Hey guys,

I got a base flash on my stock IX MR which was used just to clean up the AFRs. I just got a catback installed and I was wondering if it would affect my baseflash, either making me run leaner or more rich. Hope to hear from you soon, thanks.

- Dean

Edit: Lately I've been driving around and noticed my RPMs bounce up and down. Like my idle will go up to 1k, then drop back down to 800 ish. The highest I've seen my idle is like 1.2k and my lowest is near 500. Is this normal?

 

Hi Dean! I heard that it's a good idea to get a stock ecu reflash after you get the base mods done, so that you can make the most power out of your specific bolt-on's. I had my turbo back exhaust, boost controller, and fuel pump installed right before I got the reflash. I would check with your local tuner if you can.

 

a cat-back will not affect ur tune much. you don't need a re-tune. i sugest getting a downpipe and test pipe. also installing a fuel pump and mbc. then re-tune. Your car will feel 10 times faster

 

^^^^+1

 

Bump for more opinions!

 

You throw a catback on a car with a tune, that should lean your car out some. I would go have it retuned if I were you. If you can like they said get a full turboback first.

 

I think my AFRs with just a baseflash is 11.0-11.4. How much more would the catback lean out my car? Would it be enough to damage my engine?

 

If it goes above 12 at redline then be very careful. I don't think a cat back will affect your a/f's much if any though. It may have free'd up 1lb of boost which may affect it but most likely not. Hope that helps.

 

What's weird is that I think my boost lowered a little bit since I got my exhaust installed.. Would that mean there is a leak?

 

Cat back opens up a little but not much. Its when you do the whole turboback when tune is changed. The exhaust will only flow as much as the smallest point, so if you still have a stock dp and cat it will only flow up to that point.

We say get all your basics mods (Intake, 02 housing, TBE, BC, LIC) then get a tune.

 

With TBE and MBC as only mods on a ix you do not need a new fuel pump, but if you plan on doing more it is a cheap upgrade. A catback should not change the a/f ratio enough to be concerned, but after any new part a tune will optimize performance. I would get a downpipe and test pipe or metal HFC before getting another tune.
I read on another thread that the computer uses the mass airflow sensor to determine how much boost you are running, this means that if you can suck the same amount of air with less boost then the boost will be lower. The thread that mentioned this was debating whether a TBE without a tune would increase power. Some said that because of the way boost is controlled the boost will be less with freer flow, and power will remain about the same.