Questions about Cobb Stage 1

[ZachCouch]

My Accessport will be here tomorrow, and I'll of course be hooking it up to my OBXT (2005) immediately. But before I flash any tunes, I wanted to ask a couple of questions.

 

First of all, I discovered a few weeks ago while installing headers and an up-pipe that I'm missing one of my downpipe cats. The entire turbo-back is stock, but the first downpipe cat is missing. The second one is still in place, and I have the stock catback. The only two previous owners were older women, so I would imagine it was beginning to get clogged at some point and a well-meaning mechanic poked it out. I haven't driven my car hard since I bought it, and especially not after I discovered the missing cat. The only issue I've had as a result has been a P0420 for emissions. I know overboost and boost creep are very real possibilities, and I've been looking for a used downpipe. But until I find one, I've been wondering, just how possible is dangerous amounts of overboost when I still have one of the downpipe cats, factory catback, and stock intake? Even while doing a few small pulls before finding the missing cat I didn't experience fuel shutoff or overboost codes. I imagine I'll get my answer when I get the AP hooked up and can monitor boost and AF ratios, but I wanted to know if anyone else has experience with a similar setup.

 

Secondly, given that I am missing a cat, would it be better to run my car on the stock tune until I can find a downpipe, then flash a tune. Or would I be better off to go ahead and flash the Stage 1 tune while I look for a DP? From what I've read, the Stage 1 tune is much healthier for the engine, but I didn't know if it would amplify the issues potentially created by the missing cat.

 

Thanks for any help, guys.

[bdcvg]

Missing first cat is probably close to a stage 2 tune. Gutting the 1st cat is a common procedure to get closer to stage 2 without a DP.

[relative4]

Before flashing anything, you should see what the current setup is doing to you, particularly regarding knock. If you don't mind shelling out another $70 for an OBDLink, a learning view would be really helpful.

 

Agreed with bdcvg, so a stage 2 tune would probably be safer. But don't mess around - pick your downpipe, get it in, and tune appropriately. If you stick with the half-gutted stocker, a custom tune is essential.

[ZachCouch]

Before flashing anything, you should see what the current setup is doing to you, particularly regarding knock. If you don't mind shelling out another $70 for an OBDLink, a learning view would be really helpful.

 

Agreed with bdcvg, so a stage 2 tune would probably be safer. But don't mess around - pick your downpipe, get it in, and tune appropriately.

 

Just found a guy in my area parting out several LGTs. If I can get my hands on a downpipe, I'll be sticking it in ASAP. Whatever I do, I'll continue to stay out of boost until I have all the appropriate parts. I don't want to go Stage 2 yet.