recirculation?

[deejayS13]

yo you guys should school me on how this whole recirculation vs the blow off valve thing works...i think i got the basics, but learn me! learn me! i wanna know how recirculation works/goods/bads/how to do it.

[240Stilo]

When you have a blow off valve that vents into the atmosphere you're venting out air that the MAFS has read. Since you let some of that air escape, the ecu still shoots the fuel needed for that amount of air eventhough that bit of air escaped and there is now less air in the chamber that the MAFS doesn't know about.

With a recirculating blow off valve, you circulate the air back into the piping somewhere after the MAFS so that it isn't reading the same air twice.

I hope it's not confusing.

[Andrew Bohan]

recirc makes it quieter too. no pshhh or whoosh when shifting

[ca18guy]

A blow off valve or re circ. valve is in place to remedy compressor surge. The turbine on a turbocharger spins VERY fast, pushing compressed air in to the intake manifold when the eninge has an open throttle. When the throttle bodies close the turbo keeps compressing air but that air has no place to go, causing the turbine on the turbo to slow down abruptly causing damage over time. It also means that the turbo needs to get back up to speed when you get back onto the throttle, meaning an increase in lag between shifts. So to remedy compressor surge you need a re circ. valve or a blow off valve.

Blow off valve! What it does is it gets placed some place along the intake track between the turbo and intake manifold. When that compressed air comes rushing back to slow down the turbine, the blow off valve lets the air escape in to the atmosphere instead of going back and slowing the turbine. Sounds good but most likely your ECU allready was expecting that air and runs rich and stumbles, which is why alot of cars with blow offs have a hard time coming to a stop with out stalling.

Re circ valves! They are the same thing as a blow off valve, they go in the same location and do the same thing, they bleed air out of the intake between the intake manifold and the turbo. BUt instead of letting the air escape it holds onto it and saves it until you need it next. It saves it between the intercooler and turbo, so when you get back on the throttle you allready have pressurized air instead of having the turbo suck in more air and compressing it and sending it into the intake manifold. Also since the ECU allready accounted for the air the car won't stunmble because it was allready expecting the air. So with the re circ valve you get rid of compressor surge and get the added benifit of less lag between shifts and a car that doesn't stunmble when coming to a stop.

Where can you get a blow off valve? Spend $400 on one of this sites sponsors.
Where can you get a re circ. valve? Spend $0 if you have a SR/CA/RB cause they allready have it stock.

HHmmm I wonder which is a better value :rofl:

[Joel 180]

CA18DET doesnt have one stock.
The stock SR/RB items leak above 12psi. They have a small bleed hole in the main diaphram. If you take the BOV apart and plug this hole with a grub screw and epoxy, your factory BOV will happily hold over 20psi if you want it to.
The bleeder hole is there mainly to stop overboosting (safety feature)

[FRpilot]

isn't it rerouted between the turbo and intake filter? if its rerouted back between the turbo and intercooler, the air is still within the intake track..

[ca18guy]

Originally posted by FRpilot
isn't it rerouted between the turbo and intake filter? if its rerouted back between the turbo and intercooler, the air is still within the intake track..

Thats the point, to keep the compressed air ready for use, if its outside the turbine it needs to be compressed again. It just keeps re cirulating the air on the pressurized size. Of course in the small chance I'm wrong I'm sure some one will correct me ;)


Originally posted by Joel 180
CA18DET doesnt have one stock.

Yeah you're right, my bad :P

[240Stilo]

Originally posted by FRpilot
isn't it rerouted between the turbo and intake filter? if its rerouted back between the turbo and intercooler, the air is still within the intake track..

Yeah I know what you mean, but I think the line that routes the air back into the intake acts as a resivour. The same air is in the intake track, but now there is more space to hold the air due to that line. I think. Man someone who has read Maximum Boost could help out, but I'm sure we got it down close enough.

