I would take the advise of certified tuners who have flashed thousands upon thousands of evos over a tech service guy....

The cars may run fine with a different intake, but it is not going to optimal by any means, and in some cases, be not safe (K&N/HKS)

 

in addition while modding fuel delivery. ie rails and injectors cams and pumps redirecting duration and lift on the head. a tune will be a must Maf is simple it measures the amount of airflow to let the comp know how to match. the evos comp has a variance on its fuel and air delivery based on sepeed and volume of the airflow. even with the stock airbox and lets throw in a k&n drop filter. at hi speeds the funnel is taking in more air the faster you go... so thats way the evo comp has the variance. airflow and volume change up and down even with a stock setup ... a cone filter will simply max its a/f ratio making the comp think airflow is at high speed all the time.

 

This is incorrect.

ANY physical change that causes a change in mass airflow quality will cause a change in the MAF response signal. The factory setup is designed to create laminar flow through the MAF. Anything that changes this WILL cause the MAF to give a false and/or erratic readings. Anyone who's tuned a car or operated a dyno has seen it.

How this affects something in the real world isn't entirely predictable. I've encountered enough of these issues since dealing with MAFs and aftermarket intakes (since ~1991).

In this case, it was enough to cause a serious problem. It really illustrates one very plain fact, and that is if performance is one's goal, there is not one good reason to avoid securing a competent, thorough retuning for the ECU.

 

I don't see any reason to pay even $200 for a mail in flash just for a intake.

 

Do you have any idea of what 'just an intake' can do to the AFR curve?

I do.

In fact, I could probably say an intake is the riskiest change one can make to an untuned car - especially a car in which the boost is raised, and there is no means of wideband O2 logging.

FYI.

 

So why bother putting any money into your car for performance parts? Guarantee a ram-air style intake costs more than $200 and if you can get a safe tune/reflash for that same $200 wft not do it instead? Its a better mod. Oh, and btw, what type of wideband do you use to read AFR? Saw u run alky and an number of other parts, so I'm assuming u know the importance of monitoring AFR... and that the average dumb@$$ who justs slaps on a K&N cone filter without anything else because they saw how much claimed HP they'd gain from a magazine add probably has no concept of running lean...

 

Well for 20K I had a HKS intake, TBE and IC piping with NO problems. And I was very hard on my car. We'll see if my car is untunable on Saturday, I think it will be fine.

 

It too bad Mitsubishi doesnt make you take a 100 question exam before they allow you to purchase an evo...lol.

 

and uh, btw... I'm an ASE mechanic/Drivability specialist. I work on engines all day long. I might just know what I'm talking about

 

This isn't the first time we've seen a AFR graph that was out of whack due to an aftermarket intake. It isn't uncommon. We've also seen incidences where slapping on certain aftermarket intakes reduced power with untuned cars.

What you're saying is akin to claiming that because you skydive without a main chute, that it's ok. You've been lucky so far. Others have not. I've been around long enough to see it, and not just with EVOs.

FYI

 

Some of you guys need to read up on the differences between a hotwire MAF and a Karmann Vortex MAF.

http://www.autoshop101.com/forms/h34.pdf

It's not just the amount of air coming in that has an effect on your tune, it's how the air comes in. Changing the physical characteristics of the intake tract before the MAF sensor will change the readings of the MAF. That's why a lot of people have drive ability issues when they throw on a cone filter and MAF adapter. Sometimes the MAF will think more air is coming in, sometimes it will think less, all depending on the vortices created at the sensor.

 

The intake makes the most profound difference in tuning the stock ecu, more so than anything else. Changes like this necessitate a retune by some qualified tuner.
I am starting to see more and more cases like this.

Sean

 

Absolutely correct.

. . . but it affects hotwire sensors too. Been there, done that, many, many, many times.

 

There is a sertain level of luck in moding car anyway, tune or no tune. Even a good tuner can blow a engine up on the dyno, it happened to my WRX. But, there is a very small chance that just an intake will blow an engine. I think there had to be something else.

 

Well, I guess I am a very lucky person to not of destroyed my car. I am finially getting a tune on Saturday. But, if my engine would have blown that would have just gave my a reason to upgrade.