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Catted X-pipe or Off-road X-pipe?


ironpeddler
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Catted = catalyst built into the exhaust pipe, which means the car ought to be able to pass smog.

Off-road = no catalyst, which is the route I would go if you don't have to meet smog in your state, since you will have less restriction in the exhaust system.

 

The bigger the exhaust runner diameter, the more power you ought to be able to net. However, you will also lose some low end torque by going with bigger pipe. Good luck.

 

Ken

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Think of your engine as an air pump. The more air in (bigger intake, valves, ports, polishing, etc), and the more air out (exhaust) the better the pump performs.

 

You can go TOO big in your exhaust if your engine doesn't maintain enough exhaust velocity to keep sufficient backpressure. That's when you get backfire. I'm no expert on tuning but I know the basics. The 1.75 is usually sufficient to handle the load. The 1.875 might be a little much if your power isn't so aggressive. Removing the cats (big flow restriction) will help horsepower drastically in most instances. The engine just seems to run freer. If you gotta keep a catted crossover pipe, spend the bucks and get the high-flow models.

 

Yes, you will lose low end torque if you can't maintain the backpressure, but you'll scream on the top end once you're moving more air. There is charting based on HP v. Pipe size. Writing this from an airport terminal, I don't have my fluid dynamics materials in front of me. Your best bet is to consult the manufacturer of your aftermarkets, or see if one of these gearheads has true experience running the bigger stuff...

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