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Old 07-08-2006, 02:31 AM   #1
bani111
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Question 2.5i throttle lag?

I test drove a manual transmission 2.5i and floored it and it took about a second before the engine responded. There's no turbo so it can't be turbo lag. The dealer tried to blame it on "not being in the power band". Is it due to the drive by wire throttle? And is there any way around it?

I expected lag with the WRX and STI, but lag on the 2.5i was suprising.
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Old 07-08-2006, 04:24 AM   #2
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what gear and what rpm were you at? I notice slight lag in my RS but at low revs. Higher up top seems to respond quicker.
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Old 07-08-2006, 09:18 AM   #3
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Lag or just the engine bogging down? Engine RPM is a beneficial piece of information at this point. If you're cruising at 2500 RPM and floor it, the engine isn't going to rocket up through the RPM band in a split second.

Only other thing I can think of is open loop/closed loop transition for the ECU. Otherwise, I'm at a lose for ideas as to why this occured.
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Old 07-08-2006, 04:35 PM   #4
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I know a few people who've had problems with the Drive By Wire system not being in full working order and one of their complaints were that the throttle wasn't responsive, but this was coming from cars with atleast 20k miles.

I think that is just the way the RS is, but I notice that the throttle response is decreased sometimes when the A/C is on. Other than that my car responds right when i touch the pedal.
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Old 07-08-2006, 06:59 PM   #5
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Quote:
Originally Posted by midnx03
Lag or just the engine bogging down? Engine RPM is a beneficial piece of information at this point. If you're cruising at 2500 RPM and floor it, the engine isn't going to rocket up through the RPM band in a split second.

Only other thing I can think of is open loop/closed loop transition for the ECU. Otherwise, I'm at a lose for ideas as to why this occured.
lag. the engine doesn't even RESPOND AT ALL for about a second. I floor it and the engine just doesnt do a damn thing for a second, then it suddenly responds and tears my head off.

happened regardless of rpm, in any gear i tried.
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Old 07-08-2006, 07:09 PM   #6
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probably is a problem in the drive by wire system.
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Old 07-08-2006, 07:34 PM   #7
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Quote:
Originally Posted by bani111
lag. the engine doesn't even RESPOND AT ALL for about a second. I floor it and the engine just doesnt do a damn thing for a second, then it suddenly responds and tears my head off.

happened regardless of rpm, in any gear i tried.
Strange. I'm leaning towards electrical at this point. Might be the DBW bit, but it is hard to say.

Sounds a lot like an automatic. Step on it, let it drop a gear, then go.
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Old 07-08-2006, 08:01 PM   #8
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i think your throttle was trying to catch up with the rpms....
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Old 07-08-2006, 09:28 PM   #9
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I own a 2.5i '06. First off, it is not an RS. I had an 05 RS too haha, different package options, interior, engine blah blah.

Anyways, the throttle response ordeal (drive by wire excuse) is not really noticeable except for a very in tune driver. I am not greatly in tune, so i don't notice it much, althought 2nd gear 3500 RPMS and punching it, it's hard not to notice the split second hesitation, and I mean split second.

If you were below 3k, that is normal, even for my 6k mile car, it does this. It's just that the engine doesn't respond well to WOT under 3k RPMS. The RS did not exude this as much. I am going to chalk this up to different cams/engine setup.

I have also noticed, a problem with acceleration during cornering before 3500 RPM and it is extremely noticeable, a very large BOGGING feeling. I did not have it that bad in the RS.

Just my info.

~Levi
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Old 07-08-2006, 10:50 PM   #10
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No hesitation or bogging with my 06.
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Old 07-09-2006, 03:33 AM   #11
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It's definitely the drive by wire throttle. The 2006 Civic Si has exactly the same problem.
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Old 07-09-2006, 04:28 AM   #12
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I have a similar situation. How do you fix the DBW throttle?
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Old 07-09-2006, 12:36 PM   #13
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Yes its definately the drive by wire system and soft drivetrain bushings. I'm not really sure there is a simple fix. Maybe a lightweight flywheel?
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Old 07-10-2006, 08:33 AM   #14
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intake, exhaust, pulleys, flywheel, motor and tranny mounts, port & polish inatke and exhaust parts, valve train work, all these things will help to decrease throttle lag and help the car to go when you tell it. drive by wire will always be slower than the mechanical throttle cable setup, that's just the way it is. drive by wire has it's pros and cons and there's really no way around the cons at this point.
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Old 07-10-2006, 10:04 AM   #15
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I find the combination of this car & DBW does not respond well to a foot stomping WOT at any RPM, I've found much better response with more of a roll on application of the throttle. IMO it's a combination of the engine, DBW & the throttle control tables in the ECU. Other cars I've driven with DBW don't have the same issues, at least not to the same degree I feel in the suby.

