E46Fanatics - View Single Post - 330-style Exhaust onto 328Ci (switch from "single" to "True dual")
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Old 01-09-2009, 09:03 AM   #9
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Join Date: Feb 2005
Location: St. Louis, MO
Posts: 614
My Ride: 2000 328i
I don't know that anyone can give you exact numbers, but you might get 5 -15hp (as a rough estimate) from headers. A lot depends on what else you have done to your engine. I don't think you will see any significant difference between a 328 and a 330 exhaust system unless you are pushing huge horsepower numbers (more then you are going to get with a N/A engine).

Keep in mind that the stock catalytic converters are in the headers so if you don't add aftermarket cats you will throw a CEL and won't be able to pass emissions.

Lastly, If you take the time to do a search you can find everything you want to know about headers.

Originally Posted by ventura_328Ci View Post
sorry to hijack, but i just have a quick question (searched but had no luck..):

i have a 328Ci and i'm about to put some ebay headers on it. how much hp would the new headers alone with the stock 328 exhaust add? also, say i were to get 330 headers and a 330 dual exhaust, how much hp would that add?
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