BOV Placement...Who's Right?
02-23-2012, 03:54 PM
#21
You'd better go spread the word to everyone that put their bypass\BOV after the intercooler that they're doing it wrong and that they are going to have screaming hot air going into their engines! Oh the horror!
PLEASE post your data. You keep saying that the IATs "scream" upward but you don't put up any numbers. There is no way in hell the IATs "scream" up when the bypass/BOV opens up. That is absolutely impossible.
NO, the supercharger stores quite a bit of heat in the case and guts: friction from the gears, from pressurizing air that heats up the case, also from a hot engine bay. When you put your hand in front of an idling supercharger and feel heat, it is not from pressurizing air directly, it is from the heat retained by the supercharger's case and guts transferring to the air, hot air being sucked into the intake, etc. A cold, idling supercharger sucking in cold air isn't going to have scorching air coming out the other end, dumbass.
In any case, if you are running a valve after the intercooler then you have absolutely nothing to worry about, in just the same way running the valve before the intercooler is nothing to worry about. The intercooler's job is to reduce the temperature of the charge air and increase its density, so handling a little warm bypass air is like nothing.
There is a reason you don't see everyone scrambling to put their blowoff valve right after the turbo instead of after the intercooler: It doesn't make a damn bit of difference! THAT is the point.
Relying on the laws of physics is generally a safe bet. Relying on some contrived ideology is generally not.
Actually I initially mentioned the intake air temp sensor as an easy way to monitor it by watching the IAT readings go screaming upwards even when the BOV is open is pretty simple data, but I mentioned feeling it with your own hand is pretty easy too and something anybody can do if they don't have a scan tool.
So now it's making heat even though it's not building boost? make up your mind. Oh BTW a compressor wheel is not like a fan blade, worst comparison ever.
Actually the intake air temp sensor after the intercooler (yes with the BOV open and the engine revving) greatly disagrees with you. I'll give an example, sitting there revving the motor at the starting line staging the car will show a big increase in IAT readings right before you even leave with the BOV wide open.
Something like this is so stupid simple that anybody can test and see the results yet you keep arguing like you are correct. The facts remain, revving a blower up without "building boost" still produces quite a bit of heat that will drive up IATs even through a good intercooler with no airflow going through the front of it.
I am done arguing with you over the internet, anybody can feel it for themselves or use a scan tool it's very easy.
So now it's making heat even though it's not building boost? make up your mind. Oh BTW a compressor wheel is not like a fan blade, worst comparison ever.
Actually the intake air temp sensor after the intercooler (yes with the BOV open and the engine revving) greatly disagrees with you. I'll give an example, sitting there revving the motor at the starting line staging the car will show a big increase in IAT readings right before you even leave with the BOV wide open.
Something like this is so stupid simple that anybody can test and see the results yet you keep arguing like you are correct. The facts remain, revving a blower up without "building boost" still produces quite a bit of heat that will drive up IATs even through a good intercooler with no airflow going through the front of it.
I am done arguing with you over the internet, anybody can feel it for themselves or use a scan tool it's very easy.
PLEASE post your data. You keep saying that the IATs "scream" upward but you don't put up any numbers. There is no way in hell the IATs "scream" up when the bypass/BOV opens up. That is absolutely impossible.
So now it's making heat even though it's not building boost?
In any case, if you are running a valve after the intercooler then you have absolutely nothing to worry about, in just the same way running the valve before the intercooler is nothing to worry about. The intercooler's job is to reduce the temperature of the charge air and increase its density, so handling a little warm bypass air is like nothing.
There is a reason you don't see everyone scrambling to put their blowoff valve right after the turbo instead of after the intercooler: It doesn't make a damn bit of difference! THAT is the point.
I can see how if you didn't have any real experience and instead just relied on general physics laws you would think that.
Last edited by killernoodle; 02-23-2012 at 04:03 PM.
07-01-2012, 02:29 AM
#23
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with ambient temps around 85*-90*, I see about 100* average i.a.t. temps, thats driving @ 65mph running a 31x12x4 fmic, f1r procharger, bypass next to throttle body. I can def. see how blowers kick out heat even without boosting. I've done the hand test but does that prove anything? What would it do on a cold startup without having engine heat soak? Does anyone have any kind of data to put this to rest?
07-01-2012, 04:31 AM
#24
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I picture it this way... with no actual data.
If you can think about it this way. Two balloons one on each side of the cooler. One close to the throttle and one close to the turbo. (aka I don't care about blower cars)
You pop the one near the turbo, the higher pressure air from the other side flows towards the turbo, if you shift fast the air has to force that air into a U turn. At best its stalled. You pop the balloon next to the throttle the air is still flowing the same direction.
Manual trans turbo cars this matters the most. Other then that it probably isn't a measurable difference.
Just the way I see it in my head.
If you can think about it this way. Two balloons one on each side of the cooler. One close to the throttle and one close to the turbo. (aka I don't care about blower cars)
You pop the one near the turbo, the higher pressure air from the other side flows towards the turbo, if you shift fast the air has to force that air into a U turn. At best its stalled. You pop the balloon next to the throttle the air is still flowing the same direction.
Manual trans turbo cars this matters the most. Other then that it probably isn't a measurable difference.
Just the way I see it in my head.
07-01-2012, 08:54 PM
#25
Like I said before...
Blower cars, before the intercooler. Because it WILL heat soak it. A customers ysi car after starting cold and at an idle for 10min. (full op temp,200*) the pipes before the intercooler were from 115-120* and after the intercooler was around ambient,70-75*. With the car idling, u can feel the air coming out of the BOV is hotter than ****. If u don't think that will heat soak ur ****, ur ******* dumb.
As for the people saying "put it beside the turbo bc that's what it protects" thts the stupidest **** I've ever heard. Lol
Turbo cars, at the throttle body.
Blower cars, before the intercooler.
Blower cars, before the intercooler. Because it WILL heat soak it. A customers ysi car after starting cold and at an idle for 10min. (full op temp,200*) the pipes before the intercooler were from 115-120* and after the intercooler was around ambient,70-75*. With the car idling, u can feel the air coming out of the BOV is hotter than ****. If u don't think that will heat soak ur ****, ur ******* dumb.
As for the people saying "put it beside the turbo bc that's what it protects" thts the stupidest **** I've ever heard. Lol
Turbo cars, at the throttle body.
Blower cars, before the intercooler.
07-01-2012, 09:15 PM
#26
Turbo car - near the throttle
Blower - near the blower
On a turbo car you wont the escaping air to travel in the same direction as the boosted air, away from the turbo.
On a blower car you want to bypass ALL air away from the system unless you are WOT.
Blower - near the blower
On a turbo car you wont the escaping air to travel in the same direction as the boosted air, away from the turbo.
On a blower car you want to bypass ALL air away from the system unless you are WOT.
02-08-2013, 03:21 AM
#27
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