So I bought a track car. Well, okay, two track cars.
01-28-2014, 05:48 PM
#181
Rennlist Member
Hi Alan,
It's destined to be a spare engine, so I'm going to go ahead and install it. Be happy to share any results running it with the vacuum pump. Amsoil? I guess I'd better use that stuff just so I don't get an "I told you so" from Kibort when she blows.
Rob, can you post some better pictures of the heat shields you're running with the headers? Thanks.
It's destined to be a spare engine, so I'm going to go ahead and install it. Be happy to share any results running it with the vacuum pump. Amsoil? I guess I'd better use that stuff just so I don't get an "I told you so" from Kibort when she blows.
Rob, can you post some better pictures of the heat shields you're running with the headers? Thanks.
01-28-2014, 05:51 PM
#182
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Adam-
Can shoot more pics tonight but this is the stuff I used:
Make sure you completely clean and degrease the surface before sticking it down.
Can shoot more pics tonight but this is the stuff I used:
Make sure you completely clean and degrease the surface before sticking it down.
01-28-2014, 06:48 PM
#184
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Stock S4 breather setup. I never took the intake off the top of the motor. Sharktuner said that all the sensors were working, so I didn't mess with it.
Should be an interesting autopsy. Should we start a 'pool' on how much oil is sitting in the lower intake plenum?
Should be an interesting autopsy. Should we start a 'pool' on how much oil is sitting in the lower intake plenum?
01-28-2014, 07:01 PM
#185
The sweeper will uncover the pickup, methinks. The oil in the intake (a constant thing, as Porsche never gave a ****) will reduce your octane to that of diesel. Do detonation hammering the bearings.
Yep, that breaks them. Keep oil going to the pickup (or pump) and keep oil from the intake. I am sure Greg will help you with that.
I'd like to get a red line on where these changes need to happen in the progression from street tires and a somewhat-street suspension and a much harder suspension and slicks.
Yep, that breaks them. Keep oil going to the pickup (or pump) and keep oil from the intake. I am sure Greg will help you with that.
I'd like to get a red line on where these changes need to happen in the progression from street tires and a somewhat-street suspension and a much harder suspension and slicks.
01-28-2014, 07:38 PM
#186
Race Director
Dr Rob....you weren't running the dry sump? If you were running the wetsump did you have an accusump? The wetsump with 3/8th spacer and OB pan can survive.....even with Anderson at the wheel (& Kibort-me-Sean-Jeff-anyone) BUT if it was knocking.....forget it...
When you open it...it WILL look like this
At least it didn't do this
When you open it...it WILL look like this
At least it didn't do this
01-28-2014, 07:43 PM
#187
Race Director
Here is what it sounds like on track....fast forward to about 16:15
On a more encouraging point....here was Anderson 1st stint where he passed 158 cars in one hour!!
On a more encouraging point....here was Anderson 1st stint where he passed 158 cars in one hour!!
01-28-2014, 07:46 PM
#188
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Adam - I for one would be interested to see the effect of a vacuum pumped system for a 32V racer, (since I drive one on the street...), of course much depends on the rest of what you do too...
I do think it can have a significant benefit in reducing oil mist ingestion (reduced pre-ignition) reducing the crank oil cloud and potentially also in draining down the head oil (depending on plumbing) - but wether it can make enough of a difference is the real question. I think we need some emprical data...? With or without Amsoil?
Alan
I do think it can have a significant benefit in reducing oil mist ingestion (reduced pre-ignition) reducing the crank oil cloud and potentially also in draining down the head oil (depending on plumbing) - but wether it can make enough of a difference is the real question. I think we need some emprical data...? With or without Amsoil?
Alan
I worked hard to make an oil separator that would help there and my latest iteration is better than all the others that I've tested....but it can only do so much.....after it is completely covered in oil.
Anything that runs in the higher rpms for any length of time is going to have problems.
__________________
greg brown
714 879 9072
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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!
greg brown
714 879 9072
GregBBRD@aol.com
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!
