I want to keep the Swirl Control Valve & Butterflies and am trying to figure out what needs\can\should be capped\rerouted to allow for this. I see that the SCV Actuator connects to the SCV solenoid valve but can't figure out what to do with the rest. (Already removed are the AIV, carbon canister, egr stuff). Line (2) appears to be the direct source of vacumm (tee's into (20)?), the actuator is supplied by line (4), line (1) to FPR, if that is true then the FPR is controled by the SCV solenoid (that doesn't seem right)? I know would be easier to just remove the SCV but I want to keep it, anybody have any insite.
Swirl Control Valve & Butterflies (wanting to keep them)
Re: Swirl Control Valve & Butterflies (ppctx)
they work together, you could take a vac pump/gauge to it, see how it operates without the control,but then the ecu wont use the full potential...some debate has gone on (if its worth tuning or not)
Re: Swirl Control Valve & Butterflies (neverlift)
I'm sorry neverlift, that went over my head. what works together. Is there not a simple plug line ? and ? and rehook a vac line to the FPR, then the SCV will opperate as it suppose to, stock like.
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eazye2000
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Re: Swirl Control Valve & Butterflies (ppctx)
ppctx wrote:Is there not a simple plug line ? and ?
Haha, none of that stuff is 'simple' to say the least. You see all those vacuum lines? That's why people yank it out. I took mine out, and I notice ZERO change in driveability in my car. Low, or high RPM's. Can't even tell in the gas mileage. My car runs 12's and gets almost 28mpg.
Just my $.02 Take it how you want.
Re: Swirl Control Valve & Butterflies (eazye2000)
my bad I assume everyone on here can recall scripts from the fsm... the scv and the fprcs(fuel pressure regulator control selonoid) work in conjunction with each other in order to get the most low end torque/mileage.
like i said it has some debate as to if its worth the efforts to tune or if nissan was after better emissions, hard to tell I found no loss of low throttle performance, and made large economy gain with them removed(40 plus, mix city/highway) stock internals and cams.
like i said it has some debate as to if its worth the efforts to tune or if nissan was after better emissions, hard to tell I found no loss of low throttle performance, and made large economy gain with them removed(40 plus, mix city/highway) stock internals and cams.
Re: Swirl Control Valve & Butterflies (neverlift)
found no loss of low throttle performance, and made large economy gain with them removed(40 plus, mix city/highway) stock internals and cams Well if this is typical, I'd delete it in a second. Is your car boosted, dam that’s nice mpg, what kink of AFR are you running? If your increase in mpg is due to the simple delete of the SCV then my ratings below are blown out of the water.
Haha, none of that stuff is 'simple' to say the leastlike i said it has some debate as to if its worth the efforts to tune or if Nissan was after better emissions It does seem the easiest (not meaning best) answer usually ends up being "delete", but at the same time it seems an individual’s reason behind the "delete" solution is that the notion that all things not required for the car to start and run is some kind of "emissions crap", without understanding or even trying to find out why a very capable engineer would include the item as part of the system to begin with. (example that I've actually read: I deleted my PCV, welded shut, It's just some emissions crap)
My reasoning behind wanting to keep the SCV is the idea that the more turbulent air flow at low rpm has to help with atomization and greater dispersal of fuel within the combustion chamber and that at higher rpm's the butterflies are fully open. The minor restriction (thus minor turbulence) that the open butterflies create may help with the atomization thing proportionally. On boosted application, it would take turning up the up the boost a small fraction to overcome the minor restriction. As I'm not one of the capable engineers that designed the 240sx, this is really just an educated assumption.
Haha, none of that stuff is 'simple' to say the leastlike i said it has some debate as to if its worth the efforts to tune or if Nissan was after better emissions It does seem the easiest (not meaning best) answer usually ends up being "delete", but at the same time it seems an individual’s reason behind the "delete" solution is that the notion that all things not required for the car to start and run is some kind of "emissions crap", without understanding or even trying to find out why a very capable engineer would include the item as part of the system to begin with. (example that I've actually read: I deleted my PCV, welded shut, It's just some emissions crap)
My reasoning behind wanting to keep the SCV is the idea that the more turbulent air flow at low rpm has to help with atomization and greater dispersal of fuel within the combustion chamber and that at higher rpm's the butterflies are fully open. The minor restriction (thus minor turbulence) that the open butterflies create may help with the atomization thing proportionally. On boosted application, it would take turning up the up the boost a small fraction to overcome the minor restriction. As I'm not one of the capable engineers that designed the 240sx, this is really just an educated assumption.
Re: Swirl Control Valve & Butterflies (ppctx)
I wonder if, for boost applications, it might make since to hook the SCV actuator directly up to a source of vacuum and delete the solenoid. Please tell me if I'm wrong... under NA conditions, the mani always under vac, so the solenoid is needed at a certain point in the rpm range to switch from this vac to atm pressure to allow the butterflies to fully open.
On a boosted application, the mani starts off in vac (butterflies closed) and move in to positive pressure (butterflies open somewhere just below 0 psi) as rpms increase, so the butterflies operate similar to how they did while the car is NA, except the solenoid is not required to allow the fully open state.
Am I thinking about this too much, I just think if there is an advantage (low rpm range power) to keeping them, I'd like to.
On a boosted application, the mani starts off in vac (butterflies closed) and move in to positive pressure (butterflies open somewhere just below 0 psi) as rpms increase, so the butterflies operate similar to how they did while the car is NA, except the solenoid is not required to allow the fully open state.
Am I thinking about this too much, I just think if there is an advantage (low rpm range power) to keeping them, I'd like to.
Re: Swirl Control Valve & Butterflies (ppctx)
that was on a very tired sohc(n/a). And I would give the majority of all gains to the ecu tune I had on it ka's Luv I mean fu(kin LOVE a good tune. Other mods were a homemade short ram(kinda a cold air short ram), exhaust(2.5),ported throttle body and some knife edging on the blade as well as the intake ports smoothed and opened up SLIGHTLY, gutted a cat,big plug gap,relay mods,walbro,fpr at like 55psi..... afr were in the 17:1 ~18:1 during cruise and 13.5:1 wot. I know the cruise was crazy lean, BUT I was testing out a few theories... Motor finally blew when the stupid stock temp gauge read normal and the coolant was empty and my motor was tapping, so it wasnt due to the tune or the lean condition(had plenty of miles on the car).