BOV madness
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but you are not undesrtanding that when the TPS reads throttle closed the nissan ecu shuts off the injectors to conserve fuel.
***No I do understand that. I agree. But you will still run rich after shifts with an atmospheric BOV no matter how you adjust it. That was the original point.
***No I do understand that. I agree. But you will still run rich after shifts with an atmospheric BOV no matter how you adjust it. That was the original point.
lifelong learner
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well you said it would constantly run rich... this is where peopl eare wrong..
Yes you are correct many MAF equipped cars will do that. However nissan went against this after the flapper gate (280ZXT) maf was no longer used. As soon as they used the heated coil type it went witht he TPS as well.
and all factory cars have recirc valve instead of blow off valves for the car to be more quiet. the quieter the better. thats is why they also have intake resonators and etc etc etc. and exhust mufflers and resontaors.
i was just battling the whole rich the whole time you let off the gas thing.. its not true. its only from the time the throttle goes from 100 to zero. after its at zero you will always be lean if anything
Yes you are correct many MAF equipped cars will do that. However nissan went against this after the flapper gate (280ZXT) maf was no longer used. As soon as they used the heated coil type it went witht he TPS as well.
and all factory cars have recirc valve instead of blow off valves for the car to be more quiet. the quieter the better. thats is why they also have intake resonators and etc etc etc. and exhust mufflers and resontaors.
i was just battling the whole rich the whole time you let off the gas thing.. its not true. its only from the time the throttle goes from 100 to zero. after its at zero you will always be lean if anything
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rest in peace tim.
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Boostedz31
I would really like to know how to adjust the bov correctly...Ive tried both atmospheric and recirc. Recirc seems to work best especially inbetween shifts quicker throttle response rev hold better too idles great...etc..if you could share with me how to do it that would be great...
thanks bro
I would really like to know how to adjust the bov correctly...Ive tried both atmospheric and recirc. Recirc seems to work best especially inbetween shifts quicker throttle response rev hold better too idles great...etc..if you could share with me how to do it that would be great...
thanks bro
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I have to chime in on this one...
IF you adjust your BOV so that it does not LEAK under idle then your idle will be the same as if you recirc. all air being metered is being cunsumed.
now...as for the running rich after shifts bit...yes it happens and yes it can cause drivability issues (i have fouled plugs from lots of low speed and part throttle driving). but this can be fixed by a S-AFC.
BTW...Greddy R can also be recirced...it has the threaded outlet as well.
Scott
IF you adjust your BOV so that it does not LEAK under idle then your idle will be the same as if you recirc. all air being metered is being cunsumed.
now...as for the running rich after shifts bit...yes it happens and yes it can cause drivability issues (i have fouled plugs from lots of low speed and part throttle driving). but this can be fixed by a S-AFC.
BTW...Greddy R can also be recirced...it has the threaded outlet as well.
Scott
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IF you adjust your BOV so that it does not LEAK under idle then your idle will be the same as if you recirc. all air being metered is being cunsumed.
***At idle most engines make between 17-22 inHg of vacuum. So if you adjust the BOV towards hard so that it is closed at idle that means that BOV will need to be set to open at a vacuum level greater than 22 inHg. After a shift your vacuum will go to around 25-27 inHg which is just barely over the threshold of 22 inHg you have set the BOV at. This hard setting means that the BOV will open a lot later than normal which allows more time for compressor surge to occur.
You are much better off adjusting the BOV soft to open at only 10 inHg of vacuum and reroute it. So when you shift gears and create 25-27 inHg of vacuum you are way above the threshold to open the valve. Thus the valve opens early and quickly negating the chance of experiencing compressor surge.
now...as for the running rich after shifts bit...yes it happens and yes it can cause drivability issues (i have fouled plugs from lots of low speed and part throttle driving). but this can be fixed by a S-AFC.
BTW...Greddy R can also be recirced...it has the threaded outlet as well.
Scott
[/b][/quote]
***At idle most engines make between 17-22 inHg of vacuum. So if you adjust the BOV towards hard so that it is closed at idle that means that BOV will need to be set to open at a vacuum level greater than 22 inHg. After a shift your vacuum will go to around 25-27 inHg which is just barely over the threshold of 22 inHg you have set the BOV at. This hard setting means that the BOV will open a lot later than normal which allows more time for compressor surge to occur.
