Turbo Makes strange sneeze's UNDER boost.


Ok guys...help me solve this one....first off here what the condition of the motor is... ALl basic mods, 206/206 Comp Cam, with lifters, 15k on new rebuild runs strong, TRW forged Pistons, MSD 50s, PT 51 Turbo, 3'' SS THDP, Hooker dual exhaust, etc... I am running a stock IC...the PT 51, MSD 50s, and exhaust I just put on brand new last month, I have had 0 problems until i installed my DW neck on my stock IC. I took extar care to make sure the aluminum dust and shaving were cleaned out of the IC before reinstalling. Ok here is what is happening...the car makes a very strange noise under boost, it sound salmost like a turbo sneeze except...it is a flutter in the sound, so the turbo will be whistling and makign this flutter of "sneezes" under boost. My boost needle soemtime sshakes a little, soemtime snot, it happens at different boost levels, and soemtimes u can' hear it at all....Here what I have determined....

It is NOT smoking....plenty oil pressure, no power loss, no hesitation, no knock, no vaccum leaks, eveyrhtign seems to be ok. I thought maybe I could have blown a headgasket, but the car has no water oil mix, motor is nice a cool. I am running 15 PSI boost, on 93 octane fuel with Joe Lubrants 18* timing chip. I can brign the boost up and the noise is apparent after 10 PSI, and the boost needle really shakes when I let off. Upon installing the DW neck, I had no boost increase, I thought this to be strange. Is it possible my wastgate is malfunctioning? I have NO idea how to explain this in more detail, If I jsut give it 5 psi in runs and sounds fine no shakes....it only shakes upo about 10 or above, and when I let off. I apologize for not providing more information like scan tool data...I have been workign and this just came up... I did get a code thrown while letting the car warm up it was beign very codl natured, idle jumping around, btu after it was warm it was fine and went away...I believ it to be minimum air rate asjustment(IAC, TPS settings) because upon installin gthe new chip with combo it started to do thsi little by little, now it is bad. ANY ideas guys? Anythign to look for? Thanks for your time!

PS- This happens right when I get my new 9x11 LU converter and am abotu to redo my tranny....*sigh*...hope for the best, prepare for the worst.:(

I am going to call prescion, I noticed no one replied...lol. I'm not crazy, gimmie some ideas of hints guys...
Both times I had that noise it was a loose intercooler or up pipe hose. Since you said it happened after installing the big neck on the intercooler I would check all hoses and make sure there are no leaks where the new neck was installed.
The dutt neck allows the throttle body to "see" more boost at a given wastegate setting than it was before. Unless the throttle blade is WIDE OPEN, you may experience compressor surge or flutter.

This is very normal. Only if it is happening at WOT you have a problem.

The only cures for compressor surge are a properly set up blow-off valve (not easy) or lowering the wastegate setting so you don't have to use the throttle to regulate boost or a different set-up that gets you out of the surge region of the turbo.

If my boost is set at 23 psi and I try to regulate it with the throttle to 15 psi, the compressor surge nearly hammers me out of the car.
Originally posted by XLR8
Both times I had that noise it was a loose intercooler or up pipe hose. Since you said it happened after installing the big neck on the intercooler I would check all hoses and make sure there are no leaks where the new neck was installed.

I agree, sounds like a leak.
I agree with everyone else on here. The one other detail to check is to make sure that you dont have excessive slop in the turbo. This could also cause the problem you described.
But, my guess would be wastegate actuator tension causing it. I get a lot of surge when I have the rod too tight. It will almost put you through the windshield at part throttle. I have a stock style actuator on my car. I know that I have to get a heavy duty actuator to cure it and still be able to run to 23olbs of boost I currently run. Try loosening up on the adjustment and see if it goes away. Let us know what happens.
Called Prescion...

