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Old 12-15-2017, 08:50 AM   #1
SprinterWRX2018
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Default 2018 loud on start up

Hey guys just bought a new 2018 wrx premium with the 6speed manual back in September . Just wondering why on start up the engine sounds very loud almost like theres no oil in it for about 10 seconds then goes away. The noise is also heard in the exhaust. Not sure if this is done on purpose for an agressive tone at start up. Anyone know if this is normal? Also while in gear, 4th gear is the only one i feel vibration in the shifter. Thanks for the help
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Old 12-15-2017, 09:18 AM   #2
Raikkonen-F1
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Quote:
Originally Posted by SprinterWRX2018 View Post
Hey guys just bought a new 2018 wrx premium with the 6speed manual back in September . Just wondering why on start up the engine sounds very loud almost like theres no oil in it for about 10 seconds then goes away. The noise is also heard in the exhaust. Not sure if this is done on purpose for an agressive tone at start up. Anyone know if this is normal? Also while in gear, 4th gear is the only one i feel vibration in the shifter. Thanks for the help
Congrats on the purchase. It's programmed to idle high at start up to heat up the catalytic converter - this is normal. Not sure about the vibration, but my 15 wrx had a slight vibration in 4th when i placed my hand on it, although, it didn't occur all the time. Maybe someone else on here can chime in.
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Old 12-15-2017, 11:50 AM   #3
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You are describing the cold start cycle. As said above it idles higher and the result is a louder and more aggressive sound from the exhaust. Completely normal. I have the 4th gear vibration too sometimes and I am pretty sure itís normal. I donít think any manual car ever made has zero vibration in the shifter.
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Old 12-15-2017, 12:02 PM   #4
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everything you mentioned is normal
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Old 12-16-2017, 07:16 AM   #5
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Yup, perfectly normal - just one of the "fun" things engineers can do with direct injection...
The actual purpose as mentioned is to heat the cat up faster. The ECM is injecting fuel late in the compression cycle which then finishes burning in the exhaust after the exhaust valves open.
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Old 12-16-2017, 09:07 PM   #6
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Thanks for the info guys it all makes sense.
Is it also normal to hear some slight clanking noises from the front suspension when hitting bumps? almost sounds like bad strut mounts that i used to have in an older car. But I'm sure this is something normal due to the sport riding nature of this car. Thanks again
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Old 12-16-2017, 09:16 PM   #7
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It's pretty normal for a cold startup.
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Old 12-18-2017, 09:45 AM   #8
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Quote:
Originally Posted by SprinterWRX2018 View Post
Thanks for the info guys it all makes sense.

Is it also normal to hear some slight clanking noises from the front suspension when hitting bumps? almost sounds like bad strut mounts that i used to have in an older car. But I'm sure this is something normal due to the sport riding nature of this car. Thanks again


Do you have a video?
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Old 12-18-2017, 09:09 PM   #9
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Quote:
Originally Posted by SprinterWRX2018 View Post
Also while in gear, 4th gear is the only one i feel vibration in the shifter. Thanks for the help

THIS...I also feel vibration after shifting to fourth. And NO I am not resting my hand on the shifter. It can be felt immediately after shifting into 4th! Thought there was something wrong with mine.
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Old 12-19-2017, 03:55 AM   #10
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it will always be loud on a cold startup. kind of standard for wrxs. enjoy the car.
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Old 12-21-2017, 03:25 PM   #11
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It's loud also there is an air pump that's pumping fresh air into the exhaust to heat up the cat. It's pretty normal. Some cars sound like a vacuum when you start it.
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Old 12-23-2017, 07:51 PM   #12
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put me in for 4th gear shifter vibrations...
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Old 12-24-2017, 09:26 AM   #13
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Quote:
Originally Posted by jasonwrx86 View Post
It's loud also there is an air pump that's pumping fresh air into the exhaust to heat up the cat. It's pretty normal. Some cars sound like a vacuum when you start it.
No, you have STI and WRX confused.
There is no secondary air pump on 2018 WRX. Nor 2017, 2016, 2015...