01-28-2014, 10:38 PM
#189
Nordschleife Master
The inadequacies with a vacuum system is the same as my street breather system. The area where the vacuum pump generally draws from is the filler neck and the filler neck gets overwhelmed with oil at anything above 4,000 rpm. At 5,000 rpm, that area is a solid slug of oil....so the vacuum pump is dealing with sucking up oil, not air.
Vacuum naturally reduces the oil cloud surrounding the crankshaft. If you run more than 15" Hg in the crankcase you have to have forced oiling to the wrist pins, or they will fail in quick order.
Add to that, the vacuum seals the rings better which creates less crankcase vapors to be having to control.
If you have detonation in the engine then the volume of gasses increases drastically. A stock S4 motor I retard the timing to 26 deg max at WOT to help reduce knocking, and keep the engine alive.
01-28-2014, 11:01 PM
#190
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Colin- many apologies for pre-empting our experiment- am still game to try whenever you're ready.
01-28-2014, 11:24 PM
#192
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My data testing has shown otherwise.
Vacuum naturally reduces the oil cloud surrounding the crankshaft. If you run more than 15" Hg in the crankcase you have to have forced oiling to the wrist pins, or they will fail in quick order.
You've actually tested this, yourself, or is this just assumptions from the internet? Try to keep in mind that before I came up with my current systems, I tried vacuum first....and saw the obvious inadequacies, firsthand. Go run a 928 engine on the dyno, at 5,000 rpms steady state, and get back to me. Your "pump" will be absolutely overwhelmed, with oil.
Add to that, the vacuum seals the rings better which creates less crankcase vapors to be having to control.
I can see where the vacuum will help with ring sealing on engines that have ring sealing problems. "Healthy" 928 engines without ring sealing problems, don't push oil past the rings, so this is a moot point for anything that doesn't need a rebuild.
I'd submit that if the rings are worn to the point where they are passing oil, it's probably a bad thing to force them to seal. It's one hell of a lot cheaper to re-ring an engine than to go in and bore it and replace the pistons, because the worn/damaged rings are forced to seal against the bores, destroying them.
Nothing anyone "bolts onto an engine" is going to be a "rebuild in a box". People will be way farther ahead to address the problem than to fool themselves into thinking that "sucking" the rings onto the cylinder walls is a long term solution.
If you have detonation in the engine then the volume of gasses increases drastically.
Very few of the 928 engines detonate....the late model engines have knock sensors to keep that from happening. I've only ever seen one 928 engine that had any sign of piston damage from detonation. Detonation is really easy to see, on the head gasket....and I've yet to see a stock 928 engine with any sign of this.
A stock S4 motor I retard the timing to 26 deg max at WOT to help reduce knocking, and keep the engine alive.
That's not logical. Every engine, depending upon the amount of carbon and deposits left in the combustion chamber, the initial stack up of tolerances when the engine is built, and the actual fuel being burned is going to have a different requirement for timing. That statement is like saying the stock chips work the best for all engines. Since the Bosch engine management can remove up to 9 degrees of timing with the knock sensors functioning....you think that 15 degrees of timing is a good target at WOT?
Seriously, that's just a silly statement.
Vacuum naturally reduces the oil cloud surrounding the crankshaft. If you run more than 15" Hg in the crankcase you have to have forced oiling to the wrist pins, or they will fail in quick order.
You've actually tested this, yourself, or is this just assumptions from the internet? Try to keep in mind that before I came up with my current systems, I tried vacuum first....and saw the obvious inadequacies, firsthand. Go run a 928 engine on the dyno, at 5,000 rpms steady state, and get back to me. Your "pump" will be absolutely overwhelmed, with oil.
Add to that, the vacuum seals the rings better which creates less crankcase vapors to be having to control.
I can see where the vacuum will help with ring sealing on engines that have ring sealing problems. "Healthy" 928 engines without ring sealing problems, don't push oil past the rings, so this is a moot point for anything that doesn't need a rebuild.
