showtymers619

what do you guys suggest.... release the air b4 the air to water intercooler = hot air .. or should i release the cold air = closer to the TB?

any rule of thumb?

RenoRacing

Hey man, i was just going to comment and then i noticed it was you. I planned on putting the blow off valve before the intercooler but I'm not sure that there will be a benefit either way. It's been discussed before regarding the full-race backdoor intercoolers that have the bov mounted to the inlet side of the intercooler. Either way should function fine, kinda depends on where you have room to place it and aim it so it can/or cant be heard.

showtymers619

k LOL..

SiR Kid

In my mind, it makes sense that the BOV should ALWAYS be between the IC and the TB. IC's have internal resistances, and that is why there is pressure drop after boost flows through it... Why not relieve the boost that needs to e released, at the TB.

Just makes sense in my mind, maybe I'm way off here.

TrueNorthStar

I would put it before the IC...

Let all the HOT air out before it heat soaks your IC system.

kpt4321

You want it after the intercooler. The air in the system is moving VERY quickly, several hundred feet per second. If you put it before the intercooler, then all the air bast the BOV has to go all the way to the throttle body, slam into it, and then bounce backwards towards the turbo. If you put it after the IC, the air can keep going the direction it wants to be going.

Heat soak is not an issue. One second's worth of hot air isn't going to contain nearly as much heat energy as the air that goes through the core in any gear. Don't worry about that.

The best setup has a second BOV near the turbo outlet.

Bontke

Look at factory cars, the location of the pop off valve is by the turbo. The pop off valve keeps the turbo spooled and prevents stall of the turbine from having air rammed against it when the throttle body is closed. I'd put it on the hot side. Anyone have any technical data to support their claims, I don't...I am just going on theroy.

integraracing91

Why not put one on both sides

TrueNorthStar

With my setup I have no choice... it has to go before the intercooler.

EMod Civic

Factory setups put the BOV near the turbo because they have to pipe it back into the intake for emissions compliance. To me, it makes mores since to place it as near to the TB as practical, so you keep the air moving in the same direction.

-Chris

Sunrise City Rider

It doesn't matter where you put it as long as its after the compressor outlet...the valve is used to prevent compressor surge nothing else...

showtymers619

well i kno about the compressor surge thing.. but..i was trying to figure out the most efficient...if i let it out b4 the intercooler... it owul dbe hot air.. but it there was a rule of thumb somewhere saying.. close to the TB is how it should be... but i guess that is for air to air set up.. bah.. ill just let the hot air out instead of the cooled.. thanks anyways every1.. just wanted some opinions.. reno had the same idea as i was thinking

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bontke &raquo;</TD></TR><TR><TD CLASS="quote">Look at factory cars, the location of the pop off valve is by the turbo. The pop off valve keeps the turbo spooled and prevents stall of the turbine from having air rammed against it when the throttle body is closed. I'd put it on the hot side. Anyone have any technical data to support their claims, I don't...I am just going on theroy.</TD></TR></TABLE>

No it's not.

DSM's have them after the intercooler. Evos have them after the intercooler. Supras have them after the intercooler. STi's have them after the intercooler. Should I go on?

OEM's put them after the intercooler, you should too.

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ShowTymers619 &raquo;</TD></TR><TR><TD CLASS="quote">well i kno about the compressor surge thing.. but..i was trying to figure out the most efficient...if i let it out b4 the intercooler... it owul dbe hot air.. but it there was a rule of thumb somewhere saying.. close to the TB is how it should be... but i guess that is for air to air set up.. bah.. ill just let the hot air out instead of the cooled.. thanks anyways every1.. </TD></TR></TABLE>

It has nothing to do with whether the set is air to air or air to water, the BOV doesn't care.

b16ahybrid

I've always heard that it's best to have it as close to the T/B as possible. At least within 12'' or so. Makes sense since your relieving the pressure when the throttle slams shut, to keep it from going back to the turbo.

showtymers619

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">

It has nothing to do with whether the set is air to air or air to water, the BOV doesn't care.

