[BetweenTheWheels]

Originally posted in main forum - thought it might fit here better:

I have a 228 that I enjoy but I wanted more noise from the exhaust (natch) and retro'd an m235 axle back unit about a month ago. Transforms how this car feels to drive! Sounds great. Looks great. A nice balance between civilized and some extra snarl when pushing it hard.

Question: when I am giving full acceleration, the car sounds great and feels great 1st to 2nd, 2nd to 3rd and 3rd to 4th (I have a ZF). The car is plenty quick and even feels more lively with the new exhaust, which may be placebo. What I'm curious about is a bit of drag I feel in gear transitions as if the Hulk has hooked his finger under the rear of the car and gives me a little tug backward at each shift. It comes in time with the growls/burble from the exhaust and my thought is the higher level of back pressure that's being expelled via the dual pipes is pulling some flow from the turbo causing it to hang or lag a fraction of a second each shift. 1) Am I diagnosing that correctly ? And 2) While it's not a big deal, is my solution (should I choose to address it) a tune which increases my boost?