Hey gusy I talked to Patrick, he said it sounds like compressor surge, and he gave me a list of things to test, I am also going to test compression just to be safe. My question is, if I can run more boost will this go away? I am getting alky injection soon and maybe I can run higher boost levels and it will go away. Thansk for the help guys, I have to work today but I will have T Link with me and I will test teh car this weekend. Also, is it wise to run w/o a wastegate silonoid, by bypassing the lines to it? Gimmie some hints....
i have found that problem in the past too if the wastegate has too much tension on it...if yo dont alread just hook it up to a regulator to adjust boost and then you wont need all that tension on it..
How does installing the Dutt neck make this happen? Is this compressor surge something that we all see as we start to build up, bigger turbo, etc? As it is right now, he can't go over 5 lbs w/o going WOT? If he "removes" tension in the wastegate won't he screw up spool time, boost, or both?

Not trying to be a pain, just want to understand for future improvements.
if your problem really is surge, not at all uncommon on big turbos or engines that breath well.....part throttle boost is the problem...either floor it or put up with the surge...as some mentioned, my car at part throttle will shake apart!
A BstC can reduce the part throttle surge. Eliminate it in some cases.

A test is to unplug the wires going to the wastegate solenoid and loosen the wastegate
rod until it has 1/8" preload and see if the surge goes away.

If you can eliminate the surge at some lower boost or at least reduce it to an
acceptable level, the BstC can be used to raise the boost back to the higher levels
once you have pressed the throttle past the surge point....

Try the test and let us know.

I have found that compressor surge is impossible to predict....

Any changes to the car before or after the turbo will affect the way air goes into your motor and can cause this. Sometimes tiny little changes to the car can make it happen.

I can give all kinds of examples of changes I made to my car in the past and some caused compressor surge and others cured it.

One such example is that when I went to my MSD 50's and used my Joe Lubrant street chip, I had no surge whatsoever (TA49) where previously with the bluetops and also stock injectors I had surge. I then took out the Lubrant chip and put in the Extender and made no other changes to the car other than the one dip switch in the T+ and the surge was back. I can't explain the difference, but it was there. I swapped chips a couple times just to make sure I wasn't dreaming it up, and sure enough it was the same.

Hopefully you can figure out a way to make it stop. Good luck.
Funny day....

This morning: Got up checked everything dusted off the car, and drove out after letting it warm up... turned the corner and went WOT... 20 PSI boost no noise PULLED HARD! In fact it pulled hard enough that the officer parked at the corner of the parking lot heard me and preceded to spill his coffee on himself as he attempted to catch me...I looked over at T-Link and I had no knock....ran good, well I saw him pull out and I was almost 3/4 a mile in front of him so I slow down, and pull over , and let him catch up. I sit with looking at my lap top and scannign things whiel the car is idling TERRIBLE...so I notice the hispanic overweight officer gets out, and has his gun out....:eek: Ohh feck...he approaches from the far side out and tells me to put my hands on the wheel...and asks why I am leaning over...

"Sorry sir, I was makign sure I didn't mess my car up when I came around the corner, I was tuning it this morning and it got out of hand, I apologize, didn't mean to scare you. May I shut off the engine please sir?"

He stands there just kinda taking it all in...LOL...then he says yes, and tells me why he pulled me over...

"I didn't have my radar on, but I pulled you over because I saw your car, heard an airplane and then saw you rocket off, that is exhibtion of acceleration, you pulled the front wheel off the ground! Let me see your liscense and registration... "

I hand them to him calmy and go back to my lap top...*I was shocked that he said I pulled the front wheel off the ground but I don't belive it, it pulled HARD but I don't think I can do that on Nittos, I was pretty calm, been pulled over 10 times in two months, so this is routine now I noticed a mile down the road, two cop cars parked side by side and waited...I had pulled off to the side road. He put his gun up, and was standign otu side the car runnign my tags, and stuff...I was thinking about how cool it was that my car pulled THAT hard and soudned soo bad ass...Well he walks up and looks over up at the car...*

"What type of vehicle is this?"
"It's a Buick Grand National sir"
"Do you own the vehicle?"
"Yes sir"
"Why does it say Buick Regal on your Insurance?"
"Well sir it is just a Buick regal with a special engine option and body option, the motor is a Turbocharged V6"
"Is that what made the whistle noise when you went by?"
"Yes sir, I was tunign it this morning, and I live right off *pointed down the road* and I made a mistake on the amount of Turbo boost and I couldn't control it."

