DBW and upshifting issue
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- Junior Standardshifter
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DBW and upshifting issue
Just bought a new '09 Subaru Impreza (NON-turbo model).
Never driven a DBW throttle before and I have noticed the following issue.
When I up-shift, and get off the throttle there is a lag (seems to be known with the DBW systems) and then when I push the clutch in, the revs go up at first instead of down.
To fix this, I get off the throttle sooner... then clutch in....
However, in harder accelerations if I time it wrong, then I slow down through engine breaking, or the revs go higher than planned.... max HP at 6K, redline just after... don't want to blow the redline.
Also, I figure I can't shift as fast if I have to get off the throttle sooner. Or I guess I just have to plan ahead better?
Any thoughts?
-ELI
Never driven a DBW throttle before and I have noticed the following issue.
When I up-shift, and get off the throttle there is a lag (seems to be known with the DBW systems) and then when I push the clutch in, the revs go up at first instead of down.
To fix this, I get off the throttle sooner... then clutch in....
However, in harder accelerations if I time it wrong, then I slow down through engine breaking, or the revs go higher than planned.... max HP at 6K, redline just after... don't want to blow the redline.
Also, I figure I can't shift as fast if I have to get off the throttle sooner. Or I guess I just have to plan ahead better?
Any thoughts?
-ELI
- RITmusic2k
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Re: DBW and upshifting issue
First, Welcome!
Secondly, everyone here refuses to answer your questions until you post pictures of your car!
Okay, not really. First off, you won't incur any damage if you bounce the tach off redline because your engine employs a fuel or spark cutoff that prevents the engine turning above a predetemined RPM. The only way you could overrev and destroy your engine is via mechanical overspeed... such as downshifting into 2nd at 75mph. You won't ever do it on an upshift.
As far as hard acceleration goes, you waive the right to any smoothness in shifting, and it is acceptable to use the clutch to drag engine revs down before you complete the shift.
Secondly, everyone here refuses to answer your questions until you post pictures of your car!
Okay, not really. First off, you won't incur any damage if you bounce the tach off redline because your engine employs a fuel or spark cutoff that prevents the engine turning above a predetemined RPM. The only way you could overrev and destroy your engine is via mechanical overspeed... such as downshifting into 2nd at 75mph. You won't ever do it on an upshift.
As far as hard acceleration goes, you waive the right to any smoothness in shifting, and it is acceptable to use the clutch to drag engine revs down before you complete the shift.
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Re: DBW and upshifting issue
Thanks... I guess I will just have to practice.
At the moment, I don't think I dump the clutch fast enough when up-shifting.
I didn't dump fast in trying to keep it smoother.... don't worry, I don't do it like I am doing a launch.
However, its been years since I drove a manual.... therefore I have been on the gas too soon before when up-shifting, and therefore riding the clutch some (BUT I know this is wrong and know what to change... clutch, then gas!)
SO... if I have this right... a smooth progression for up-shifting.
Seamless, yet separate right? Overlapping these steps (too much) is where clutch wear and rev problems occur, right?
Gas off.... clutch in.... shift... clutch out... gas on.
Sounds simple enough!
Car has less than 200mi on it so far... and no pictures exist yet.
-ELI
At the moment, I don't think I dump the clutch fast enough when up-shifting.
I didn't dump fast in trying to keep it smoother.... don't worry, I don't do it like I am doing a launch.
However, its been years since I drove a manual.... therefore I have been on the gas too soon before when up-shifting, and therefore riding the clutch some (BUT I know this is wrong and know what to change... clutch, then gas!)
SO... if I have this right... a smooth progression for up-shifting.
Seamless, yet separate right? Overlapping these steps (too much) is where clutch wear and rev problems occur, right?
Gas off.... clutch in.... shift... clutch out... gas on.
Sounds simple enough!
Car has less than 200mi on it so far... and no pictures exist yet.
-ELI
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Re: DBW and upshifting issue
200 miles and you're already shifting at 6k? I've never had a new car, but this seems like making and olympic runner sprint a mile in his pajamas right when he wakes up.
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Re: DBW and upshifting issue
I did a shift at ~5K once.... and then remembered that there is a break in procedure.
((I knew to at least stay away from red-line when its new... but I could see going over it IF shifting at 6k for max power))
Looked it up when I came to a stop... no reading manuals while driving manuals.
So, I stopped driving with anything over 4k (3.5k to be safe most of the time).
