dragon831

iTrader: (1)

when someone says they need to get their car tuned, what exactly happens? is that just adjusting the air to fuel ratio? Why don't the manufacturers tune cars (performance cars like the evo) to get max power? Are there big disadvantages? I plan on getting an evo soon. I have an 07 si with an intake and catback exhaust and have never gotten it tuned.

Thegame

iTrader: (26)

"Tuning" primarily involves maximizing Air / Fuel ratio's and ignition timing for power gains. From a car manufacturer's standpoint, maximum power leaves little room for error such as poor quality gasoline.

DynoFlash

iTrader: (91)

In most cases with Evos they are modfied to a greater or lesser extent

To me tuning in those cases means adjusting the stock ecu tuning to compensate for the modifications which the customer has made to the car

Modifications effect the boost level and VE of the motor and in the case of the Evo X they result in CEL's and driveability issues which proper tuning can correct

Also, additional power throughout the power band can be achived by adjusting the tune to match the modifications.

In other less common situations we have customers with bone stock Evos who just want to pick up an additional 20 - 30 whp and a reflash tune can easily do that. This is where the rasiing of boost levels and altering air fuel ratios, ignition timing and cam timing. In addition to peak power gains, a good tune makes the car "feel" crisper and smoother. The OEM tune is not optimal for performance becuase it must meet emissions and regulatory limitations and it must work with a wide range of fuel and climatic conditions.

Finally, a tune can alter rev limits, boost limits, speed limits and two step limits to suit the customer's needs.

Al

EvoX562

Great question, I was about to ask the same question. To add to the question, if say my only mods would be to add an exhaust, intake and boost gauge would I then tune after those mods? Do I only need to tune it once or is it something I do repeatedly?

BerserkerX

I would say repeatedly if you want more info even though it is on the VIII and the IX check out the how to tune an EVO thread in the ECUflash forum. While it goes into great depth on what to do it will of course tell you what all is involved.

KPerez

While this is all true, it begs the question of why, after spending >$35K, all EVO X owners are trying to improve the OEM "tune". Does BMW 300 series have this awful a tune? Do they get 21-22mpg? I'll bet they do not and they are a 6 cyl while we sit with a 4 cyl. Does their torque curve look like the surface of the Pacific Ocean or is it smooth? Do they have A/F ratio's in 8:1 and have black rear bumpers after racing a couple of hours a la Dave Burschur in his last track day? If the answers to these questions is no, then can someone tell me why Mitsu engineers tuned this car the way they did (assuming they were sober)? The usual explanation is, Oh, they had to compensate for altitude and other atmospheric conditions. Even if true, why the extremely rich and erratic unstable torque curves resulting in not only lost power but also the burning of more fuel which has to increase emmisons. So the bottom line is, why would a car company create this bad a product that the entire customer market has to pay hundreds of dollars to correct it. Perhaps some of our tuner community can shed some light on this wonderful ECU present from Mitsubishi motors.

Mountainbiker54

iTrader: (2)

Probably because if it was already perfect you would be complaining that the evo isn't tune-able and then not get one on those grounds. There is always someone out there to complain....

KPerez

This issue is of concern because I did buy an X so I am stuck with the fix. Second, your comment suggests that a car with an OEM "tune" superior to that in the EVO X is not amenable to any retunes yeilding better performance. This is, of course, not true. So I was not so much complaining as I am perplexed with the rational for Mitsu. producing such a poor base tune when same is not in their best interest.

Sim66

I wonder the same thing. Really, even Chris at AMS think so:

https://www.evolutionm.net/forums/sh...d.php?t=341677

So why did did it that way? Could a tuner guru please enlighten us?

BerserkerX

I would like to know this also since that according to a lot of sites that I read about the JDM style EVO they actually run much better and they have no problems with AFR's being pic rich and in fact the car is way below the requirements for emmisions.

