2017 Subaru Forester 2.5 6M- rev hang?

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Tough to find a real answer but I wonder if this is normal. Say I'm in 1st gear, accelerate to 3000rpm and clutch in, off gas. Revs stay at 3000rpm for a very noticeable moment. Like over a second before they start to drop. Makes the 1-2 shift tough unless you really exaggerate a double clutch with a chance for the revs to fall. Even if I don't clutch but leave in gear. 1st gear up to 3000 or so and let off the gas it stays there a second or more like I'm still holding gas about the same position. Thoughts? A lot of talk on forums about it being for emissions but I've never driven a vehicle that did this. I'm going to bring it to the attention of the service manager when I take it for the 6k oil change.
 
Common in a lot of "modern" manual transmission cars I have driven. My 2016 Chevy SS Sport Sedan has a noticeable
Rev hang when going up through the gears. Makes a smooth quick shift up all but impossible.

Emissions thing I guess I have to live with...in the 60s and 70s I could upshift smoothly as fast as you could snap your fingers. The "good old days". But I do enjoy the horsepower advantage of my current LS3 V8!
 
My 2012 Regal GS does the same thing making 1-2 and 2-3 shifts smooth is tough especially when the engine is cold. The tune is stock but if an aftermarket tune would take care of that for me, that might just push me over the edge for getting a tune.

On the other hand, the Camaro, you can rip shifts off quick because those RPM's drop like a meteor when those butterflies snap closed.
 
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Yeah I'm used to timing upshift to the drop in rpm but this involves literally putting it in neutral, letting clutch out, wait a sec, clutch in and shift. It's weird and hard to get used to it. Otherwise bringing clutch right to the friction point to scrub off some rpm before getting on the gas but is it going to wear synchros earlier since it's at higher rpm while shifting? Any idea if a tune is available for a 2.5 NA Forester?
 
Its to prevent a hydrocarbon burp when the throttle slams shut. Many manual equipped cars in the last 10 years or so do it.
 
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Can you not adjust your driving to it? I had one, and never had a problem, but I wasn't racing my Forester. Double clutching? Scrubbing off rpm? Maybe you can't drive a stick.
 
Originally Posted By: Colt45ws
Its to prevent a hydrocarbon burp when the throttle slams shut. Many manual equipped cars in the last 10 years or so do it.


Exactly, and not limited to ten years either. My Dad's 70's Corona did the same exact thing. I found it maddening.
 
How could that be implemented in a non drive-by-wire vehicle? I presume most of what people are experiencing in recent memory is direct control of the electronic throttle by the ECU.



Originally Posted By: SteveSRT8
Originally Posted By: Colt45ws
Its to prevent a hydrocarbon burp when the throttle slams shut. Many manual equipped cars in the last 10 years or so do it.


Exactly, and not limited to ten years either. My Dad's 70's Corona did the same exact thing. I found it maddening.
 
Originally Posted By: deanm11
How could that be implemented in a non drive-by-wire vehicle? I presume most of what people are experiencing in recent memory is direct control of the electronic throttle by the ECU.


This can be implemented with a traditional throttle cable quite easily. These devices are called a number of things...idle speed control motors, idle speed solenoids, idle control solenoids, throttle kickers, etc. Simply, these devices are mounted to a carburetor (my '84 Cutlass had one) or to or next to the throttle body and a plunger would extend (electronically-controlled) to keep the throttle lever from returning to its true "closed" position under certain circumstances. Most of the vehicles I've owned use external devices, but I think I remember our two Mopar minivans (with the 3.3/3.8 engines) having this function internal to the throttle body, so you couldn't see an external device.

I'm pretty sure that nearly every engine built in the past 30-40 years has had one of these. I don't mean that in a condescending way, but only as an observation -- these came about in the emission control era and have persisted since. I bet each of the vehicles in your signature has one. That doesn't mean that it's as intrusive as on the new Subarus, but there's almost always a way for the ECU to manipulate the throttle, regardless of drive by wire or physical throttle cable.
 
Try using more throttle or a bit more revs, as it might kick the ecu into more of a sport mode. I suspect you have a fairly low first gear and the jump to second is a bit larger than you are used to, and with a heavier dual mass flywheel it can take some time even without some rev hang for the revs to drop. My old Tracker was like this and eventually I just revved it to 3.5-4k in 1st and getting into 2nd didn't seem to take so long.
Another thing you can try is letting off the throttle a bit earlier before you push in the clutch, then the throttle trickery atleast results in some forward motion...
 
Its 100% normal. Take foot off gas before shifting.. and it will reduce the hang immensely.
that is for mid-rpm shifting
if shifting at high rpm its just a timing thing.. you will adjust.
Also if the A/C is on the revs will drop much faster.

Its like driving 2 different cars (fun right?
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As stated above it is an emissions thing with the DBW throttle body.

If you hook up a obdII device you can see even with the foot totally off the gas it takes a few sec to drop to 0% throttle. It usually stops around 14% IIRC.

If shifting at 3000rpm in first try to be off the gas for just a moment before shifting and it will drop much faster.

FWIW try turning on defrost or A/C and try your shift again it will be different.

If the car isnt cold(or brand new) I much prefer going to about 3500rpm or even slightly higher.
If it is cold I just live with it.. you definitely can adjust to it.
 
Surely less of a pain in automatic cars - but from renting a number of cars each year there is some lag in electric throttle in some cars ... plus all the weird stuff they make them do at traffic lights ... (trans interface stuff in other threads) ...
 
Originally Posted By: deanm11

How could that be implemented in a non drive-by-wire vehicle? I presume most of what people are experiencing in recent memory is direct control of the electronic throttle by the ECU.



Originally Posted By: SteveSRT8
Originally Posted By: Colt45ws
Its to prevent a hydrocarbon burp when the throttle slams shut. Many manual equipped cars in the last 10 years or so do it.


Exactly, and not limited to ten years either. My Dad's 70's Corona did the same exact thing. I found it maddening.



It was a little thing called a TPS, it electro-mechanically held the throttle open until the car was nearly still. I have seen older vehicles
with a mechanical throttle body setup that uses an air bleed system to increase revs, and others that have a small electric motor to move the throttle a small amount when desired...
 
Originally Posted By: SteveSRT8
I have seen older vehicles with a mechanical throttle body setup that uses an air bleed system to increase revs, and others that have a small electric motor to move the throttle a small amount when desired...


Yep; my '84 Cutlass with a computer-controlled Quadrajet would do it. It's not related to, or caused by, drive by wire throttle systems. It's an emissions mitigation technique that's enabled by the use of computer or vacuum control, and has been in place for decades.
 
Whoever said I can't drive a stick is wrong. I've driven mostly stick since I was 16, learned when I was 14. It would make more sense if I took a video to explain it. I'm sure it has to do with emissions but it's annoying to not be able to let the revs drop naturally between shifts. I'm sure I'll get used to it but I special ordered a manual transmission because I enjoy driving stick. This makes it less fun. Even our 2013 Corolla, with drive by wire, decelerates instantly when you let off the gas. Never had one do this.
 
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