Added Plenum, GT3 TB, Fister mod - Tune needed?

Quick question since search didn�t give clear peace-of-mind and the various currently active threads on similar topic haven�t either: i recently added GT3 TB, IPD 82mm plenum, Fister Mod, UAOS, Deep Sump. Do I need an ECU Tune now in order to properly operate these mods? I�ve read somewhere here that without the tune, the engine will run rich and potentially risk washing down cylinders with fuel. Is that something that can be addressed through tune or not even a risk? Thanks so much!

You should never listen to whoever told you that garbage. If indeed your engine is more efficient now after the mods, it will be running leaner.

Quotes source post: 18269800

Sorry man. My original response made no sense. Thats what i get with doing it on the fly. Here goes. You have a 3.6 and get your performance enhancement primarily from cats and headers and you havent done them yet. All software will do is give you more throttle response. Which is fine, but you may be better off taking the 1k for the software and putting on a good set of 200 cell cats. Figure 8-10 hp with cats. Your ecu should adjust to the plenum and TB. Software would make sense after you do your cats. Other may have a different opinion.

@Justin76 had his car tuned after adding some items... he might have better insight after having his car done.

Until you get the car on a chassis Dyno and monitor AFR through the entire rev range you are just guessing . Yes the factory ECU will monitor and adjust various parameters but it is limited on what it can do on its own . You need that Dyno data to truly know what's going on . I completed my 3.8 install in my 99 C4 about three weeks ago . When I first started it you could tell/smell it was running rich . I have driven it about 120 miles so far and can tell/feel/smell the car is making corrections . My plan is to get about 300-400 miles on her and then get on a Dyno . The Dyno will tell us if any additional adjustments or tuning is required .

I would hazard the 996 still runs in open loop at WOT under most conditions so adaptations probably don't matter much (edit: for dyno runs). This likely differs some between trims and Bosch EMS versions.

OP - In a nutshell a canned tune from a service that’s been doing programs for M96 engine will adjust idle, advance timing a small amount, fiddle with throttle signal, etc; depending on their acquired data for generic categories of mods and engine displacement. They have flow calculations for different “potential” intake and exhaust volumes, not “actual” data from your individual system set up. If you read somewhere about running rich, as brontosaurus pointed out, that’s at initial readaptation (or readaption, according to some documentation).The ECU does the same thing every time you reset a CEL. A lot goes on with the readings between pre- and post-cat O2 sensors to adjust timing and fueling. Look at the details in how to try to get Ready status for passing an MOT or annual smog cert. Complete PITA. GC996 is also correct: More air in means nothing without better exhaust flow out. Better-than-stock manifolds and 200 cats will help you benefit more from the larger throttle body.

As others have stated you need to address your exhaust first. Once you selected the diameter and type of headers and cats you will use, then the ecu is done. It is hindsight, but it would have been better to have had your Tuner in the loop before any mods were done. I have had similar mods for 35,000 miles plus. Others here as well. I went with Evolution Motorsports, after a lot of research and personal correspondence. I have dyno information if you want PM. The results were exactly as expected before one bolt was turned.