The subject was Vaccum pumps for clearing the crankcase. The stock pump was brought up. We simply said the stock pump pulls no nowhere near enough volume to provide anything useful under boost and mentioned real vacuum pumps need to be used. We mentioned we are running one. See how those two relate, vacuum pump - vacuum pump. Then Tyler asked for full details, we prefer not to share those, Pretty simple stuff.
This set up is for 100% race cars only. It requires the removal of AC, PS, etc. We have it installed on both our half-mile car and the upcoming drag car. At some point, once we get some new trap speeds at 1/2 mile events, and some ET's we will post up some build notes. Its just a little premature currently. We like to put results before build details.
That’s pretty solid.Here is a log screenshot on a low boost run from early testing. After dialing the pressure relieves in we have it pulling about 12 in/hg at redline now regardless of boost. At idle it pulls about 5-6 in/HG which is perfect. Run is attached for reference of what kind of power it makes on 10 psi...
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Here is a log screenshot on a low boost run from early testing. After dialing the pressure relieves in we have it pulling about 12 in/hg at redline now regardless of boost. At idle it pulls about 5-6 in/HG which is perfect. Run is attached for reference of what kind of power it makes on 10 psi...
12in/hg is generally considered to be ideal for reducing windage and reducing blowby while being low enough to not pull air past seals or prevent oiling. I’m sure there are variations from engine to engine, but I’d imagine Tony has played around with his vacuum break to set the highest vacuum he can under full load without causing any seal howling and the 5-6 is where it falls at idle.
The stock PCV system uses manifold vacuum to pull at idle. That is generally between 15-20 in/hg depending on the vehicle. The factory PCV system restricts this down, and you end up with a small amount of vacuum being pulled. If you go External PCV, plug the head ports, and leave that same 15-20 in/HG unchecked you are pulling vacuum past the seals, and need to use a vacuum relief or metered leak to get it down to a usable level. 5-6 In/HG is a perfect place to be at idle to avoid pulling vacuum past the seals, and also giving enough vacuum to evacuate the crankcase.
Can get the vacuum down as low as you want. There is no set level. 10 in/hg is fine if you are running manifold vacuum at idle. You want 5 remove the shims, and trim the spring to get what you want.
That you think a Vacuum pumps main goal to keep oil out of the combustion chamber is your right, it doesn't mean it is correct. The vacuum pump is there to clear the crankcase of crank windage, crankcase pressure from combustion making its way past the rings, etc. This frees up pumping losses and increases the engine efficiency and therefore additional power is usually made. On the other hand. A catch can is designed to keep oil out of the combustion chamber by removing the oil mist from these removed gases before they routed back into the intake tract if you are not going VTA. But we appreciate the opinion.
I never said it was the main goal so don’t put words in my mouth. You made a statement that is misleading and incorrect in regards to what a vacuum pump does on a racing engine. Maybe you were speaking in terms of n54 only??
Tony, If you think it is not possible to blow oil into the combustion chamber with weak rings and excessive crank case pressure then you should probably go back to selling sneakers. I’m out.We have been building turbos kits in some way shape or form since 1978 when we pulled turbos from aircraft and put them on race cars, boats etc. Just an FYI, If you are here to compare resumes and length of time working on race car things.
What Omar stated is incorrect, what you are stating backing him is inherently incorrect. As I said you can disagree all you would like, it doesn't make you right. No, unfortunately a vacuum pump does not "during WOT it basically prevents oil from being brought into combustion chamber" That is the job of an engine catch can or crankcase filter" The vacuum pump is removing pressure from the bottom of the piston, not the top, it has nothing to do with keeping anything out of the combustion chamber, it has everything to do with keeping things out of the crankcase. Two distinctly different areas of the engine. Crankcase gases are never going to be sucked into the combustion chamber even on a motor with tired rings the combustion process produces much higher pressure, and with poor ring seal, it will pressurize the crankcase. The crankcase will not pressurize the combustion chamber and dilute it with oil. You are perfectly describing the purpose of a catch can again, but hey everyone has their opinions. There are people out there that actually believe the earth is flat, enjoy your holiday sir...
The only possible way your crankcase could be pressurized above the pressure in your cylinders is if your pcv system were totally f*cked, you were running insane boost pressures, you were at bdc, and even then at worst would be at a the same psi on both sides of the piston.
We have been building turbos kits in some way shape or form since 1978 when we pulled turbos from aircraft and put them on race cars, boats etc. Just an FYI, If you are here to compare resumes and length of time working on race car things.
What Omar stated is incorrect, what you are stating backing him is inherently incorrect. As I said you can disagree all you would like, it doesn't make you right. No, unfortunately a vacuum pump does not "during WOT it basically prevents oil from being brought into combustion chamber" That is the job of an engine catch can or crankcase filter" The vacuum pump is removing pressure from the bottom of the piston, not the top, it has nothing to do with keeping anything out of the combustion chamber, it has everything to do with keeping things out of the crankcase. Two distinctly different areas of the engine. Crankcase gases are never going to be sucked into the combustion chamber even on a motor with tired rings the combustion process produces much higher pressure, and with poor ring seal, it will pressurize the crankcase. The crankcase will not pressurize the combustion chamber and dilute it with oil. You are perfectly describing the purpose of a catch can again, but hey everyone has their opinions. There are people out there that actually believe the earth is flat, enjoy your holiday sir...
The vacuum pump required is LARGE to move the volume needed. A shotgun bracket is not going to work. Much too small. Look up the GZ pumps, it's what we use. Not cheap, not small, but most race car things are neither. Whats the point of going through all the work of adding the small vacuum pump if it doesn't move enough volume to actually clear the crankcase. The N54 makes big power it needs a full size vacuum pump if you want to realize the full benefits. Getting one to fit as akin to fitting 10lbs of shit in a 5lb bag, and once it's on, getting it dialed in was another adventure unto itself
