Stop BOV flutter & hold high boost?

[Artago]

Hi all,

I have a Forge 1G BOV recirc with yellow spring (15-23psi spring) and 2 shims installed.

At around 5-10 psi when letting off the throttle it flutters likes crazy.

I've read other threads and most say that it's to tight and that I should loosen it up. Either by installing a weaker spring or removing shims or both. Although this should get rid of the flutter it will also cause the BOV to leak at higher boost.

My question:

Is there a way to stop BOV flutter at part throttle while still holding high boost around 20-22psi?

Thanks all,
Tom

 

[Lofty]

http://www.dsmtuners.com/forums/bolt-tech/262536-forge-bov-flutter-2.html


Have a look at this thread!



I don't have much experience with these blow off valves, but it seems that forge will sell you a different spring!

 

[Artago]

http://www.dsmtuners.com/forums/bolt-tech/262536-forge-bov-flutter-2.html

Have a look at this thread!

I don't have much experience with these blow off valves, but it seems that forge will sell you a different spring!

Hey Scott, thanks for the quick reply. I've actually read that thread already along with most of the other BOV flutter threads on DSMtuners.

Some more info:

I have the new style ring at the bottom of the BOV, the one that doesn't have holes/leaks.

I'd double check to make sure the ring is tight enough but I cranked that puppy down pretty tight when I installed it.

I'll try adding grease to the piston, I didn't put enough on it the first time around.

I'll also remove the 2 shims and run just the yellow spring alone. I have the 3 springs that came with it. Green, Yellow and Blue.

Last thing I want to try is a bigger diameter VAC line to the BOV, maybe that will help.

Any other thoughts?

Cheers,

Tom

 

[JusMX141]

Forge doesn't have a quick-release feature. You should be choosing the spring based on the amount of vacuum you draw, not boost level you plan on running.

Any time you're on boost, the upper chamber is pressurized with the same amount as the piping...so you want to tune the valve based on your vacuum level to adjust how quickly it opens and how long it stays open.

 

[turboglenn]

I have to agree with justin, the adjustments or spring pressures chosen should be set according to vacum. I set mine to barely be closed at idle, and again like justin said when your on boost there's pressure on the BOV from the same line that opens it and that helps it stay closed against' boost. the only time it should leak is if it's bad or on some they have a second line on the bottom for the "quick release" like justin mentioned, I have had those constantly cause leaks on BOV's i install, so if you have one and are using it i would recomend disconnecting it and running just the top line.

 

[Artago]

I see, that makes sense. I get about 18-20 HG vac at idle when warmed up. I'll try removing the shims and see if that helps.

Thanks Justin / Glenn / Scott

Cheers,

Tom

 

[Artago]

Quick update:

I disassembled the BOV and reapplied some grease. Lots of it.

I also removed the 2 shims and am running just the Yellow spring on it's own.

This did not eliminate the flutter but did make it less frequent and less violent.

I also did a WOT test up to 6500 RPM and the car bucked a couple up times around 5000 RPM.

I'll be doing some BLTs to make sure I don't have leaks.

I'll also try the Green spring (weakest one) to see if that eliminates the flutter.

I'll keep you posted,

Tom

 

[Kevin Jewer]

The only time it should leak is if it's bad or on some they have a second line on the bottom for the "quick release" like justin mentioned, I have had those constantly cause leaks on BOV's i install, so if you have one and are using it i would recomend disconnecting it and running just the top line.

The best way to handle the quick release port IMO is with the Gus Mod or similar. Leave it connected to the IC pipe at anything low boost low throttle, and have it redirected to atmosphere under boost/throttle with a three port valve, activated by a throttle switch, pressure switch, or ECU control. I prefer the latter. ECMlink's nitrous controls work well for this. I modify all of my 1G BOVs to work like this (along with a moderate crush), even if I skip the automatic operation and just pull & plug that quick release vac line at the track and connect it on the street. They hold to really high boost like this, I've never had one leak in a boost leak test. Ran it on my EVO too.

 

[Artago]

The best way to handle the quick release port IMO is with the Gus Mod or similar. Leave it connected to the IC pipe at anything low boost low throttle, and have it redirected to atmosphere under boost/throttle with a three port valve, activated by a throttle switch, pressure switch, or ECU control. I prefer the latter. ECMlink's nitrous controls work well for this. I modify all of my 1G BOVs to work like this (along with a moderate crush), even if I skip the automatic operation and just pull & plug that quick release vac line at the track and connect it on the street. They hold to really high boost like this, I've never had one leak in a boost leak test. Ran it on my EVO too.

