Hey everyone.

Just got the twin turbos installed on my car (GTM tuner stage 1 with GTM reflashed EMS and fuel Walbro 255 and 600cc) and almost everything is wonderful now! I love it and it's amazing to finally have boost after waiting so long. Only having one issue well 2 but they are related. The idle is a little rough, hunting at times. and on decel when I press on clutch to stop, it will stall out most of the time. Idle vac is right around 20in/hg which is what it has always been so I know no vac leaks. I found a way to make it happen without actually driving it to test things. Only thin that stopped it 100% is to diconnect the vacuum line to the BOV and plug it. Hooked the clipher up and MAF voltage is all over the place with the bov connected. It's nice and steady with it unhooked. Now I know I need a bov to prevent compressor surge. My question is how can I remedy this stalling and what not while still having a BOV that vents to atmosphere? (recirc would make things worse with counting that air twice...blow through setup) I appreciate all the help from all you FI gurus

 

What brand is the BOV? If tial 50mm, you may have the wrong spring in there. The springs are rated for vacuum while engine is warmed up at idle. Chart:

http://www.tialmedia.com/documents/w3_tial_bov50_sp.pdf

 

I have about 20 in/hg at idle so by the chart that would be the -11 psi spring. And it said on the box it has a 10 psi spring. But this was written on box. I'll check that when I get home.

 

Just checked and I do have the 10 (unpainted) spring in there.

 

problem solved! This is my first turbo car so I didn't know a few obvious things. Like the BOV should be closed at idle. I had the right spring in there, or at least I think (it is right by the tial chart) So I put some washers in there to increase the spring tension and now closed at idle and low load but still lets off all the boost pressure and runs like a champ and doesn't stall anymore!

 

crazy as most people put lighter springs in their BOVs.

at least its fixed

 

I was going to say tighten or shim the thing. Good work.
That is a little weird because those Tial BOV's are pretty stout to begin with.

 

Yea that's what I kept reading online. I almost bought a lighter one than really thought about it and realized I wanted to go the other way...lol

Once I got it apart I could tell how well built it was. I think even tho the spring was for the right vac maybe it was a weak spring maybe, Used 4 regular thickness washers and it's great. Just wish tial had included adjustment without having to take it apart.

 

Hate to revive my own old thread. But I have a similar issue again I was getting some bad compressor surge this summer so naturally. I loosened the soring tension by taking out the washers I added before. No more surge. And surprisingly no stalling either. Yay! But now back to winter come to find out the tune I had (came with turbo kit) had horribly wrong injector latency and such. Fixed that and now back to square one. Stalling with open bob and when I add the washers back its fine but now it surges any ideas?

 

Consider upgrading to a standalone so you can tune a with a map sensor and eliminate the MAF problems.

 

That is in the future most likely after a built engine.

I did solve this issue though. Being new to the turbo thing, I didn't realize the you had to follow the instructions to a "T" I had the Tial 50mm BOV on a 1/8" nipple and had my boost gauge teed off of that line. I just fixed that to be the Tial recommended exact 1/4" barb and 1/4" hose with no tees. That plus 3 washers and I have no stall and no surge Ran out of energy for tonight, going to try no washers tomorrow just for fun, but I doubt it will e any better. Also, I was just curious, with the MAF being after the bov, shouldn't it not matter if the valve is open or not? Is it a turbulance thing?

This is a pic of he setup



Is that too close to the maf?