Thoughts on Vacu-Pan setup on A DSM?

[92tsifwd]

I have heard that vacume is good for the crank case. I have heard it helps ring seal. The factory runs both the oil breather hose and the pcv ventalation line to vacume source at the intake manifold and the turbo intake pipe. The bad thing with this is the oil breather gums up the intercooler and ic pipes and the pcv valve tends to leak boost into the crankcase causing the dipstick to pop out and lots of other problems. So the solution to both of these problems is to run a vacu-pan setup like the V8's do Basically you eliminate the pcv valve and tee both the oil breather and where the pcv used to be to a larger line and run it to the exhaust pipe. This creates a vacume alot like in the stock setup only with no downsides. I have seen alot of v8s using this setup. They run the lines from each valve cover to the colector on each header. What I was wondering is where would be a good spot to tap into the exhaust for a dsm for the most vacume and what size of line would you run to the exhaust? Who has this setup on a dsm? What are your thoughts on this setup and how are you running yours? Any thoughts or suggestions are welcome.
Jason

 

[DSMJim]

I would suggest you stick with the intake, it has a lot more vaccum to deal with. Using the exhaust works and we have done it however it's not quite that easy. You will have to be on the down pipe behind the engine away from the heat of the manifold pretty well just before the cat. You will have to weld on a thin piece of tubing about 12 inches long before you put your hose onto that. It takes almost a foot of material beofre the heat is not too high to melt high temp rubber tubing. You can then run your vent and PCV into that.

We did this setup on a honda all motor race car with limited success but it was nothing better than just runnign it into the intake. I'm not sure what the problem is with running it back into the intake? So what if there is oil inside your intercooler pipes and it's all gummy. Do you have some neon inside there and the judges are taking points away for the dirt inside your intake manifold or something? It's not gonna harm anything and is designed that way. If it makes you sleep better at night, pull your IC pipes and IC and clean them once per year. Really though it does nothing, has no ill effects and you need not worry about it.

On the other hand if your motor has a lot of blow by and your dumping huge amounts of oil into your intercooler pipe then your in trouble and that will cause a problem.

 

[gixrman]

plus its illegal because your pulling oilly air into your exhuast, which creates emissions. Why not just use a oil seperator between the valvecover and the intake.

 

[thegreatms]

i heard about someone using the AC compressor to pull air out of the case and into a catch-can. then you just have to drain the can once in a while

 

[pboglio]

Just buy a vacuum pump from jegs or summit if you want to get crazy. They ain't cheap though. Hooking it up to the exhaust seems at odds with creating a vacuum. Maybe they use a flow obstruction (protruding nipple or angled plate etc.) in the exhaust pipe that creates a negative pressure zone around it to lower the pressure below ambient. If not then your only going to see pressure in the exhaust pipe and not vacuum. I'd hook it up to the intake via a oil separator, Moroso has a few nice ones with internal baffles. You should pull a good 2-3 psi or so of vacuum that way if you have a restrictive intake, 1 psi or less if your running no MAF and a huge airfilter.

 

[92tsifwd]

I have heard from alot of people that when the ic gets full of oil film it becomes less efficiant. When I had it hooked up like the stock setup my car smoked ocasionaly because of the oil in my ic pipes. I cleaned my ic, pipes, and turbo and it has stayed clean and it does not smoke now. So you are saying that the oil in the ic and pipes has no effect on ic efficiantcy? Then why does everybody recamend cleaing it? Also my brand new pcv valve leaks both ways when I tested it leaking boost into the crankcase. However when I eliminated the pcv and ran both the lines to the ground it seemed to be loosing more oil then with vacume applied. BTW my car has perfect compression. I could care less what the inside of my ic and pipes look like but, I don't like my car running less efficiant. So you are saying that a vacupan setup is less effective over the stock setup? Why do alot of people run them then? Thanks guys for the replies.

 

[pboglio]

If you just tap the exhaust pipe by the downpipe with no other modifications, you'll likely get 3-4 psi pressure, NOT vacuum. This is not what you want. Now if you tap a hole immediately ahead of this hole and thread in a large bolt or something INTO the exhaust flow, then the pressure zone right behind it may be lower than ambient. Your using a localized low pressure zone to your advantage. Depending on the geometry of the object, you can create localized vacuum or high pressure, depending on whether you measure the pressure on the frontside or backside of the blunt object. This is one reason why OEM's place the exhaust outlet at the rear of the car (i.e. low pressure zone) and not the side. The car is the blunt object obstructing flow in this case, immediately behind it is a low pressure zone. This is all basic fluid dynamics.

Just do it on the turbo intake like it is stock, use an oil separator and you've got 2-3 psi vacuum no sweat. This is hard to beat short of running a vacuum pump, which is extreme overkill for a street car.

 

[92tsifwd]

Thanks guys for the replies. I will do it like it was exept now my intake pipe don't have the nipple for the line. Its the dejontool 2gmass in a 1g car intake pipe. I will probably thread one in a couple of days and get a oil seperater.