This is EXACTLY what I've decided to do.

How do you hook it up to DSMlink? Is it auto activated at some TPS value say 100%? Or can you activate it with other parameters such as boost pressure at 15PSI?

Can you do it with DSMlink v2.5 or do you need v3?

Thanks,

Tom

 

[Kevin Jewer]

You can choose whatever parameters make sense to you or whatever fixes the fluttering. You could start with >75% throttle and >15 psi and adjust from there. V2 must work for this, since that's what I had on the EVO.

 

[Artago]

Cool. What's a happy median for a street care? 75% TP and 15 PSI?

 

[Kevin Jewer]

I can't really rememeber the numbers I used, I last did it on the EVO and that was probably 4-5 years ago. I'd start there, and adjust it as needed. You may find that it works just fine like that. The point to remember is that a good 1g BOV won't leak appreciably until over about 20 psi, and at part throttle you're not terribly concerned with maximum performance even if boost does go that high (otherwise you'd be at full throttle , so you only need it locked at high throttle and high boost. I think the 75% TPS will work fine as is, if anything needs to be adjusted you'll be raising the boost limit if it still flutters at a ~15 psi release.

 

[Artago]

Awesome. I'll probably start conservative and see how it goes.

 

[twdorris]

The best way to handle the quick release port IMO is with the Gus Mod or similar.

Agreed. That's how I do it too. Write up here.

usenitrouscontrolsfordejontoolbovmod [ECMTuning - wiki]

Thomas Dorris

 

[Artago]

The Gus page has this note regarding using check valves:

This will shorten it's life, however. You might get 3 months to a year out of it before the plastic ruptures.


What's this all about? Is this true that it will it destroy it in 3 month?

 

[Kevin Jewer]

I don't remember what that was all about, I don't use any check valves. Just a three port valve with the two switchable ports to UICP or Comp cover boost and to atmoshpere, with the common port on the BOV's modified fast release port.

 

[Artago]

Update: I've modded a 1G bov and running it in quick release mode. Next step, hook up solenoid.

The 1G also flutters but not where near as much and very rarely. Is that anything that can be done about this?

 

[Kevin Jewer]

I've never known a 1g BOV to flutter. Is it crushed? I always try to crush them to just the point before they start to flutter, but maybe someone went to far on that one.

Where are you taking the pressure source for the fast release port? What size line? Something in the UICP near the throttle body should give the quickest response.

 

[Artago]

I've never known a 1g BOV to flutter. Is it crushed? I always try to crush them to just the point before they start to flutter, but maybe someone went to far on that one.

Where are you taking the pressure source for the fast release port? What size line? Something in the UICP near the throttle body should give the quickest response.

I flutters slightly at part throttle release. Only done it once so far.

It is not crushed at all.

Source if the intake manifold BOV line. The line is fat, haven't measured it but it's big.

You mentioned UICP, I thought the source was supposed to be off the intake manifold which sees vac?

 

[Kevin Jewer]

Nope, vac on the fast release port will defeat the purpose. In stock trim that BOV took the fast release signal from the UICP as well since it was that hole in the bottom of the flange.

 

[Artago]

Nope, vac on the fast release port will defeat the purpose. In stock trim that BOV took the fast release signal from the UICP as well since it was that hole in the bottom of the flange.

Oh yeah, that's how I have it. I thought you meant the top port.

Just to clarify I have the top port sourced at the intake manifold.

Regarding the quick release port, I actually did the 2 port mod.

See here: http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/220909-1g-bov-101-mods.html

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I connected the 2 ports shown above together. So the BOV should be operating in "stock" mode.

One more carification. The 1G BOV showed signs of slight flutter even before it was modified. That's why I bought a Forge, I was hoping to get rid of that. It just made it worse.

Thoughts?

 

[Kevin Jewer]

That should work then.

My next questions is how much does it flutter now and does it really matter. If it's only a slight bit I don't think I would go crazy trying to sort it out. If you must, I think I would still try a nice fat hose to a UICP port near the TB in case that arrangement is too restrictive (unlikely, but possible). If you're still running the stock cams listed in your profile I'd expect you to have plenty of vac to pull open a stock BOV. Not sure what's going on there.