Ecu flash with Air intake

Mitzunoob · Jun 6, 2008, 10:15 AM

I've tried searching the forums and couldn't find anyone who's already asked, but does the ecu need updated if a aftermarket intake is added? I know with some american cars like mustangs airintakes includ flash updates but I don't know about the lancer, can anyone help?

nunyas · Jun 6, 2008, 12:53 PM

no... The current Intake offerings do not require you to reflash your ECU.

However, reflashing your ECU after adding one will help you maximize the performance you gain from it.

ambystom01 · Jun 6, 2008, 09:45 PM

While no intakes say they require you to reflash the ECU, you won't get the full benefit of the intake and may in fact lose power if you don't.

Bladed · Jun 7, 2008, 01:09 AM

Usually the ECU will adapt to the increase airflow. But with tuning you can maximize the fuel to air ratio. Most intakes are designed to improve power, so I personally wouldn't waste money on a tune for just an intake. Now if you have other mods and are still using a stock tune, then a tune should yield great results.

nunyas · Jun 7, 2008, 11:40 AM

The ECU will only adapt "to the increased airflow" IF the new intake was designed to work with the stock MAS (i.e. the air velocity that flows past the MAS vs engine RPM isn't significantly altered from stock trim). Intakes designed to work with the stock ECU aren't capable of delivering the same amount of power increases as an intake that requires an ECU flash, because they can't flow as much air.

ambystom01 · Jun 7, 2008, 05:40 PM

Quote:

Originally Posted by nunyas

The ECU will only adapt "to the increased airflow" IF the new intake was designed to work with the stock MAS (i.e. the air velocity that flows past the MAS vs engine RPM isn't significantly altered from stock trim). Intakes designed to work with the stock ECU aren't capable of delivering the same amount of power increases as an intake that requires an ECU flash, because they can't flow as much air.

Bingo.

Mitzunoob · Jun 9, 2008, 02:07 PM

Great, thanks for the help guys, I kinda figured I wasn't going to need one but wanted to check and make sure.

TouringBubble · Jun 11, 2008, 01:12 PM

Quote:

Originally Posted by ambystom01

Bingo.

Not quite ...

intakes that require a tune don't necessarily flow more. They generally require a tune because the do throw off the MAF reading enough to toss the fuel trims out of wack and possibly cause drivability issues. Not many intakes fall in to this category though and how much they change the MAF reading has little to do with the amount the can flow.

Nunyas, you are correct in saying that the ECU doesn't "adapt" to the increased flow. The fuel trims will make some closed loop changes for idle and cruising, but that has basically nothing to do with power production.

The actual power potential is in the increased flow capability of an open or high flow filter. Without a tune, you will also get the benefit of a slightly leaner A:F mixture at WOT or high throttle input. Since the car is tuned rich from the factory the leaner mix can produce more power. If you tune the car, you can get the same AFR with or without the upgraded intake filter, so I don't really count the leaner mix as a benefit of the filter itself.

ambystom01 · Jun 11, 2008, 01:23 PM

You're incorrect, part of why most intakes require a tune is because they flow more and by doing so, they change the MAF readings. If you have a larger pipe, you will flow more but whatever is flowing will move slower (unless of course you have some way of equalizing the speed). This is what distorts the MAF readings. It sees air moving slower, equates this to less overall air (since it thinks the diameter of the pipe is stock) and adds less fuel. Yes you will run lean but this is a very dangerous game.

TouringBubble · Jun 11, 2008, 02:21 PM

I've found that intakes generally only change how the MAF meters at low flow volumes ... as intake velocity/flow increases the MAF reads like stock. This leads me to believe that it's not really the amount of air that throws the MAF off, but the difference in the flow characteristics/dynamics themselves. At low velocity, the air moves over the MAF in a different manner ... as velocity increases, so does the volume and the flow straightens itself out and MAF reading corrects itself.

This is based on my experience tuning the MAF scaling on the previous Lancer and Evo.

An intake on a stock ROM should be no where close to dangerously lean ... but I haven't logged an '08 Lancer so i can't say for sure.

TouringBubble · Jun 11, 2008, 02:28 PM

Quote:

Originally Posted by ambystom01

If you have a larger pipe, you will flow more but whatever is flowing will move slower (unless of course you have some way of equalizing the speed). This is what distorts the MAF readings. It sees air moving slower, equates this to less overall air (since it thinks the diameter of the pipe is stock) and adds less fuel.

This example assumes that you've changed the diameter of the MAF housing as well as the intake pipe. If the MAF housing diameter stays the same, the MAF should read the same assuming that the air flows over the sensor in the same manner.

ambystom01 · Jun 11, 2008, 06:03 PM

Most intakes change the MAF housing diameter though since it requires a lot more R&D to keep it the same. It's a pretty big problem in the WRX/STI world.

TouringBubble · Jun 12, 2008, 08:38 AM

I haven't seen that often for Mitsu parts, or VW for that matter. You might be right on the Subaru stuff though.

nunyas · Jun 12, 2008, 02:40 PM

Well, I can tell you the Injen CAI changes the diameter of their intake to a SMALLER diameter where the MAS mounts to the intake for the '08+ 2.0L equipped Lancers. I assume this smaller diameter is equal to (if not equal then very close) the stock intake diameter at the MAS mounting point. They are obviously doing this to prevent the ECU from making the mix too lean. The MAS mount point on the Injen intake is 0.25 to 0.5 inches smaller in diameter than the rest of the intake piping.

This step down in pipe size takes a bit of research to keep things balanced for obvious reasons. If you make the step down too small you strangle the intake's ability to provide better flow volumes, and end up with to rich of a mix. If you don't make the step down small enough, you'll end up too lean and risk burning out the engine.

~Most~ "bolt-on" manufacturers ~should~ be smart enough to not make their intake piping too big. Obviously, if the intake piping at the MAS mount point is too big the stock MAS will ALWAYS report data to inject too little fuel. If it's only marginally larger than stock then at high RPMs it may balance out, but if the size increase is large enough it can lead to dangerously lean conditions at all RPMs.

Of course, there's a point of diminishing returns when it comes to "bolt-on" intakes. When you start encroaching in this territory, you need to start looking at having your cylinder head flowed and looking at cams, assuming you already have a free flowing exhaust.