I can understand that. It can be expensive to repair cars these days.That's good news. The only problem is that it will void your warranty, so I'm waiting until my warranty is up for any tunes. It's too bad GM decided to create a way for the computer to record any attempt to alter the factory tune.
I looked at the ducting and there are two resonators. One is a Helmholtz resonator, so we can't mess with that or we'll lose power. The other looks like a regular resonator on the boost pipe. But I doubt you'd see any gains replacing it.Funny, I was just under the hood tonight looking at the routing of the intercooler and thinking how a bigger one might fit. Trifecta was on my mind. Their tunes on the 1.4L were impressive on paper.
Anyone pull the intake ducts yet to look for any removable baffles? If present they quiet the turbo noise but also restrict the intake airflow as well.
Similarly, who has access to monitor KR on 87? (KR isn’t a std PID on my scantool.) Wondering how much…if any…factory knock the engine has heatsoaked (eg, daily conditions) on 87 versus using 89 or 92+. I won’t be surprised to see a steady dosage of KR with 87. A tune on premium, with perhaps a thicker IC, 20-25hp/tq gain could be possible without going too extreme with timing advance. That’d be plenty for me.
I understand why it was factory tuned for 87; the vehicle & buyer demographic isn’t one where requiring 92+ would be advisable. But for some of us, well….it’s not easy to squash the mod bug - and I’ve been out of the scene for 10 years.
The good news is the exhaust itself is actually pretty good aside from all the resonators and muffler. I'm pretty sure the stock size is enough for anything we'd be able to get out of this engine.The intake side isn't bad and a drop in K&N will probably be more than sufficient for incoming airflow.
The real problem is the exhaust. There's a small muffler (more of a resonator) just behind the cat, then there's a huge restrictive muffler behind the rear bumper. That rear muffler has to go, lol. I'm going to try 2 setups. The first one will leave the resonator and remove the big rear muffler. In place of the rear muffler will be a y-pipe that routes exhaust to the dual outlets in the bumper. If that sounds good I might just stop there, but if it doesn't sound good I'll replace the resonator with a Borla XS Pro series muffler which is just a straight through design, perfect for a turbo engine.
I've already had the rear muffler off and it wasn't very loud until you get over 4k. As some of you know engines with turbos aren't very loud because the turbo removes alot of the exhaust noise and it provides more than enough backpressure, so you want the rest of the exhaust to flow as freely as possible. I'm just waiting on a few 90° degrees pieces of stainless tubing to get started, so I'll definitely post some pics and get a sound clip before and after.
The 2" exhaust should be adequate. Most 4cyl engines use 2-1/4". The factory exhaust becomes restrictive after the cat which doesn't help a small turbo engine. It was designed for sound control not performance.The good news is the exhaust itself is actually pretty good aside from all the resonators and muffler. I'm pretty sure the stock size is enough for anything we'd be able to get out of this engine.