Rich9928p

Dave Roberts informed me that Porsche left 2 parts out of the list, so I updated the PDF document and sent the revised information out to all who requested the PDF. Thanks Dave.

Mike87S4

blau928, PorKen,
I am about 90% finished the install of the GZ Motorsport VP101 vacuum pump to my 87S4. My digital camera broke on christmas day so I dont have photos. I can tell you that the pump mounts ok using the stock airpump mounts and tensioner, you just need to make some spacers to suit. I needed to remove a small amount of metal from the rear of the mount to accomodate the inlet fitting. The vp101 needs some oil so the A/O seperator is after the pump mounted where the charcoal canister used to be, the 5\8 id hose passes through the existing side panel holes for the charcoal canister hoses without the need to cut. The outlet from the seperator joins to the pipe from the cats at the stock fitting near the exhaust manifold flange. The pump is fed from the rear cam cover fitting, with a hose from the front cam cover fitting going under the water manifold to the air pump filter where the vacuum relief valve is located. I used the 5 inch pulley from GZ and the power steering veebelt is a perfect fit.
This is all being done as part of a general underhood refresh which probably won't be finished for a couple of weeks. If I get my camera fixed I will post photos. If you have any questions just ask.
Regards,
Mike Egan
87S4 Felsengrun
Darwin Australia

John Veninger

Mark,
When have you had your intake off to actually see this?
How much oil do you use duing a race?

I have noticed that the 16V with the catch can will fill the can quickly if I have the oil topped off. It seems to be much less when I run in the middle of the dip stick. I'm not to worried doing this since the accusump takes up any "low oil" issue.


FYI-I removed the intake on the GT several years ago and the intake ports were coated with oil goo except were the injectors were shoting fuel. This is on an engine with 30K at the time and I had put on 1/2 of those miles using Mobil1 and alsoCastrol Syntec. Remember, street car. The car will use a qt. about ever 1800-2000 miles if its being driven "easy". Getting on it will reduce that to about 1200miles, which is common for me.

DR

Hi Rich,
Thanks for letting me "compare notes" with the Info from Porsche. It was great to have some official validation to what I have been doing.

BTW, I have the "Kit" on the Website now, look under "928 Specialists Kits" for the GTS "Dual" Cam Cover Breather System Kit for 87-92. Total price for the complete Kit is not too bad and includes everything you need, even new Cam cover Gaskets and seals. I designed it as a "non-required" Kit so you can remove any of the items you may already have or feel you do not need (not recommended).

Full Instructions with some "cheater tricks" will also be online later today or tonight.

Thanks again,

Dave

ErnestSw

I'm confused. (my normal state)
I'm aware that many GTS use a lot of oil. I thought that this oil consumption was a result of the breather set-up and that the oil was being sucked up into the intake and burned.
If that's the case why would I want to convert to the breather system that causes the problem?
I'm sure I'm missing something (like a brain), so please, educate me.

Bill Ball

The GTS oil consumption is related to the piston (forged) and oil rings leaving more oil on the cylinder walls, more or less on purpose.

DR

Hi Ernest,

I will try to take a stab at this in "laymen's" terms.

First off, a Ventilation System of any sort will not cause Oil consumption of any measurable amount.... and certainly not on a heathy engine.

IMHO, the true main purpose of the ventilation system in the first place is to get unburned fuel vapors out of the engine crankcase and cylinder head areas. These vapors are the natural effect of the blow-by around the pistons that all internal combustion engines have (to some degree or another, the more wear the more blow-by), plus any fuel vapors that sneak past worn valve seals etc. These fuel vapors break down the oil and causes it to be less effective and increases engine wear. As you may know Fuel Vapors are lighter than air and will mostly accumulate in the upper areas of the Crankcase area. The Cylinders heads have direct open paths to the crankcase and are therefore the "highest" area (with exception to the Oil filler Housing which is also vented).

In the old US V8 days we simply used Vents/Filters on EACH Valve cover to vent these fumes. Of course as emmisions and the EPA got more involved the PCV (Positive Crankcase Ventilation) system was developed to vent these fumes back through the intake to be burned instead of the open air.

Ok, back to the 928 system. The 32 Valve engines prior to early 93 only vented the crankcase/Cylinder heads from one side. This would allow fuel vapors/pressure to build up in the left (cyl 5-8) cylinder head. This has never made sense to me, and obviously around 92-93 it finally didn't make sense to someone at Porsche either.

Hence the simple change to allow Crankcase Ventilation from both Cam covers.

Hope that makes some sense.

There are other more complicated issues such as crankcase pressures, etc. involved, but that would take someone like Wally to explain :-)

Rich9928p

Dave, you better have a bunch if kits made up. I've had ton's of requests for the PDF so far, several from Australia, one from Sweden. Though, unless your cheater tricks are pretty damn good the intake manifold must be removed for the upgrade, so it will probably become a while you're in there kind of job. I'm sure a lot of S4s need a powdercoat on the intake to make it look nice .... time to fix vacuum leaks and make sure the idle speed regulator is working properly, replace the flappy bearing, etc.

blau928

Mike,

Please post pics of the vacuum pump install when you can, it seems like a very good idea how you routed it. I am curious on the setup for superchargers, as I am thinking that it may be interesting to run this setup for the street with an Accusump instead of a hybrid dry sump system.

Thanks,

ErnestSw

Dave,
Thanks for the explanation. What benefits do you feel the improved crank case ventillation would provide? Durability? Power? It might be a good marketing move to include an explanation with your kit of why the upgraded ventillation system is an improvement for those of us who don't "get it".

DR

Ernest,
You are welcome, hope it made some sense.

In my opinion benefits are Durability/Longevity Only.

However, with all the TBF (Thrust Bearing Failures) and Rod Bearing Issues out there it certainly wouldn't hurt as Oil is a factor in both of these failures, among others. Not saying by any means that this will stop those from happening, but every little bit helps the 928 Engine last just a little longer.

Good idea about the "Why Do I Want/Need This" , thanks!

PorKen

Very well though out!

Could a different fitting be used, that might not require trimming?

Please buy, borrow, or steal, a camera and post a new thread on this! (If not now, then when the car is running. But I want to see it now! )

If you need photoshop assistance, please contact me, and I will gladly help.

heinrich

Hmmmm .... sucking right off cam cover and depositing into the exhaust?

DR

>Hmmmm .... sucking right off cam cover and depositing into the exhaust?

Makes the best dang mosquito Killer you will ever see, just ask the Guys from our second "Fall Drive" coming thru Deal's Gap.

I thought someone had blown their engine or worse the first time I drove behind a 928 equipped with such a system.. SCARY!!

I refrain from mentioning the friend/928 owner and I think he had the issue solved/changed shortly after that.

PorKen

heinrich,

He is using a air/oil separator (although I would still dump after the cats, if possible).
...

DR,

So people have used true vacuum pumps (not stock smog pumps) with good results? Or no?