Question on new WRX drivability
07-22-2003, 04:05 PM
#1
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Question on new WRX drivability
I have an 04 WRX wagon, 2300 miles on it now. I've been breaking it in, was very careful the first 100 miles, and kept it mostly under 3-4k RPM for the first 1000 miles with the occasional jaunt to about 5k RPM. My question has to do with some hesitation and slight bucking that I've been encountering. This isn't a new development, it's done this sort of hesitation thing ever since I drove it off the lot with 11 miles on the odo.
Basically, if I go from low RPMs like 1500 or 2000 RPM and just floor it in any gear, I'll usually (although not every time) experience some hesitation. It will make positive boost and accelerate but not very smoothly. And sometimes if I'm at full bost and I let off the accelerator it will buck a bit.
Oh by the way, by "hesitation" I am not talking about turbo lag. I mean even at full boost sometimes it feels like it's holding back, then it will suddenly start moving faster... without any change in boost pressure. And it will do that at a constant throttle position, i.e. WOT.
I was wondering if this was normal at all based on experiences of other new WRX owners. I mean if this is just a quirk that all WRXes have, fine. I just want to know if there's something actually wonky with mine. And in this vein, I've heard that a manual boost controller will do wonders to help smooth out the boost curve, in addition to allowing you to raise the boost level a bit. Something about boost restrictions in 1st gear? Can anybody clarify that? And possibly relay any experiences with manual boost controllers?
Thanks, I'm just trying to get a handle on my new car, which I love.
Basically, if I go from low RPMs like 1500 or 2000 RPM and just floor it in any gear, I'll usually (although not every time) experience some hesitation. It will make positive boost and accelerate but not very smoothly. And sometimes if I'm at full bost and I let off the accelerator it will buck a bit.
Oh by the way, by "hesitation" I am not talking about turbo lag. I mean even at full boost sometimes it feels like it's holding back, then it will suddenly start moving faster... without any change in boost pressure. And it will do that at a constant throttle position, i.e. WOT.
I was wondering if this was normal at all based on experiences of other new WRX owners. I mean if this is just a quirk that all WRXes have, fine. I just want to know if there's something actually wonky with mine. And in this vein, I've heard that a manual boost controller will do wonders to help smooth out the boost curve, in addition to allowing you to raise the boost level a bit. Something about boost restrictions in 1st gear? Can anybody clarify that? And possibly relay any experiences with manual boost controllers?
Thanks, I'm just trying to get a handle on my new car, which I love.
07-22-2003, 04:16 PM
#2
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Your problem sounds like the problem that a lot of people have had. To fix it is seems like the consensus may be to put in an earth ground kit. I am not sure exactly what the problem is. But I have seen it come up quite a bit here. You may want to try a search as well. I know there should be some posts on it around here.
Stephen
Stephen
07-22-2003, 06:47 PM
#3
it would be good to get a boost gauge, just so you can see what exactly is happening with the boost. also, an EGT gauge would be good also. these won't void warranty and are good monitoring tools for turbo'd cars. that way, you can see what exactly is happening and what is causing the "hesitation" or your description of it. right now, it could be a number of things. the ECU could be pulling timing a bit, as it is very finicky. i think that when cobbtuning or vishnu come out with a '04 WRX ECU reflash, i suggest you get it. it's the best mod you can do to a stock WRX, with the exception of freeing up the exhaust flow. the stock WRX as i remember was way way restrictive. with simple bolt-on modifications, driving will be much more enjoyable. i warn you, once you start, you can't stop. 
another thing, it could be the wastegate regulating boost pressure as you still have all three cats in. as the stock boost controller is like a bleed valve, so it's letting off boost to keep from overboosting. it's normal in a stock car. just learn to drive around it and start modifying that BAD BOY. have fun.
another thing, it could be the wastegate regulating boost pressure as you still have all three cats in. as the stock boost controller is like a bleed valve, so it's letting off boost to keep from overboosting. it's normal in a stock car. just learn to drive around it and start modifying that BAD BOY. have fun.
Last edited by clamdip; 07-22-2003 at 06:50 PM.
07-23-2003, 09:47 AM
#5
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Thanks for the replies guys, I appreciate it.
XstephenX, that's a good suggestion. It does actually feel like a sort of "ungrounded MAF" problem, based on my experiences driving other cars with bad ground issues.