You are much better off adjusting the BOV soft to open at only 10 inHg of vacuum and reroute it. So when you shift gears and create 25-27 inHg of vacuum you are way above the threshold to open the valve. Thus the valve opens early and quickly negating the chance of experiencing compressor surge.
now...as for the running rich after shifts bit...yes it happens and yes it can cause drivability issues (i have fouled plugs from lots of low speed and part throttle driving). but this can be fixed by a S-AFC.
BTW...Greddy R can also be recirced...it has the threaded outlet as well.
Scott
[/b][/quote]
Cafe Racer Extraordinaire
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I like the feel of the BOV air blowing up my
shirt...yeah....wait.....uhhh....yeah
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shirt...yeah....wait.....uhhh....yeah
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R.I.P. - Jason Harrill - 6/12/06
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R.I.P. - Jason Harrill - 6/12/06
"Well, here's the thing".....you will be missed.
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I totally agree with you jay thats why I run recirc on my car.at10 lbs/vac.for the best results I was still curious how one properly adjust the bov so you can run it to the atmosphere...thats all...ive tried adjusting mine putting in a stiffer spring making sure that no air leaks out at idle etc etc...but still car runs like crap when vented however correctly one may do this...its like night and day when its correctly recirculated...
hows kevins car
peace bro
hows kevins car
peace bro
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jay:
in running my greddy R i have gotten mine to open at 0 vaccum and 15psi of boost on the other side. you can over ride the standard spring.
If you have teh Racing spring in then yes i would reccomend setting it softer.
anybody that is blowing huge cfm from a good sized turbo will immediatly open the bov regardless of the spring.
in running my greddy R i have gotten mine to open at 0 vaccum and 15psi of boost on the other side. you can over ride the standard spring.
If you have teh Racing spring in then yes i would reccomend setting it softer.
anybody that is blowing huge cfm from a good sized turbo will immediatly open the bov regardless of the spring.
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rest in peace tim.
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in running my greddy R i have gotten mine to open at 0 vaccum and 15psi of boost on the other side. you can over ride the standard spring.
***I would *not* recommend supplying boost to the lower nipple of the BOV. It sounds like that is what you are doing. The only reliable way to do this would be to supply vacuum to the upper nipple and then supply boost to the lower nipple that is regulated by a solenoid. Have the solenoid supply boost to the lower nipple only under closed throttle conditions. That way vacuum will suck the valve open and boost will help push it open as well. This way you will not open the valve prematurely and cause the turbo to overspin.
If you have teh Racing spring in then yes i would reccomend setting it softer.
***On MAF equipped cars the street spring is the wiser choice. You want it to be easy to open the BOV.
Remember if you have only the upper nipple attached to vacuum the valve will stay closed even under very high boost levels. Under boost boost pressure will be trying to open the valve from the intercooler piping. Boost pressure will also be trying to close the valve from above via the vacuum line. Therefore these two forces cancel each other out. Lastly you have the force of the spring keeping the valve closed. So when you have only the upper nipple attached any spring stiff or soft will be enough to keep the valve from popping open.
With your Type R do you have one or two ports connected?
anybody that is blowing huge cfm from a good sized turbo will immediatly open the bov regardless of the spring.
***Not if only the upper port is attached to vacuum!
***I would *not* recommend supplying boost to the lower nipple of the BOV. It sounds like that is what you are doing. The only reliable way to do this would be to supply vacuum to the upper nipple and then supply boost to the lower nipple that is regulated by a solenoid. Have the solenoid supply boost to the lower nipple only under closed throttle conditions. That way vacuum will suck the valve open and boost will help push it open as well. This way you will not open the valve prematurely and cause the turbo to overspin.
If you have teh Racing spring in then yes i would reccomend setting it softer.
***On MAF equipped cars the street spring is the wiser choice. You want it to be easy to open the BOV.
Remember if you have only the upper nipple attached to vacuum the valve will stay closed even under very high boost levels. Under boost boost pressure will be trying to open the valve from the intercooler piping. Boost pressure will also be trying to close the valve from above via the vacuum line. Therefore these two forces cancel each other out. Lastly you have the force of the spring keeping the valve closed. So when you have only the upper nipple attached any spring stiff or soft will be enough to keep the valve from popping open.
With your Type R do you have one or two ports connected?
anybody that is blowing huge cfm from a good sized turbo will immediatly open the bov regardless of the spring.
***Not if only the upper port is attached to vacuum!
