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STI v11 basemap (pushbutton) - question about some tables


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Hey Adam  (or anyone else who knows the answer and is not guessing at it like me) :)

I'm just about ready to send my GRB (cold air intake, tmic, injectors/pump, exhaust) down to the dyno shop i love the most, to get the boost controller setup and take it off wastegate only, and give it a proper retune after fitting a new turbo and had a couple of questions about the base map settings and tables if you have a moment.

Is the "Charge Temp Approx" table for the base map setup setup for a factory top mount or did you do your dev work with a front mount on your test mule?

Also the "Fuel Charge Cooling Coeff" of 15% in the basemap - is that an arbitrary number or was that what worked out to be perfect for NZ BP/Mobile 98 octane?   Would you know offhand if NPD 100 is going to be significantly different for that setting from 98 fuels and require a change at all?  I'm not planning on running any Gull, or ethanol in the car for now and want a 98 tune and then run it on NPD for that extra knock prevention :)

(sorry to everyone outside NZ - these are questions for fuels we get here - not sure what you guys have on pump anywhere else)

And randomly - my question a while back about the afr changing and being leaner on the road in lower gears under full load (7% leaner in 1st compared to 5th) and was there a per gear fuel correction table available (i made one for onboost vs rpm in the end) , was mostly sorted by changing to ID1050xds injectors and using the plug and play data for a g4 ecu - now its muuuuuch closer in 1st than the old (larger) injectors I had installed last time it was tuned and when I asked the question.


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Our test car was a 2.0JDM GRB, dead stock including air box, MAF, exhaust, injectors and top mount IC.  

I never got around to removing the injectors to characterise properly so there could be some deadtime error baked into the tune which would consequently bake some error into the test you do for the fuel charge cooling coeff, so I cant say for sure that is representative.  Be aware injector spray pattern affects charge cooling a lot also.  having said that, the fuel control was quite stable in that car, the long-term fuel trims would average around +/-3% whenever I looked at them over different seasons and varied driving conditions.   I mostly ran the Mobil 98 in that car.  

I use the test described in the help file for the charge cooling coeff to approximate both the deadtimes and the charge cooling.  Ideally you need to do this on the dyno while holding steady and light load to get the PW up around 2ms where things are linear, I then set lambda target to 1.0, set the fuel table so it is flat around the operating area and lambda is sitting close to 1.0.  Then change the lambda target to 0.95, note how much measured lambda changes, then change target to 1.05 and again note measured lambda.  If it overshoots/undershoots the target significantly more on one side of 1.0 than the other, then the charge cooling needs adjustment.  Tweak that and try again until you get a similar amount of over/under correction when you step the target leaner or richer from 1.0.  Then do the same but tweak the deatime with each test until the measured lambda no longer over/undershoots a change in target.  This sounds complicated but its really only about 15mins work once you get the hang of it and have everything set up to display and adjust all on the one page.

The charge temp approximation table worked well in that car with the top mount, I dont think a front mount would change it significantly unless the manifold gets significantly cooler with the top mount removed.  We were using the stock JDM sti IAT location beside the throttle.



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