163 | TPS + MAP Tuning for Turbo and ITB - Alpha N

Hello Andre, first of all, thank you for your great support!

I went through this webinar twice, just to make sure it is all clear for me. Here is my situation - I'm dealing with a turbocharged BMW S54 and this engine is, as far as my knolage goes, the most demanding I have ever come across. It's a high CR, E85, double VANOS, ITB and DBW. It is running on ECUMaster Black ECU. I have learned alot of things trying to make it work correctly. So far so good, went on a dyno and found VANOS issue witch I have solved how. Before I go back, I just whant to share my experience to find out am I on the right trail. First I have selected fieling strategy "Alpha-N with MAP mult. and MAP based ignition", then clicked "Use MAP for Lambda target" as I followed your reccomendation in this webinar. Now my question is how to properly tune fuel..? I have used "MAP vs RPM" correction table to add fuel above 100kPa and assuming I need twice the fuel at 200kPa I put 200% at the 200KPa row and interpolate verticaly to a 100 % at 100kPa row. I'm not sure is this is correct as I don't have alot of room for errors.

Here is something ealse - when I've searched for info about this engine, I came across a tuner who suggest to disconnect the chardge pipe and tune the VE table as a NA engine and then tune correction table when boost is added. I'm not sure is this the case or the correct approach.

The rest of my strategy is, once I have dialed VE and correction tables in the ballpark, to turn on the Labda correction and tune VANOS as reccomend in one of your other webinars about tuninig dual VVT. After that, come back to smooth the VE. Finally I will turn my attention to the ignition, as this far I should be able to set my Plex KM V2 to correct levels and be able to provide reliable knock detection.

If you give me some toughts or directions , it will be great as this is really interesting for me and learning curve is pretty steep. Thank you!

I did more research - I assume I need to turn off all corrections and leave the MAP to do it's job on the backgound based on the Lambda target table.

I haven't used the ECU Master Black so I can't speak from experience here. It really depends if the ECU Master does a background compensation for MAP or you still need to use the MAP correction to do this manually. It should be pretty apparent as soon as you start tuning though as you'll be either super rich/super lean and the numbers won't make any sense if you've got it wrong.

Essentially you should set the lambda target table to the specific lambda values you want to achieve and then just tune the VE table until you achieve that. It's quite simple with an ITB/turbo engine since you just tune at WOT and then raise the boost and the fuelling should follow your targets - If it doesn't then this is a hint that you've got something wrong in the basic setup.

Here's a webinar that covers dual VVT tuning that will help you understand the work flow (it becomes an iterative process of tuning fuel, timing, VVT angle, and then back to fuel and timing).

https://www.hpacademy.com/previous-webinars/113-dual-vvt-tuning-strategies-motec-m1-2/

Thank you Andre, the car was previously tuned with Alpha-N and MAP based ignition strategy. Then corrections where used to get the AFRs on place, but was not possible to enable Labda guard or EGO feedback, as there was no Labda targets.

So far with all corrections turned to 0 and correct fueling strategy and AFR targets , the VE table starts to look like a normal speed density VE. I assume this is the correct direction.

Hi Andre, with the secondary table for this method that you have used eg (lambda target table) using map so we can track our lambda according to various boost pressures accurately. Does this table only work if you have an on board wideband built into the link and the ecu? What if I don’t have it and am only tuning my vehicle using the dynos wideband? Do I just use the 4d fuel table as a secondary and the map (boost) pressure can be tuned there?

cheers

Julian,

I can't speak for every ecu, although if you're running a Link Ecu then no you don't need a wideband fitted. You can do it with a 4D table although doing it with the "Open Loop Lambda Table" is a much easier way.

Example how it works without a wideband.

Say you're running the car at 200kpa and your Open Loop Lambda Table is .82 lambda in this zone. You tuned your main fuel table (which is Alpha N based so at 100% TP) so it is now .82 lambda on your dyno wideband. You then raise the boost to 250kpa and you want to target .78 lambda, In your Open Loop Lambda Table at map value 250kpa you set it to .78 lambda and the ecu will calculate the fuel required to match this target Lambda at 250kpa. Meaning you should not need to adjust the main fuel table again.

This is also helpful for making quick changes to lambda as needed. Example, you're going to the race track and decided to run 250kpa which is currently tuned to .78 lambda. You decided you want to run a little richer for cooling and safety. You can go into your Open Loop Lambda Table and change the target to .76 lambda and done. Easy.

There is some instances though when you will still need to run a 4D table as well. I find this common when tuning Nissan's RB26 on the stock turbo twin turbos, as you increase the boost you start to run in different areas of the turbo efficiency and you might need to add or remove fuel to match your target. This is when I will also add a 4D table based on Map and either add or remove fuel here to match my target.

Awesome thanks for the response! Exactly my case to, r32 gtr with upgraded rear turbine wheels so wanting to see what I can push them to and learn and develop the car also.

Chris does the same method apply when tuning the ignition timing? Or does it use map on the load axis

Julian, No, with ignition timing we use MAP as the load axis. Because ignition/spark is sensitive to cylinder pressure, we want to reference MAP here.