Can someone explain the MK7.5 and 7.5’s pcv magic?

[StorableComa]

What ratio of water/methanol is recommended? A 50/50 ratio is recommended. This has been demonstrated to be the best for charge/air cooling, excellent detonation control, and safety. Ratios of anywhere from 30% to 50% methanol work well and deliver excellent octane gains and cooling.
https://www.nitrousexpress.com/gaso...r/methanol,excellent octane gains and cooling.

 

[GTIfan99]

50/50 is what most people use. I briefly played with meth injection on my 05 STi, but the tracks I frequented didn't allow a fuel source to not be contained in a gas tank or fuel cell.

So that's another concern if anyone is planning on tracking with meth. That will be track or sanctioning body dependent.

The small track local to me now doesn't car at all. They let Miatas do track days with the factory hoops. I've removed the plastic covers over those hoop, no way I'd stake my life on a 1 inch thin wall tube.

 

[jimlloyd40]

That won't tell you if the nozzle is clogged or if the controller failed.

I know good systems have failsafe, but even then, shit happens.


And you'd be a good candidate, because you're an astute car owner and stay on top of maintenence. I just think it's a waste if you're only cleaning valves with it. The power potential is similar to E85.

But there's risk with even a good system. I've seen fancy controllers with failsafe, flow monitoring, and boost controlled spraying fail, like any electronic device can, and it only takes one pull when you didn't notice the controller has no power. Seen it too many times.

If you're happy with your current power levels and from what you've posted, don't have an issue with carbon buildup, then I just don't see the point.

Good points. And I would be looking at it more from the standpoint of keeping the valves the cleanest. I would like more power but with the miles I drive and the fact that I can't afford breakdowns I'll probably stay away from it. And when I say I can't afford breakdowns I'm talking about reliability not financial just because of what I use my car for. That's why I'm staying away from MPI also because the reliability with the increased power would be too risky.

 

[GTIfan99]

Good points. And I would be looking at it more from the standpoint of keeping the valves the cleanest. I would like more power but with the miles I drive and the fact that I can't afford breakdowns I'll probably stay away from it. And when I say I can't afford breakdowns I'm talking about reliability not financial just because of what I use my car for. That's why I'm staying away from MPI also because the reliability with the increased power would be too risky.

Over the years, I've gotten more conservative modding. I find tuned OEM or OEM+ is the way to go for reliability. The more exotic the parts get and the higher the power, reliability exponentially takes a turn for the worse.

 

[jimlloyd40]

Over the years, I've gotten more conservative modding. I find tuned OEM or OEM+ is the way to go for reliability. The more exotic the parts get and the higher the power, reliability exponentially takes a turn for the worse.

I agree. For me at this stage of my life I wanted to have fun. I was willing to take the risk but going even higher power would be foolish. I'm at that point where the next step would be to risk being one of those part out threads.

 

[Keehs360]

It won't burn off the blowby only the condensation.

Oh no it won’t burn the oil in the blow by. Just the unburned fuel and condensation. With 0w20 it would be easy to burn it all off in the winter. The 5w40 might be an issue in the winter since it might not get warm enough. Though I suppose it depends on where one lives and how cold ambient is.

5w50 in the winter wouldn’t let me see beyond 175f - 180f oil temps usually. But the wrx gets about 2-5 oil changes a month. So meh

 

[Keehs360]

It doesn't have oil in it. It has runny black combustion blowby. I'm sending a sample to Blackstone and then I'll be able to precisely say what it is but it sure isn't oil. It has the consistency of water and is black even after just changing the oil.
It's combustion blowby. The stuff that gets by the piston rings and is pulled from the crankcase.

Isn’t the catch can contents just a mix of oil, unburned fuel and water condensation? What else could it be but that?

 

[StorableComa]

You can use either 5w30 or 40, at least on the pre 0w20 models. 30 might be a good swap to for the winter.

 

[El_bigote_AJ]

I would use caution with water/meth. More than one engine has destroyed a piston or two when the system failed.

If you do it, don't skimp. Get a reliable system with a fail safe.

that’s when a car is tuned for it and dependent on it with a port injection system as is used a supplemental fuel system. Kits that spray pre throttle are more for cooling the air charge, by the time it’s In the combustion chamber it’s already atomized to where you can’t even tune the car aggressive Enough to where it’s a supplemental fueling.

 

[GTIfan99]

that’s when a car is tuned for it and dependent on it with a port injection system as is used a supplemental fuel system. Kits that spray pre throttle are more for cooling the air charge, by the time it’s In the combustion chamber it’s already atomized to where you can’t even tune the car aggressive Enough to where it’s a supplemental fueling.

NASIOC is littered with threads of meth failures from systems spraying pre throttle. Maybe it's because Subaru makes pistons out of paper mache or the ECU is about as powerful as an 80's handheld football game, but even spraying pre TB allows significant timing advance and would cause significant knock if flow is suddenly stopped. Maybe VW's ecu is so good it's quick enough retard timing and prevent damage? I don't know, but that isn't my observation on other platforms.

 

[GTIfan99]

You can use either 5w30 or 40, at least on the pre 0w20 models. 30 might be a good swap to for the winter.

I use 5w-40 in my 2019. There's a few others that do too.

 

[jimlloyd40]

Oh no it won’t burn the oil in the blow by. Just the unburned fuel and condensation. With 0w20 it would be easy to burn it all off in the winter. The 5w40 might be an issue in the winter since it might not get warm enough. Though I suppose it depends on where one lives and how cold ambient is.

5w50 in the winter wouldn’t let me see beyond 175f - 180f oil temps usually. But the wrx gets about 2-5 oil changes a month. So meh

No oil in the blowby I have collected in a large coffee can. I'm going to get it tested.

 

[Keehs360]

NASIOC is littered with threads of meth failures from systems spraying pre throttle. Maybe it's because Subaru makes pistons out of paper mache or the ECU is about as powerful as an 80's handheld football game, but even spraying pre TB allows significant timing advance and would cause significant knock if flow is suddenly stopped. Maybe VW's ecu is so good it's quick enough retard timing and prevent damage? I don't know, but that isn't my observation on other platforms.

I have experience here

the boxer motor design is full of drama. The bottom end fights gravity way harder than an inline 4. Meth can be done only if the bottom end is built. But you’ll want direct port. Post throttle

you can also do pre throttle too but the problem with pre is it runs best at a 75% mix but your adding more points of failure since it has to be piped after the turbo and as far from the intercooler as possible.

eventually and possibly, the pressure can create a lean situation of the nozzle gets loose.

 

[Keehs360]

No oil in the blowby I have collected in a large coffee can. I'm going to get it tested.

If it’s dark, that’s oil. Condensation is transparent and fuel kinda is too.

 

[jimlloyd40]

If it’s dark, that’s oil. Condensation is transparent and fuel kinda is too.

It's black even immediately after changing the oil. It has the consistency of water. It is combustion blowby that gets past the piston rings and is collected from the crankcase. I'm having Blackstone test it.