I've read a few posts where they mentioned locating the electronic throttle control maps in the ECU, so if we're really lucky and the Cobb N/A Access port ever comes out perhaps it will be able to solve the problem.
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Old 07-10-2006, 05:40 PM   #16
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I heard rumors of Cobb making an AP for N/A but they said that they won't even make an intake for the 2.5RS and 2.5i then why would they bother with the AP? I do hope they do come out with something, I would love to have some more engine mangment options for my car.
Are there anyways in improving the throttle response? Would things like the Grounding Mod help?
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Old 07-11-2006, 01:18 AM   #17
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The Grounding mod won't do anything
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Old 07-11-2006, 08:19 AM   #18
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not true. it wont do a lot but it will do something. it will smooth the car out at idle, through the power band and get rid of most noise from the electrical system. i found it to be well worth the time and money to put a grounding kit together yourself. i wouldnt buy one, but DIY is worth it. like i said, it's not a lot but every little bit helps. but dont expect any more power, just a bit smoother car.
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Old 08-02-2006, 11:22 AM   #19
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I just bought a 2006 2.5i less than two weeks ago, and I was wondering why I couldnt drive this thing smoothly. Just this afternoon I did some extensive experimentation, and realize this throttle lag is the cause of my problems. If I just stab the gas real quick the rpms just burble up a little. ugg. Its really not the instant gratification I'm used to.

Anyone have any advice on how long this takes to get used too?

It really sucks pulling out on a steep hill, I end up reving the crap out of the engine and slipping the clutch like an idiot.

What are the "pros" to the Elec. throttle that someone mentioned above?
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Old 08-02-2006, 02:31 PM   #20
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Quote:
Originally Posted by moestock
I just bought a 2006 2.5i less than two weeks ago, and I was wondering why I couldnt drive this thing smoothly. Just this afternoon I did some extensive experimentation, and realize this throttle lag is the cause of my problems. If I just stab the gas real quick the rpms just burble up a little. ugg. Its really not the instant gratification I'm used to.

Anyone have any advice on how long this takes to get used too?

It really sucks pulling out on a steep hill, I end up reving the crap out of the engine and slipping the clutch like an idiot.

What are the "pros" to the Elec. throttle that someone mentioned above?
it's almost like the dbw/ecu is trying to spin up a non-existent turbo...
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Old 08-02-2006, 03:09 PM   #21
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For the start lag, you might want to check out this TSB: http://www.scoobymods.com/forums/showthread.php?t=5833

I've never really noticed any lag except if I start the car from a stop at below 1500rpms. It's fine at 2k, which is still a little higher than I expected but then my old car didn't have a tach. Under 1500rpms tho and the car feels like it's just rolling, but it really might just not have any torque that low.

The only thing that's been bugging me about the DBW has been when doing heel-toe. It's also noticable when dbl-clutch downshifting to engine brake. Even if you match the rev perfectly, and have the clutch up all the way, there seems to be a second lurch that happens about a half second after the clutch is fully up. I say second because I feel the first lurch from a bad rev match sometimes, and then a second one after that. This is most noticable going from 4->3 or from 3->2. Feels like I've underrevved, but the clutch is already fully up, and the tach is not jumping. Only when your foot is off the gas after you shift is this noticable; if you get back on the gas after downshifting one gear, i.e. during passing, this doesn't happen.

I'm planning on taking it to the dealer to ask about this next time I go in, I've only had the car a month (well, 2days short of a month actually hehe) but I've spent most of the last 2300km trying to figure out why my downshifts won't stay smooth, and this is the ONLY thing that still bugs me. With the AC on, the lurch sometimes feels strong enough to be putting some really bad strain on the drivetrain.

Last edited by Naito; 08-02-2006 at 03:11 PM. Reason: clarification
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Old 08-02-2006, 09:39 PM   #22
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Quote:
Originally Posted by Naito
For the start lag, you might want to check out this TSB: http://www.scoobymods.com/forums/showthread.php?t=5833
Ya, I saw that, but I dont think it really helps anyone... There needs to be better software installed to help with this problem, but SOA hasnt come out with anything yet.

Ive been driving around some automatic 06's and the 06 auto forester is just horrible with the throttle lag its not even funny... However, the 2.5i legacy with the auto sportshift in sportshift mode is quite responsive, I actually enjoy it much much more than the 00 legacy GT auto I drive on occasion.
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Old 08-03-2006, 10:53 AM   #23
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laaaaaaaagtacular in my 2.5i 4EAT, and it's not just because it's auto
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Old 08-03-2006, 01:10 PM   #24
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Quote:
Originally Posted by Naito
For the start lag, you might want to check out this "link"
.. sorry not cool enough to post a url yet.

I just tried the method in this link today, their is still a lag. Its probably my imagination... but its seemed less severe after I stopped the car and started it again. I'll be doing this a few more times to try to "train" the ETC.

Like I said, I'm probably imagining the improvement, just getting used to the car maybe. But regardless, thanks for the placebo effect this had. At least I'm trying something to help!
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Old 08-03-2006, 01:33 PM   #25
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Quote:
Originally Posted by M-e-X-x
laaaaaaaagtacular in my 2.5i 4EAT, and it's not just because it's auto
What sucks is the Legacy 2.5i with the sportshift is much much better
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