I've had my setup on my car for a few months now and had it tuned and all that good stuff but have had a flutter issue. The car will do fine when I go through the gears at WOT. Holds 14psi with no problems. I have the flutter issue when the car is in a higher gear and I try to speed up and not gear down. Like if I was on the interstate at 70mph in 5th gear and floor it, it will build about 3lbs and bounce back and forth from 3lbs to 7lbs until it reaches like 10lbs then it is fine, continues smooth up to 14psi. Pretty much it will flutter until it hits full boost and then it will be steady as could be. Another example would be if I did a 20mph pull in 3rd it would happen. It sounds like ch ch ch ch ch ch when it does happen. Its not quite the same sound as compressor surge. Its like the wastegate is fluttering.

I have a tial 38mm wastegate with the 13lb spring. It is dumped to the atmosphere, maybe this could be a cause?

The wastegate line is ran correctly as well.

I am positive its not my BOV, my BOV is adjusted properly.
I have a mechanical boost controller and thats not the cause either because it will still do it even if the boost controller is removed.

Could it possibly be that I am out of my compressor map? The turbo is a 50 trim T3/T4 .48 hot, .60 cold.

Any help would be greatly appreciated, this is extremely annoying and affects drive ability on the interstate tremendously.

 

your not out of your compressor map. If your getting a fluttering while building boost it could be the bov isnt staying closed or the WG isnt workign properly. What BOV are you running? Is the tial wg new or old/used?

 

I am running the tial bov as well. I originally thought it was my bov as well so I ordered the stiffest spring that tial has to offer and tried that. But it was so stiff that it just caused major compressor surge because it wouldnt open at all. To make double sure it wasnt my bov when I got new intercooler piping I took it down the road without a bov, bc the flange wasnt welded on yet, to see if it would still do it and it did. Thats the only way I could think of trying it.

It is a brand new tial wastegate. I even took it apart to make sure there is no holes in the diaphragm and such.

I even borrowed another tial wastegate from a friend and put it all on and stuff and it still did it.

Bump for more help.

 

ok so its not the wg or bov but your getting a fluttering. have you pulled the turbo off and checked that your housings are tight and the nut for the comp wheel is tight? is there any damage to the turbine wheel? what manifold are you running?

 

That sure is an interesting one!

Turbo-LS seems to know more about this, but I just want to point out that a .50-trim with a .48 A/R housing is going to spool up SUPER fast. Maybe it really could be surging?? Some kind of funky closed-loop oscillation?

 

I checked all that and everything is tight. There is no damage to the turbine wheel and there isnt even any shaft play.

I am running a full-race ramhorn manifold.

Here soon I am going to route my dumptube back into my exhaust and see if that fixes the problem, it seems like the exhaust pulses from the manifold is forcing the wastegate open or something random like that. Not sure if thats even possible...

 

I was having the same issue when I first installed my turbo and found that it was from having too small of a pipe going to the turbo inlet. I replaced the tube with a larger one and it completely got rid of the fluttering as well as made the car run a bit better in the higher RPMs, even though I wasn't technically seeing a change in boost.

 

I have actually done the opposite and it made it alot better but it still does it. Originally I had 2.5" from the turbo to the throttle body. Now I have 2" from the turbo to intercooler and from the cold side of the intercooler to the throttle body is 2.25" It made the flutter a little better but like I said its still there. I did notice a decrease in spool time with the new set up tho.

On a side note, it seems like I am running leaner now. Could changing the pipe make that happen or is it just my imagine? I wouldnt think I would have to retune just for the ic piping change, unless it is flowing that much more air.

 

i really like that input and it made my wheels turn. That is a smaller turbo. not really small but smaller. I think ive figured it out.

Your turbine isnt flowing quick enough and causing to much pressure in the turbo manifold and forcing the wastegate open and then it slams shut and gives you a fluttering. Thats what it seems like to me. In higher gear with lower rpms there is alot of load on that motor which is where your get it from. and when you tear through the gears your essentially already in boost when you shift the turbo wheel is already spinning so when you hit the next gear it doesnt have that flutter

 

So pretty much there is no way to cure this, except for going with a different turbo? Would creating more back pressure through the wastegate help solve this problem?

I was afraid that was the problem but was hoping that there might be a different solution.

 

honestly im unsure. It might not be what i said but its very plausable.

What size gate are you running?

 

Its a 38mm wastegate

 

I was meaning the actual inlet to the turbo, pre-compressor, since the air is moving much fast before the compressor than after.

 

Are you talking about the pipe that the filter connects to? Im still not quite sure what you mean. I just have my filter connected directly to the turbo.