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Ever thought of installing a catch can or that Sharkvent system I saw from 928 Specialists a while back? May solve the oil consumption issue and keep the EZK from messing with the timing thanks to the oil intake.
A healthier approach might be, your only weakness is what you don't know.
Don't try to beat anything, or over extend what you DO know.
I've watched 10s of 1000s of people attend track days, and the only ones that hurt their cars are the ones that "planned to" but not planning to only exercise the strengths and weaknesses that they were already aware of. What you dont know will hurt you.
Done right, you'll learn those things in _small_ pieces..a tire or two off here and there, and not a screaming exit from a turn with more energy than physics will allow safely. Those are the people to go out and bite off to much, for time, for honor, wo’ batlhvaD!
Learn you, not the car..its a time driven process, and a fun one!
Increasing the driver's ability, in a 928, means that the the vehicles generally turn more rpms longer and pull more "G's" in the corners than they do, in beginner's hands.
The sustained rpm's drive more oil into the cylinder heads (reducing the amount of oil in the crankcase and forcing more oil into the intake system) and the increase in cornering forces pushes more oil away from the pick-up.
This is a completely different problem, with the same exact same appearance and outcome.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Would a missing check valve in the breather hose that attaches to the oil filler neck negatively affect oil consumption in this instance?
No question. That separate valve must be present on an '85/'86 engine and built into the filler neck on an '87 and later.
My latest "iteration" of evolved valve cover breathers/oil separators helps greatly in keeping oil from reaching the intake....no doubt one of the very best upgrades anyone can make to their 4 valve 928.....street car or track car.
The addition of these breathers on Jorge's open road racer virtually eliminated oil volume loss on his car.
I my experience racing a few different 928's on near stock oiling systems it varies quite a bit based on condition of the engine. The 16V usa 4.7 didn't burn much maybe 1/4 qt per hour during our 8 hour days racing in lemons. We just added a qt at the 1/2 way point, but all my racers ran 3/8th inch oil pan spacers which increased the oil volume by nearly two qts for endurance racing...for sprint racing I kept the oil level lower since the longest event was 30 minutes. My sprint racer burned closer to 1 qt per hour but was turning higher rpm's at much higher G forces on slicks. The lemons ran on street 200 treadwear tires so the forces on the car were much lower, typically maxed at 1.2g vs nearly 1.6 peaks on slicks
In short you are fine, go out there and have fun. On street tires with a new to track driving you will have lots of fun with minimal damage to the car. Once you start upgrading suspension-tires and G forces-RPM go up....then you need some modifications to keep things reliable. I also agree with Doc Brown about aftermarket chips on track. HP is the LAST thing you need to upgrade when new to track driving. IF you do have a chip, buy 100 octane or at least blend some in for some extra piece of mind. $10 per gallon is much cheaper than an engine!!!!!
I my experience racing a few different 928's on near stock oiling systems it varies quite a bit based on condition of the engine. The 16V usa 4.7 didn't burn much maybe 1/4 qt per hour during our 8 hour days racing in lemons. We just added a qt at the 1/2 way point, but all my racers ran 3/8th inch oil pan spacers which increased the oil volume by nearly two qts for endurance racing...for sprint racing I kept the oil level lower since the longest event was 30 minutes. My sprint racer burned closer to 1 qt per hour but was turning higher rpm's at much higher G forces on slicks. The lemons ran on street 200 treadwear tires so the forces on the car were much lower, typically maxed at 1.2g vs nearly 1.6 peaks on slicks
In short you are fine, go out there and have fun. On street tires with a new to track driving you will have lots of fun with minimal damage to the car. Once you start upgrading suspension-tires and G forces-RPM go up....then you need some modifications to keep things reliable. I also agree with Doc Brown about aftermarket chips on track. HP is the LAST thing you need to upgrade when new to track driving. IF you do have a chip, buy 100 octane or at least blend some in for some extra piece of mind. $10 per gallon is much cheaper than an engine!!!!!
Nah..RPMs dont go up..appreciably.
The -same- shift points are there, the bottom of your rpm range changes shape, your peak RPMs dont..a 5mph gain per lap is huge, and its all in the corners.
