Alpha N tuning

[KennyJ]

How do i go setup wise ? never tuned in alphaN mode
i would assume tps vs rpm in the tables

what do the settings need to be ? i have a tps and a baro sensor , 
iat is in the airbox so that normal 

how important is fuel injection timing ?

[k4nnon]

Injection timing is important to making sure the most amount of fuel possible enters the cylinder. you dont want to spray fuel while the valve is still closed. so the timing makes sure the fuel spray event is while the valves are open so all of the fuel gets in. pretty easy to figure out as well if you can watch fuel correction values.

[DerekAE86]

Wait - I was under the impression it was literally the opposite? You want your entire injection event to finish just before the intake valve starts to open.

Isn't the theory that the fuel hits the hot valve and turns to mist which helps geting an even mixture.
And then the full volume of fuel is there ready to be sucked in when the valve does open?

[dx4picco]

what engine do you have? is it runnning ITBs?

Do you have an idle air control valve?

No map sensor post throttle? where is your "baro sensor" reading the pressure? 

Ecu also have a baro sensor. 

Are the injectors pre-throttle? 

[k4nnon]

16 hours ago, DerekAE86 said:

Wait - I was under the impression it was literally the opposite? You want your entire injection event to finish just before the intake valve starts to open.

Isn't the theory that the fuel hits the hot valve and turns to mist which helps geting an even mixture.
And then the full volume of fuel is there ready to be sucked in when the valve does open?

Hey great point, There is actually a lot of back and forward information on this and no real direct best way to do it. Simple matter is the fuel needs to get into the cylinder at some point and every engine is going to be different as far as when it wants that to happen. Another point is that some really efficient engines and depending on fuel type,, the valves on the intake side may not even get hot enough to flash all of the fuel into vapor before it enters the cylinder. Great for cooling the cylinder temps, but not ideal for the mixture and combustion event. Another portion of this has to do with the actual time it takes from the fuel injection event to the time it takes that fuel to then enter the cylinder, this is all verses engine speed and how smoothly and how much air is also entering the cylinder to help pull the fuel in with it. The key is to fine out where the engine is happy, Adjust injection timing to the richest lambda/AFR point and that will tell where the most efficient spray event is happening. Only things that may change this is more or less engine speed, Airflow or variable cam timing events..

[KennyJ]

thanks for the replies

i was mostly looking for the setup in the ecu, the fuel mode etc

i have no map , only tps , the car allready had the baro externally , i replaced the ecu to a Link

its an MK2 Renault clio with a MK3 "vvti" head , it has itb's , fuel injectors are behind the butterflies i believe(so in vacuum)

the fuel injection timing question was more of a question is it worth the effort ? or do i used a fixed number
 

[dx4picco]

If you have no idle air control valve, then use table axis as TPS and RPM, in the settings use BAP as load equation. 

 

Depending on the size of your cams and with ITB, injection timing may have a big impact on drivability at partial throttle.

[castillaricardo]

The main thing is to use TPS as the load axis in your Fuel, Ignition and Lambda Target tables. Generally use high resolution at the lower throttle openings for the Fuel Table (e.g 0, 1, 2, 3, 4, 6, 8, 10, 15, 20, 30, 40, 60, 80, 100), a little less is needed for ignition, and AFR table is up to you. Since you don't have a MAP sensor, you should set Equation Load Source to BAP. Fuel Equation mode is up to you and how much data you have available. The help page has good information on this.

Injector Timing is important for fine tuning. It can reduce fuel consumption and help with transients at part throttle. The angle depends on the design of the intake manifold, angle of injectors and distance between injectors and valves. The consensus seems to be to use the number that gives the richest condition for your chosen RPMs and re-adjust the fuel table. I use a 2D table for this.

[essb00]

@k4nnonYou'll get max wall wetting with open valve injection, but not much atomization/fuel evaporation which isn't so good with combustion. That's why it is better to have the end of injection before intake valve opening.

@Wanderer Since ECU has built-in BAP, it would be better to use your external BAP sensor as MAP sensor connected to a common vacuum block for fuel compensation.

 

[k4nnon]

On 4/28/2023 at 6:42 AM, essb00 said:

@essb00 hey thanks for the input, all is educational. I assume the lambda sensor will still give us the information we need as far as best injection timing event correct? Like either way valve open, valve closed if we set our injection timing event to where the lambda is reading its most rich value, this is the ideal injection timing? I also haven’t compared numbers in relation to crank and cam timing and valve opening/closing events so my values and thoughts on this may be when the intake valve is closed as you say. I wish more people gave good solid information on this because it’s a confusing topic and many different opinions. But also goes in relation to every engine is different and will flow fuel and air different. 

[DerekAE86]

I've played around with Injection Angle a bit recently and I'm not sure I can detect any real difference. I'm begining to think it has such a minor effect it's not worth the time investment lol

My map was default to 360BTDC, and I've changed that between 300 and 500 while monitoring and logging Lambda/CLL Corr. and the only time I really saw it change was needing to add fuel around the 430+ mark. Which indicates to me my "richest" area is less than that and I was already in that ballpark.

[essb00]

@k4nnon Yes, you should be able to see the best injection timing with the highest lambda - but that might only be on light to medium loads as with above 50% injector duty cycle, or high rpms where the intake velocity is high, injection timing does not matter much.

[Adamw]

Nearly always with road car engines with the injectors spraying directly at the back of the valves, the ideal injection angle for efficiency is around 360-400BTDC at idle and light loads, this same angle usually gives the best transient behaviour as well.  

In many cases with mild engines the difference between ideal injection timing and "timing miles out" is small, you may only see a small correlation in lambda Vs PW or maybe hear a slightly sweeter idle without any obvious measured changes.  On a well-balanced low inertia chassis dyno with a good control system you can usually just detect the small change in torque but it is not much above the general noise level.  Above about 30% DC the timing becomes irrelevant in this type of application.

As the engine gets more serious however - increased valve overlap, high compression, itb's, outboard injectors etc, then the differences become far more apparent and worth chasing  - often even essential in terms of airbox fire risk from stand off etc.  

[mldc]

@Adamw

I need some advice on ITB and Boost while cruise.

I've tuned a car with Evo 9 turbo and ITBS. Power runs, race mode is fine. But I see that on low rpm and high gear, ~2800/3000, 4th 5th gear, while car is cruising turbo gives me a positive boost. Around 0.45 bar of boost. Fuel economy is horrible!

What do you recommend on those cruise areas? Leave a safe lambda but horrible fuel economy? Or chase lean lambda with low timing? for example .95 lambda?

I just dont want to cook the engine

 

[Adamw]

It is hard to believe it would make 0.45bar with little load, what is the throttle position when cruising at this boost level?