monte-ss

ok Ive been reading a few of these posts and Ive been running into a couple probs one where I take it your supposed to rerout the vent line off the throttle body to the PVC line. perhaps this is why that side valve cover is spraying oil all over . so if someone has these scanned and could email them to me please do so or if you need to mail them Ill pay postage.
thanks in advance
Jack

Willie

iTrader: (1)

I'm not sure who gave this information, but it is not correct. The original design has a vent running from the valve cover to the throttle body. The vacuum in the plenum aids by "pulling" crankcase blowby. When in boost, the opposite occurs and additional pressure is pushed into the crankcase. Not good at all.

The correct procedure is to plug the throttle body port and route the crankcase vent either back into the air filter assembly (to be recirculated -- emissions legal) or vent it to the atmosphere.

On the PCV (think about this one), under normal operating conditions (vacuum), the PCV is open allowing crankcase blowby to circulate into the intake. This is normally a good thing, BUT if the crankcase vent is free to vent (previous paragraph), a huge vacuum leak occurs. The pressure under the valve cover (crankcase) is relieved through the breather. The PCV sucks air from the valve cover. With the breather, the PCV sucks air from the atmosphere through the valve cover!! Result: Huge vacuum leak.

So in addition to plugging the throttle body port, the PCV port should also be plugged and valve cover breathers (one for each side) installed. I plugged my PCV by inserting a plug into the PCV hose. It still appears to function, but does not.

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
Current ATI D1SC (Initially 10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited May 01, 2001).]

89GTA5spd

Willie:

I have some questions, sorry if it's long, but I just don't want to do this twice.

Paxton says to plug the breather line going to the throttle body, and install a new breather where the oil-cap is and re-route the new breather as well as the original one (on the pass side valve cover) which then goes to the air filter.

... and you are saying to plug the pcv as well. (which I am assuming paxton doesn't tell you to do because it makes the car officially emmisions illegal)

I wanted to just use one of the generic breathers you see in 60's cars (either the closed ones or the one with a tube coming out of it, or the open element style), but I don't know if using these will cause a vacuum leak.

Is the best way to just use 3/8" hose and just vent two breathers into the air filter and then plugging the pcv?

Or would plugging the PCV and using the big shiny 60's style breathers work better? If so, which big shiny breather (with tube, without, or open element) would be best?

Won't venting the breathers into the atmosphere cause a vacuum leak? This is the final thing I am working on before firing up my S/C for the first time, and I want to do it right, which usually isn't what paxton tells you to do.

Thanks.

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89GTA5spd **** Came: Completely Stock w/ 3.42’s, rear disks, dual cats, LB9 305, T5, bad paint & interior **** I did: Conical K&N, TPIS Airfoil, Ported Plenum/Runners, TB By-pass, Home Made AFPR, MSD Cap/Rotor, Jet Fan Switch, 180 T-stat, Flowmaster 3” Cat-back, Eibach 1” Drop, KYB’s, Hotchkis STB, BFG 255 Comp T/A’s, AC Plugs, NOS TPI #5151 w/extra's , Sony CD Deck, Orion Amp, 2 Fosgate 10’s, 1991 GTA interior, new flame red metallic paint **** I have but have yet to put on: Alston Bolt on SFC’s, LT1 24lb Injectors, Paxton SN-92 (almost on now) **** Soon: MSD 6al, MSD Boost Retard, Autometer Phantom Elec. FP guage, N20 Guage, Boost Guage, Fuel Pressure Safety Switch, Bottle Heater **** Not So Soon: L98 w/ alum heads!? who knows. Always a work in progress..

Jeremy_84_F41

iTrader: (3)

If both breathers are vented to the atmosphere, and the PCV port is plugged, then it won't cause a vacuum leak.

Willie

iTrader: (1)

First off, Jeremy in his reply above is right. You can use any kind of valve breather, just make sure to plug the PCV pipe.

So far so good.

Exactly right. I ran my Paxton for about two years according to their instructions. Then I was reading on a Corvette board about plugging the PCV. It made complete sense.

No problem as long as the PCV is plugged.

Two issues here. First, I don't know if you have a yearly emissions check in your state, nor do I know how extensive the visual is, assuming you have one. The crankcase vent is emissions legal as long as the blowby is vented back into the intake tract. By connecting it to the air filter (or thereabouts), it is recirculated. The original design does this but through the throttle body. The reason this cannot be done with a supercharger because of the positive pressure within the plenum/throttle body. That's why Paxton's system recirculates the blowby BEFORE the blower -- into the ducting between the air filter and supercharger.

So, if your yearly inspection is extensively, you really don't have a choice but to recirculate it back into the draw through side of the blower (air filter). If you do not have an inspection, by all means use one of those little air filters that mount on the valve cover. My yearly inspection will not allow the breathers on the valve covers, so here's what I've done. Paxton's setup has both valve cover "breathers" (hoses) routed into a tee, then into the air filter. (Analogous to a single exhaust.) I took both 3/8" hoses and kept them separate (analogous to a true dual exhaust). I mounted two valve cover breathers (yes, the little air filter-like devices) out of site and routed both 3/8" hoses to them. So at my emissions inspection, they do not know whether the two hoses recirculate air back into the air filter or to the atmosphere.

No. Just plug the PCV and you're ready to rock and roll!!

Willie

monte-ss

Ok with this post and my other post I guess Ive asked a couple good questions, also if you run the PCV line into the intake system prior to the paxton I am assuming this does nothing to the inside of the paxton? will it gum it up after eventual use and if so how do you clean it out? I didnt mean it to sound earlier like the stock system was correct cause I could tell the first time I got on it and it sprayed oil all over and smoke started rollin out from under the hood.

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'87 Monte Carlo SS,with '89 IROC 350,700 trans, blew up 3.73 posi stuck with crappy 2.73's neeed gears! hooker headers, flowmaster 2 1/2" exhaust true dualls, recently installed a set of alum vette heads 58cc, new cam for a paxton, recently installed paxton, OMG need a posi bad. So if anyone knows where a buick GN 8.5" rear is let me know.