eviltwin_1987

iTrader: (18)

same here

bboyferal

iTrader: (9)

lol, same for all of us... lol


Here are the instructions FROM TurboXS THEMSELVES for the OP's BOV:

http://www.turboxs.com/uploaded_images/525.pdf

Hmmm... Why would they say to check if the engine's idle is not smooth, and if so that the spring needs to be tightened with extra washers? Why would it need to be tighter?

Unless... AIR IS BEING SUCKED IN! lol


OP, unless you have that Bimmer's twin set-up with a small displacement motor, just follow the instructions for your own BOV...

It should be closed at idle. lol

1. Any air in the intake charge will be filtered.

2. Filtered air will not be "exiting" anything at idle or cruising or whatnot. It can go to your TB.

TiAL

the exact same thing that would happen when you take your foot off the gas and let the BOV do it's job...

if your TB is closed and your air metering system is post bov it really doesn't matter where it goes

TiAL

incorrect, idle would be not smooth if the bov was open at idle and the MAF was before the bov, the air exiting the bov was meterd as air going into the engine which it obviously wouldn't be anymore causing a rich condition and jumpy idle

tightening the bov spring would close the bov at idle and let all metered air into the engine smoothing the idle out.

that is why they say IF you are having issues...MAF post bov wouldn't make the idle rough with the bov open at idle...unless the tune was way off

bboyferal

iTrader: (9)

Not incorrect really, just written incorrectly. You're right, in a condition where the MAF is before the open/semi-open BOV ... AND ... the intake charge at idle is being pulled from the motor the car's idle will miss, yes...

However, if the MAF is not before the BOV, an open BOV will not confuse the idle.

BUT... You didn't mention that in a condition where the intake charge is pulled, even without a jumping idle the motor will STILL draw in unfiltered air through the open BOV... That, to me, is ALSO undesirable.



That is why the Bimmer video guy mentioned the need of filtering the BOV uniquely lacking in that particular car, he definitely didn't mean all cars, did he?

His own quote speaks for itself.

Of course, by "efficient turbo" he means small turbo. lol


Again, you're not understanding the context... I'm not saying a BOV can never be open... Clearly that's not the case with that Bimmer's small turbos, small motor, and small TB.

I'm saying that's not the case here.

Or, are you telling me that the OP that posted this thread should leave his BOV open DESPITE his intake charge at idle DEFINITELY NOT being pushed in by his T-70? If so, I would say that advice is unsound. He would be drawing in unfiltered air into his motor in the best case (MAF not before BOV) or his idle would miss in the worst case (MAF before the BOV).

In both cases, the OP's particular car, unlike the not-too-typical Bimmer's turbocharged conditions you posted, would be drawing in unfiltered air ANYWAY.


What do you think the OP would feel at idle with his T-70'd LS1 if he put his finger by an open little hole in his intake tract? You really think he'd feel air exiting?

That's why for him, and for most of us, the BOV "should" be closed at idle.

Shearer

To answer the OP. If your spring selection is correct, yes it's normal.

Or you can believe the LS1tech experts.

TiAL

turbos get much more efficient as they get larger...you keep tolerances the same as the small turbos but increase the size of the unit...efficiency goes up

yes i'm saying air blows out, the TB is closed, he'd feel air blowing out, small has nothing to do with it what so ever...a large turbo (T70 etc) is going to move a much larger volume of air idling at a lower speed that a smaller turbo spining (bmw turbos) at higher speed...

bboyferal

iTrader: (9)

Actually, a smaller exhaust housing A/R such as those found on a small turbo will move more air at idle (because it moves the turbo more) than a large A/R, large turbo I think... For example... Let's say we have an LS1 with a T-70 and a 0.96 exhaust A/R and an LS1 with a smaller 60-1 turbo and a 0.68 exhaust A/R. The second turbo will be pushed more at idle... But anyway...



Since you're so inclined to explain things today, I'm sure you don't mind some more instruction... I get to learn new things today.

1. Why did the Bimmer video dude mention the need of filtering the open BOV in some cases?

2. Why do some LS1 owners feel air being drawn in instead of out? Take myself for instance... When I was tightening my BOV, until it was finally shut at idle, the BOV was not expelling any air at all... It had a slight suction to it. Why? I have basically the same turbo kit as the OP by the way... A PTS kit (aka the new ebay kit).

vogun16

iTrader: (7)

wow guys didnt mean to start an all out war with this question haha, but my car is idling fine, and i tried putting in washers to tighten up the spring and it didnt help, so im guessing it must be ok?

TiAL

the T70 will be moving more air (and more free flowing), the 60-1 will be building backpressure and make it harder for the car to breath (restricted A/R). plus the engine is big enough where it can move both turbos freely with little resistance. and remember the bov is in a pressure only (minimal vacuum area - this is key)

if it were a 88mm on a 2.0 then it would be a different story.

don't listen to a word the guy says in the vid, you'd take more away by watching it on mute.

i'm not even going to get into ebay kits

mike13

iTrader: (27)

Another issue I have is the bov companies tell you to add washers, adding washers increases preload but doesn't change spring rate.

mike13

iTrader: (27)

If it's making it to the TB when the blade is closed that's what stalls the turbos impeller, the whole point of the bov is to not stall the turbo. If the turbo is pushing air and it's not being bled off when the TB is closed it's going to stall the impeller even at idle.

OUTLAWZ RACING

iTrader: (9)

Well my mega sonic is closed at Idle and loud as hell Im happy.

bboyferal

iTrader: (9)

Well, the fact is many BOV's do draw in air... Some even attach filters to them.

Coincidentally, I was at my buddy's 240/Silvia shop today and saw this:



And NO it's not running a huge 88mm turbo either.

It happens... Many intake tracts draw in air from the BOV...

mike13

iTrader: (27)

It's common to have a filter or reroute the air into the intake tract. More people should do it.

TiAL

it's to quiet the bov down...

bboyferal

iTrader: (9)

I agree... Exactly... Sometimes, air is re-routed to the intact tract... Like on my friend's customer's 240.

But, that's kind of NOT possible if it's blowing the air out is it?

That's my point I've already said... Sometimes, it DOES not blow the air out at idle.

bboyferal

iTrader: (9)

It can perform that purpose too, yes.