Tuning the car without doing mods is VERY bad for the oem components, especially the cats. Your adding more heat and airflow over the cats then they where designed for, which means the cat will break down faster. Overnight? No, of course not, but significantly faster than it would on a stock tune. You are also going to pushing the efficiency of the turbocharger. Adding more boost with the oem intercooler and oem exhaust means that turbo now has to work significantly harder to spin faster and produce CFM, which means more heat into the engine, which means less efficiency over-all and a higher risk of pre-detonation. I get staying stock. But getting torque below 4000 rpm at the cost of long term reliability just seems silly to me.
Another thing to note is this: Though you are not "making more power" with bolt on's, there are many other benefits. The intercooler for instance. After 1-2 highway pulls we have seen the oem interooler double intake temps, which means a massive loss in torque/power. It cannot keep up with the heat from such a small turbo. By upgrading that you MAINTAIN consistent intake temps which means consistent power.
Same goes for the oem diverter valve. It is trash. At the stock boost it leaks, quite a bit. It uses a plastic on metal "seal". Even doing the "upgraded internals" on it, it still leaks. I have done smoke and pressure tests to confirm this. By upgrading to a better valve you reduce turbo wear, increase turbo efficiency, and do actually see an increase in fuel economy. Skip to 1:05 to see what I mean:
How V2 MR16DDT Boost Control Works - YouTube
These are just a few examples.
I had a sentra SR turbo here yesterday. He has a FMIC and diverter valve. That's it. Installed well over 2 years ago. He still talks about how much better the car drives and how it does not feel like a slug anymore when he's been beating on it.
The first ever v2 downpipe installed, was on a gentleman's car in Michigan. He drove to me in Boston to do it. He saw a 3mpg increase on his ride home. Which is pretty substantial. No other mods to the car.
Common misconception is you mod an engine to make more power. This is just not true. Builders who only look at a peak power figure are not looking at the whole picture. Efficiency should always be concern number one. Power comes second. Well, actually: Safety comes first, Reliability comes Second, Efficiency comes Third, and Power comes Fourth. Especially on a tiny turbo car, where the graph looks like a cliff after the turbo runs out of steam with a tune, which any good tuner will tell you means the car will not be fast, it will just hit hard when you take off.
Just so you are aware of where my information comes from: I have been doing V2 work since they came out and am still the only person offering a downpipe upgrade due to the cat failures I saw when ecutek tuning on these had started.
