Stutter at high revs, bov has a mind of its own

[amaank]

Hey guys,

I am indeed a complete noob to dsms. I am not a complete noob to turbocharged cars.

The car is a 92 TSi AWD. I have not created this setup so i'm not sure about every single parts but here it is as i was told:

2.3l bored and stroked
t3/t4 60 trim
pretty chubby fmic
s-afc 1
some purple turboxs bov
Dunno what injectors
Dunno what engine management/chip
walbro 255 pump
38mm external wastegate

ANything else you need to know i can estimate or find out. its running on 91 octane fuel which is pretty much the highest we can get here in CO. its set at 16 pounds of boost right now.

What the car does is stutters at high revs and bov somewhat releases by itself. The bov is routed to atmosphere and from what i've read on the forum, this could be my problem. So i'm thinking i either need to recirc the bov or get a maft, either way i would like some advice. The car still has the stock mas or whatever it is dsms have. I really have not driven the car much and don't exactly have it right now to be able to drive it and answer questions/diagnose it more.

I have not had the car long enough to see if it does this at a lower boost level (7-8psi)

Engine pic if it helps anyone out

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ANy help would be appreciated.

Thanks!

 

[ChicksDigBoost]

Those Turbo XS BOV's are junk, its probally just leaking. Do a boost leak to make sure that its not leaking. Also double check to make sure the vaccum lines are connected and routed properly.

 

[amaank]

Could you recommend a new bov that would bolt right in place of that one?

I will definetly do a boost leak test, just need to build myself one of these

http://www.vfaq.com/mods/ICtester.html

while the car is at the shop i'll make the contraption and test it when it gets back.

 

[ADrewzki]

Doesn't really sound like a bov problem. Especially if you're only boosting 16psi. It's always possible that it's not set right and you are leaking a lot but that usually results in running very rich and even backfiring. Do you have any sort of logging software? You have an upgraded pump so it may be a fair assumption that you have upgraded injectors as well. Turn the boost down and see if it still bucks at high revs. Do you get any sort of smoke out the tail pipe when it's stuttering?

-Drew

 

[amaank]

I will check for smoke.. i think i get small puffs but really almost none. I wish i knew what injectors i had, i'll ask the previous owner when i have a chat with him. I'm certain they are upgraded.

I actually don't think i have any logging software... i think my s-afc replays some info it catches. I really don't know how to work it very well yet. What should i look for if i can replay the car's actions.

I really thought it was the mas accounting for a certain amount of air and then not getting it... so yeah boost leak.

Is it even possible that the bov would release on its own... perhaps its an illusion i dunno. Its just so much fun up in the revs that i tend to lose track of what the car sounds like and what its doing

Thanks guys for the help so far. WHen i get the car back i will run it at 7 psi because it'll have a new clutch which will need breaking in.