1bar map + no maf + turbo'd
10-24-2008, 08:14 PM
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1bar map + no maf + turbo'd is it possible to run any boost at all with no maf and a one bar map, I just got done building my PT88 turbo'd 6.6 LQ9 and the guy who is tuning it said leave the one bar map in it for now and I can run low boost by using the weldon fuel pressure regulator to richen it up.. sounds like hes clueless to me should I trust him?
10-24-2008, 09:16 PM
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to a point you can get away with it due to the MAP referenced rising rate reg adding fuel with boost. I can see where this guy is going with it, but I certainly would't do it.. Not hard to get a 2 bar sensor and do it right the first time.
10-25-2008, 04:23 PM
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You can tune with 1-bar SD, but it's certainly not optimal. Definetly would be detrimental for 25PSI. The boost referenced pump is not related to the MAP sensor. That's simply adjusting the FPR diaphram from the boost pressure in the vacuum lines when making positive pressure.
The problem is that the MAP sensor will be pegged out at 105kPA (about 1/2lb of boost). You need to tune the Ve Table to the appropriate value for the engine to receive enough fuel at full bosst. I hd thi setup initially on my STS at 5PSI. The result is that the car receives too much fuel and runs pig-rich at part-boost (1-4PSI) settings and when the engine is under less load (like 1st and 2nd gear) when set to receive the proper fuel at full boost/higher load settings. End result is a fuel-smelling sluggish transition till at full boost.
The 2/3 bar MAP (depending on your boost level) allows to tune the Ve Table for all the areas between full boost and no boost. This allows for a constant AFR in boost and no fuel loading. Result is faster spool (as rich AFR cools the exhaust gas) and no sluggishness/ better economy.
So.....after this long-a$$ed explanation
, you can tune on 1-bar, but much better off using the proper 2/3 bar setup (2-bar till 15PSI; 3 bar above that)
The problem is that the MAP sensor will be pegged out at 105kPA (about 1/2lb of boost). You need to tune the Ve Table to the appropriate value for the engine to receive enough fuel at full bosst. I hd thi setup initially on my STS at 5PSI. The result is that the car receives too much fuel and runs pig-rich at part-boost (1-4PSI) settings and when the engine is under less load (like 1st and 2nd gear) when set to receive the proper fuel at full boost/higher load settings. End result is a fuel-smelling sluggish transition till at full boost.
The 2/3 bar MAP (depending on your boost level) allows to tune the Ve Table for all the areas between full boost and no boost. This allows for a constant AFR in boost and no fuel loading. Result is faster spool (as rich AFR cools the exhaust gas) and no sluggishness/ better economy.
So.....after this long-a$$ed explanation
, you can tune on 1-bar, but much better off using the proper 2/3 bar setup (2-bar till 15PSI; 3 bar above that) 