He is now looking at the VIN number and tells me registration is out *DOH* ..he glance ove rinside the car and ask what teh laptop is for...

"What is the computer for?"
"It tells me how to tuen the car sir and what the engine's computer sees."
"What's in the black case, is that the computer case?"
"Yes sir, I usually don't have it out but I wanted to make sure everything was ok since I tuned the car this morning"
"Is the....Turbo...that what makes the whistle noise?"
"Yes sir"
"It is very loud, at first I was confused and thought a jet was going over, then I saw you go by..."
"Yes sir, I apologize about that I couldn't control it, I was going to stop at the gas station ahead and fix it"
"Well, make sure you are careful this is a nice car and I don't want you to get hurt or hurt anyone else, just turn that thing off of something till you can go out of town, and get your registration done soon, don't let me catch you back out without it."
"Yes sir"
"You can go, but be careful..."
"Thank you sir"

Well he walks off and gets on the radio, and thsoe cops came down, I tunr aroudn and idle/lope off easily, they follow me to the gas station where I stopped to get gas and figure out what was hissing...they go on....LOL...I got off, but man that guy was freaked out, he wasn't a slow guy he just was confused, especially when i said V6, TURBO....BUICK....he was....well it was funny...
This afternoon....

I was comming home nice sunny day...and these girls pull up behind me, I tap my brake and they pointed at teh third brake light that says "BUICK" and they pull next to me...we are going 55, and I started to show off...they were smiling and we had our windows down, I give her some boost 15 psi, 3/4 throttle and she shoost off...it was making a slight flutter and so I backe doff at 90 MPh and then I went to hit the brakes......no brakes....ohhh feck.... :eek: I looked ahead and I had 1/3 miles to stop...so I hit them hard and I hear them slighty grab...whiel I am pushing on the pedal HARD I downshifted into D, and tried to slow down...I finally get it to slwo, and then coast into a 7 11 parking lot and hit the e brake to stop.....the motor dies.....ohh feck, it smells wierd and is hot...I pop the hood, and notice the water reserve is bubbling a little, look and low and behold THREE vaccum lines blew off....Vaccum brake tap, PCV valve, and the turbo boost guage line....pop them all on, restart T link, clear the ECM, and she has plenty oil pressure idles good, so I pressur eup the brakes to see if they still work...all is good...and I coasted home..... whew
What I noticed...

Well, when I went WOT teh turbo screamed this mornign no noise solid boost and PULLED HARD...but I am blowing off vaccum lines right and left, should I just turn down the boost to 15 WOT? I guess it is set to nearly 20 WOT because this morning it seemed to enjoy it thouroughly... After I filled up I lost my methanol that I mize din the tank, so it detonated when I tred to bring it back up... From what you guys are describing compressor surge can occur at any time almost, and is assciated with the boost needle quivering, the sound of the turbo pitch changing and a surge in the car's behavior? Mine doesn't act up when it occurs, it runs smooth, and pulls. I was just worried abou tthe needle shaking and the noise. I am going to redo all my vaccum lines, turn down the boost, to 15 PSI WOT, and set my IAC, TPS< and all basics, I will also pull my plugs and check them...any other suggestions guys? Or questions for me? Thank you for listening!

Cory Gober ;)
are you done YET? :D

i'll toss in what i do on my vacuum lines is clean em good and slide them on with a little super glue and put a small wire tie around them.

the super glue acts like locktite it will come back off but it takes some force to get it loose

Thanks guys...I'm having a lil party tonight we are all hanging otu workin gon the GN woohoo! See you guys tomorrow!

I fixed it, running tuner mode. Ran the Turbo line to the wastegate and set teh boost real low and tete dit then brought it up to 15 @ WOT, 0 knock, runs smooth and pulls hard! I left the wastagte silonoid plugged but removed the lines. It was all just compressor surge, I have a bleeder valve that my friend gave me...will it help anything? How do I hook it up?
Thanks guys!!! :cool: