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I also use a PCV valve along with my evac system.
Quote:I was running a PCV, but had reservations with a closed crankcase system? I did buy a vacuum relief valve and have it set at about 12". I'm sure I will never see that number with the full exhaust in place, but until I get a chance to run it at the track, I won't know how much it will suck with just the shorty extensions.
never had much luck with welding the bungs past the collector. Mine are in the collector about 2" before the flange. At idle there is zero inches of vacuum. At around 2500 rpm there is about 2" of vacuum. I also use a PCV valve along with my evac system. Works real good now for about 10 years.
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This is the tube I am working on right now. Kinda did my own thing on the exit section of the pipe. It's in the header extension ( I run with the extensions on at the track )about 1/2" and I have 1/2 of it capped off. Had the car running on the stands yesterday with the rest of the exhaust system in place and got about 1 - 2"hg at idle. Didn't change when I wound it up. Been snowing like a banchee here, so I can't take it out - nor have I tried it with just the extensions and no exhaust.
Quote:Actually 3". They go back to a pair of Summit chambered muffs and just dump in front of the axle. Only have them on when I'm street testing and so I don't piss the neighbors off too much.
"never had any pipe after that" , that's funny.
Crizila , that is the exact set up i'm talkin about , i see you have 3 1/2" exhausts?
Quote:I don't know? I have several sets of extensions, and plan on trying some other ways. Moroso's instructions ( with their evac kit ) suggest they be in 1/2" off the pipe wall - that is with them located just down stream of the primary tube junction in the headers.Quote:
This is the tube I am working on right now. Kinda did my own thing on the exit section of the pipe. It's in the header extension ( I run with the extensions on at the track )about 1/2" and I have 1/2 of it capped off. Had the car running on the stands yesterday with the rest of the exhaust system in place and got about 1 - 2"hg at idle. Didn't change when I wound it up. Been snowing like a banchee here, so I can't take it out - nor have I tried it with just the extensions and no exhaust.
Would it of been more effective if the evac tubes entered into the ex pipe as opposed to welding them in flush?
Thanks for the pics.
Quote:I've heard all kinds of claims on this board from nothing to over 30HP and I'm sure there are a million variables as to why. My car only runs low 11.70's, so I'm not expecting much, but I don't see any negatives. If I could get get a tenth or so out of it ( for the $ I have in it )I'd be a happy camper.
How much does the evac help? I mean say on a 11.90 car?
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I also use a PCV valve along with my evac system.
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Why?
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also if you use a O2, have the
O2 up stream of the evac otherwise it will give the
O2 bad numbers
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also if you use a O2, have the
O2 up stream of the evac otherwise it will give the
O2 bad numbers
so the o2 sensor cloer to the collector than the evac nipple?
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This is the tube I am working on right now. Kinda did my own thing on the exit section of the pipe. It's in the header extension ( I run with the extensions on at the track )about 1/2" and I have 1/2 of it capped off. Had the car running on the stands yesterday with the rest of the exhaust system in place and got about 1 - 2"hg at idle. Didn't change when I wound it up. Been snowing like a banchee here, so I can't take it out - nor have I tried it with just the extensions and no exhaust.
Would it of been more effective if the evac tubes entered into the ex pipe as opposed to welding them in flush?
Thanks for the pics.
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didn't the moroso also have slice cuts out of the pipe some where on the pipe that fit inside?
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If I can ever get out from under the friggin snow, I wil continue with my evac testing.
Quote:Quote:I've heard all kinds of claims on this board from nothing to over 30HP and I'm sure there are a million variables as to why. My car only runs low 11.70's, so I'm not expecting much, but I don't see any negatives. If I could get get a tenth or so out of it ( for the $ I have in it )I'd be a happy camper.
How much does the evac help? I mean say on a 11.90 car?
Quote:Yes, those were locator cuts, so you could position the pipes corectly - per Moroso. I do plan on trying s set as Mr P Body has suggested - perpendicular to the exhaust flow verses parallel. With 11.2:1 CR, standard ring package and tight piston to wall clearance, I don't have blow-by issues with this motor, so I probably won't see much if any gain. Still think it would be a benifit to run negative pressure in the crankcase at all times though.
didn't the moroso also have slice cuts out of the pipe some where on the pipe that fit inside?
Quote:Just curious - do you remember how much vacuum you pulled at idle with the PCV hooked up on a closed ( not open to atmosphere )crankcase?
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I also use a PCV valve along with my evac system.
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Why?
No, it doesn't defeat the purpose. At idle, there is a negative pressure in the crankcase due to the PCV valve. Anything above idle, there is also a negative pressure in the crankcase due to the crankcase evac. system.
Quote:This is dependant on the cam being used. In my case with a stick car, I pull 9" at 1200rpm(idle). One thing to remember. Any negative pressure is better than a positive pressure in the crankcase.
Just curious - do you remember how much vacuum you pulled at idle with the PCV hooked up on a closed ( not open to atmosphere )crankcase?
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Quote:This is dependant on the cam being used. In my case with a stick car, I pull 9" at 1200rpm(idle). One thing to remember. Any negative pressure is better than a positive pressure in the crankcase.
Just curious - do you remember how much vacuum you pulled at idle with the PCV hooked up on a closed ( not open to atmosphere )crankcase?
10-4 that.