[Kwiktoy]

I just installed a Tial Q BOV with an 8 psi spring. It's opening and closing at idle, causing a rough idle and a CEL has now come on (and keeps coming back after I clear it). I think the ECU has also retarded timing 'cos the power is noticeably down.

Clearly the spring is too weak. Has anyone used shims to increase spring pressure rather than buy a stronger spring?

Also, I wonder about the longevity of these BOVs. The valve and seal are so open to the elements. I certainly would advise keeping this BOV in the engine bay.

 

[kylejohns]

Why in the hell would you shim it? Springs are cheap. If you shim it too much, it will not be able to open all the way.

 

[Kwiktoy]

It's not really a cost thing although 50 cents vs $30 is quite a difference. Those springs ain't cheap. Main reason I ask is because I know that several BOVs have a screw adjustment that effectively does the same thing. My Greddy Type R was an example. The Tial is a massive 50 mm and shimming it a bit should not interfere with it's ability blow off the required amount of air. Just asking if anyone has done it, that's all.

 

[SleeperWagon]

It's not really a cost thing although 50 cents vs $30 is quite a difference. Those springs ain't cheap. Main reason I ask is because I know that several BOVs have a screw adjustment that effectively does the same thing. My Greddy Type R was an example. The Tial is a massive 50 mm and shimming it a bit should not interfere with it's ability blow off the required amount of air. Just asking if anyone has done it, that's all.

I mean I don't see why you couldn't do it. Just get some washers that are the same diameter as the spring and add one at a time till it stays closed at idle. It's kind of a ghetto fix but it should work. I think your going to run into a problem though if you have to add to many washers to get the right point.

 

[SUPRASSS]

add an extra spring

 

[Scott Duncan]

or see if someone has an extra one that would sell you one for cheap.

i think i have an unpainted one 11psi that's just sitting in my garage. need to see what ur vacuum is at idle to see which is the correct spring too.

 

[Mega_Blue]

I never "shimmed" one but have ran different springs. I would say just buy the spring and be safe. Also be careful with the diaphragm as it damages easily. I personally will never run another Tial... ever

 

[zmw]

My tial is flawless, but I'm running an 11 spring not an 8, an 8 seems very very weak and according to the tial Q manual says that the -8psi spring should be used if you are pulling between -12 and -15 in/hg at idle...

so two things i'd say...

1. if you are only pulling between -12 and -15 at idle you probably have another issue
2. The reason you have a problem isn't just the weak spring but also because you are venting to atmosphere on a stock ECU car - you're venting off metered air

The reality of it here is the problem is caused by lack of research, and improper configuation/tuning for a BoV.... I'm not trying to be an ass but i'm sure it'll come across that way ;P

 

[Hukhuksupra]

If you have big cams you can pull between -12/-15 at idle.
I agree with zmw but i think you just ordered up the wrong one and didnt research enough.

 

[Dego Red]

I bought my Q with an 11psi spring, but had to make adjustments since Im running two BOV's. You can have my new 11psi spring for $20 shipped if you want it, just PM me.

 

[Kwiktoy]

Thanks everyone for your replies and offers. Actually I ordered the BOV from Sound Performance and asked what spring I should use. I was paranoid of compressor surge because my last turbo compressor sheared off and they said the 8 psi spring would work. Seems I went too weak. I have just ordered a 10 psi spring.
I also wonder about the longevity of these BOVs, the working mechanism and seal are just so exposed to the elements. Definitely would keep the location well within the engine bay.

 

[Dego Red]

As for keeping the valve in the bay - three guys in Portland I used to hang with all have theirs mounted in the passenger side bumper opening below the headlight/turn signal. I can see what you're saying, but they've had there for years with no adverse effects. Unless you're driving your car in winter with salt and gravel conditions, I wouldn't sweat it.

BTW OP, where in MI are you?

 

[KumiJr]

11 psi Spring here, on the passenger air duct, other than a duller finish, the BOV works great