Paul Booth Posted September 26, 2001 Author Share Posted September 26, 2001 Start a list, of things I want to talk about in the flesh some time. That's something I'd like to understand, but not urgently. Quote Link to comment Share on other sites More sharing options...
Rich J Posted September 26, 2001 Share Posted September 26, 2001 My 2p not very technical with no real figures to back it up but worth thinking about (just what I found running my Supra TT). I installed one of those cheap A/F meters in my car as I was worried about leaning out when running 1.2kg/cm2 boost, I found that at 1.2 the last (richest light) was still on (indicating a rich mixture). I know that these things aren't that accurate but I did manage to get it to only illuminate the second "richest" light by adjusting the fuel down with the APEXi S-AFC (for experimentation purposes), so it must have been working (it also bounced from rich to lean and back at idle and cruising). So it seems like the ECU still provides enough fuel at 1.2kg/cm2. Could it be that the fuel pressure regulator allows higher fuel pressure the higher the boost you run (to a point), that way it could add more fuel at 1.2 even though the ECU only thinks it's running 1.0 (because of an FCD)? Quote Link to comment Share on other sites More sharing options...
Guest Ash Posted September 26, 2001 Share Posted September 26, 2001 You may well have been running rich, but that would have had nothing to do with the ECU or the FPR. The FPR is there to simply keep fuel pressure 36psi above manifold boost pressure. Yes, the FPR will raise fuel pressure, but only in-line with boost pressure. As the injectors will "see" the boost pressure in the manifold, during the time they are open, any increase in fuel-rail pressure will be offset by an corresponding increase in turbo boost. Fact is, the ECU is blind beyond fuel-cut. The car runs "rich" because the air density decreases considerably due to having taken the turbos way off their pressure maps. There are two ways an engine car run rich... increase the fuel relative to the amount of oxygen molecules entering the cylinder, or, keep the amount of fuel delivery the same and decrease the number of molecules of oxygen. The stock turbo'd car, with a big boost increase, does the latter. Yours, J Quote Link to comment Share on other sites More sharing options...
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