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Old 09-12-2006, 10:09 PM   #20
1st Gear Newbie
Join Date: Sep 2006
Location: Canada
Posts: 24
The 325i uses Bosch 0 280 150 715 injectors, which have a rating of 149cc/min, or 14.6 lbs @ 43.5 psi(3.0 bar)

The the M30 engine in the 535i uses Bosch 0 280 150 203 injectors which have a rating of 185cc/min or 17.6lb BUT at 36.25psi(2.5 bar) at the m20 b25 3.0 bar that is 19.30 lbs.

The m50 (green ) injectors do flow 17.5 lbs but at 3.5bar(50.7psi) so on the m20b25 3.0 bar they flow 16.2lbs.

I have never seen proof that the stock injectors are maxed out. Alpina got 210hp using stock AFM and injectors. Most people notice a difference after swapping injectors simply because they are replacing dirty injectors with clean ones.

The M30 AFM gave Dave a 4.6 HP increase with adjustable fuel pressure and dyno tuning. The majority of the people who try this mod get drivability problems. If you want to replace the AFM have a look at an MAF. The biggest restriction in the intake is the intake manifold, followed by the head.

The stock intake is a cold air intake and is well designed so you won't get any increase from adding a cone.

Sadly, the only easy/cheap hp increase for the M20 is a chip.

Last edited by Curtis; 09-12-2006 at 10:12 PM.
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