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turbodaytona87
06-28-2010, 10:20 PM
I have a 3" exhaust from the turbo back. How far in should my exhaust evac tube stick into the exhaust?

puppet
06-28-2010, 10:30 PM
I've seen some tests that do show some variance in vacuum depending on the depth of the tube. Closer to the center of the pipe produces the most vacuum draw on the evac tube. Make sense when you consider that flow velocity will pick up the farther away from the 3" exhaust wall you get. ... but we're only talking a couple points here.

turbodaytona87
06-28-2010, 10:31 PM
I could use all the vacuum I can get. I took a look at my rear main seal yesterday and it was being pushed out of the retainer from pressure buildup.

86Shelby
06-29-2010, 03:35 AM
Are you sure it's not you PCV leaking (a lot of) boost into the crankcase? If you have THAT much blowby it wouldn't run for sh1t. I have trouble blaming your ring seal alone for the rear main seal being pushed out. The wagon pushed out 1 single old cam end cap due to old/hard rubber and MASSIVE blowby that was bad enough the cloud of white oily smoke would billow out from under the hood at idle. The billowing smoke was what came out of the airbox crankcase vent after the engine tried to inject the smoke through the airflter.

turbodaytona87
06-29-2010, 09:53 AM
My PCV hasn't even been hooked up. I thought I could get away with just a vent, but I guess not. My dipstick also comes up. Honestly I think this has become more of a problem with the GN (S70) turbo.

Stratman
09-02-2010, 04:13 PM
Venting the crankcase does not work well at all and leaves a nasty mess once the filter starts getting soaked. Vacuum on the crankcase via PCV to catch can (without ventilation) to intake, or venting through exhaust vacuum will work best and is great for some power increase and ring seal.

Speedeuphoria
09-02-2010, 05:09 PM
right if you evac the block and not the VC

boboli
09-05-2010, 03:56 AM
I put an evac in. You need to get it as close to the turbo as you can. put the pipe in at a 45 degree angle so the exhaust passing it will cross straight across the evac pipe. This causes a venturi effect and sucks air from the tube. I 1st had mine way down the pipe and it didn't create any suction.
I removed my evac after awhile because it ended up pulling too much!
Mine was connected to the VC and to the fuel pump block plate. I know the FP block plate sees a lot of oil, but I could not stop the car from sucking oil at high rpm. I even installed a valve to adjust the suction on the system with little effect. I now just have a working pcv and I have no problems

turbovanmanČ
09-05-2010, 04:12 AM
right if you evac the block and not the VC

That's what I am using and I fill the catch can once a week, good rings, :(

Juggy
09-05-2010, 11:13 AM
I put an evac in. You need to get it as close to the turbo as you can. put the pipe in at a 45 degree angle so the exhaust passing it will cross straight across the evac pipe. This causes a venturi effect and sucks air from the tube. I 1st had mine way down the pipe and it didn't create any suction.
I removed my evac after awhile because it ended up pulling too much!
Mine was connected to the VC and to the fuel pump block plate. I know the FP block plate sees a lot of oil, but I could not stop the car from sucking oil at high rpm. I even installed a valve to adjust the suction on the system with little effect. I now just have a working pcv and I have no problems

hey im running an evac from the valve cover to the bottom of the downpipe. last time i ran the car and gave it, she SMOKED hard. it scared the hell outta me and i thought i blew the seal on the turbo or something. let it idle out and smoke went away after 10mins.........car hasnt smoked again yet, but i havent boosted again lol

am i gettin too much pull??? i was thinking of eliminating it and gettin the oil pan modded up for a evac instead


edit: btw i eliminated the pcv baffle on the VC as i am running a TBI curtain over the cam....maybe i should switch back?

puppet
09-05-2010, 11:36 AM
A better solution to it pulling too hard might be to put in a vacuum break in the VC or the pan instead of trying to regulate the flow with a valve. Then you can dial in the crankcase vacuum pretty accurately.

Juggy
09-05-2010, 11:36 AM
A better solution to it pulling too hard might be to put in a vacuum break in the VC or the pan instead of trying to regulate the flow with a valve. Then you can dial in the crankcase vacuum pretty accurately.

nice thinking!

puppet
09-05-2010, 12:00 PM
I'd use the handy "g" valve. Can be had in 1/4", 3/8" or 3/4" NPT

boboli
09-07-2010, 09:29 PM
I think mine was pulling oil out of the fuel pump cover. I removed the evac because i was installing my 3" SV and could finally use my 3" Dp. I didn't want to deal with the evac so I just made sure the pcv was working.
I would only get puffs of smoke at the track at the top end. It would clear out after a while. I didn't seem to have too much trouble on the street. I would see it every now and then. I did use a valve from the hardware store to limit the suction to the fuel pump cover but left the VC open to full suction. I had th standard vc baffle installed.
I did have a breather on the Vc and it seemed to ooze oil at times so I also didn't like the mess it was making
I may consider going back to the evac but at this time I don't beat on the car a lot and I didn't want to deal with installing it again on the new Dp.