Simple questions. I need to get my car to pass smog. I have a single turbo, street port and straight through exhaust to my RE-AMEMIYA exhaust. Steve Kan did the tune and AF sits around 13-14 idle/lean cruise and the car almost passes the sniffer.

I need to add a cat but wondering if it's easier to just weld in a cat or buy a HF cat already in the midpipe. This should help a lot would it not? Also, do I need to modify anything since I have a single turbo kit to connect to my downpipe?

 

where do you live?

 

I went the route of purchasing an aftermarket Magnaflow CA-Legal cat and attempting to weld it into my midpipe. The problem I encountered was the bends of the straight pipe and length of the cat; simply put it would not fit properly. A straight pipe will have as few of bends as possible whereas a pipe designed to hold a cat will position is correctly.

That being said, get a cat pipe. Make sure it as an air fitting. If you do not have your air pump installed anymore, look at installing an electric air pump (I myself use one from an RX-8).

 

I don't have any smog equipment as I've gone single turbo and removed all of that. When I brought it to the test station, they said it barely failed due to a clean tune by Steve. He said that if I add a cat, it should be able to pass.

Obviously with straight through exhaust, I have a catless downpipe and catless mid. What I'm wondering is will a hf cat midpipe such as one from RX7store (http://rx7.com/store/rx7/fdexhaust.html) mate with the downpipe problem free?

 

hmm
I have the rx7 store one and its great
but if you dont plan to keep it in your car, it would be a waste
as to whether it fits with your downpipe, that depends on if your downpipe is standard or not
no special pipe is required, it bolts in stock
have you thought about finding an OEM cat maybe at a junkyard or borrow one from a friend?

 

The car is being sold so the cat would stay on the car. If the new owner wants to remove the cat, he'll just have to remove 4 bolts and swap the catless midpipe in.

I just want to make sure that the midpipe will mate up with my downpipe prior to purchasing. I have an Aspec 500R single turbo kit.

 

you need to contact Aspec, bro
they will know if the mid pipe is the same length as the stock cat or if they sold you a custom build
I am quite positive it will be stock specifications though

 

I'm fairly positive the Aspec kit drops the downpipe from the turbo down to the stock downpipe ending flange location, so that RX7store cat pipe will bolt up.