
 
I don't think the stock cats are that bad, it's just the stupid bends they have.

I would have new downpipes made with aftermarket hi-flow cats and a good resonator. So you're on the right track.

What are you putting 15% od on ?
 
I meant what setup ? What other mods are you running ?
Oh, I have a cold air intake and I will be buying a C&L MAF and a throttle body, maybe a set of 42lb injectors and exhaust. That's probably all I'm going to do with the car. I'm only 19 and I have already totaled a sweet fox Mustang. I don't need to be making this car crazy fast and wrecking it too, haha. It's too nice of a car.
 
Oh, I have a cold air intake and I will be buying a C&L MAF and a throttle body, maybe a set of 42lb injectors and exhaust. That's probably all I'm going to do with the car. I'm only 19 and I have already totaled a sweet fox Mustang. I don't need to be making this car crazy fast and wrecking it too, haha. It's too nice of a car.

run only 5% thats more than enough for u if u r not going krazy on the car:cool:
 
I am looking to free up my exhaust before I throw my 15% OD pulley on and I have heard that eliminating the resonator is a bad thing, and I have heard it's not bad if you leave on the cats. How restrictive are these cats if I am planning on throwing more boost at my car? My plan was just to delete the resonator and replace it with a dual in/single out Magnaflow. Will this hurt my boost?

On a stock motor, 15% will likely hurt something besides boost. Depending on the year of the motor I wouldn't go any higher then 10% on the 89-93 and 5% on the 94-95 motors after you open up the exhaust.
 
I doubt u could even successfully run the 10%.

Stick with 5% until you've porter the blower and added an ic fan and/or upgraded the ic.
 
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