When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
His car is so highly modified I figured it's plausible some kind of knock detection system could be installed.
Originally Posted by Bulvot
Only if there is a place for the water to leave the system. An AOS condenses the water, and it doesn't leave the system. Even if it's heated. Not a huge problem in the summer, but in the winter it builds up significantly. Take it or leave it. Those are the facts.
This is a legitimate issue to be aware of, even stock systems struggle at times in cold weather. It takes a lot of driving to heat up oil to 100C in winter.
did some street test runs to work on jetting and think i'm in the ball park ! around 12.5 at WOT . First runs i had no oil in the cola bottle... but as engine heats up the last runs did give again some oil.
I use 10W60.
After a lot of thinking what is possible i cut of a spare oil tower from it's base , ( now some welding to do ) and will mount that one in series with the oem one.
Of course also with flow back to sump through a T mounted just above the metal pan tube.
Hope this works....
I have that baffle plate in my car as part of my oil control solution. The rest of that kit is what I replaced with my Verus one. The 928MS baffle plate works much better than a previous one I had installed.
While I am no expert when it comes to blow by or crank case venting, I will share with you another option to consider
Something you may want to consider for your rally car is a crankcase vacuum pump system like those used in drag and other racing systems. These systems help reduce / eliminate piston blow-by and excessive pressurization of the crank case, which can impede oil returning from the heads. The operating theory is applying some vacuum to the crankcase will help pull the rings against the piston walls and thus preventing blow-by. This a fairly well proven system for preventing blow-by in racing applications with tested benefits to HP gains and managing oil consumption. You can read more about the application here: https://www.gzmotorsports.com/vacuum-pump-guide.html.
A few of us GTS owners are running a similar system, running a vacuum pump in the air-pump location. On my GTS, the pump pulls from the oil filler neck (OFN) and sends the oil laden air to an Air-Oil separator (AOS). Oil is returned to the sump and air/water vapor can be returned to the intake or vented to atmosphere (racing applications). For those of us who have installed this In the GTS this has really helped eliminate oil consumption.
Here is diagram of how the system on my car is laid out. It seems to be preforming very well, although I am not racing my GTS yet. Hopefully this is useful for your troubleshooting.
Last edited by Michael Benno; 03-28-2021 at 03:57 PM.
Michael, i have installed a Moroso vacuum pump on my supercharged 850i.... but only to avoid excessive oil leaks through gaskets.
I keep it at 100 mbar .
You mention 12 inch Hg which is 0.4 bar .... at that vacuum you can have problems with oil pressure ... ? Yes , one benefits blow by at that vacuum but needs special oil pressure needs.
Michael, i have installed a Moroso vacuum pump on my supercharged 850i.... but only to avoid excessive oil leaks through gaskets.
I keep it at 100 mbar. You mention 12 inch Hg which is 0.4 bar .... at that vacuum you can have problems with oil pressure ... ? Yes , one benefits blow by at that vacuum but needs special oil pressure needs.
Correction, I just checked my documentation, I have the relief valve set to 10in-Hg. I have not observed any impact to oil pressure at the gauge under load, but remember, the gauge maxes out (5bar) well below the system pressure relief (i think it's 10bar). So to answer your question properly I would need an oil pressure gauge that went above the max system pressure.
According to my research (review the information on recommended vacuum https://www.gzmotorsports.com/vacuum-pump-guide.html) 14in-Hg vacuum is the maximum recommended vacuum that should be applied on the crankcase before there is a theoretical impact to oil pressure. I haven't been able to find any documented evidence to point out that these vacuum systems will pull oil out of the pressurized lubrication surfaces. Although, I would be very interested in any information on this topic.
Even though the vacuum relief is set at 10in-Hg, my system does not pull more than 9in-Hg at 6300-redline. The vacuum range pulled by the pump is determined by the pulley size. In my case here are some data points:
sounds like excessive blowby,
might be time for fresh rings
With carburetors, you also have to be careful of how much "over fueling" is occurring.
Alusil engine's rings are not happy with too much extra fuel.
The OP needs to monitor the accelerator pump discharge amount.
And depending on how old the Webers are, they may or may not have my transfer circuit modification.
I personally have a Porvent 200 in my 89 taking the gasses from the filler neck and the passenger's side head and hooked it's out port to the smog pump.
Then I unhooked the vacuum valve that controls the air being pumped to the cat so it only sends air to the airbox netting a very minor vacuum effect using the factory parts and keeps pretty much all oil out of the intake.
It also sneaks it by the smog shops
A real vacuum pump obviously is better than this but it is something to consider if they're outside of your price range or comfort zone.
With carburetors, you also have to be careful of how much "over fueling" is occurring.
Alusil engine's rings are not happy with too much extra fuel.
The OP needs to monitor the accelerator pump discharge amount.
And depending on how old the Webers are, they may or may not have my transfer circuit modification.
i have now the 50 pump jets and 00 bypass ( as standard mounted in IDA48's )
Next i want to try with 50 bypass valves... so reducing the shots to half and see what it does.
Would like also to try 40 pump jets ... so duration is longer but i do not have those. Must look for a Europe vendor as i buy those up till now in the UK but with ridiculous import taxes now !
what i fear is that when you want real performance gain out of vacuum it must be that high that it becomes dangerous on oil pressure without special modifications.
I use it on the supercharged 850i just to prevent the sump gasket ( in fact all gaskets ) leaking oil... so 100 mbar is already enough.
Moroso pump installed were oem was a second alternator
oil separator made out of a dry sump tank.
so i mounted a second oil separator ( also with drain to sump ) in series with the oem one.... curious if it will solve my problem... we will see next dyno run.
Still to find a hose in one piece that fits both diameters....
Last edited by belgiumbarry; 04-08-2021 at 07:11 AM.
With carburetors, you also have to be careful of how much "over fueling" is occurring.
Alusil engine's rings are not happy with too much extra fuel.
The OP needs to monitor the accelerator pump discharge amount.
And depending on how old the Webers are, they may or may not have my transfer circuit modification.
i ordered pump jets 40 ( smallest available for IDA48 ) and will try that first . So the pump volume stays the same but over a longer period ( x 1.56 ), and less liquid spray vaporizes better to help combustion. It stays a short period but will be leaner .
In a later test i can try bypass valves to reduce pump volume.
03-26-2021, 01:16 PM
