Suprizingly, despite the inherant difficulty, through a ton of R & D and testing I amd other have been able to dxeleiver well thought out remote tunes which work well and provide a good value

I strive to make a living doing it as I find it interesting and my customers enjoy the results

 

No disrepect.
I am new to this community and I don't typically tune already turbo'd cars.

I'm here to learn and not a lof of people can actually provide 1st hand knowledge. I'm assuming you can.

If you don't mind, and hopefully this doesn't affect your business, could you help me finger out a few questions I have about this?

1. When does the car switch from closed loop tuning to open loop?
2. I can see how you can make a map that will allow a car to run closed loop, but what happens when the car switches to open loop? All cars respond differently and with open loop tuning, how can you ensure that people are running safe AF ratios as well as lean enough to produce power?

 

Plenty of people ask for other peoples maps...and get them! How do you think Dynoflash maps were exposed?

 

I think the switch from closed loop to open loop is voltage related. From what I read, the NBO2 sensor switches when the vlotage is 450mv.

From the Innovate forums:

An ECU expects a NBO2 sensor to go to high voltage (800mV to 1.2V) when richer than 14.7 and low voltage (100-200mV) when leaner than 14.7. The 14.7 switchpoint is at 450mV. The ECU only compares the output of a NBO2 to 450mV and leans out when higher or richens up when lower.
If you want the 450mV switchpoint to be at 15.2 instead of 14.7, add 0.5 AFR to each value because 15.2 - 14.7 = 0.5.

Regards,
Klaus

http://www.innovatemotorsports.com/f...5618#post25618

 

I already know what the exact answer will be for question 2. "I have tuned over 3000 evos, I have the largest evo database of bin files and pretty much have a map for any combination. I have not had any reported engine related failures." What should be added to that though should say, "because the evo knock protection is so good, many engines are being saved" Now as far as custom tuning cant speak on that, but seems to be no problems for the people that have it done.

 

I say this as a mustang tuner only and a n00b to evo tuning with only my personal car under my belt as I learn ecuflash. There is so much you can do in a flash that has nothing to do with fuel or even timing for that matter that can make you car run alot faster and more fun to drive. Such things as tip in timing retard that is rediculiously high, removing that or lessining it makes the car feel more torquy and have better throttle response. You can have the fans come in earlier to compliment a low temp stat which can add as much as 15rwhp on forced induction cars. There are things like speed and rev limits that can be raised or completely removed. You can control open loop blending (how fast the car goes from full closed to full open. Idle speed can be raised for cammed cars. You can even command a richer lamda (closed loop target) than 1.0 for cammed cars that like running a bit on the rich side to idle right yet still be in closed loop. You can even have the car open loop all the time if its a track only car. Lets not forget mivec. The 05 stangs have variable cam timing similar to mivec but its one cam per head so the intake and exhaust overlap do not change like the evos as well and we can add alot of "area unde rthe curve" power by cam advance alone. I can only imagine how much more mivec can bring out. I can go on and on and on and on.

 

I've been wondering the same thing. On my previous car which was N/A, it was pretty simple. It switched to open loop at about 25% throttle. It was easy to tell by looking at the NBO2 signal. On a turbo car, I'm wondering if the ECU keys off throttle position only or perhaps a combination of throttle and MAF or something else.

 

There are a lot of variables that go into closed loop to open loop switchover. For example, when you start your car, you're in open loop operation until coolant temps come up, the o2 sensor heats up, etc.

When fully warmed up, in my experience with DSMs, the switchover is again related to a few variables, mainly TPS and airflow, though.

nj1266,

What you quoted is talking about how the ECU uses the reading from a NB02 to keep a stoich mixture. It's not talking about the switchover from closed to open loop. It is talking about the switching back and forth around the .45V, or stoich reading of the NBO2 sensor, during closed loop operation. The ECU simply richens the mixture when the reading is below stoich (.45V) and leans it out when the reading is above .45V. This in done in a cyclic fashion to to keep the car at a stoich mixture.


Eric

 

I misunderstood his question then. My mistake. I too would like to know when the switch to open loop happens. I am especially wondering what will happen if you modify the NBO2 switch (like I did with mine) and then go open loop with the full or partial throttle.

 

Thanks for that response. I do realize there are a lot of things aside for AF that can be optimized. However the type of responses I read from people are "once you get an intake you need to pay for someone to flash your ECU"

So from someone who tunes mustangs, would you ever send someone a list of your mods on your Mustang and they would send a map to you...you'd load it up and go drive the hell out of it, think nothing of it?

That's sort of my point. When I heard of that, it just sort of shocked me.

I tune IS300's. I send people maps only to get their car driveable with different injector sizes, idle speeds for rumble cams... basic parameters. But everyone I send maps too, absolutely knows that it is not to be driven on. It's only a base to start off a real tune with.

I'm not sure you fully understand what the 02 sensor does and why it absolutely cannot be the trigger for closed loop and open loop. Unles I'm misunderstanding you.

 

I was referring to the Throttle being the switch and not the NBO2. What I want to know if there is any impact on open loop operation from making the car leaner in closed loop. My car is now @ 15.5:1 at idle and cruising. Would there be any negative impact if while driving in closed loop I go WOT and move to open loop? From what you are saying, there is NOT any impact. Am I reading you correctly?

 

Most computers use throttle position and/or load at a selected rpm to decide to go into open loop. Best way to log open loop is to watch your o2's go from a bouncing sin wave from close to 0 to close to 1 to a high value close to 1 and not bounce around. So technically you can use your 02 readings to tell if your car goes into open loop but it does not trigger open loop. the 02 is only used for closed loop operation only to adjust trims to keep within your target a/f which is usually stoich 14.7-15.3 on most cars (the values vary especially of you have a cat and reading after it).

If your car is reading 15.5 at idle and you have a wideband before the cat and your car is running fine, I would say you either have an exhaust leak, bad oem narrow band o2 or bad wideband o2. It should trip a lean code if its not your wideband. Pull your codes and see if there is a lean code Just because the SES light isnt on, doesn't mean you dont have a code stored. Remember this lean code is for closed loop operation only, it doesnt mean you have a lean tune at WOT. Also check for leaks between your maf and turbo. I really doubt your car would run 15.5 closed loop unless you played with your fuel table at low load/rpm.

 

I know on the IS300 the car adjusts the open loop map based on your closed loop trims.

For a given point on your map; say your closed loop operation necessitates trims of +5%. Then your open loop map will also adjust a certain +X%.

I'm not sure the EVO ecu works this way.

 

Here are the stock switch-over points. I think these are expressed in TPS voltage, but I'm not sure.

BTW: I have yet to hear a definitive answer as to whether the ECU adjusts the open loop fueling based on the fuel trims. I'd like to have a firm answer and we may get one once the ROMs get disassembled.

 

Interesting picture.
Honestly I'm not really sure what I'm looking at.
Where is the switch-over point in that? All I see is a color gradient. Open and closed loop literally "switches". So why is there a gradient at all?

Learn me. I'm new at EVO's.