So I put my cat back on so I can get emissions done, and noticed I was running really lean. I have a Mellon tune at 21psi, I was getting knock at about 5k, has anyone had this problem? Is this normal?

 

Well if you were formerly tuned for a test pipe then the cat will definitely add back pressure. I am not a "tuner" however I feel that the car would shift the powerband thus tweeking your current map. Your best bet is to contact Chris Mellon seeing as hes in your signature

 

send me a link to this thread and a log spish and I'll gladly take a look and see if we can figure out what's going on

 

Is your WBo2 in the stock rear o2 sensor location? If so that could explain the lean reading.

 

So I took my car to get emissions, apparently I don't need emissions since its newer than 05. So I'm going to put my test pipe back on tomorrow and do some datalogs.

 

I sent you that datalog, just let me know what you think.

 

will do

 

+1 for mellon finding this.

OP be sure to contact your tuner first thing!

Nice work Mellon

 

thank you, I don't know if customers just don't want to "bug" me or if they just aren't used to getting service after the sale, but I often find customers asking questions while looking around. I like to catch them early like this before they start getting random advice from people who don't really know what they are talking about

 

I kinda like just seeing some of the stuff that people post up, I had every intention of sending you the logs, I just figured I'd wait until after I put the test pipe back on. Did you get a chance to look at the log? I've been noticing lately its been pretty lean up top.

 

yep, your load is way up like the boost was turned up or something, you're running out of fuel it seems (IDC wasn't logged)

 

I haven't turned it up, I marked it on the Hallman where 21psi was at and its still at the same spot. Do you think the 65 degree difference in the weather would cause it? I'll do another log with the IDC logged tonight.

 

when people say run out of fuel, i assume that means IDC over 100%?

ive noticed when the weather goes from warm to really cold my boost will spike up a few lbs (1-2) and ill have to turn it down

 

normally a restriction in the exhaust tends to richen up the tune and vice versa.

at least that is what I have seen on my car.

 

^ I actually forgot to log the IDC, so I'll do that tonight and see what I'm at. When I was getting tuned I had no problem with running out of fuel so it might just be the weather. I'll wait and see what Mellon wants me to do.