I have a 92 integra gs with a (ebay) Bomz CAI and a (ebay) Tsudo catback exhaust system.
I want to put in a Megan header and test pipe to complete the IHE upgrade.
I’m new to this sort of thing and want to make sure the pipe sizing is correct because I read there will be power lose for improper sizing.
The header outlet says it’s 2.0" and the test pipe that goes with it has a 2.25" inlet and 2.5" outlet.
My exhaust has 2.5" piping I believe, so the test pipe outlet should connect easily to the exhaust but what about the header outlet to the test pipe?
my friend gave me an analogy saying that i’ll only be getting power from the 2" piping. the rest is just sort of lost exhaust pressure. his analogy was connecting a big straw to a smaller straw. when you blow through the small straw, all the power is restricted to being inside the smaller straw (2.0" piping). so its like a reverse bottleneck.
now what i don’t understand is:
how do you connect a header with a 2.0" outlet to a test pipe with a inlet of 2.25"?
i thought stock piping on most cars is 2.25". y is the header piping 2" instead of 2.25" is that normal?
[QUOTE=wdkwang;2048517]my friend gave me an analogy saying that i’ll only be getting power from the 2" piping. the rest is just sort of lost exhaust pressure. his analogy was connecting a big straw to a smaller straw. when you blow through the small straw, all the power is restricted to being inside the smaller straw (2.0" piping). so its like a reverse bottleneck.
now what i don’t understand is:
how do you connect a header with a 2.0" outlet to a test pipe with a inlet of 2.25"?
i thought stock piping on most cars is 2.25". y is the header piping 2" instead of 2.25" is that normal?[/QUOTE]
[QUOTE=wdkwang;2048517]my friend gave me an analogy saying that i’ll only be getting power from the 2" piping. the rest is just sort of lost exhaust pressure. his analogy was connecting a big straw to a smaller straw. when you blow through the small straw, all the power is restricted to being inside the smaller straw (2.0" piping). so its like a reverse bottleneck.
now what i don’t understand is:
how do you connect a header with a 2.0" outlet to a test pipe with a inlet of 2.25"?
i thought stock piping on most cars is 2.25". y is the header piping 2" instead of 2.25" is that normal?[/QUOTE]
When you go to install it, you’ll see. it’ll be fine im sure.
Unless you’re building something more then just bolt ons, you’ll be fine.
You don’t need pressure, “back pressure” is actually very bad. You want to concern yourself with exhaust velocity.
the 2" outlet will be more of a restriction then your different sized setup. I would actually do a 2.5" collector mod on the header and go all 2.5" if you can.
On us H22 guys, the 2.5" mod has been proven to show anywhere from 8-10whp… which is a noticeable difference.