Last edited by Elbert Bass; 12-25-2017 at 10:21 AM.
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Old 12-25-2017, 06:25 PM   #14
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I believe the loudness is the ignition timing retard that is on the OTS tunes to heat the cat up. I have an etune and noticed that my car no longer does this, but still have close to 2k rpm idle on a cold start. Have a catted grimmspeed jpipe.
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Old 12-26-2017, 10:29 AM   #15
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Originally Posted by That_Boosted_Life View Post
I believe the loudness is the ignition timing retard that is on the OTS tunes to heat the cat up. I have an etune and noticed that my car no longer does this, but still have close to 2k rpm idle on a cold start. Have a catted grimmspeed jpipe.
Nope, it's injection timing. Subaru calls it "Stratified Mode". It injects a lean pulse of fuel on the intake stroke and then a rich pulse during compression. The result is the fuel/air mixture is still burning as the exhaust valves open creating that noise.
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Old 12-27-2017, 08:07 PM   #16
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Mine drones until it settles @ 850
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Old 12-27-2017, 08:42 PM   #17
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Quote:
Originally Posted by Elbert Bass View Post
No, you have STI and WRX confused.
There is no secondary air pump on 2018 WRX. Nor 2017, 2016, 2015...
Actually there is. I can hear it turning off.
It stays on after you shut off the engine for a couple of more seconds to cool down the cat.
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Old 12-27-2017, 08:49 PM   #18
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sounds like a normal cold start to me.
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Old 12-28-2017, 06:38 AM   #19
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Originally Posted by Elbert Bass View Post
Nope, it's injection timing. Subaru calls it "Stratified Mode". It injects a lean pulse of fuel on the intake stroke and then a rich pulse during compression. The result is the fuel/air mixture is still burning as the exhaust valves open creating that noise.
nope, it's ignition timing.
My STI sounds the same way due to ultra retarded timing when cold.
I'm pretty sure my STI isn't injecting a rich pulse during the compression stroke considering the intake valve is closed.

The spark timing is what affects 'when' the majority of the burn takes place.
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Old 12-28-2017, 07:18 AM   #20
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nope, it's ignition timing.
My STI sounds the same way due to ultra retarded timing when cold.
I'm pretty sure my STI isn't injecting a rich pulse during the compression stroke considering the intake valve is closed.

The spark timing is what affects 'when' the majority of the burn takes place.
No, you can't inject fuel after the valves are closed on your STI (last century port fuel injection technology). The discussion is regarding a later model WRX equipped with a very different engine than your EJ25 STI with port injection and a secondary air pump.
Since 2015 WRX has had an FA20 with Direct injection Turbo and it can (and does) inject fuel at different times and multiple times during intake and compression strokes depending on conditions.
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Old 12-28-2017, 08:25 AM   #21
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Quote:
Originally Posted by Elbert Bass View Post
Since 2015 WRX has had an FA20 with Direct injection Turbo and it can (and does) inject fuel at different times and multiple times during intake and compression strokes depending on conditions.
no doubt, direct injection can inject during the exhaust stroke if you really wanted it to.

The louder, deeper, later ignition timing exhaust sound on cold start ups is from a later ignition timing.
That's why it's the same louder, deeper, later ignition timing sound in my STI.
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Old 12-28-2017, 04:31 PM   #22
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Quote:
Originally Posted by SprinterWRX2018 View Post
Hey guys just bought a new 2018 wrx premium with the 6speed manual back in September . Just wondering why on start up the engine sounds very loud almost like theres no oil in it for about 10 seconds then goes away. The noise is also heard in the exhaust. Not sure if this is done on purpose for an agressive tone at start up. Anyone know if this is normal? Also while in gear, 4th gear is the only one i feel vibration in the shifter. Thanks for the help
Piston slap, normal. take it easy until it warms up
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Old 12-30-2017, 07:47 AM   #23
Elbert Bass
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Originally Posted by rtv900 View Post
no doubt, direct injection can inject during the exhaust stroke if you really wanted it to.

The louder, deeper, later ignition timing exhaust sound on cold start ups is from a later ignition timing.
That's why it's the same louder, deeper, later ignition timing sound in my STI.
I'll be sure to tell Subaru, they will need to correct the description for Stratified Warm-up Mode in the "2014 Forester" and "Direct Injection System" training literature and curriculum.
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Old 12-31-2017, 05:40 PM   #24
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I'll be sure to tell Subaru, they will need to correct the description for Stratified Warm-up Mode in the "2014 Forester" and "Direct Injection System" training literature and curriculum.
training literature and curriculum?
are you serious man?

What am I missing about cold start operation?
serious question too. why is my sti no different if it's the direct injection fundamentals causing this?
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