Hi Guys,


Below is the csv dump from my log file using FA53. Does anyone here have any suggestion/experience that you can share on what Target AFR I should be running?


This will be my first shot at tuning. I'll also post the Fuel MAP from my FA53.


My car has 15% SC and 2% on the main pulley, CAI, Cat back Borla, 550cc bosch injector.


I'm not really sure where to start.


My idea of modifying the Fuel map is changing the values on the map where the RPM and AirMassKg/h intersect (if its rich then decrease the value by a decimal value and vise versa).


The Green values "Target AFR" are what I was thinking of to be my target afr.




The x axis on the MAP at full load is AirMassKG/h.

 

Hi,

This mostly come from second hand knowledge of VW turbos and personal experience tuning NA motorcylce engines (so the same as a Mini right?)

10.8 is really, really rich. Especially since the peak VE on these cars (which should be at peak torque) is lower in the RPM range then what you have it set at. Why do you plan to run so much fuel at that speed?

That said it is certainly safe

You don't want to go crazy though because it can hurt power and wash down the walls of the cylinder (seen both of these on the bike engines, and know of the former being an issue on other turbo apps).

I'm about to try and do a roll my own tune myself. There are a couple good books on amazon that give the general concepts behind tuning. After that though you need to start looking at things that are application specifc (ex: how is the air distribution between the cylinders at different RPMs and do you end up in a situation where one runs leans and one runs rich).

I can ask my friend what he is doing for his Miata turbo if you are interested.

 

Definitely interested in more information! Thanks! The log file that I posted is from running my car on the base tune and I haven't changed anything yet.


I want to learn on what I should modify on the map. My idea on how to modify the map is basing the data from the WOT log and getting the approximate location in the map where the RPM/AirmassKGhr intersect and modify those values a bit then test again.


There are 2 fuel maps on the Bytetronik Fullaccess, one map has 1's and 0.9xx(range is -100 to 100%) on it and the other one mostly has 2.5's to 10.xxx numbers (range is 0-50%)


Did or do you also modify your VE map when your tuning? which map do you first touch and which part of the RPM range?


The Airmass on my log by the way has gone over that 576 which I think is caused by the 15% SC pulley and 2% main pulley.


How do you decide on the Airmass resolution if I have to add more or replace the existing X axis points, as well as the Y axis (RPM, I raised my redline to 7500).

 

So this is one issue you will run into Tuning with this software, is it is completely closed off.

I don't know how Bytetronik has set up their maps but it is certainly different from most stand alones. You can go download a copy of Adaptronic Wari or Eugene (thats what my Miata friend uses) or Syvecs/Performance electronics which is what we use on the formula car to see how that works. It's going to be a little difficult to help just because Bytronik may be using some of there own naming conventions and they are certainly using their own scaling factors.

A factory ECU, even one from ~17 years ago is very powerful, there are actually far more maps and tables in the ECU then what the Bytetronik software gives you the ability to tune. Stand alones are just starting to catch up with these old ECUs (the syvecs I talked about is pretty close). The big adavantage of stand alone is it is documented and you are essentially programming it from the ground up, it really doesnt have anything to do with one being more "powerful" then the other.

BMW/Siemens spends millions on R&D developing an ECU, XYZ stand alone company can't compete with that.

Anyway...

Generally speaking I think your approach is correct. You do a pull, find the cells in the map you crossed through, and then edit those to get to the AFR (or Lambda) you want. The WARI software adaptronic uses has a trace function to facilitate that.

You cant just tune the cells your pull is crossing through, you need to tune the cells around it and make sure the map is smooth.


ECUs interpolate between map points. The more the value changes the more resolution you need in terms of cells on the maps.

EX TPS vs Fuel.

10 15 20 30 40 50 70 100
2.1 2.1 2.4 2.4 2.4 2.5 2.6 3.0

So between 70 and 100 you are saying that whatever this map is responding to is linear, so the ECU just need two points to interpolate between. If on the other hand there was a big shift in airflow or something else between 70 and 100 you would add points to make sure you fuel output tracked what was actually happening.

So if your maps stops at 6850 and the redline is now 7500 you could probably start with 1 point at 7500 and 1 point in between. Look at what your airplow is doing, if it is pretty linear between 6850 and 7500 then you might just need the 1 point at 7500...

I attached a file that is worth reading to help understand what the ECU is doing. It's by no means complete but it's a good place to start.

 

Hey Thanks for that info! That really gives me something to start with. It makes total sense about what you said.

I would've gone with standalone but it'll get expensive here in SoCal when Smog comes along.

Have you played with yours R53's tune?

 

This attached might be helpful as a general guide.

Somewhere in the low to mid 12's (AFR) is probably what you are shooting for at high rpm WOT.


My car hits the high 10's at 4000 rpm so I know it is way rich up high and there is some hp to be had with a good tune.


Regards,
Jerry

 

I'm no tuner by any means, and trust all my tuning to the professionals, but from what I have picked up, l personally wouldn't go any higher than 11.7 or so above 5500 at WOT without at least upgraded valves.
But again that's a non-pro opinion.

 

Banish is even more cautious for a supercharged car that you are not regularly logging for Knock. Recommends starting at 11.4

I highly recommend both his books. At least get:
Designing and Tuning High-Performance Fuel Injection Systems Paperback – September 22, 2009
by Greg Banish (Author)

 

Fair points on those AFRs. Especially with how much heat the SC put out and how aggressive the factory timing is.