Thread: Finding a way to Reduce Oily Blow By Gases

I know it's just the way you said it was so nonchalant that it was funny

Post 33 is this:



The PCV valve is show to run into the big hose.


Post 29 is PCV Hose runs to a Air compressor filter, then to the intake manifold.



Hmm interesting, and I do need a new engine, so while I'm looking for a new one, I am willing to try some dangerous tricks to see if they help the HP/MPG and if it kills it well would be nice to get a new engine.

If you really want to improve gas mileage put a throttle stop so you can't go over half throttle.

Funny that everyone seems to think that a lead foot is always an issue to low gas mileage, but no one ever things that possibly sludge, vacuum leaks, oil, gas leak, gas evap leak, etc. etc. could be the problem.

Today I took a 269 mile trip. Left at 4:30 in the morning, was in DC by 6:30, car stood in the parking garage until 3PM at which time I left to go back home. This was in DC traffic, and I redlined the car about 5 times. I drove 198 miles and fueled up 6.175 gallons, giving me a gas mileage of 32.13.

I fueled up 69 miles before reaching home, there is a Shell gas station that I really like, I only use Shell 87 gas in my car. I drove 69 miles, redlined the car 2 times, hit the 4krpm couple times, ran with AC on all the way. Fueled up 1.833 gallons to be getting an amazing gas mileage of 37.64.

Now if you take the mile to redline ration, in 200 miles you can fit almost 3 (2.869) 69 mile runs. Say I would redline my car twice in every 69 mile run, that would be about 6 times would redline the car.

So in that 69 mile stretch, I floored the car more in ratio then in the 198 mile run. Yet I still got a gas mileage about 5 miles higher.

Now I may floor the car, but trust me sometimes you are at just hardware limits. Like no matter how hard you try a stock SE-R will only give you 140 BHP.

Now the reason I am looking at this is because I'm looking for a vacuum leak. It has occurred to me that every time I have to turn off the car for longer then 5 minutes to gas up, my gas is evaporating, thus giving me bad gas mileage.

This makes perfect sense because on the highway I would constantly get above EPA numbers, but in the city I would get 20-21MPG (my friends Camaro gets 23). In the City I fuel up once every few days, while highway driving it all gets used in one trip.

Anyway onto the PCV data, I will post it in the next post.

Alright so I tried to cap off the PCV Intake manifold spot and leaving the PCV just breathe.

After couple minutes, the cap that I used for the intake manifold started growing! I thought the intake manifold was supposed to suck in gases not push them out.

I did have more luck with capping off the intake and the VC breather. The car did seem to idle a little funnier with it disconnected hehe.

So to my conclusions:

• I'm beginning to think that my VC is bad thus releasing a lot of oil (not filtering it the oil before it hits the PCV Valve.
• My PCV valve has been replaced recently, and it rattles when I shake it, but it seems like the intake manifold vacuum gases seems to be constantly sucking the air and keeping the valve open even at idle.
• With all the extra unmetered air in the Intake Manifold, my car is running richer then it should be.
• I do have some Valve Cover gasket oil leaks, which are most likely sucking in more unmetered air.
  

Either way, fun fun

for turbo guys you can run 2 lines to a 2 one way check valves on the DP...

Lol ok man, I wouldn't worry about low gas mileage because of evaporating gas while you fill up

The reason highway and city are different... are well obvious an I'm sure you know. Nothing to do with evaporating gas lol.

few things though..

Your PCV valve will always be open as long as the pressure inside the VC is lower than that of the manifold. But I don't see how that's a problem? That's the point of it

If you haven't done so, you should also disconnect and cap the other hose going to intake, and that will solve your air metering issue (and put a breather on the open spot on VC). I think you are currently running what I had before I just switched it over now.

Actually it is the evaporating gas, it's the only thing that makes sense.

One week, I drove about 20 miles, and then had an oil leak, so the car was on jack stands for a week.

When I fiinished her up, I started the car, needle dropped a bit, went to fuel up and got 16MPG. So unless I had someone come up and siphon some gas out where else could it go but evaporate



Yes, I figured that was a point, but didn't think it should be constantly sucking on it , I thought it should be only under high load (per diagram?)

Thats what I did yesterday, I disconnected the Intake hose and capped off the intake, then I tried to disconnect the Intake Mani's PCV hole but the cap started getting bigger, I was afraid it would be like a balloon haha.

I'll post pictures when I get home

I've also been thinking about the T breather on the side of the valve cover.



I wonder why Nissan put after the maf, not before the maf?

Like with NX's and B13's didn't they run the other breather to the Stock Airbox, which should be before the MAF.

To the people that are wondering what I did there and why here are a few threads:

http://www.sr20forum.com/sr20de-technical-corner/59377-oil-accumulator-purpose.html#post501053
http://www.sr20forum.com/technical-information-library/80048-how-reroute-stock-oil-seperator.html

Nope, it's the same on B13's. It's after the MAF so that the intake mani doesn't take in unmetered air