I am not sure how the Timing maps look on this car but I can tell you that I have looked at the ones on the IX and they are extremely rich to they get as low an 8.3 AFR. To compensate for it they just made the Timing maps extremely aggressive to compensate for the rich afrs.

Evo_Jay

iTrader: (17)

Car are not tuned to max power from the factory for many reasons.....

1- emissions

2 - The fact that some one might put bad gas in it. If the car was tuned, making max power and someone put bad gas in it, it would blow up.

3 - Sometime manufactures have to stay within a power range, like say, less then 300HP, so they detune the car to meet that.

4 - theres other reasons i cant think of right now.

FYI - Every car that comes from the factory CAN be tuned for more power, honda, mitsu, BMW, etc.

A tune consist of modifying Fuel, timing & boost to optimize performance. This involves change fuel and timing maps, and usually raising boost a lil bit. Other thing like rev limiter, factory 2step, injector scaling, can/may also be modified if needed.

KPerez

Thanks EVOKid but how can running so rich reduce emmisions? Seems like the opposite would be more desirable. Now adjusting for the input of low octane fuel does explain somewhat the reason for running rich. But it is still unclear why it has to be so rich such that the car missfires and, if related, has an erratic torque curve. In addition, the cars you listed e.g., BMW all require high octane fuel from the factory and yet their A/F 's are considerably higher than the X and do not missfire up top so again, why do these car company's have a good base tune and Mitsu does not? It would appear that this was a rushed tune but yet Mitsu. claims they were developing the X three years prior to production. Was all their effort then done on the drivetrain and little on the tune? I do not understand this whole OEM "tune" or lack there of, rather odd I would say.

Mr. Evo IX

iTrader: (5)

The USDM Evo is tuned for survival from the factory, as is the BMW. The car was engineered to last for several hundred thousand miles of flogging, IX's have a 10yr 100,000 mile powertrain warranty. Would you warranty a Evo for 100,000 miles? And if you did would you put a conservative or an aggressive tune on it?

Also, I know mitsu warranty doesnt amount to a hill of beans once you start modding, but I bet it's better when your bone stock.

By your logic, BMW's must have pretty bad tunes, because BMW tuners make a ton of money making them faster as well.

Do BMW owners drive around everywhere WOT? (answer to your mileage question)

KPerez

Thanks Mr. EVO IX for your response. So are you saying the EVO X's engines long term survival is better when it is burning very, very rich (A/F 8-9) as opposed to something with a "moderate" A/F of 10-11? And that missfiring at higher RPM will also result in increased longevity than a car that does not missfire? Other car manufacturer's, I think, do not have these ECU settings but are also conservative to increase longevity but do NOT have the characteristics of this 4B11 OEM "tune". As proof of this condition, less than two months since its release there have been two TSB all of which corrected the poor idle (documented in many places on this forum) and missfires at the higher rpm range. So you have to ask yourself, how these performance problems were not corrected before the release of this vehicle? And these are not the only problems that still remain vis., burning too rich.
Now it is difficult to compare one vehicles mileage to another with the potential for different "styles" of driving (WOT vs moderate some percentage of the time) but I suggest that a 6 cylinder OEM BMW will get better mileage than the OEM "tune" in the EVO. But with some proper tuning to the EVO X the opposite will result. My point here is Mitsu did a lousy, no, miserable job in tuning the 4B11 out of the box and we X'er will have to spend ~$750 to correct just the base tune. I do not think this "adjustment" is necessary for the other brand cars listed earlier, like BMW and the real question is why did Mitsu allow this "tune"to be released? Their life and ours would be a lot better off if they had just taken the time to do the job correctly in the first place after all others have said are trying to have the X be competitive with BMW. The question is, is this OEM "tune" consistent with that objective? In my view, the answer is no.

nj1266

iTrader: (6)

The irony is that when you flash the ECU to make the Evo run better and effecient (around 11.5:1 AFR), then you lose your warranty. But if you let the car run like crap, waste gas and blacken your bumper, then you keep your warranty.