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Hi,
I only posted a few times in regards to finding more about the WRX, reliably etc. Anyways I just picked up an 03 Wagon a few months ago. It had a few maintenance issues I had to fix myself the last few weeks. Leaky valves cover gaskets, torn CV boot, A/C out.

I'm going to keep this car purely a daily and I don't want to sink in too much into it. I wanted to add a few basic parts to it that won't interfere with CA smog like a catback exhaust. I was curious about putting on a short ram intake so I could hear the turbo spool better. I've read somewhere that 02-04 EJ205's don't really need a tune on a short ram is that true?

Thanks
 

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Registered
Joined
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477 Posts
Hi,
I only posted a few times in regards to finding more about the WRX, reliably etc. Anyways I just picked up an 03 Wagon a few months ago. It had a few maintenance issues I had to fix myself the last few weeks. Leaky valves cover gaskets, torn CV boot, A/C out.

I'm going to keep this car purely a daily and I don't want to sink in too much into it. I wanted to add a few basic parts to it that won't interfere with CA smog like a catback exhaust. I was curious about putting on a short ram intake so I could hear the turbo spool better. I've read somewhere that 02-04 EJ205's don't really need a tune on a short ram is that true?

Thanks
I'm afraid you were misinformed on the intake. The older years may complain less and NOT throw a CEL like the later years, but that does not mean it's a good idea to put one on.

Here's the reason:
Your car runs in two fueling modes: closed fueling (normal driving / low boost) open fueling (under boost / high load).

Under closed fueling, the car runs a guess and check type system between your MAF, o2 sensor and other readings to keep your car around 14.7 (stoich) fueling target... in this case an incorrect intake will be compensated for because the amount of fuel is always adjusted based on target AFR, and what actually gets read at the oxygen sensor.

However, in open loop fueling, the ecu basically takes a reading from your MAF and based on a few environmental compensations such as elevation and temperature, squirts a predetermined amount of fuel.

Here's why that's a bad thing:
Changing the shape (especially the size) of the air intake drastically changes the relationship between the MAF sensor voltage and the actual air mass going into the engine. What's dangerous is, if you add a larger diameter tube, you now have a larger volume of air moving by the maf, but at a much slower speed so you are getting more air into the engine than the car thinks and thus it no longer adds enough fuel (ie running LEAN). Running lean not only destroys engines by itself, it also makes the engine more prone to knock. What's worse is that this happens at the most aggressive part of the map (high boost, high load, high RPM) when the engine is most susceptible to failure.

The intake tract is definitely at the top of the list of mods you really need to get a tune for.

Good luck!
 
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