Couple Q's. First is I want to replace the restrictive Cat. But for some reason there doesn't seem to be anything out there for my 2001 LX? All the products for 01's are for the EX. However there are a couple on ebay that say they are specifically for the EX, but then state they won't fit the HX or SI. So does that mean they'll fit my LX? this auction states; "Fits All Honda Civic EX 1.7L SOHC VTEC 01-04 ( Will not fit DX or Si model)"

CLICK HERE for ebay link

My part 2 to this is what is the most restrictive part to the exhaust, is it the cat? I've been thinking that it is the most restrictive but is it? I really want to keep it quiet too.

FYI, I have a SRI K&N intake, and Im doing all this to increase mileage. Typically freeing up restriction in Intake and exhaust equals HP gains, and Higher HP typically equals a more efficient engine, which typically equals better mpg. That is if you're light on the skinny pedal!

Thanks

 

I have an 02 DX.. no-one makes specific DX/LX parts. All parts made are for "EX" models. Basically there is no difference. In order to upgrade the exhaust on an LX/DX you need to buy everything needed in the EX model and hook it all up. So what you would need is a header (DC-Sports or Megan Racing are good, also heard good things about Headman), a high-flow cat (random-tech or magnaflow) [unless you want to go test-pipe and no cat which is illegal], and a catback exhaust.

What I am going to do is buy a universal high-flow cat from magnaflow and have it welded into my cat-back, but I know that random-tech makes ones that are already put together that you bolt right on.

As you probably know in order to replace the cat on a LX/DX you have to replace the header and the cat, because the cat is built into the LX/DX header on the 7th gens.

 

Actually no I didn't know that. I thought they were two peices. I guess they are 2 pieces on the EX. That answers a lot. Thanks.

I wonder if I got a used one, (in CA I think obtaining a used cat is illegal), and just tore out all the insides of the cat, if that would make a difference. I've heard they are very restrictive.

 

holy crap. you couldn't have been more wrong.

example:

look at an aem v2 for for ex and one for the dx/lx

OR

look at a Greddy Evo 2 Exhaust for the EX - it won't fit an lx

 

ractive also makes specific bolt on high flow cats for your 2001 and many other models

 

And, why exactly won't the Evo 2 fit an LX? I haven't looked (mainly because I went with magnaflow), but I am guessing it is because of the way the headers/cat are different on an LX/DX and EX models. Like, with the exhaust I bought, there is a small extension piece you need to install if you have the EX model becuase the header is a little higher up than the DX because of the difference in the headers.. So, like what I said, if you buy the header for the EX model and put that on your DX/LX and then get the EX model cat back, everything should be good to go.

[edit] - Actually I was just looking around and found a guy with an 01 lx who's selling his EX exhaust swap setup, and what do you know, he has the Greddy Evo2 EX model with an DC sports 4-2-1 and random tech ex cat pipe... so like what I said, all you need to do is swap everything into the ex model and should be good to go. [/edit]