Welcome to the SR20 Community Forum - The Dash.
Register
SR20 forum logo

Thread: Atmos vs recirc dumping

+ Reply To Thread
Posts: 1-9 of 9
2009-05-04 21:14:47
#1
Atmos vs recirc dumping
I got into a convo with a friend regarding this with a car with a MAF. What is the harm in running a Atmosphere dump on a car with a MAF apart from it running pig rich everytime you shift?
2009-05-04 21:25:39
#2
I have stalling issues with my rb26 due to the loss of metered air. it is a royal pain in the ass at junctions and stop lights. but a remap will sort it out, on a sr20 you will only have 1 maf though so if you have stalling issues a hks eids will sort it out im too cash strapped to buy 2 of them though so im getting a remap
2009-05-04 21:30:44
#3
Also, many of the cars that 'run fine' with an open BOV have serious compressor surge.
2009-05-04 22:17:03
#4
i recently went from recirc to atmos and my car runs fine but i do notice some surge from time to time
2009-05-04 22:22:44
#5
Compressor surge is when the air pressure after the compressor is actually higher than what the compressor itself can physically maintain.
This condition causes the airflow in the compressor wheel to back up, build pressure, and sometimes stall.
In cases of extreme surge, the thrust bearings of the turbo can be destroyed, and will sometimes even lead to mechanical failure of the compressor wheel itself.

You can run atmospheric or recirculated , just dont push the turbo out of its limits.

I have been running atmospheric Blitzz BOV for over 5 yrs no problem, my car does not smoke , nor does it stall, RPMS do go down from a fast cruise to a stop but it stabilizes on its own .
I am also running a JWT 4 bar ecu, and JWT says only run recirculated,

A Blow Off Valve (BOV) is a valve that is mounted on the intake pipe after the turbo but before the throttle body. A BOV's purpose is to prevent compressor surge. When the throttle valve is closed, the vacuum generated in the intake manifold acts on the actuator to open the valve, venting boost pressure in order to keep the compressor out of surge.
Bypass valves are also referred to as compressor bypass valves, anti-surge valves, or recirculating valves. The bypass valve serves the same function as a BOV, but recirculates the vented air back to the compressor inlet, rather than to the atmosphere as with a BOV.
2009-05-06 17:10:32
#6
Saying atmosphericly vented BOVs cause compressor surge is retarded. Maybe cheap BOVs do, but most BOVs worth their weight are adjustable to compensate for your driving style.

A turbo is most likely to surge if you:
1) Drive it in the surge zone
2) Have a turbo that is unmatched to your engine
3) Crappy BOV or a BOV adjusted too tight

A proper BOV is supposed to be a mirror of your throttle plate, this allows maximum engine response and prevents surge.
2009-05-06 18:18:40
#7
Originally Posted by mafoose
Saying atmosphericly vented BOVs cause compressor surge is retarded.


Easy killer.

Originally Posted by mafoose
3) Crappy BOV or a BOV adjusted too tight


That's what I was talking about. I've seen plenty of cars that had them adjusted as tight as they would go to keep the valve from staying open at idle. It keeps them from having idle issues, but surges like a mofo as a result.
2009-05-06 18:37:26
#8
^^ that's how my S14 was set up when I first got it.
2009-05-07 05:57:08
#9
Originally Posted by swiss
Easy killer.
That's what I was talking about. I've seen plenty of cars that had them adjusted as tight as they would go to keep the valve from staying open at idle. It keeps them from having idle issues, but surges like a mofo as a result.


Most people who have them vented to atmosphere should be running them in blow-through where this doesn't matter.
+ Reply To Thread
  • [Type to search users.]
  • Quick Reply
    Thread Information
    There are currently ? users browsing this thread. (? members & ? guests)
    StubUserName

    Back to top