I want to thank everybody for the support, no one can truly relate 928 experience except you guys.
I was having some "point by fatigue" I guess.
Humbling to have a Hellcat open up on the straight next to you like an SR-71.
I was surprised at how bad I was initially (I thought I was a pretty good driver already, pfft).
And then surprised again at how much better I got.
It really is an amazing thing to be out there.
Also some good technical points raised.
Yes, I have Porken chips installed. I have a wideband in the cockpit and never even looked at it.
Dumb, but just too much going on at the time in rookie brain.
The track is half of the nascar oval and then gran prix type through infield.
Turn one was pretty spooky until I learned to track out further. You carry a lot of momentum towards the concrete.
Six was just a bitch, I never did get it down cold. I hit it 90 different ways and had 90 different outcomes, seems like.
After setting it, I could turn and throttle and get what felt like oversteer but may may have just been losing back end.
That worked, but got the instructors attention ;0
Things that are worth looking, are values that dont change fast, and at a glance should always be in the same static place at any point. Temps and pressures.
Wb is going to take conscious thought to process and humans do not multitask, they task switch. That bends metal.
Greg does have a point WRT porken timing maps and consuming large amount of octane reducing oil into the motor..
There really isn't much....I refuse to provide a picture, so the thieves can avoid all the development work and simply "knock off" copies.....like what happened with my filler neck baffle.
And the only way to purchase the pieces are to agree that you will never take a picture, show the instructions with pictures to anyone, keep all pictures or descriptions off of the Internet, and obviously, not produce copies.
I was not going to release these pieces to the public, but my clients encouraged me to figure out a way that all 928 owners could benefit from my work, so those are the rules. I'll see how this works and may release more "secret" pieces, if it does.
These oil separators install inside the valve covers and replace the stock plastic "baffle". I suggest installing one on each active elbow...regardless if the elbow is incoming or outgoing air (Starting the oil separation as soon as the air/oil mixture enters the valve cover works best.) I had been plumbing the driver's valve cover, much like the passenger valve cover, with a complete oil breather system (big dollars), but the oil separators really work great and significantly reduce the amount of oil that can reach the intake, all by themselves. The breathers are economical enough ($50.00 each with all the pieces required to install them), that I am now recommending just installing the breathers and seeing how the engine responds (there's quite a bit of variance from what one engine to the next requires to breathe and not allow oil to get to the intake....some engines are so worn, that nothing short of a rebuild will repair them.)
To any and all reading this thread...get the GB baffles. They are wicked bitchin'! My S3 has oil consumption in her genetics. Don't let the fact that she doesn't currently run dissuade you. These baffles will keep the oil in the engine and not in the intake.
What I didn't mention is that on my race cars I took all oil breather lines and routed them to either a breather-vent or breather-catch can. Oil vapor or even worse oil from crankcase pressures has no business in the intake! No smog rules on a race car, so thats easy.
The upside its now you have two ways to determine oil loss, off the dip stick and volume of catch can. On the lemons racer is was nearly nothing....after a whole day racing the little vent I bought from autozone was just moist on the inside...didn't even have a true catch can and didn't need it
I think we were shifting the 4.7 USA 16V at 5500rpm, then upped it to 6000rpm which is well past power peak for that engine, but with the tall automatic gears needed the extra ommphh for the next one.....
On my euro 16V racer I also shifted at 6000-6250 max...same for 32v racer However none of the "real racers" lived that long on track...the best was Casper at around 26 hours for me, plus a few more for owner who built her. The Krankenwagon ran basically forever with minimal engine issues.....nearly 200hours on track for me and more for its current owner until it blew up from excessive ignition timing chasing HP
I am burning about a quart and a half per day (four 20 minutes / session) But it is burning a bit of oil on street.
My engine have 250,000 kms. I just installed Greg's Oil Filler neck baffle and the next DE is in May. So I will see then.
I need to talk with Greg concerning his evolved valve cover breathers/oil separators.
I've got a pretty good idea on what the piston to wall clearance and the valve guide clearance is, after 250,000 miles....I've seen several apart at this mileage.
While there isn't a magic cure for wear, it would be really fun to know what is possible and see if anything, beside a fresh engine, would help.
04-08-2019, 05:12 PM
