2.75" vs 3" pipe on supercharged vehicles.

SS_Firehawk

So I was helping a guy with his Y pipe issues here on this forum the other day. His 3" Y pipe terminated to a 2.75" or 70mm mid pipe. I basically told him it's an insignificant difference on a bolt on car. So over the past couple days I've been searching to find an answer for my own car.

So as many of you all know, my exhaust system is not of the same manufacturer. PPE's mate to the Motordyne Y pipe at 2.5" The Y pipe is also 2.5" and when it converges at the Y and increases to 3". A 3" 200 Cell HFC is connected to the Y pipe. My Tanabe mid pipe is 2.75" and connects to the Motordyne HFC that is 3". Exhaust is then split to two 2.5" all the way out to the tail pipes.

Again, many already know twin superchargers are being installed. 475-525whp is expected. I can't find anything that tells me if this will pose a problem at higher rpm. I understand the Rotrex superchargers like some back pressure to get them up to speed, but is a single 2.75" pipe going to flow enough to keep the top end happy? I'm not stressing about it too much right now until I get the results, but this is something I'm watching closely. I'll send an email to GTM just to see if they think.

Has anyone else seen any tests on this? If it's causing a big restriction, I may have to part with my beloved Frankenstein exhaust.

Edit: Attached exhaust pics. Notice on the mid pipe to HFC connection, the mid pipe is visibly smaller.

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