So I swapped/installed my catless downpipe onto my car today.

Also cleaned my air filter and did an oil change with synthetic.

I went for a drive and noticed my car only holding about 18PSI. During the hot summer it always held 20PSI, sometimes 21 even...With my stock catted downpipe I always held 1-2PSI less than the catless for whatever reason.

So I was shocked to see only 18PSI after the swap. Though this isn't very scientific because I didn't go for a drive right before I took off my stock down pipe.



Now my understanding is GMS1 is basically aiming for 20PSI, but will adjust to 18min to 22max according to the temps and altitude outside. It is still cold out, so that would account for the lower than average (summertime 20PSI) it usually holds.


Here is the kicker, I put a weeee dent in the bottom part of the inter cooler when I jacked up my car, so thats the only reason im suspect of boost leak of some sort. But the fact that its consistantly holding 18PSI makes me think its not likely.

Last time I had this catless DP on, I had no muffler. Now that my muffler is on I can honestly say it sounds great! Loving it.. just curious what people have to say about my 18PSI its holding. Again, all last summer it seemed to like to hold 21PSI. Though if traction were anything to go by, it seems to have MORE power or just as much @ 18PSI as it does @ 21PSI during the summer..

looking for peoples 2 cents.. thanks

 

You can still hold boost with a boost leak and not throw a code if its small.

 

Supposedly my elevation is (1,580 ft) + it being colder out: I guess 18PSI would seem right..

Il see when it warms up it it changes....

 

GMS1 is a canned tune, and you just added a part to it that it wasn't designed to handle. You're probably just reaching your learndown limit with less boost because of less restriction.

 

Um, I thought we all decided the learn down is set to a value that no one will see.

OP. What are your outside temps? I have a hard time seeing 20psi and it's 30 degress F down here.

 

I think is was -10c or about 14f when I was out testing and it was only hitting 18PSI

Today is -27c or about -17f...

My elevation is low, too. But like I said, and FasterIsBetter clearly didnt read O_~ is last summer I was boosting and holding 21-20psi all day all night with my catless downpipe.

So I would agree there is a learn down due to temperature going on, or I have a boost leak. Which is why I made the thread ^____^


At this point im fairly confident its the temperature. First time ive ever been able to drive on pavement and boost. With it being so cold at the same time; so ive never been able to see this computer adjusted psi before..