Earlier this week i installed my boost controller. When i am acceleratng at partial throttle and the turbo has begun to spool, when i hit about 3800 rpm and up tho boost rises and falls rapidly and the car bucks like it doesnt know if it wants to boost or not. When the boost falls off the BOV even releases.
2003 evo 8
boost is set at 17.8-19 psi
waste gate crack pressure is at 11.5
any input would help
Sounds like you’re falling into the issue with compressor surge on the stock 16g. Trust me, I dealt with this on a customers Evo a couple years ago and even went as far as to make a custom one-off anti surge 4" inlet compressor housing for the 16g. The issue would be VERY apparent when trying to ease past someone on the highway, or when gradually accelerating up a long hill. The problem is that that stock twin scroll turbocharger is so effieceint that at low throttle input/high boost levels the turbo wants to force more air into the motor than the motor is actually taking in. Essentially causes a pressure wave in the compressor housing and forces the turbo to surge. The antisurge housing I made eliminated this problem on Erics car, but then he had a CBRD billet center installed and removed the OEM 16g. I still have the compressor housing though.
You either need to modulate the throttle easier, or you need to boot it.
You can talk to EJEvo on the forums, he is the Evo owner I mentioned above.
Its really annoying and not safe at all for the turbo… I had plans to run an evo9 turbo in the near future and thats probably just gonna make it worse
it could also be BOV flutter
If I remember this situation correctly Boxersix approached that issue as a possible BOV flutter and they tried a high end valve I sourced for them. It didn’t fix the issue until the fix he listed in his previous post.
yeah i have a greddy type s on my car right now… the strange thing is, everyone that has posted about “compressor surge” said it sound like a bark when it happens. Im not getting any strange noises besides when the boost falls the bov will release and then it will spool again and unspool and the bov will release again. i did a boost leak test a few days ago and my bov holds up until 25 psi. my recorded peak boost on the guage its it says 19.7. possible wastegate flutter? im also going to change the hoses that go to and from the boost solenoid. maybe i sliced one putting it back togethr or something that fan shroud is pretty sharp, ask me how i know haha.
The compressor surge causes a pressure wave in the plenum which trips the bypass valve diaphram/piston and causes it to flutter.
What JVG is referring to me doing was I took a Synapse Engineering valve, thinking exactly what you were, and tried to “tune” out the bypass valve flutter. That didn’t fix the problem. After that I ended up creating a solenoid circuit and used the Syncronic valve as a “wastegate”, bypassing excess flow from the turbocharger. This solved the partial throttle surge problem but caused a slow reacting valve at throttle lift. It is what held me determine that it was surge and ultimately lead me to making the comp housing for Eric.
Believe me I spent countless hours chasing the problem on Erics car. If you do enough searching you’ll likely come across my posts in threads relating to this topic in various forums, as well as in a specific syncronic valve thread on Evo M.
I can post pictures of the antisurge housing i made to combat this problem which solved the issue 100% right off the rip.
The pics were gone off of evom… I trust what youre saying ive heard about your legendary quality of work. I just find it strange that the only thing i changed was the controller. Im gonna boost leak test it again after i change my throttle shaft seals. Reduce the boost controller vacuum hose diameter (its much bigger than it should be) and next time im over at Brooks’ house ill see if youre available to come over and take it for a spin. Also, im very interested in seeing the anti surge housing because i dont plan on straying from a stock frame turbo, theres so many options that will put my car within the realm of my goals.
Yes we can work that out.
I’ll take/post pics of the comp housing in a few
Bump for pics!
I will take them tomorrow, I pulled it off the shelf today but left it at the shop this evening. I’m actually working on Erics Evo all day tomorrow prepping it for race season for him so I’ll bring the camera and take a few pictures for you 
Youre the man! Thanks.
lol, forgot to take pics again. man i’m a forgetful POS. when i get back from syracuse tomorrow afternoon I’ll bring the f-ing thing home so i have no excuses.
sad thing is i took the camera down to lock 9 today and stood in the river bed taking pics of the damn and shit :rofl
haha no problem man!
Bump for pics!
If he hasnt remembered by now he never will. You should have offered him a mountain dew. hes like a crackhead for mountain dew
You shut your face you whore! Trying to get shit done before I leave for the upcoming event and tend to overlook the little things :shifty 
You’re right, I did forget again. I just took some shitty pics here in the house. Can get better ones if needed. It’s been flooded with white paint for pleasing aesthetics while mounted on the wall as random shop art. Was the prototype I made to test the theory(which worked)with intent to offer them as a core exchange but decided against it.
That looks awesome!