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Discussion Starter #1
I understand it is possible to plumb the bov (reversed ?)into the secondary air system
Anyone here tried/running this ?
Im guessing this is the way round stalling the turbo ??
 
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Discussion Starter #2
Pluto,
I believe that Howard_B (who recently left the MLR) had a similar setup to what you describe on his E6. I'll see if I can find out for you and get him to either post on here or send you an E-mail.

Andy
 
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Discussion Starter #3
Pluto,
I've spoken to Howard and I've also done a bit of research myself on the BOV / secondary air system. Here are the results:

Howard's car ran with the BOV (right way round) venting into the secondary air system. The problem with doing this is that the secondary air valve only opens after v. hard driving (flat out acceleration for 3 secs and engine still above 4,000 rpm) and so if the engine is not in this state when the BOV opens, the secondary air valve will remain closed and the excess boost pressure will go back down to the compressor, spin it in reverse which causes it to stall. This will also cause problems with a reverse flow of air through the airflow meter.

One possible solution to this is to link the BOV in with the secondary air valve so that they both open together. This would then vent the excess air to the exhaust manifold via the secondary air line and the ECU would adjust the fuel and timing to allow detonation in the exhaust manifold, thus providing the gas flow to keep the turbo spinning between gear changes and reducing the lag. This also has the potential to produce nice flames from the exhaust

This is how I believe that the secondary air system works but HH6 can correct me if I'm wrong http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >

As for turning around the BOV there has been plenty written on this subject on here and I'm sure you can go back and read it all, but all I would say that I wouldn't do it because a. the BOV wil no longer vent the excess boost pressure from the turbo and this will result in b. eventual damage to the turbo because that is what a BOV is there to stop in the first place.

Hope this helps

Andy
 
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Discussion Starter #4
Andy,
Your solution won't work because the Secondary Air Valve is controlled electronically by the ECU (via the Secondary Air Control Solenoid Valve) and the BOV is operated directly by vacuum from the intake manifold so there is no way to syncronise the two without some major reprogramming of the ECU to provide the fuel. Having said all that I am still unsure if the ECU does actually provide any fueling for proper Anti-Lag or whether it is just air (hence Secondary Air).
The flameouts that people see could just be the fact the ECU naturally overfuels and not the fact the ECU is specifically supplying fuel through to the exhaust manifold for SAS.

Just a thought but the ECU over fuels most of the time to cool the engine which leads to unburnt fuel entering the exhaust. Unburnt fuel means HC emissions shoot up (assuming the CAT can't cope). Whack some air into the exhaust just downstream of the cylinders and hey presto the fuel is burnt. Call it SAS, get it to work when deaccelerating after 3 seconds of full throttle (lots of unburnt fuel!) and its almost a performance mod but really its for emissions.

Anyway I would say having the BOV makes the the SAS less effective and it may be possible to arrange it so the BOV doesn't vent when the Secondary Air Valve is working. It means plumbing in another SA Control Solenoid Valve in line with the BOV vacuum operation. The BOV would work normally when the SAS is not operating but remain shut when the SAS is working. Just a thought and I don't know how effective it would be. (Also it would mean the extra SACSV would be on all the time until the SAS operated, not idea electrically but I am sure a suitable solenoid valve could be found that worked the other way around.)

Enough of this insane mumbling by me, I am sure if I thought about it enough I could find another 100 reasons why what I have said above won't work. Personally I don't think its worth the hassle of bothering with, Anti-lag is vastly over rated on a road car. Its only really worth it when you can gain a second or two a mile on a rally.
 
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Discussion Starter #5
HH6,
I only said it was a possible solution, I didn't say it would be easy to do http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >[img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >[img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >

Like you said, it would require reprogramming the ECU so that the SAV opened at the same time as the BOV in order to vent the air. I also don't know if the ECU provides the fueliing for true anti-lag but the chances are that someone clever enough with mapping an ECU could probably do it if so required.

Seems a good idea about the emissions too and if that is the reason then the ECU wouldn't put in extra fuel to give true anti lag because you'd be then adding more fuel and causing more problems with emissions.

Personally, I'll just stick to my OEM setup and forget about a tiny bit of lag when changing gear [img]http://www.ltregister.f9.co.uk/graphics/biggrin1.gif border|EQU| 0 align|EQU| absmiddle > ...

Andy
 
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Discussion Starter #6
Its nice to dream of mods to do though ain't it http://www.ltregister.f9.co.uk/graphics/wink1.gif border|EQU| 0 align|EQU| absmiddle >

Thats two fantasy mods now, this one and converting the AYC to normal LSD operation electronically [img]http://www.ltregister.f9.co.uk/graphics/wink1.gif border|EQU| 0 align|EQU| absmiddle > If I had the time and inclination I might have had a fiddle with the AYC conversion.
(If 21st Century Performance can build a manual adjustable torque split device for a Skyline then it must be possible on an E6, infact it should be less complicated.)
 
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