compressor surge with td06-20g

[jpar196]

Hi guys, ive recently installed and tuned a 20g into my v7 sti, but ever since i went fmic and bigger turbo, both of my blow off valves are not opening?? Sounds cool but its surging quite bad, even at 5000rpm and 20psi its surging??? Any idea why its doing this and what might fix it?

Thanks in advance

[ADIKT]

Loosen the springs on the bovs.

[Timmah]

 ADIKT said:

Loosen the springs on the bovs.

And where did you mount the BoV on the piping?

[Swindog]

Why do you have two bovs on a 20g?

Anyway. What brand are they and location of them.

[Stoffa]

Are they plumbed in with their own vacuum feed off the manifold? Or t'd together or onto something else?

[jpar196]

I mean I tried two bov to see if it fixed it,

and its located at the hot side, just after the turbo outlet. a boost gauge is T'd off it, but I took it off so it has independent vacuum source to see if it fixes it, no difference

[jpar196]

oh and bovs are blitz dd, and hks ssqv

[ADIKT]

Change the position of it. Cold side. as close to the throttle body as possible.

not nescesery (cant spell)

maybe find a bigger valve and try that

[ADIKT]

and personelly id go with the hks ssqv

[jpar196]

the valves are not tight at all, you can quite easily push them in with your finger,

but I think its just not getting proper vacuum,,,, but boost gauge shows healthy vacuum, I dont know if its just an instant thing when throttle is closed?

[ADIKT]

Where are you getting the vacuum feed for the bov?

[Swindog]

Your boost gauge might show healthy becuase its actually plumbed to a healthy vacuum. Your BOVS might not be. You should in theory have two different vacuum connections for them. Post a pic up of how you have it plumbed up.

I had surge on my td06 and mostly fixed it with a tial 50mm bov and a 7psi spring.

[jpar196]

basically using the original BOV vacuum/boost source, and it has a boost gauge tee'd off it.

I removed the t for the gauge so its connected to the BOV only, but still surged.

[Stoffa]

Is thr turbo a cheap chinese one?

[ADIKT]

http://www.trademe.co.nz/motors/car-parts-accessories/performance/other/auction-466009459.htm

[Guest]

seems common in america for bovs to be on hot side close as to turbo but they are normally them tial bovs above. im sure steve goes into comp surge on here somewhere have you searched it?

plenty of info on here

http://www.clubsub.org.nz/forum/index.php/topic,26005.msg363029.html#msg363029

http://www.clubsub.org.nz/forum/index.php/topic,1643.msg16764.html#msg16764

[Pappu1]

as above - us a new line straight to the loccation of the stock bov port

failing that

try another bov perhaps u can borrow mine

not too much can go wrong with a bov especially at 20 psi

where u get it tuned bud?

[Swindog]

Like i said it was a weird issue that never really got resolved on mine either, even with Steves help. His agent in Invers was a complete numpty, sorry Steve, but he just ended up giving up and I could never get ahold of him again.

However, i think it came down to a blockage somewhere in the system so the BOV was the obvious starting point hence the Tial but that never worked. I cleaned and recleaned the front mount, i pullled the front end off numerous times to get it and cleaned the piping and checked and triple checked everything and still couldnt figure it out so had to live with it. I put it down to that turbo wasnt the right one for that application in the end. I had quality parts, an MSE td05/td06 turbo quality build, good tune..still no go.

Even played around with diameter of the vacuum hose...larger smaller, made no difference.

[funkytown]

Running a gtx turbo with anti aurfe housing and one hks ssqv bov. exactly the same car setup with a smaller gt turbo and no anti surge housing and it surges like a bitch

[Pappu1]

Don't think the Hks flow a whole lot of air for bigger turbos

Seen how small the opening is

Hmmm Gfb on the othe hand ;D

[sultan]

i put it down to the sheer volume of air that a subaru front mount setup introduces, with the monsterous length of piping. putting a bov every 2 feet will probably help.

my bov doesn't open until around 10psi, and unfortunately my turbo flows quite a bit still below 10psi (well not really unfortunate at all) so i get surge before then, but hammer and tongs it opens nicely. old school blitz bov

[WRXONP]

surge off throttle is simply bov is not flowing enough - try a better bovand dont tee anything into the line if you can as it will just give it less vac

[Pappu1]

 sultan said:

my bov doesn't open until around 10psi,

mine seems to open at almost any hint of boost even as low at 2.5krpm with a partiatial throttle...

[ADIKT]

 pappu']

[quote name='sultan said:

my bov doesn't open until around 10psi, /quote]

mine seems to open at almost any hint of boost even as low at 2.5krpm with a partiatial throttle...

what bov you using? my ssqv opened real early...

[Pappu1]

 ADIKT']

[quote name='sultan said:

my bov doesn't open until around 10psi, /quote]

mine seems to open at almost any hint of boost even as low at 2.5krpm with a partiatial throttle...

what bov you using? my ssqv opened real early...

yes ssq

but my GFB also opened nice and early and surprisingly didnt have much backfire at all