It's just turbo-lag.....Before you get all hot and bothered keep in mind that the STi probably has the least amount of lag out of a lot of turbo powered motors.

 

It is not turbo lag. there is a little hesitation where it feels fine moving along then a little bogging.

 

First thing I'd check are spark plugs, and maybe wires, either that or it's a boost leak.

 

First thing I'd check are spark plugs, and maybe wires, either that or it's a boost leak.

Well, it feels fine in higher gears. I think it is something in the fuel map.

 

FS: Cusco Turbo Heat Shield

I noticed it too but only once during a really hot and humid day. I stomped on it in 3rd, power built quick then suddenly died for a split second then ramped up again. That hasn't happened again.

 

It is not turbo lag. there is a little hesitation where it feels fine moving along then a little bogging.

Well I had a friend that had a similar problem and it turned out to be detonation so I'd go have it checked out

 

I was wondering if you guys are getting any hestitations at under 3k rpm when in lower gears? I have heard the with a UTEC this problem can be tuned out? Anyone exoerience with this problem?

Mine has that too. Maybe it's an '05 thing? It's NOT turbo lag. It almost feels like a lean surge at medium throttle from 2000-3000 rpm. The dealer demo car that I drove prior to purchasing mine had this issue as well. In fact, it was slightly worse on the demo car. When the car was just below full temperature I floored it at around 2100-2200 RPM and the car bucked enough that I had to get out of the throttle. I just figured is was the demo car and never gave it a second thought.

 

I notice it especially when having the AC on. Most of the time it happens, I am not even stomping the gas so I do not think that I was even in much boost.

 

mine does that in 1,2,3rd gears but only when the motor is cold... From 1500-2500rpm it spits, sputters, misses, and just gets downright cranky until the motor gets to operating temperature, then all is well...

EDIT: I should add it only does this on low acceleration (like pulling out from a stop street while babying the car), not while maintaining speeds.

 

mine does that in 1,2,3rd gears but only when the motor is cold... From 1500-2500rpm it spits, sputters, misses, and just gets downright cranky until the motor gets to operating temperature, then all is well...

EDIT: I should add it only does this on low acceleration (like pulling out from a stop street while babying the car), not while maintaining speeds.

my 04 does this exact same thing only when it cold and accel slow, right as i let the clutch out and go to accel in gear it sputters just for a brief second. when the engine is warm its gone. ill look at my psi 3 ecu monitor in the morning on my wat to work and note any a/f or timing that looks to happen when cold vs when warm.

 

Strange, I've not experienced any hesitation, hot, cold, winter, summer.

NskGenakuDuckie,
It couldn't be the plug wires because there aren't any. Direct ignition.

Also couldn't be a boost leak, because at the revs we're talking about the engine is pulling a vacume, definitely not a boost leak.

Don

 

My 1st race in STI..

i have never experienced any hesitation in the year and a few months that i've owned my STi. i do know that anytime you mash the gas under 3000rpm the car takes a minute to respond. the sweet spot of the STi is 4000rpm to 6000rpm. i actually never let my cars RPM drop below 2000rpm and i certainly don't ever floor the gas pedal down that low in the powerband.

 

My car doesn't seem happy below 2000 rpm. I know in my head it won't hurt, but it still feels like its lugging. At least in higher gears. Around town I find 2000-3500 to be a sweet spot. Easy to drive smoothly. I tend to baby my car when I'm not actually driving fast. i.e. I short shift it when just keeping up with traffic. Conversely, I think nothing of red line runs when there is nothing in front of me.

Either way, its not hesitation. It just doesn't make a whole heck of a lot of power below 3000. It is amazing though, it feels like a torquey normally aspirated engine below 3000. Unlike most turbos, which just feel dead off boost.

Don

 

its happening to me as well, the car just feels sluggish and its right around 2-3k rpm range it just kinds dies and slowly builds power...ive only noticed it since i did my intake silencer removal mod...

 

In progress,

Why not try putting the silencer back on and seeing if it goes away?
I'm sure we'd like to hear if it made a difference.

Don

 

i was also thinking about resetting the ecu and im also gonna go at making a intake with some pvc piping, but the only thing im worried about that is the CEL...should i be worried?

 

How do you like these apples?

mine does that in 1,2,3rd gears but only when the motor is cold... From 1500-2500rpm it spits, sputters, misses, and just gets downright cranky until the motor gets to operating temperature, then all is well...

EDIT: I should add it only does this on low acceleration (like pulling out from a stop street while babying the car), not while maintaining speeds.