I'd submit that if the rings are worn to the point where they are passing oil, it's probably a bad thing to force them to seal. It's one hell of a lot cheaper to re-ring an engine than to go in and bore it and replace the pistons, because the worn/damaged rings are forced to seal against the bores, destroying them.
Nothing anyone "bolts onto an engine" is going to be a "rebuild in a box". People will be way farther ahead to address the problem than to fool themselves into thinking that "sucking" the rings onto the cylinder walls is a long term solution.
If you have detonation in the engine then the volume of gasses increases drastically.
Very few of the 928 engines detonate....the late model engines have knock sensors to keep that from happening. I've only ever seen one 928 engine that had any sign of piston damage from detonation. Detonation is really easy to see, on the head gasket....and I've yet to see a stock 928 engine with any sign of this.
A stock S4 motor I retard the timing to 26 deg max at WOT to help reduce knocking, and keep the engine alive.
That's not logical. Every engine, depending upon the amount of carbon and deposits left in the combustion chamber, the initial stack up of tolerances when the engine is built, and the actual fuel being burned is going to have a different requirement for timing. That statement is like saying the stock chips work the best for all engines. Since the Bosch engine management can remove up to 9 degrees of timing with the knock sensors functioning....you think that 15 degrees of timing is a good target at WOT?
Seriously, that's just a silly statement.
01-29-2014, 02:04 AM
#193
There are some points to data to compare when talking about this (on the internet).
The knock sensors and LH are sort of clunky when listening for knock. They do hear knock - but not the subtle knock events that happen very often in stages of pre-ignition and also detonation. I have talked directly to many people about how modern ECUs work and what the aftermarket is doing with knock detection. Its much more subtle -
Its actually in line with what you normally state about pounding the bearings Greg. These engines are not high compression, but we are talking about a barely 91 octane fuel.
My supposition is that there are your big Two happening to destroy the engine, but prior to that, the bearings are getting pounded from small detonation events not being seen by the knock sensors, and this is causing higher crank case pressure (detonation will shake the rings and blow pressure past them). Boom - we are back to the basic story of a slug of oil going into the intake and heads and nothing is left in the crank case.
Add in the oil coke on the chambers and the pistons, and there is even more preignition and detonation.
Where there any knock sensors on that engine that Rob has video of? The one that was being tuned with Link.
The knock sensors and LH are sort of clunky when listening for knock. They do hear knock - but not the subtle knock events that happen very often in stages of pre-ignition and also detonation. I have talked directly to many people about how modern ECUs work and what the aftermarket is doing with knock detection. Its much more subtle -
Its actually in line with what you normally state about pounding the bearings Greg. These engines are not high compression, but we are talking about a barely 91 octane fuel.
My supposition is that there are your big Two happening to destroy the engine, but prior to that, the bearings are getting pounded from small detonation events not being seen by the knock sensors, and this is causing higher crank case pressure (detonation will shake the rings and blow pressure past them). Boom - we are back to the basic story of a slug of oil going into the intake and heads and nothing is left in the crank case.
Add in the oil coke on the chambers and the pistons, and there is even more preignition and detonation.
Where there any knock sensors on that engine that Rob has video of? The one that was being tuned with Link.
01-29-2014, 12:09 PM
#195
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Borescoped a little last night- the engine is seized so I couldn't get pistons to BDC to look at the cylinder bores, but the tops of the pistons are remarkably clean.
There is a comically large lake of oil in the lower intake plenum. Will measure just for S's & G's, remind me to take a graduated cylinder home..
♫ One of these things is not like the other, one of these things just doesn't belong . Can you tell me which one is not like the others, before I finish this song? ♫
Plugs were brand new, ~2 hours of running time ago
Cylinder 1:
Cylinder 2:
Cylinder 3:
There is a comically large lake of oil in the lower intake plenum. Will measure just for S's & G's, remind me to take a graduated cylinder home..
♫ One of these things is not like the other, one of these things just doesn't belong . Can you tell me which one is not like the others, before I finish this song? ♫
Plugs were brand new, ~2 hours of running time ago
Cylinder 1:
Cylinder 2:
Cylinder 3: