recirc. BOV, hot or cold side?
#1
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recirc. BOV, hot or cold side?
I'm sure it's been discussed here as it has on every DSM/SRT forum, however, I thought I'd bring it up.
I'm currently plotting my over the top intercooler set up for my 1.6 - hoarding parts, convincing family members that Dad really needs that tig welder for his birthday , etc.
The one detail I've been back and forth on is where to mount my recirc. BOV (I like silence). It seems miata tradition is to mount it to the cool side near the TB which seems to make some sense - TB closes, pipes pressurize, air is evacuated at the point of pressure concentration. There's nothing really preventing me from running this set up except I'd prefer to not route 2-3' of 1" tubing back to the intake. Then I started questioning whether it really needed to be near the TB at all. It seems that the delay (if any) in pressure onset near the TB vs. the hot side piping would be pretty negligible and releasing the pressure anywhere in the piping would still prevent the compressor wheel from 'stalling'. By running it on the hot side it would allow me run a much shorter return line there by avoiding the cluster **** caused by a relocated radiator with stock fans.
I've noticed in a few forum searches that there's a couple members who have gone this route - perhaps they can chime in.
-Zach
I'm currently plotting my over the top intercooler set up for my 1.6 - hoarding parts, convincing family members that Dad really needs that tig welder for his birthday , etc.
The one detail I've been back and forth on is where to mount my recirc. BOV (I like silence). It seems miata tradition is to mount it to the cool side near the TB which seems to make some sense - TB closes, pipes pressurize, air is evacuated at the point of pressure concentration. There's nothing really preventing me from running this set up except I'd prefer to not route 2-3' of 1" tubing back to the intake. Then I started questioning whether it really needed to be near the TB at all. It seems that the delay (if any) in pressure onset near the TB vs. the hot side piping would be pretty negligible and releasing the pressure anywhere in the piping would still prevent the compressor wheel from 'stalling'. By running it on the hot side it would allow me run a much shorter return line there by avoiding the cluster **** caused by a relocated radiator with stock fans.
I've noticed in a few forum searches that there's a couple members who have gone this route - perhaps they can chime in.
-Zach
#3
The closer to the tb it is the less the flow of air is reversed. Lets say you put it on the hot side then after you close the tb then all air has to slam to halt and gets swirled around, and when you get back on the throttle the air has to straighten out and start moving forward again. However if you put the bov near the tb then all air continues to move forward and when you get on the throttle the air is already moving in the correct direction.
#4
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The closer to the tb it is the less the flow of air is reversed. Lets say you put it on the hot side then after you close the tb then all air has to slam to halt and gets swirled around, and when you get back on the throttle the air has to straighten out and start moving forward again. However if you put the bov near the tb then all air continues to move forward and when you get on the throttle the air is already moving in the correct direction.
Perhaps I'll just slap a filter on the BOV and call it a day.
-zach
#5
Also you don't need a filter on a BOV since the air only goes out. Well expect if you use some stock recirculating valves (BOV's).
Last edited by ZNuT; 04-17-2010 at 05:14 PM.
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If you are still running the stock ecu or any MAF setup then you car will go rich when you shift and will most likely bog. If running MAP setup then no worries.
Also you don't need a filter on a BOV since the air only goes out. Well expect if you use some stock recirculating valves (BOV's).
Also you don't need a filter on a BOV since the air only goes out. Well expect if you use some stock recirculating valves (BOV's).
As for the filter, I realize there's positive pressure so the engine should ingest anything, however, there's nothing stopping dirt ingress at rest (I live in a dust bowel) and sliding seals + particulates = fail.
-Zach
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The closer to the tb it is the less the flow of air is reversed. Lets say you put it on the hot side then after you close the tb then all air has to slam to halt and gets swirled around, and when you get back on the throttle the air has to straighten out and start moving forward again. However if you put the bov near the tb then all air continues to move forward and when you get on the throttle the air is already moving in the correct direction.
This was recently discussed in another thread and it makes no difference really.
#9
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...and the logic for putting it on the hot-side closer to the turbo is to let the turbo more quickly dump pressure while it holds more turbine speed. Is there more to gain by maintaining the inertia of the air or more to gain from letting the turbo freewheel? I'm certain that you won't tell a difference either way and it doesn't matter.
This was recently discussed in another thread and it makes no difference really.
This was recently discussed in another thread and it makes no difference really.
+1 It really does not matter anyway. Whatever is easier to install.
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