Author Topic: Some Winter Thoughts  (Read 454 times)

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Offline Airboy

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Some Winter Thoughts
« on: February 05, 2019, 11:30:51 AM »
Some Winter thoughts...

1) Engine oil take longer to heat up than coolant. Even longer if the under tray is missing.

2) PCV valve can freeze, AOS drain hose can clog, especially with sustained highway driving in extreme cold temps. Subaru with FMIC should block off the hood scoop. Ones with TMIC could block off part of the TMIC above the PCV valve.

3) Boost creep (high boost even with fully open waste gate) will happen at full throttle and mid to high rpm

4) Cold air has higher density (more oxygen per volume). More power? Yes, and also more fuel required. Going from +20C to -30C, air density changes by ~20% so fuel demand will also increase by ~20%. Stock fuel systems in STI/WRX or EvoX will see ~90% max injector duty cycle (IDC) at +20C so, it doesn't have the headroom for high boost at -30C. Boost creep from (3) above adds to the problem. If that doesn't sound bad enough, the 90% IDC number is at Calgary elevation (3500'). Air density increases at lower elevation....

Exercise caution...

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Offline kijho

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Re: Some Winter Thoughts
« Reply #1 on: February 05, 2019, 11:44:52 AM »
So what you're saying is we shouldn't send it into oblivion in this weather? ;D ;D

Offline Cagare

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Re: Some Winter Thoughts
« Reply #2 on: February 05, 2019, 11:50:56 AM »
So what you're saying is we shouldn't send it into oblivion in this weather? ;D ;D

Unless it's a leased vehicle.  >:D

Offline Tremor

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Re: Some Winter Thoughts
« Reply #3 on: March 03, 2019, 06:58:25 AM »
So just clarifying, on a '13 STI you'd recommend blocking off the right half of the TMIC for highway driving in the cold to prevent PCV freeze up?

Offline deedz

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Re: Some Winter Thoughts
« Reply #4 on: March 03, 2019, 09:30:11 AM »
So just clarifying, on a '13 STI you'd recommend blocking off the right half of the TMIC for highway driving in the cold to prevent PCV freeze up?

I'm curious of Airboy's thoughts on this, but personally I'm running a Ver. 7 STi scoop on my 07 FXT along with a Grimmspeed splitter going to a 2012 STi TMIC. It didn't see much winter in the first two that I owned the car, but last winter I started blocking off both long sections of the splitter so only the very small section to the turbo gets air. I also started covering lines with foam pipe insulation. My PCV system looks a lot better overall, and it hasn't caused any issues with cooling the TMIC. With our common winter temperatures in SK, more than enough cooling still makes it's way in from the front of the car.
| 04 WRX [STi'd] Sport Wagon JBP | V7 EJ207 | V8 6-Speed/R180 | 02 WRX Sport Wagon PSM | Rebuilt EJ205 | 4EAT | SOLD 04 Forester XT PSM | 5-Speed | 07 Forester XT Limited OBP | Built EJ257 | 4EAT | SOLD 03 Subaru Forester XS Premium AW | No Engine | 99 GMC Sierra Classic SLE Z71 SGM | 6.0L LQ4/4L65E Swap | 05 Chevrolet Silverado SS AWD SBM | 6.0L LQ9 | 4L65E | 70 Chevrolet El Camino | 454 BBC | Turbo 400 |

Offline Airboy

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Re: Some Winter Thoughts
« Reply #5 on: March 03, 2019, 07:17:41 PM »
So just clarifying, on a '13 STI you'd recommend blocking off the right half of the TMIC for highway driving in the cold to prevent PCV freeze up?

Yes, a snug fitting piece of cardboard on the passenger side of the TMIC should be sufficient.  I am hesitant to block off the entire TMIC, as I would probably forget that it was blocked off...

Gain 50 ft-lbs, ask me how! :-)

Offline deedz

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Re: Some Winter Thoughts
« Reply #6 on: March 04, 2019, 12:29:48 PM »
Yes, a snug fitting piece of cardboard on the passenger side of the TMIC should be sufficient.  I am hesitant to block off the entire TMIC, as I would probably forget that it was blocked off...

Haha that would definitely be a worry.

For myself I grabbed some foam packaging pieces out of the packaging for a big PLC panel enclosure at work. They literally fit perfectly right up in my splitter. For me there should be no forgetting as I can see the ugly foam every time that I walk up to the car. At least it's black so it doesn't stand out and isn't as ugly as it could be.
| 04 WRX [STi'd] Sport Wagon JBP | V7 EJ207 | V8 6-Speed/R180 | 02 WRX Sport Wagon PSM | Rebuilt EJ205 | 4EAT | SOLD 04 Forester XT PSM | 5-Speed | 07 Forester XT Limited OBP | Built EJ257 | 4EAT | SOLD 03 Subaru Forester XS Premium AW | No Engine | 99 GMC Sierra Classic SLE Z71 SGM | 6.0L LQ4/4L65E Swap | 05 Chevrolet Silverado SS AWD SBM | 6.0L LQ9 | 4L65E | 70 Chevrolet El Camino | 454 BBC | Turbo 400 |