</TD></TR></TABLE>

i know that already... the point i was trying to see is should i relive the hot air out.. or the cooled air....but ive already decided... i rather lose hot air then cool air LOL also im asked this because it will show me where to put my intercooler... closer to the TB or futher away... i guess ill just do what i feel LOL hot air it is..!!!!

Bontke

Ahh, touche kpt4321. But what about the RX-7? I think mostly it is done near the throttle body because the intake is closer for the vaccum line. On the RX-7 the intake and turbo happen to be on the same side of the engine. Shorter vaccum lines = quicker reaction time of BOV...right?

TrueNorthStar

You could always put it before the IC and less than 12" from the TB at the same time I am

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ShowTymers619 &raquo;</TD></TR><TR><TD CLASS="quote">
i know that already... the point i was trying to see is should i relive the hot air out.. or the cooled air....but ive already decided... i rather lose hot air then cool air LOL also im asked this because it will show me where to put my intercooler... closer to the TB or futher away... i guess ill just do what i feel LOL hot air it is..!!!!</TD></TR></TABLE>

What was the point of asking the question, if you were going to do whatever you wanted and not what was right anyway?

showtymers619

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">

What was the point of asking the question, if you were going to do whatever you wanted and not what was right anyway?
</TD></TR></TABLE>

ay if you were to think about it and stop trying to follow as you say " stock cars with BOV rules"

air to water set up are alot different.. there is heat to think about... after i asked this question i started too look at some aftermarket supercharger "vortech" specificly...and since its ALMOST exactly what im doing.. there BOV set up is NOT after the intercooler...which means they dont want to perge the coooled air already...thats the efficiently that i was talking about..and i just wanted to kno everyones ideas and opinion..is that wrong of me....

Bontke

Yah, I agree. Why not purge hot air and let the intercooler work a bit less and stay a bit cooler.

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bontke &raquo;</TD></TR><TR><TD CLASS="quote">Yah, I agree. Why not purge hot air and let the intercooler work a bit less and stay a bit cooler.</TD></TR></TABLE>

I already explained why in this thread, I'm not going to explain it again.

The amount of air we are talking about is so much less than the amount that flows through the intercooler even in one gear, it's not an issue.

Bontke

Support your theroy kpt4321. Pressure won't slam into the throttle body and bounce back, your cutting it off and it builds. Pressure is filling a volume (intercooler, piping), so if you relieve the pressure it removes the pressure of air working against the compressor blades. Thus keeping the turbo spooled. And if the air did have velocity wouldn't relieving it closer to the pressure source (turbo compressor) be better than further down the piping? Venting the pressure that is running against the compressor blades at the source would be more effective due to a shorter distance for the pressure to travel to escape. I have in no solid evidence to support this, it just seems logical.

kpt4321

Pressure does slam into the throttle plate an bounce back. The pressure that causes compressor surge is waves, not one constant push.

The air in the intake piping is moving at several hundred feet per second. Let's say you're a little running air molecule, and I want to open a door for you to run through. You're also running at 300 feet per second, which FYI, is really freaking fast. Would you rather I opened a door in front of you or behind you? Yes, that's right, in front of you.

The pressure doesn't come back to the compressor until it hits the closed throttle plate and is forced backwards. If you let it all blow out the open BOV, what happens is essentially it never sees the open throttle, it just sees a constant lack of restriction.

Bontke

That makes sense. How would it affect performance to have the pressure relieved at the turbo outlet? The waves have to travel back to the compressor to hit the wheel and the BOV releases the pressure at the throttle body in a linear flow. But what about a situation where the BOV is at the compressor outlet? The air hits the closed throttle body and at the same time the BOV is opening releasing the pressure at the compressor. If there is molecule collision at the throttle body it is quickly disbursed by the BOV opening and you again have a linear flow from the compressor through the BOV in a shorter path. The air ahead the throttle body then becomes "stagnant" or isn't moving from the BOV being at the compressor. Is this bad? The air in the intercooler has more of a chance to dispose of heat, but wouldn't the air just pick up speed after the BOV is closed? It seems that the engines short cycle from vacuum (pull the air) to boost (push the air) would move the pressure waves foreward again. Where is the performance loss in all of this? Is the pressure that is "stagnant" in the intercooler/piping a bad thing, could it lead to decrease in performance? And if it is bad, Why?