Guest Anonymous Posted January 17, 2001 Share Posted January 17, 2001 Other than the calibration problem, the problem is that the airflow isn't smooth or linear after a turbo and/or intercooler, so an airflow meter would give inconsistant measurements. Use an excessively large AFM or no AFM at all would be even better. ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted January 17, 2001 Share Posted January 17, 2001 Brian, I've seen it work in both configurations: before and after the turbo. It's ideal to have the MAF before the turbo, but in some applications, this is not achievable. When the MAF is placed after the turbo, more tuning and tweaking will be required from the ECM. This is because of the way the MAF works. Basically, a wire is heated inside the MAF and as air moves past it, the cooler it will become. When the MAF is placed after the turbo, the air is already pressurized. The MAF will not know what the pressure of the air is flowing through. It assumes the air is 1 bar (normal atmospheric pressure). The "flow" of air through the engine will theoretically be the same at different pressures. Also, compressed air creates heat. Even with an intercooler, a MAF placed after the turbo can give false readings of flow. By placing the MAF before the turbo, the flow measurement will be much more accurate. This is because all the air the turbo(s) is(are) using flows through the MAF first, before it is compressed. Placing the MAF before the turbo will make tuning and drivability much, much, easier to deal with. Personally, I would seriously think of an aftermarket EFI system that would eliminate the MAF entirely. If this kind of money is not in the budget, seriously consider putting the MAF before the turbo(s). Good Luck -Andy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 18, 2001 Share Posted January 18, 2001 I've been doing a paper sturdy on turbo system layouts for my project and have been unable to find anything on the placement of the mass air flow meter. Most systems I have seen up to this point have had the MAF placed on the intake side of the turbo. Assuming that the ECM can be recalibrated, what are the pros and cons of the MAF being placed in a "blow through" configuration... after the intercooler and before the throttle body? Quote Link to comment Share on other sites More sharing options...
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