Im going to buy megan headers for my 5th and figured i might as well do something with the cat while im down there. I already have cat back exhuast. My question is ,it worth getting a test pipe or just a high flow cat. Also if you install a test pipe on a 5th gen with obd II won't the secondary 02 sensor pick up way too much oxygen and turn the check engine light on? AND if that comes on won't the ecu start using pre set data tables from the factory insted of live sensor input since it is finding an error in the system?

thanks!!

 

anyone??? someone has to be using a test pipe or race pipe or highflow or SOMETHING are you check engine lights going on?

 

your car will throw a cel with a test pipe..

 

its not worth messing with since you have OBDII, I had a regular cat on my h22civic and I did not gain any power, and it didnt run any faster times when it was removed

 

I wouldn't mess with a test pipe unless you have future plans of FI.

 

For starters-a test pipe is absolutely ILLEGAL. It is not a matter of what state you are in-it is Federal. Second-without a simulator you will throw codes and have some issues with drivability. IF and only IF the car is a track car can you remove the CAT. IF you have done some serious interanl modification to the engine-then a High Flow CAT will be of benefit. The Megan header is not what you think it is. Save up for a real one from MUGEN or SMSP if you want a serious increase compared to stock. Fact is, the stock header is just fine as designed for the 5th gen. It is claimed (no proof I know of) that the 99-01 is actually better than the 97-98. ANother thing-you WILL need the sensors or simulators if you want the engine to not go into "limp mode." The Helm manual does explain a lot of this.

We put a Thermal cat-back on an otherwise stock car (FOR SALE) and it helps with both driveability and fuel economy. Then again we also put a K&N drop-in filter element in the stock airbox and saw an improvement from that alone. Remember, my car is completely stock. I agree when one mentions the OBD-II ECU. This is part of the problem with tuning any newer car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jc836 &raquo;</TD></TR><TR><TD CLASS="quote">It is claimed (no proof I know of) that the 99-01 is actually better than the 97-98.
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It's not. It's been proven to be exactly the same.

Anyway....Megan header?? There is no reason to change your cat.

 

now that u brought up the stock prelude header how big are the primarys on the 01 lude header and how big is the collector?, and one more question what is the inner diameter of the prelude's stock exhaust