Charley B

Laguna Seca is counter clockwise with 11 turns, four to the right.

Sears Point is cloclwise with 12 turns as configured for club races and track day's. Six of them are right handers. There are really about 14 turns due to kinks, but still about half are right handers.

Thunderhill is counter clockwise. Fifteen turns; with five of them right handers. Thunderhill is also run backwards with some regularity.


Button Willow has about 20 different configurations and they run both way's so I won't even try to describe that.

FlyingDog

Summit Point Main - 10 turns - 7 right, 3 left
VIR Full Course - clockwise - officially 17 turns - 8 lefts 12 rights (no turn 13 and 4 turns have an "a" turn after them)

Neither is run backwards, but VIR has 5 different configurations.

Alan

Bump - any comment on degree of suction from the air pump's (currently unused) side port (under the filter). Is it just ~the differential pressure loss across the smog filter?

Alan

heinrich

Portland is Clockwise, Seattle is Anti-Clockwise

Alan

DR - another thought from an exchange with Louie Ott... have you considered a domed (open) cover over the filler intake tube for the extreme version - don't know if there would be room under the cap - but it would sure make filling easier/less messy. Is that elebow intake fitting for the extreme availabe in black or only white/clear as shown?

I do plan to get a kit from you - I may reconfigure contents a little (sounds like you are OK with customizing amongst what you have) - I think you have fabbed up some great parts for this system - Porsche seemed to have given up on the breather system as an incomplete assignment...

Alan

mark kibort

I still have a oil injestion problem that shows itself as puffs of blue smoke after accelerations after turns that had long acceleration going into them. Its not horrible, and plugs are clean, but it does look bad to have a "smoker" on the track. I didnt have any issues with the original Holbert engine, but the stroker is now causing some issues there. time for some changes to the breathing system.

I was thinking of just raising the tubes to have much taller loops to avoid the drain and suction into the intake. does most of the oil come from the two lines from the passenger side valve cover? the only other line comes from the filler tube, right? If all of these lines had more hight, couldnt that fight any stream of oil coming up the tubes, and then backing down the tubes under decel. Or, is it a pressure induced stream of vapor that just feeds the intake and accumulates more on decel, so that when you apply full throttle, it sucks it into the cylinders? The dynamics are interesting if you think about the changes in pressure from crankcase to intake ports under WOT and off throttle and varied RPM.

mk


mk

Alan

Mark

I think it is mostly sucking an oil laden mist so - except at very low flow - gravity probably won't cause much to 'condense' & drain back... hence the air/oil seperator.

see the links I posted earlier to Louie's site.

He did some experiments with a cam cover modified with lexan windows then videoed what happens inside at high rpm/cornering...

Seems the pass cam cover fills with a frothy oil mist that he speculates isn't pumped up but is ejected by blowby up the head oil return drains - primarily because thats a route out of the engine and back into the intake (e.g. direct crank breathing is not enough to handle all the blowby volume). Since the drivers cam cover has no exit path it doesn't happen there.

A side effect is that there is more oil in the pass cam cover because its having a harder time draining back - this reduces sump oil level and may even cause more froth/mist in the pass cam to get ingested... however you look at it these effects aren't good...

This is one of the reasons I'm looking at just venting air into both cams (check valve) and getting all the suction from the crank direct - via the sharkvent extreme (with oil seperation/drainback).

Conceptually this is similar to what Louie did too.

Also note:

Deccelerating you are in fuel cut-off mode..

Perhaps when WOT accelerating you are sucking as much oil since that is the max blowby case - But then you will be fully burning it mixed with fuel - while in fuel cut-off you will be pumping it straight through the cylinders unburned & into the hot exhaust(/cats?)... You will be sucking as much oil mist in as WOT for a short while - whatever is still in the crank/pass head).

I'd expect it smokes/smells rather more then...

Alan

DR

Hi Alan,

I have been looking for just the right part to cover the fitting in the oil filler neck without blocking crankcase vapor flow or making it even harder to fill with oil. Haven't found it yet, but am always open to suggestions. In the mean time we supply the factory rubber tow eye plug to aid in adding oil without getting it inside the Provent. ( see page 2, Post #17).

