# Crankcase Ventilation Filtration on the Xty



## LEONGSTER (Apr 9, 2006)

I thought I'd start on another potentially contentious topic:

Crankcase Ventilation Filtration.

About 2,000 km ago I began documenting the effects of fitting an oil-mist separator to the QR25 DE's crankcase ventilation system.

Prior to this I used something called an oil-catch can (D-Spec), but found this to be quite useless as (being unbaffled) it was not condensing any of the blow-by and the oil mist was simply being sucked back into the intake.

I eventually swopped the oil catch can for a compressor oil mist separator, fitted between the PCV valve and intake manifold. The idea being to reduce the amount of 'blow-by' that gets sucked back into the engine.

The effect has been positive: better idle, smoother acceleration, less discernible 'detonation' under load, and interestingly - slightly better fuel economy. More important is the fact that I am now collecting about a teaspoon of oil in the filter every week - which would otherwise have ended up in the combustion chamber.

Many relatively low-mileage QR25DE engines have been found to have had unusually high levels of carbon build-up which I suspect is not just the result of an excessively rich fuel map.

Can improved crankcase ventilation filteration improve the lifespan and performance of the XTY. Time will tell of course.

But for now I am just curious: Anyone out there with a similar experience?


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## bas (Oct 12, 2005)

Hey, any progress or results of this mod. Sounds very interesting. Was it a DIY, or 'off-the-shelf' product. Any pics.


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## LEONGSTER (Apr 9, 2006)

bas said:


> Hey, any progress or results of this mod. Sounds very interesting. Was it a DIY, or 'off-the-shelf' product. Any pics.


I've been running the air/oil separator since late October last year. The amount of blow-by collected has been significant - about 4-5 ounces of oil by my reckoning.

Originally, I got a D-1 Spec oil catch tank but found it didn't do anything to filter out the oil. (I have since modified the D-1 catch tank with a separate filter chamber and will be installing it in a couple months).

Here's a pic of my existing set-up, which uses a simple compressor in-line oil separator which I got for around 20 bucks. I empty it every couple weeks.










Results: 

- After an initial jump in FE to around 10.7 km per litre the first tankful after I fitted it, fuel economy has settled back to the usual 10.2 -10.5 km per litre (using 95ron - which is the equivalent of USA 89 ron).

- My XTY's rough in-gear idle has improved considerably - although I cannot say if the lack of blow-by is the main cause as I am running several other mods alongside it.

- It's also stopped detonating under hard acceleration (use to occur sometimes under WOT around 3000-3500rpm).

-The engine's got a nice "sewing-machine" smoothness to it - although this is subjective. Also on a subjective note: I've been getting a lot of wheelspin in first gear driving like I normally do on dry tarmac ( but maybe someone squirted armourall on my tyres? ha ha.).

I'm just glad all that gunk isn't going into my engine anymore.


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