EMan 928

Thanks, Greg, for this great product. I'm in the process of getting a 93GTS with about 70k miles. There was a recent leak down test performed with only 2-4% variance between cylinders. Car has mild pinging in the mid range. If I get your kit, is there a chance that pinging could be eliminated/reduced? i realize that I would probably need to do a BG treatment or something similar to try to remove the oil. Once I have your kit installed, what do you think the chances would be to not have any further crankcase pressure/oil related engine problems/failures.

Alan

Greg - On my GTS I've already got all 4 cam cover ports vented - Provent installed with drainback & an alternate oil filler port - but I do like the parts you have made and still need to finish up my installation.

I understand the desire to keep the proprietary stuff protected.

I'll PM you - certainly interested in all those other parts.

Alan

GregBBRD

Anytime that you add oil into the intake system, the effective octane of the fuel drops. The more oil that you add, the worse this problem becomes.

Additionlly, the higher the crankcase pressure gets, the more oil that is going to be "left" on the cylinder walls.

On the engines that we have added this system to, we have had significantly less "intervention" of the knock sensor system.....and significantly reduced "pinging". On several vehicles, we have actually been able to "add" additional ignition timing, after we removed the sources of additional oil.

However, it is difficult for me to tell how much of the pinging from your particular vehicle is resulting from oil in the intake. It is possible that the rings are so "gunked" up that they are extremely poor at wiping residual oil from the cylinder walls. It is also possible that the years of burning oil has left a considerable amount of carbon build-up in the combustion chambers.

You certainly may have to perform some addtional steps to both clean the rings and remove any excessive carbon build-up.

17prospective buyer

I wonder how many engines are in 928's that people say feel "slow"... are due to the excess oil vapor consumption.

GregBBRD

Please understand that I've assembled these parts as a "system". Although I have no issues with providing pieces to people that already have "partial" systems (and I have already have several orders for "partial systems/individual parts), I certainly have not experimented with all combinations of pieces that individuals are going to "come-up" with, on their own.

It will be totally up to you to "mix and match" pieces in your own experimental system.

It comes down to this....yes, I will sell individual pieces (keep in mind that the custom pieces I have to fabricate is where most of the costs of this kit are "hidden".) Once you start "mixing and matching" my pieces with your ideas of what works, please do not complain about "my" stuff not working, when it may indeed be your own design that isn't functioning, properly.

There's a lot of things going on here....to cure a lot of different "issues". While I've shown a signifcant amount of pieces, there are several pieces/subtle changes are not shown. intentionally.

C3 is going to have to figure this out, on his own.

GregBBRD

I'm going to guess a significant amount.

I "fixed" a GTS in 1998 that pinged so badly that it was virtually undriveable. It "pinged" so badly that there was actual pitting right in the center of the piston, directly below the spark plug. The customer had a file one inch thick of what Porsche had done, under warrantly, to repair this problem. They had replaced virtually everything (except the actual engine) in an effort to fix this terrible pinging. Exhaust system (all) computers (twice), all injection components (many multiple times).

We rechecked everything we could....down to removing the valve covers and checking the cam timing. We ended up "reducing" the ignition timing 9 degrees everywhere (we removed the flywheel, removed the trigger ring, and put it back on 9 degrees retarded.)

"Fixed" the pinging problem and the car ran exceptionally well....perhaps as well as any GTS I've ever driven.

I'd sure like to have it back, today, and see if "removing" the oil from the intake system/reducing the crankcase pressure/improved the breathing of the entire engine would have "fixed" the pinging.

Alan

Greg,
Missunderatding perhaps - I have stuff already installed that is exactly as shown in your GTS system, and some different but similar configs too - interested in seeing if i can just convert over to your plan...

I'm OK with making some changes as needed here - just need to understand what the differences/ advantages are here. I know you've put a lot of thought, experimentation, testing & finish fabrication into it so thats the value for me.

Not looking to build a frankenstein version. Agree that when changed all bets are off - its a different system...

In your system I assume its a closed loop system with the Provent O/P feeding back to the intake at the TB?

It looks like the Provent intake feed is from both cam covers? - can you say more about the generakl plumbing without giving away any secrets? Just tring to understand what you have done...