I am driving it all nice and per-manual break in instructions now. However, I feel it is hard to vary the engine speed as it requests when I only have 2k to 4k and driving on the HWY. Seems like gentle county road driving would be the best with accel and decel periodically.
Please don't get too upset, I have learned my lesson.... and before anything bad really happened.
But you have to admit... its hard not to have fun.
They say to keep it below 4k for the first 1k miles... but at 4k is when the variable timing seems to kick in and its gets fun (at least with the tester-- see below).
My car was not used for test-driving at the dealer luckily.
The dealer I went to wanted to demonstrate the power and handling... so we pushed the demo car (with only 80mi on it) rather hard.
I feel sorry for who ever buys it.
I think that most people don't read manuals, and don't care about break in procedures at all. Then we buy them used.
The dealer warned me about that "new engine" smell that takes a few hundred miles to get rid of. My guess is that it is some parts coating meant for engine break-in.
PS - I hate new car smell... plastic is really not that good smelling!!!
-ELI
((I knew to at least stay away from red-line when its new... but I could see going over it IF shifting at 6k for max power))
Looked it up when I came to a stop... no reading manuals while driving manuals.
So, I stopped driving with anything over 4k (3.5k to be safe most of the time).
I am driving it all nice and per-manual break in instructions now. However, I feel it is hard to vary the engine speed as it requests when I only have 2k to 4k and driving on the HWY. Seems like gentle county road driving would be the best with accel and decel periodically.
Please don't get too upset, I have learned my lesson.... and before anything bad really happened.
But you have to admit... its hard not to have fun.
They say to keep it below 4k for the first 1k miles... but at 4k is when the variable timing seems to kick in and its gets fun (at least with the tester-- see below).
My car was not used for test-driving at the dealer luckily.
The dealer I went to wanted to demonstrate the power and handling... so we pushed the demo car (with only 80mi on it) rather hard.
I feel sorry for who ever buys it.
I think that most people don't read manuals, and don't care about break in procedures at all. Then we buy them used.
The dealer warned me about that "new engine" smell that takes a few hundred miles to get rid of. My guess is that it is some parts coating meant for engine break-in.
PS - I hate new car smell... plastic is really not that good smelling!!!
-ELI
Last edited by ELI_the_ICE_man on Wed Apr 01, 2009 6:28 pm, edited 1 time in total.
- RITmusic2k
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Re: DBW and upshifting issue
There are a few different schools on thought on the break-in process, actually... I think the guys over at jalopnik have gathered up a bunch of info that illustrated how pretty intense loading and revving did a much better job of getting piston rings seated and so on, and the cars that were broken in this way ended up running much smoother and with less consumption than cars that were babied for the first few thousand miles.
On the other hand, if you trust the manufacturer to design and build your car, you can probably trust them enough to follow their break-in suggestions.
On the other hand, if you trust the manufacturer to design and build your car, you can probably trust them enough to follow their break-in suggestions.
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Re: DBW and upshifting issue
I just edited my above message on break-in and stuff..... see there for what would have been.
I guess I have the best of both worlds.
Gentle break-in like the designers say... with an occasional fun burst (until I feel guilty, which is right away).
The break in on the Subaru is only listed as 1k miles... which shouldn't take that long to put on.
Not at this rate, I like to drive it... so I have been taking the long way home!
-ELI
I guess I have the best of both worlds.
Gentle break-in like the designers say... with an occasional fun burst (until I feel guilty, which is right away).
The break in on the Subaru is only listed as 1k miles... which shouldn't take that long to put on.
Not at this rate, I like to drive it... so I have been taking the long way home!
-ELI
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Re: DBW and upshifting issue
Funny... but not the song I would have pictured!
Then again, how do you picture sound? Unless you use drugs... or are in wonderland with Alice... yet again, that is basically the same thing.
Anyway, not the driving music of choice. But appreciated none-the-less.
-ELI
Then again, how do you picture sound? Unless you use drugs... or are in wonderland with Alice... yet again, that is basically the same thing.
Anyway, not the driving music of choice. But appreciated none-the-less.
