('14-'18) Cold engine/ CVT tranny = delayed upshifts? - Page 2 - Subaru Forester Owners Forum
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post #16 of 27 (permalink) Old 11-29-2013, 01:05 PM
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Direct injection totally transforms a turbo engine.

First, you get good detonation resistance, so the car can run a higher compression ratio. For example, the EJ20 engine in my previous car had 8.0:1 compression, and felt very soggy off boost. There's a lot more snap with the FA20-DIT's 10.6:1 compression. Off-boost doesn't last long though, as...

...turbo direct injection engines are able to generate peak-torque fast (<2000 RPM), and hold it there throughout the power band. Basically the fine-grained control over fuel metering (plus other stuff like the variable valve timing) allows the tuner to fill in any lumps or troughs in the power curve with boost. Whereas my EJ20 had sort of a wiggly, hilly torque curve, the FA20-DIT is table-top-flat. That's what makes it nice when you punch it at 60 mph to pass someone. The torque turns on like a switch, and just applies constant thrust (the CVT really accentuates this effect) throughout the maneuver, and before you know it, you are going 90+. Oops.

DI is also apparently good for emissions too, but that's not the reason I'm into it.

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post #17 of 27 (permalink) Old 12-02-2013, 04:04 PM Thread Starter
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Some update about the rpm. Today I did about 25 miles before the rpm goes down to normal. I am really curious about that if its really normal for it to take so long to go down to normal?

Thx

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post #18 of 27 (permalink) Old 12-02-2013, 04:11 PM
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Quote:
Originally Posted by micross50 View Post
Some update about the rpm. Today I did about 25 miles before the rpm goes down to normal. I am really curious about that if its really normal for it to take so long to go down to normal?

Thx
It takes a long time for transmissions to warm up. Somewhere on Nasioc there is a guy that ran around during summer and recorded how long it took his transmission to get up to a steady temperature. All said and done the average time was around 70 minutes before the transmission fluid stayed at a steady hot temperature. To be fair, that was a manual. Auto's will heat up faster because of the torque converter (when it is unlocked the RPMs are higher and it produces a lot of heat) but especially when it is cold, it takes a fair amount of time to warm up to operating temp.

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post #19 of 27 (permalink) Old 12-02-2013, 04:15 PM Thread Starter
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So maybe I dont drive long enough each day to see a good gas consommation. It will probably take longer than 25 miles to get the real good mpg of the car.
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post #20 of 27 (permalink) Old 12-02-2013, 04:56 PM
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I use manual mode and shift it at 2500 and it seems to heat things up faster.
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post #21 of 27 (permalink) Old 12-07-2013, 06:29 AM
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Has anyone been able to read the temp of their CVT fluid ?

The manual just shows its turns on the high temp light at 125 C (approx 257 degrees)
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post #22 of 27 (permalink) Old 12-13-2013, 10:29 AM Thread Starter
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Torque convertor

I'm thinking it could be torque converter not locking up. Thats why I am getting less good fuel efficiency and a highger RPM.

I am not sure but I think it could be a problem there...


Thx
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post #23 of 27 (permalink) Old 11-07-2015, 11:12 PM
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To answer a question...

I've been monitoring CVT temps for a bit. It takes a ONG tme to warm up, and never gets what I'd call hot.

eg. 10c ambient temp, tranny takes about 40 miles to come to a stable temperature somewhere around 55c. Gentle highway running will have it slowly drop back towards 50c, crawling in traffic might make it raise a degree or two as might a steep climb.

I've yet to find a situation where there's enough slippage to make much heat. Rock crawling or walking-pace traffic up a mountain pass maybe? Certainly the load would need to be sustained for quite a time and at high ambient temps...

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post #24 of 27 (permalink) Old 01-28-2016, 01:26 PM
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I've read the messages in this thread and have a few questions. I have a 2014 Subaru Outback Limited 2.5 and when driving in cold weather the RPM at 50 mph will often be as high as 3000 (continuous 50 mph on the flat). When I move it over to manual setting, it tells me it's in 3rd or 4th gear. Is this normal? The RPMs seem way too high and the engine sounds like it's straining. This has been going on for about a month. It doesn't happen every time I drive it. Feedback appreciated.
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post #25 of 27 (permalink) Old 01-28-2016, 10:17 PM
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I'll add some temperature data here.

Playing with some corrugated board as a "winter front", I can confirm that the front-mount fluid cooler makes a large difference to peak temperatures but rather less to warmup speed.

As above, normal temperatures are 55c or so
Radiator grille closed off completely brings normal temps up to the mid-60s, and sustained hard highway use (80mph-ish) has temperatures into the low 70s.

But merely cutting a 3" hole in the closer just infront of the cooler, and temperatures again stabilise to 55c or so.


2015 SJ XCdiesel CVT
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post #26 of 27 (permalink) Old 02-18-2016, 12:42 AM
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...and some more, now that it's cold. For the EU diesel of course but it might not differ that much.

If fluid temperature is <= 3c, the torque converter remains unlocked until fluid temp passes 10c.

2015 SJ XCdiesel CVT
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post #27 of 27 (permalink) Old 02-18-2016, 04:08 AM
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Quote:
Originally Posted by micross50 View Post
So maybe I dont drive long enough each day to see a good gas consommation. It will probably take longer than 25 miles to get the real good mpg of the car.
You would be correct ... if you only driving 16 km (10 miles) to work your car is just starting to get warm when you get to your destination (during very cold weather). You're not going to ever get good gas mileage.

As others have said, shifting manually and keeping RPM's low is counterproductive to getting your engine / transmission up to temperature; and going so is also lugging the system, which is not good in the long term.
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