Shouldn't a 50 trim require more fuel than a 16G?

[blcknspo0ln]

I'll have logs & SAFC stats later, but here's my main question:

I basically had -30 on the HI's with my 16G to get 18* peak timing.. on the SAME settings with my 50 trim [ all else equal ], my logger say's i'm running pig rich and getting timing pulled all over the place. At 6200 i'm getting about 17* peak timing.

Correct me if i'm wrong, but since the 50 trim flows a lot more air, shouldn't it require more of a fuel compensation? I was thinking i'd be tuning down in the -27 range with this new turbo?

Also, my car put-put-put's at idle.. new plugs/wires/boostleak/comp test checked. Is it time to replace the fuel filter?

 

[CanadianTSi]

I was at -34 with 650's and a 16g...put my 50 trim on and gave it some fuel, after tuning I ended up right back at -34...

 

[johnnytsi]

I noticed the same thing, I think in my case, the bigger, more effecient turbo requires less fuel to combat knock.

 

[DSM90AWD]

The AFC compensation is more to correct for a modified MAS, larger injectors, higher base FP as the ECUs MAPs are calibrated to the stock pieces/settings. With all the above accounted for on my ePROM, I've little to adjust on my S-AFC.

I have noticed that my O2V are now much lower (.86-.90V) under WOT than when I had it tuned for my 16G (.88-.92V). This supports Johnnytsi's comment on the ability to run leaner without knock with the larger (more efficient) turbo.

As an FYI (if you didn't already know), having that much (-) correction on the S-AFC is also putting you on a much more aggressive timing MAP making you more succeptable to knock. By using a modified EPROM/DSMLink to make the major corrections at the ECU level would allow you to run more boost / lower AFRs on pump.

Then again if your running race gas, you'll be fine

 

[blcknspo0ln]

OK that makes more sense. thanks guys