Boost Flutter is killing me! Wastegate related??

[F1]

You ever say to yourself, I just should of left it alone! It was running great, but we are never happy…. Well after the install of my TA49, Stretch IC, 3” DP and Adj Wastegate. I have been getting this flutter (boost jumping up and down) and loss of power under WOT.. Most dominant in when the car shifts to 3rd gear, Especially if the converter is locked…. This is @ 15-16 lbs of boost.

It seems whenever there is an extra load (like going into 3rd with a rpm drop) it happens. All vac lines & hoses are tight, FP is dead on, plugs and wires are new, and so on……

I have a feeling it is wastegate related. I am using the “Tuner Style” set up with a valve in the car. It was thought that the wastegate was not tight enough, causing it to “blow open” under an extreme load. Funny thing is it will mostly clear up after the rpms build back up.

So I tried this… I turned the rod on the wastegate in 4 turns, then turned my in-car valve down, to get me back to the 15 lbs of boost. Well no change. What I did then was try this, I turned my in-car valve closed, guess what, NO FLUTTER. But this was with 10-11 lbs of boost. What happened when it shifted into 3rd (converter locked) was a boost lost of 3-4 lbs but came back up with rpms with no fluttering.

What is this telling me? Should I leave my valve closed and adjust my wastegate rod in till I achieve 15 lbs of boost then work the in-car valve to up it when needed?

Need some opinions here.

Thanks, Dave


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"WE4" XP+ pump, TA49, Stretch IC, Bluetops, HEMCO, K&N in stock box (open bottom)160 thermo, ATR adj FPR, ATR 3" DP & Crossflow exhaust, RA chips, TB BP, 275/50 BFG DR's, Bleeder Valve

11.95 @ 110.97 - 1.679 60ft w/RA 108 & VP C16

[TurboDave]

Depending on the quality and length of vacuum hose being used, you could be setting up some "echos" or "harmonic" pulses in those extremely long, and probably soft vacuum lines going into the in cocpit valve!
Try this, disconnect those long hoses and move the valve into the engine bay with much shorter lines (somewhere closer to the turbo).
This will likely clear up your problem(assuming the vacuum lines are very soft)

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TurboDave & Kathy Huinker, mailto:TurboDave@turbobuicks.comTurboDave@turbobuicks.com</A>
TurboD Racing,BGNRA San Diego,GSCA-5311,Turbo Buick Web Ring
San Diego CA http://home.san.rr.com/buickv6/
86 GN 11.50; 118.50 "corrected"(actually 11.80@115.3 at 2,900 feet).
(MM/MAF Xlator/Extender,MM BstC Boost Command,THDP,PTE44,CAS V2FM,MSD50's,9.5"vigilante 3500)
87 GN 12.95@105.50(Stock)
84 L69 Z28

[F1]

Dave,

I understand you theory, but...

Why all of the sudden? This never was an issue before. Would the extra volume of air (turbo, ic, dp) cause this and if so how?

Thanks

[F1]

Just trying to put the pieces of the puzzle together:

Before the new Mods… I would get a boost spike when it shifted to 3rd with the converter was locked. This was with the stock turbo, and actuator. When I removed the actuator it was filled with oil… So I thought that might have been why I was getting the spike.

Now I have kinda the opposite…

[TurboDave]

Originally posted by F1:
Dave,

I understand you theory, but...

Why all of the sudden? This never was an issue before. Would the extra volume of air (turbo, ic, dp) cause this and if so how?

Thanks

Yes, it's very likely that has a great deal to do with it. All of these factors combining to give you fits.


TD