Alan

GregBBRD

Yes, Provent intake is from both valve covers.....easy enough to see that. Please understand that there have been changes inside the valve covers, which are not shown, intentionally. The breather elbows are also specific, as we've talked about in "Heinrich's thread".

mark kibort

my car, as you know, is as perfect as it can get. i just added a short block 6.5 liter, kept the mixture the same, and it works perfect as well. not huge hp, but a 5 liter at 330rwhp and the 6.5lter at 370rwhp is decent. THEN, we look at my buddy's 6 liter. same S4 computer. less 400cc, same compression, at least statically (190-200 psi per hole, while mine is more like 220psi) , yet, his pings like a network manager (network computer joke ) i dont get it. he has S4 cams, i have GT cams. his were timed horribly, then we fixed it, and it ran better. dual exhaust sounds AWEFULL, and no headers, while mine has a single 3.5" pipe out of a merge collector after equal length headers. now that i think about it, it sounds so awful, that maybe it is the exhaust that makes these things ping!! i dont know. But, its worse on hot days, but mine on any day, 105 track temp and ive never heard a ping.

the only think i can think of is i still need to bump up his fuel because most of the pinging is out of the hole, like coming off a stop light. maybe its oil , i dont know, but ill check its consumption. i dont burn more than .5 quarts after a race and qualifying weekend and nearly nothing on the street. i have a feeling his is not that bad either.

im ready to give up and give the car back and wave the white flag! cams of the S4 are that bad??? could that be it???

anyway, just thought i bring up the pingiest 928 ive ever seen or heard.

Thom

May I ask how oil vapour is being sucked into the Provent air/oil separator if the outlet of the Provent is not being routed back to the air inlet before the throttle plate?
Looking at this picture the oil vapour will be sucked back into the oil filler neck at the T drilled into the oil filler neck and no vapour will actually be forced into the Provent unit.
What am I missing?

GregBBRD

You are missing the complete details of all the plumbing.

Not sure where you got the information that the Provent was not hooked up to the intake, but this is incorrect.

Thom

Well, I was brought to this thread by seeing pictures of a set up that also uses a Provent unit but which was made apparently by someone else, and on this other set up the way the hoses were routed just did not make sense to me. I can see from your picture now that the hoses seem correctly routed, at least as far as the Provent inlet is concerned. Sorry for the confusion and thanks for the clarification.

GregBBRD

Yes, I've also seen some crazy arrangements of plumbing that make little sense. I just removed a "system" on a GTS that vented to atmosphere, which made no sense, in terms of hose routing.

I've continued to design and test pieces to reduce the oil that gets to the intake....it is one of the things I'm constantly working on. I've made such great progress that I'm now testing a system that doesn't use a Provent, at all. I've also now able to virtually eliminate oil that gets into the S3 intake....which collects copious amounts of oil. That was a tough task!

SteveG

Greg: I've had your updated system installed since Aug 2017. It has about 1,300 miles on it via 2 road trips of +/- 650 miles each. There is very little residue on the white filter inside the canister. It is burning about 0.5 qt per 300-400 miles, which is about what it was doing previous to installation; I can live with this, but I thought I'd see more evidence of oil in the canister. Maybe I should be glad it is what it is. Since it is designed to drain into the dip stick tube, maybe there is not going to be much evidence. The central lattice in the canister also seems dry. My question is: with the cover off the canister, engine at 2,000 rpm, with hand over the canister, would there be much suction "felt"? This is not a scientific test, but the suction feels minimal? Pictures upon request.

GregBBRD

If there is very little residue inside on the Maan filter, the system is doing its job by keeping oil out of the intake system (which is what it is designed to do.) That tells you that your oil consumption is coming from either the rings or the valve stem seals....inside the engine. Run a carbon remover/softener the next time you run it....and try to run it hard, in order to heat up and try to break up the carbon/hardened oil.

As far as the suction is concerned, it comes from the airflow going past the opening in the rear boot....on the "suction side" of the airflow meter. This means that it is not directly hooked to intake vacuum, so you will feel very little suction until the air flow goes up in that boot....something you can not simulate, in your driveway.

How many miles on this engine?