-ELI
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Re: DBW and upshifting issue
Oh, I know about the whole "driving it hard to get oil onto the rings", but that has to be done within the first mile or two of a brand new engine to get FULL effectiveness. Basically, what has to happen is this:
1. Warm up brand new, never fired engine
2. Take it up to 5000 rpm(under load, ie, in gear), engine brake back down to 2k
3. Repeat 10 times
4. Shut off engine, change oil
Voila, you have perfectly broken in your new engine. Rev it to your heart's content from now on. (once it's warm, of course )
1. Warm up brand new, never fired engine
2. Take it up to 5000 rpm(under load, ie, in gear), engine brake back down to 2k
3. Repeat 10 times
4. Shut off engine, change oil
Voila, you have perfectly broken in your new engine. Rev it to your heart's content from now on. (once it's warm, of course )
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Re: DBW and upshifting issue
I hate rev hang. Srsly.
1980 Buick LeSabre 4.1L 5MT
Put your car in your sig!
Learn to launch/FAQs/lugging/misused terms: meta-sig
Put your car in your sig!
Learn to launch/FAQs/lugging/misused terms: meta-sig
watkins wrote:Humans have rear-biased AWD. Cows have 4WD
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Re: DBW and upshifting issue
yeah, that engine has been broken in for the past 2k miles, it was broke in on the test drive for that matter.
ring seal is the only thing that break in does these days, machining tolerances are so perfect in the bearings that they will be perfect when you put it together, unless you hack the shit out of it. if it blows up when you do the break in pulls, it wouldve blown up anyway
start up. let it warm up. check for leaks.
drive around, WOT to 4500-5000, let it engine brake back down to almost idle. do this a few times
drive bakc, change oil, and take it to the track.
just change the oil at 100 and 500 to flush out the little leftovers.
ring seal is the only thing that break in does these days, machining tolerances are so perfect in the bearings that they will be perfect when you put it together, unless you hack the shit out of it. if it blows up when you do the break in pulls, it wouldve blown up anyway
start up. let it warm up. check for leaks.
drive around, WOT to 4500-5000, let it engine brake back down to almost idle. do this a few times
drive bakc, change oil, and take it to the track.
just change the oil at 100 and 500 to flush out the little leftovers.
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Re: DBW and upshifting issue
didn't read the whole thread, but yay another Subie!
actually my DBW does have a bit of rev hang also, but it's consistent and it actually helps me because the revs fall so fast. and i kind of like the overrun sound on those times when the revs spike a bit as i upshift. vrrrrrrRRRvrrrrrrrRRR really you just kinda have to get used to the timing, and don't worry about the using the clutch to pull down the revs for an upshift, it's no big deal.
actually my DBW does have a bit of rev hang also, but it's consistent and it actually helps me because the revs fall so fast. and i kind of like the overrun sound on those times when the revs spike a bit as i upshift. vrrrrrrRRRvrrrrrrrRRR really you just kinda have to get used to the timing, and don't worry about the using the clutch to pull down the revs for an upshift, it's no big deal.
2013 Subaru Impreza WRX in Orange
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Re: DBW and upshifting issue
Good deal... thanks all.
I will drive it like the manual says too.... and about the first oil changes?? Don't know.
But my father used to build cars, and I will see him in a few days.
Car will have ~350mi on it then. We'll see.
Manual says nothing about first oil changes, or special oil, or anything during the break in or newer engine.
Oh, and to the other Subaru drivers... with that AWD stuff, ever notice that when you are turning in a parking lot, full steering to the lock turn, that there is a slight vibration and or noise?
I am assuming this is the newness of the car, combined with the front drive linkages being pushed to the limit. The turning radius is very tight, so I guess there is some forces at work to make the universal-like joints bend that far?
I am sure everything is completely normal... but it is my first NEW car, and I am paranoid.
-ELI
I will drive it like the manual says too.... and about the first oil changes?? Don't know.
But my father used to build cars, and I will see him in a few days.
Car will have ~350mi on it then. We'll see.
Manual says nothing about first oil changes, or special oil, or anything during the break in or newer engine.
Oh, and to the other Subaru drivers... with that AWD stuff, ever notice that when you are turning in a parking lot, full steering to the lock turn, that there is a slight vibration and or noise?
I am assuming this is the newness of the car, combined with the front drive linkages being pushed to the limit. The turning radius is very tight, so I guess there is some forces at work to make the universal-like joints bend that far?
I am sure everything is completely normal... but it is my first NEW car, and I am paranoid.
-ELI
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Re: DBW and upshifting issue
that's probably just the power steering pump working hard. in any car with power steering it's not a good idea to keep the steering wheel at full lock for very long.
2013 Subaru Impreza WRX in Orange