|So this is what I was trying to post before all hell broke loose on the server....
A few days ago I suggested that I thought I might be seeing compressor surge after installing 2.5" induction and intercooler pipes and BDE GHKs on XtraVerTT.
Here is the link to the original post:
As you can see in original post, several people commented "no, that is just the sound of your recircs working". Then Maxxaction posted a video that shows a type of surge called "flutterdump" and states that it results from the BOV opening a little too late/slowly resulting in compressor surge. Here is the link to his post:
After watching the vid, I thought "that sounds exactly like my car" less the BOV dump at the end. I recorded the sound on my camera phone. Listen carefully as I come off the throttle to shift. It happens twice in the vid - once at 4s and again at 8s into the video:
Noise recorded in my car
Sound like "flutter" to you?
Going back to the flutterdump video that Maxxaction posted, I started to wonder if the GHKs are the issue. (The large spring effectively killing the goose honk, but suppressing the response time on the recirc resulting in flutterdump as described)
I removed the GHKs and re-installed a set of unmodded factory recircs. Result: No more noise.
So I have drawn my own conclusions. I am simply posting the info here so that you can draw your own.
The un-modded stock recircs will be staying on XtraVerTT. I may try the whole exercise again when Project SlickTTop is ready next month.