All of the fittings are now either black or powder coated black, only the mounting bracket is silver to blend in with the engine. My aim is to make it as factory looking as possible.

There is no problem making the changes you like. I even try my best to accommodate requested custom options/configurations when I build each system, as long as I don't think it will affect the function and reliability of the SharkVent system.

Thanks for the compliments and when ever you are ready just let me know!

928ntslow

Dave, nice work. I played with a venting system on the black 85 I had and it seemed to work quite well, but you have taken this a few steps further. Being that I am now down to just one 928 (GTS), this is the car that needs a venting system. I am about to pull the trigger on the GTS kit, but too am concerned about a couple of things. The car is stock(kinda). Not crazy about the filler neck mod for one. What about a filler cap with a quick connect or hose slip on fitting that fits on top of a filler cap? You would just pull off the hose when you want to twist off the cap and add oil. I also have an X-pipe which of course does not have the rigid line from the air pump connected. Also, the air pump belt is not connected, so this system is pretty much useless. What happens with the Provent line now?

Alan

Keith the non-extreme version doesn't have the filler vent adaptation at all... also the standard version is just vented to atmosphere so you don't need to use the air pump - as long as this passes your local inspections - which since you have no airpump I assume it will..

Dave can probably elaborate but I think his std. GTS system has what you want...

Alan

928ntslow

I recently had to go through a smog test and all I did was put the cat back on without hooking up the airpump...passed with no issues.

Good to know on the kit. I guess if I ever decide to put the car on an iron lung, than I would have to address the extreme venting issues then.

When I have had the intake off, I found a good half quart sitting at the bottom. I too get the puff(cloud) of smoke under hard throttle. Not to mention the nasty residue that gets all over the back of my nice white rear bumper cover...which is now the euro version with no bumperette cut outs

Jim M.

I had a sometimes smoking problem with my 93 GTS 5-speed. I then added an X-pipe and the smoking became VERY bad. For some reason, much worse than Roger's 93 GTS with a "Rogerbox" and the same X-pipe. In an attempt to reduce the smoking, I added about 18" of hose to the exit from the passenger side cam cover that goes to the MAF. At the same time I removed both cam covers and added aluminum expanded metal, rolled as tight as possible to fill the plastic cups Porsche uses for air/oil seperators.

These two mods almost completly eliminated the smoking (almost). But, I still had a light accumulation of oil/soot on the rear bumper cap near the exhaust tips and on rare occasions a puff of smoke.

Last month I installed Dave's Provent system. After just 300+ miles, smoking is completly gone, no oil/soot accumulation on the bumper cap, oil consumption seems to be down (really to soon to tell with my GTS).

This mod should be the first step every GTS owner or 928 owner with excessive smoking should take! The kit is exceptionally well designed, fit is damn near perfect, and it works! Everything else is a half assed attempt to accomplish the same thing. My hats off to Dave Roberts for this fix.

john gill

Hello Jim
Where did you get that front scoop for the over the radiator air intake ???

slate blue

BY JIM M While I don't disagree with your statement in fact I agree, for the sake of completeness that crank scrapers are the one of best fixes for this but are far more involved, dry sump probably being the best but being very expensive. I suppose the main difference is at what point are you treating the problem.

Greg

Benton

Hi Dave,
Two questions:

1) Can I purchase the hoses, fittings, and bracket a-la-carte (extreme version for my 86 32V)? I purchased the Air/Oil separator from you about two or three years ago before you came up with this kit, and your fittings and the flow of everything is much better than what I came up with. I won't need the fitting or hose for the oil pan return, as I already fashioned something before you made this available.

2) Also, for the 85/86, I'm having a hard time figuring out what is done with the hose that comes out of the filler (at the base in the galley--there are two hoses here, shown in your diagrams; front one goes to cam cover, I'm talking about the rearward hose) and attaches to the intake on the driver's side. This is the same hose that has a tee in right before the intake that the brake booster gets vacuum from. Are you removing and plugging the part that goes to the filler and just leaving the hose for the brake booster to get vacuum? I think only the early 32V cars have this hose, and I'm still getting quite a bit of oil in my intake from it.

I know that was a bit confusing... if you don't know what I'm talking about I can take a picture and circle it.

Thanks!