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      12-07-2012, 09:10 AM   #11
Brigadier General
JimD's Avatar

Drives: 128i convertible
Join Date: Apr 2009
Location: Lexington, SC

iTrader: (0)

It's all guessing but the dyno runs of the guy who put the 3 stage on but didn't re-tune suggest to me that the 3 stage inlet is not a magic bullet (he didn't do a before and after but others have posted a stock 128 at about the same rear wheel power - but the car that was changed had some miles). Perhaps it's a lot different with the tune. I wonder what removal of the carbon filter on our inlet + possibly an intake + possibly a cat-back exhaust (i.e. magnaflow) would do versus the 3 stage. You could, of course, do all these things.

I'm wondering if the 3 stage doesn't do more in the mid range than the upper end where ultimate power is developed. Part of my speculation is that my car feels pretty strong above 3,000 rpm but a little sluggish below that. I also tend to assume 2 stage = one stage for low rpm and another for high. Same logic suggests to me that 3 stage = low, medium and high rpm intake runners.

128i Convertible, MT, Alpine White, Black Top, Taupe Leatherette, Walnut, Sport
Ordered 5/22/09, Completed 6/4/09, At Port 6/9/09, On the Georgia Highway 6/13/09, Ship Arrived Charleston 6/24/09 at 10pm, PCD 7/21/09