acceleration hesitation

Posts specific to the 2.5 litre turbo engine

acceleration hesitation

Postby Boxer » Wed Sep 05, 2007 10:02 pm

Has anyone else noticed a tendency to get a small hesitation sometimes immediatley following the depressing of the accelerator after a period of trailing throttle/part throttle. Generally in the lower RPM range (1500-2500).

I get a small 'hesitation' after I have been in traffic and letting the car coast for a while and then suddenly accelerate. If I have been on and off the throttle for a bit - I dont get it - only after a period of trailing throttle or idling. Tends to be more pronounced in S mode - haven't noticed it in I mode

Its a tuned by STi BTW
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Postby EJ25 » Wed Sep 05, 2007 10:18 pm

do you mean a lag? if so, it happens to my 2.5 too.. but im blaming my missing res..
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Postby Roddez » Thu Sep 06, 2007 10:55 am

Boxer,

I have similar problems, especially in 2nd Gear.

I tend to notice surging/hesitating.

I can understand some type of hesitation or slow pickup if the boost pressure is low and you then floor it.

I talked to subaru about the problem and they offered to reset the computer, but that hasn't solved the problem. It is also a little intermittent, similar to the rough idle I also have.

Take it to Subaru and it behaves perfectly. Leave the service centre and it will misbehave on the way home.
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Postby GTSPECB STI » Thu Sep 06, 2007 1:04 pm

Yep I have experienced the same thing partiucularly in sport mode. In the USA the Leggacy and STI owners are up in arms about this and it is ref to as a stutter on the forums. A good tune would fix this I believe but yet to find an option.
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Postby WhiteGTB » Thu Sep 06, 2007 2:13 pm

Hi guys, this might help... but not sure if it is worth it...

My mate had this exact same issue on his MY07 GT STi, I posted the topic here - http://forum.liberty.asn.au/viewtopic.php?t=1220
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Postby Roddez » Thu Sep 06, 2007 3:50 pm

Trieu wrote:... but not sure if it is worth it...


Dude, there's no way I'm going to pay 2K to get the car to do what it's supposed to do in the first place.

What does having MRT play with the electronics to do your new car warranty?
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Postby WhiteGTB » Thu Sep 06, 2007 4:41 pm

Roddez wrote:
Trieu wrote:... but not sure if it is worth it...


Dude, there's no way I'm going to pay 2K to get the car to do what it's supposed to do in the first place.

What does having MRT play with the electronics to do your new car warranty?


I hear ya bud.. I think it is some tuning done to the ECU, but don't quote me...

Just thought it might help is all :)
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Postby Boxer » Thu Sep 06, 2007 5:10 pm

GTSPECB STI wrote:Yep I have experienced the same thing partiucularly in sport mode. In the USA the Leggacy and STI owners are up in arms about this and it is ref to as a stutter on the forums. A good tune would fix this I believe but yet to find an option.


Yeah a stutter is a valid description - its definatley not lag.

Also only happens if the pedal is pressed quickly - feeding the throttle slowly is fine
Lifes pretty straight without twisties:

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Postby adam » Thu Sep 06, 2007 5:33 pm

this happens with our GT as well. if you kick it in the guts too quickly the power delivery is REALLY uneven. it respond much better if you get quicker as your foot goes down or in other words as the revs rise. if you keep it above 3grand you can put your foot down as quickly as you like...
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Postby Bobolicious » Sat Sep 08, 2007 12:37 am

Yeah mines the same and I have an aftermarket tune as well.
Sometimes it's that bad that my head nearly hits the windscreen!

Very annoying and also dangerous... You don't want this happening when making a right hand turn into oncoming traffic... :shock:
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Postby Boxer » Sat Sep 08, 2007 12:40 pm

Bobolicious wrote:Yeah mines the same and I have an aftermarket tune as well.
Sometimes it's that bad that my head nearly hits the windscreen!

Very annoying and also dangerous... You don't want this happening when making a right hand turn into oncoming traffic... :shock:


Geez mines no where near that bad - just a slight stutter you can feel, it doesn't make you decelerate in any way
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Postby viriix » Sat Sep 08, 2007 3:24 pm

Yep, I noticed that same problem when I first had the car..

Most times it's fine, the odd times it just decides to bog down and go yeah.. i'll just sit here and "wham" it comes back on.. by then a bit too late :p

I've ordered a sprint booster, hopefully that'll get rid of the problem completely..
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Postby MY07GT » Sat Sep 08, 2007 3:29 pm

I remember that bog.

After the turbo back exhaust i havent seemed to notice it much.

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Postby EJ25 » Sat Sep 08, 2007 4:44 pm

viriix wrote:Yep, I noticed that same problem when I first had the car..

Most times it's fine, the odd times it just decides to bog down and go yeah.. i'll just sit here and "wham" it comes back on.. by then a bit too late :p

I've ordered a sprint booster, hopefully that'll get rid of the problem completely..

first MY07 to have sprint booster?
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Postby MY07GT » Sat Sep 08, 2007 5:27 pm

If the other adaptor fitted on mine then he woulda been the second.

Well mine will be on first! LOL!

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