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FG NA+T


TravisR

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Morning,

Just seeking some advice on an FG NA that's been converted to turbo, has turbo map sensor, BF XR6T injectors, 4 bar fuel pressure reg and a walbro 340. I've disabled closed loop, imported speed density + variable camshaft tables from an FG XR6T, scaled the load axis, It starts and idles fine @ 14.7, cruising is a little rich in the 13.5's but soon as boost is introduced it leans out, I've played with the breakout settings, low scope, high scope but this just results in the whole map being rich and gets a lean condition on gear changes. Attached is the map, any advice would be much appreciated.

Cheers,

FG NA-T.tec

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If you datalog the load is it pegging at 1.05? This is a common problem. You can fix it by changing to a turbo operating system or playing with the settings discussed here.

https://forum.pcmtec.com/topic/269-air-load-capping-at-105-in-na-turbosupercharger

Also check you aren't overboosting on gear changes (would further peg the load explaining your lean), this is also common if you don't adjust the spark delta wastegate adder.

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They are already both set to 1, it goes from cruising (13.5AFR) to sinking the foot in which reaches 1.02 load and the AFR leans out to 14.7 and then the gear change spikes it to 16-17AFR. Feels like the scopes on the injectors are off or something strange.

Edited by TravisR
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If load pegs at 1.02 then that is your problem, with boost you should be seeing 1.6 load easily, this means your airflow calculation is pegging at atmospheric pressure hence the lean out. Some of the NA operating systems do not measure boost properly. You can copy heaps of stuff over to make them work but it is easier to start with an original turbo strategy in the first place.

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Does it go all the way to 1.6?  If it is measuring load properly then you would have an injector scaling/mechanical issue. Have you measured your fuel pressure and cam angle error?

Yes if the operating system is different you would have to relicense the file, but if the load is not pegging there would be no reason to do this.

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I'm honestly to concerned with how lean it is to dig the foot in deeper to reach 1.6 load, it seems to be measuring load properly. Haven't measured fuel pressure however it's a brand new fuel pump, new regulator with known working injectors, but if it comes to it I will measure it. It kind of feels like the injector scaling but it's the stock settings from the stock BF XR6T map so it's hard to believe it's that. I logged the cam angle and it seems to be commanding what's put in the map, attached is a little log.

1.04 load log.teclog

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It should be a requirement to measure fuel pressure on every car you tune before you touch anything else. Very common failure point with new installs and the return line popping off etc, or the return being too small and the pressure spiking at idle/decel. Sometimes customers use the stock wiring which burns out etc. You need to verify this.

Easy to test as well by putting stupid numbers in the injector high slope, half the value and it should go pig rich. If it doesn't then you've got fuel issues.

With the cam angle log the cam angle error instead as this will tell you if its doing funny business. It shouldn't be more than a few degrees error. Also make sure you aren't running into valve float.

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I'll verify fuel pressure just to rule it out.

I have played with the high scope previously, it does make it run pig rich everywhere, I'll give it another shot with halving the slope and see if I can get into more boost. I can't seem to find the cam angle error channel? Doesn't appear to be there for me.

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  • 6 months later...

Just wanted to update this thread and also hopefully seek more info on this topic. So setting auF0049 to 0 fixed the load issue but am running into other fuelling issues. Installed some 980cc bosch injectors (0 280 158 040), I have tried multiple low/high scope, breakpoints and deadtimes but ultimately nothing seems to provide a nice fuel curve. WOT is always in the 7-8AFR, I waned to rule out my injector settings so I put back the BF XR6 Turbo injectors, put in the stock settings for them and resulted in rich pretty much everywhere and once again 7-8AFR under WOT. Has anyone run into this before or have any suggestions?

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