DrBob

I am installing a Pettit resonated midpipe, but I would prefer not to go the full airpump elimination/removal route. I want the option of putting the cat on without a lot of effort. As I understand it, I need to tie-wrap the tube from the airpump to the cat so that it stays up and out of the way. The question is should I pull the airpump relay or not? What are the pro's and con's? Is there anything else that should be done for this installation?

Flybye

Just disconnect the airpump. The plug is on the upper back side of it.

KZ1

Leave it connected, just let the tube hang. If you disconnect it and leave it in, you are liable to break it.

That is what I haev heard anyway, plus I think it supllies ACV too.

Flybye

Really, you aren't going to loose or gain any HP by either leaving it connected or disconnecting it. The airpump has an electrical clutch in it, so it's not constantly enganged, anyways.

I've never heard anything positive or negative about the ACV. A lot of people remove it, especially when you need to go to a larger fuel rail for the secondaries. From what I remember, it's a device used to simply release additional air within the lower intake manifold when decelerating and at idle. It's also the device which causes the MOOing sound so many people hear after they have upgraded their air intake box.

I disconnected mine, and had no negative effect on the engine. Nor did I feel any improvement in performance when I reconnected it. I know many a people that have also disconnected theirs. After not having a maincat, of course.

Now completly removing the airpump is a different story. It will be one less of an accessory to have, you will have more space around the turbos, and you will also have less weight on the car. The thing about the airpump, is that I have heard that it is SO freespinning as it is, that you only get 1-2hp from removing it. IF that at all.

Whatever you do, just DON'T leave it disconnected from the airbox if you need the airpump for emissions. Dirt and dust particles WILL enter the pump and will eventually damage the bushings when you try to spin it back up.

FastX7

I put on my mid-pipe and the ONLY thing I did with the air pump was move the pipe going to the cat up and out of the way... PERIOD. You don't HAVE to do anything else to it, leave everything else connected if you want to put the cat back on later.

DrBob

Thanks for the information, guys. Pettit's parts salesman said that I might encounter idle roughness after the installation. Any problems and solutions along those lines?

FastX7

none here... if you don't count my pulsation dampener going out (not related to midpipe BTW)

m0t03

so when installing the midpipe you JUST have to dissconect the pipe going to the cat from the air pump?

FastX7

that's all I did... just means that the air pump is pumping into the atmoshere instead of the cat

Flybye

The idling issue tends to vary from one FD to another. It makes SOME FDs idle a bit funny and some not.

For example, mine had no problem idling with the stock ECU. When I installed the MP, I had the PFC, though. My buddie's FD in miami DID idle funny after disconnecting it. I always hear of cases where someone's FD idled funny and someone elses didn't