Part throttle surge flutter issue

[bluestreak9999]

I have been having this trouble for some time now and have not been able to find any threads with this exact problem. When under part throttle as the boost builds and the engine reaches around 4k rpm it will start surging pretty violently. This will also happen at wide open throttle if i am cruising at low rpm and go WOT when the turbo hits around 15-20psi depending on what gear I'm in. 3rd gear around 20, 4th gear around 17, and 5th gear around 15. 1st and 2nd gear are fine. If I keep it at WOT it will surge for maybe 2-3 seconds and then it will smooth out. I originally thought it might by the BOV. Upgraded to a Forge open atmosphere BOV and it does the same thing. I have tried all 3 springs and a combination of washers and it still does it. I put a different gm maf on and didnt help. If I go from a dead stop and go thru the gears at WOT it will not do it. Not sure if this compressor surge or something else. Hoping someone else has had this issue and has a solution. I am posting a video link to help out. It's hard to describe exactly what it is doing.



I have a fully built 6 bolt with eagle rods, wiseco pistons, maf-t w/gm 3 in maf, moderate port work on the head, magnus smim, stock 1g throttle body, full 3in turbo back exhaust, ported 2g manifold and o2 housing, PTE 57 trim, PTE 780 injectors, Aeromotive afpr (set at 41psi), SAFC-1, Coil on Plug kit, DIS-2, Eprom with DSMchips stage 3, 2.5 intercooler pipes.


MVI_0004.mp4 video by bluestreak9999 - Photobucket

 

[highlandgst]

well I watched the video . it looks like boost leak to me or possible a vaccume leak . I always get flutter with a vaccum leak and the boost jumping leads me to think its a boost leak . I can't really tell but does the car jerk alot also ? Check all vac lines especially ones to the BOV and your boost controler . and do a BLT

 

[bluestreak9999]

Yeah the car jerks pretty violently when it does it. I thought about a boost leak but, (I assume) if it was a leak it would continue to do it and not smooth out, and even get worse the higher the boost. It usually only does it between 4k-5k rpm and then smooth out. I havent done a blt yet but it is next on my list.