[240_keyy]

Originally posted by ca18guy
Blow off valve! What it does is it gets placed some place along the intake track between the turbo and intake manifold. When that compressed air comes rushing back to slow down the turbine, the blow off valve lets the air escape in to the atmosphere instead of going back and slowing the turbine. Sounds good but most likely your ECU allready was expecting that air and runs rich and stumbles, which is why alot of cars with blow offs have a hard time coming to a stop with out stalling.


you people should really stop perpetuating this myth. This is not true for most SR's if you have your BOV adjusted correctly. If your car is stalling when you come to a stop it is because your BOV is leaking at at idle, so you will run rich and stumble and sometimes die. The car will idle up at a point and eventually your BOV will stop leaking and then the car won't die again. However, if you have your BOV adjusted correctly, it will not leak and you will not have this problem. Trust me on this one, I have experienced this first hand. I fooled around with it the other day just to make sure that I am right, and it turns out that I am. I loosened the screw on my Greddy BOV by half turn incriments and after only 1.5 turns, I got this stumbling problem. You can also watch your vaccuum pressure change as you do the adjustments and very slight adjustments will change the pressure in your intake tract by (in my case) up to 6mm/hg (or whatever the proper measure is for vaccuum, I can't remember) If your car is stumbling as you come off boost and stop, tighten your BOV until it stops and once you get it dialed in, you will both not surge and not stumble, which are good things :)

Cliffs Notes: People are idiots and they need to research problems before they make statements based on secondhand knowledge. Don't just regurgitate everything you hear, try to figure it out for yourself...

:boink:

[deejayS13]

you guys are my heroes...thanks...now im smarter! hahaha!

1 month, 5 days till sr20det...seems like the closer i get, the longer the days get.

[ca18guy]

Originally posted by 240_keyy

Cliffs Notes: People are idiots and they need to research problems before they make statements based on secondhand knowledge. Don't just regurgitate everything you hear, try to figure it out for yourself...

:boink:

:ugh: Its a fairly common problem with alot of different cars, I'm sorry I didn't get every single detail down when I wrote that off the top of my head :rolleyes: :smash:

[bl200sx]

Originally posted by 240_keyy
you people should really stop perpetuating this myth. This is not true for most SR's if you have your BOV adjusted correctly. If your car is stalling when you come to a stop it is because your BOV is leaking at at idle, so you will run rich and stumble and sometimes die. The car will idle up at a point and eventually your BOV will stop leaking and then the car won't die again. However, if you have your BOV adjusted correctly, it will not leak and you will not have this problem. Trust me on this one, I have experienced this first hand. I fooled around with it the other day just to make sure that I am right, and it turns out that I am. I loosened the screw on my Greddy BOV by half turn incriments and after only 1.5 turns, I got this stumbling problem. You can also watch your vaccuum pressure change as you do the adjustments and very slight adjustments will change the pressure in your intake tract by (in my case) up to 6mm/hg (or whatever the proper measure is for vaccuum, I can't remember) If your car is stumbling as you come off boost and stop, tighten your BOV until it stops and once you get it dialed in, you will both not surge and not stumble, which are good things :)

Cliffs Notes: People are idiots and they need to research problems before they make statements based on secondhand knowledge. Don't just regurgitate everything you hear, try to figure it out for yourself...


:bs: :boink:

Man that is BS pal, you can get by running a open BOV on a stock SR, just turn your idle up to 975rpm, it will work, but it is not the best thing for preformance, you are running rich when venting out air into the atmisphere. Put a Big28 on your SR and see how bad it runs with a open BOV, been there done that, my SR runs much better with a recirulating BOV, its night and day better. Hey just call Jim Wolff Tech, they can school ya on open BOV, I could care less how good my BOV sounds, when I hit the gas my SR preforums, thats all I care about.

[240Stilo]

I thought turning the screw on top of the blow off valve caused the spring to be under more tension which then makes it harder for air to escape. Wouldn't this make it more likely to get compressor surge? Since there has to be more air pressure in the intake for the blow off valve to do it's job.

[kazuo]

You can tighten/loosen the BOV all you want, its still gonna run rich and stall... I know this because I just spent like three hours trying to "fix" the problem... no matter how much I tightened or loosened the valve it just kept doing the same stupid-ass stalling ****.

Time to recirculate!