b18vtec

I have a Tial BOV and when I boost anything over 20 psi it starts fluttering and opening and closing under boost, causing my boost to climb and drop from 30-20 psi. Under 20 psi it works fine. Anyone else have this problem? I'm thinking it might just have a bad vacuum source, but thought I would post before I changed it. It is teed into my FPR line. I thought it might be the spring, so I tried my buddies BOV and it did the same thing. His car is on 24 psi with no problems.

I did search and found a couple people with a similar problem, but never any answers!

TiAL

only way this would be possible is if there was a tear in the vac line going to the top of the valve

b18vtec

I will replace the line and see what happens

TiAL

if it is still doing it after the swap, the turbo itself is probably going into surge, nothing to do with the bov

b18vtec

what would cause the turbo to go into surge? It's a Garrett t3/t4 60 trim, probably has less then 1000 miles on it.

TiAL

your flow numbers are riding the far left side of the compressor map

dpetro1

i would give it a dedicated vac source while your at it.

HiProfile

No kidding. You can get a cheap vac block for all of $20 with every sort of fitting. I've seen COUNTLESS stemming from teeing off tiny lines such as the FPR - especially when it feeds everything else. Its the only time you'll see the datalog show the MAP at a steady RPM, while the boost gauge vibrates from 0-15psi a hundred times per second.

More often than not, removing all tee'ing from your system by using a vac block solves this issue. If it was a steady leak I'd say no, but if it bounces around, its very likely.

b18vtec

Tried giving it a vac source of its own and still the same thing. I even unplugged it from vacuum and the car still does the same thing. I tried a different boost controller to see if it was causing my wastegate to flutter, but still the same. After talking with Tial and reading about compressor surge, I think that is what I'm experiencing.

Andr3w

i got the same problem so any help would be awsome!

b18vtec

ok I have been searching and going through every single post I could about compressor surge, but almost all of them are talking about the sound the bov makes when they let off the throttle. Mine sounds like the bov opening but I'm still in WOT. I'm guessing this is true compressor surge when it does this. My question is what exactly causes this? The turbo is out of it's efficiency range, but is it because it flows more then the motor can handle or can't flow enough?

To maybe help my setup is a vitara built d16z6 with a stock head and intake manifold. Mini ram exhaust manifold, Garrett t3/t4 60 trim, .63 exhaust, 3 inch dp, Tial 38mm wastegate-15 psi spring, 50mm Tial BOV, 2.5 inch intercooler piping, ebay 29x12x3 intercooler, precision 1000cc injectors.

TiAL

check this link out
http://www.turbobygarrett.com/turbob...o_tech103.html

b18vtec

There are tons of people running turbos larger then mine on d16z6's without surge. One thing I have noticed is it doesn't do it in 2nd gear, but there is less load because it just spins and rpm's climb a lot faster.

kyden

a larger turbo than yours won't surge at the same level, cause its in a different area in the compressor map.