What he said.
Pretty certain it's normal.
-M

 

I had this same problem when I first got my car - easiest way to avoid it is to let it warm up

driving a turbo engine when cold will cause issues down the line... proper warm up is just as necessary as proper cool down - 1 or 2 min is all you should need :wink:

 

Yep, I feel it too, but its the worst starting off in first. I didn't feel it that bad till I started modding, I decreased the amount of boost my Perrin BOV lets off and it seemed to make a difference in lower RPMs, so maybe in my case it was a semi boost leak issue since the valve was completely open. =/

 

i reseted my ECU and now my car is back to normal

 

I have it on ann intermittent basis on my 05 also. I personally think its the erratic stock ECU pulling fuel timing and/or whatever it needs to do when it detects either a lean condition or a slight knock sequence, so you are correct, good engine management like a utec, and a good tuner should be able to get rid of this annoying hesitation.

There is also occassionally clutch shudder with these cars but not half as prevalent a problem as I've had with my 03 wrx wagon. But you should be able to tell the difference quite easily.

 

...bringing the thread back to life...:tup:

The title of this one most closely matches the issue I want to discuss; I have some interersting information for those with the hesitation under 3K, and perhaps some other helpful information from various tests that I did to try to solve it.

I have on '05 that just clicked over 13K miles. I've been playing with this hesitation problem since I got the car six months ago. The car is totally stock, except what is called out below. And yes, I've been to the dealer twice in town about it, but still got no advice from the techs, other than it's a known problem, and no reflash is available. Now, I've been around Subarus since '94, and have had two WRX's and an '05 OXT - none of which had this crazy problem.

Here's my story (sorry for the novel, but I think it's a worthwhile read)

I have the stock airbox, with the stock filter; I tried the K&N, and even the Perrin filter, but still the hesitation was there.
I tried it with and without the intake silencer delete, but it still hesitated.
I tried it with and without the air intake duct from the grill into the airbox, but it still hesitated.
Resetting the ECU would give me a quick fix for 10 miles, but then it was back to its old ways. In fact, after each of my changes described herein, I reset the ECU, and meticulously drove the car for 30 mi before passing judgment.

Initially, I had a leaky Perrin turbo inlet hose - no clamp at the turbo end.
Even with some good clamps, some serious tweaking on the hoses, and a 6-pk of beer, I hated the way that product fit and could never get it snug up against the turbo end, so I bought the Samco turbo inlet hose, along with the Samco airbox hose, and the Samco intercooler hoses. I used good t-bolt clamps as suggested in this forum, but I never did completely lose the hesitation under 3K. I went a step further, and tried a combination of these Samco hoses and the stocker hoses, but still I could not lose the hesitation. I can tell you that IT DOES INDEED make a huge difference how you position and torque down the clamps on the intercooler hoses and the turbo inlet hose - too tight, and you begin to push out the rubber, too loose, and you will not reach full boost.

I use Cenex 94octane fuel - several months of it from the same station, and I saw no improvements at all. I did the same with Chevron 92octane over a few months, and still no improvements.

I went about clamping each of the PCV hoses going to the turbo inlet hose with a hose clamp to see if I could locate a leak - still nothing. I went further, and used some brakeKleen to see if I could find any leaks in my setup - no leaks at all.

And to top it off, I use my stock boost gauge to see if I can reach max boost in 3rd gear and sustain it well through the powerband. After getting the hoses torqued well, I now see max boost in 3rd through 6th gears, and very little lag. I can say with confidence that I can reach boost quicker with my current setup, but still the severe hesitation between like 2,800-3,200 revs.

Now, most of us have learned over the years that wet air filters work well when oiled properly. They'll choke up the MAF with gunk if you lap them in oil. Well, the other day, after pulling apart the airbox for yet another go at this problem, I decided to look at the MAF sensor - sure as heck, it was loaded with black soot, not terribly coated, but enough to notice when looking at it closely under a light. I simply never bothered to look at the sensor since it looked clean from a distance. And yes, I did do some testing with the K&N, but kept the lube to a bare minimum. I noticed that my bare finger could not remove the soot. Some alcohol and a q-tip cleaned it right up. I took the spent q-tip, and lightly moved the sensor to the center of the probe's field. For some reason, the sensor's probe was not squarely centered, so I gave it a light push to recenter it. (I have no idea why, it just seemed like a good thing to do)

I test drove the car, after resetting the ECU, and saw a noticeable improvement right away, and after three tanks of fuel now, the hesitation is still gone:clap:. Either the STi MAF's probe gets dirty over time - really dirty - or I've got an extremely odd exception to the rule.

Hey it worked for me,
-Paul