Clamdip, I do have a boost gauge. And yeah, I realize SoCal is not the best place to be for performance cars because of our crappy oxygenated (barely) 91 octane **** water gas. Thanks for the heads up on a possible upcoming 04 reflash from Vishnu or Cobb, that sounds like something I'd like to do. I would like to find out what's causing my hesitation though, and it seems to me that if the ECU isn't causing the hesitation, reflashing it might only exacerbate the problem.
And yeah, the bleed valve releasing pressure is fine, but it hesitates not only at part throttle but at WOT as well. If I'm in 2nd gear at about 2k RPM, I can floor it and it will bog a bit then accelerate, then power will drop off, then it will pick back up, then drop off then pick back up, sometimes a bit violently. The boost pressure goes where it's supposed to, i.e. ~1 bar, but I'll still get hesitation as the RPM climb.
I'm somewhat familiar with turbo systems [check out my other car], but not with the subtleties of my Rex yet. And it just seemed to me like the type of hesitation and slight bucking I'm getting just didn't seem normal for a new stock car.
I do plan on modding the Rex a bit, hehe. I do like the idea of the reflash and I'll probably do it when it's available.
Concillian, thanks for the advice. There's a 76 in Pasadena that sells 100 octane, I think I'll run a couple tanks of that to see if it helps. Again, thanks everybody for the helpful advice, I really appreciate it.
XstephenX, that's a good suggestion. It does actually feel like a sort of "ungrounded MAF" problem, based on my experiences driving other cars with bad ground issues.
Clamdip, I do have a boost gauge.
And yeah, I realize SoCal is not the best place to be for performance cars because of our crappy oxygenated (barely) 91 octane **** water gas. Thanks for the heads up on a possible upcoming 04 reflash from Vishnu or Cobb, that sounds like something I'd like to do. I would like to find out what's causing my hesitation though, and it seems to me that if the ECU isn't causing the hesitation, reflashing it might only exacerbate the problem.And yeah, the bleed valve releasing pressure is fine, but it hesitates not only at part throttle but at WOT as well. If I'm in 2nd gear at about 2k RPM, I can floor it and it will bog a bit then accelerate, then power will drop off, then it will pick back up, then drop off then pick back up, sometimes a bit violently. The boost pressure goes where it's supposed to, i.e. ~1 bar, but I'll still get hesitation as the RPM climb.
I'm somewhat familiar with turbo systems [check out my other car], but not with the subtleties of my Rex yet.
And it just seemed to me like the type of hesitation and slight bucking I'm getting just didn't seem normal for a new stock car.I do plan on modding the Rex a bit, hehe. I do like the idea of the reflash and I'll probably do it when it's available.
Concillian, thanks for the advice. There's a 76 in Pasadena that sells 100 octane, I think I'll run a couple tanks of that to see if it helps. Again, thanks everybody for the helpful advice, I really appreciate it.
07-25-2003, 12:19 PM
#7
it could be the plugs or a misfire happening. i've heard some cases of this. you may want to go check it out at the dealer, have it serviced, then get a reflash stg 1, turboback, reflash stg 2, then on and on, until you have a beast just waiting to be unleashed. good luck and have fun.
good luck and have fun.
07-26-2003, 05:58 PM
#8
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Join Date: Jul 2003
Location: 03 WRX Wagon Southern California
Posts: 42
Car Info: 2003 WRB Wagon
My MY03 wagon had the same hesitation problem when I got it. What fixed it was an improvement to the grounding system.
The theory, in a nutshell, is that the ECU needs VERY accurate voltage readings from the MAP snsor, O2 sensor, etc. to perform at its peak. The conventional wisdom seems to be that the stock grounding setup has enough resistance that voltages are sometimes attenuated before they reach the ECU.
Now this may or may not be true, but it seemed plausible to me, and acting upon it removed the symptoms you describe from my car.
There are other plausible theories, but I'm not a pro typist.
Anyway, the commercial "grounding mod" packages seemed like overkill to me. I changed the battery terminals and added 3 or 4 ground straps which together linked the battery to the intake manifold, engine block, and then to the firewall very near the ECU.
I don't know if all of these were necessary, I'm just reporting what worked for me.
The theory, in a nutshell, is that the ECU needs VERY accurate voltage readings from the MAP snsor, O2 sensor, etc. to perform at its peak. The conventional wisdom seems to be that the stock grounding setup has enough resistance that voltages are sometimes attenuated before they reach the ECU.
Now this may or may not be true, but it seemed plausible to me, and acting upon it removed the symptoms you describe from my car.
There are other plausible theories, but I'm not a pro typist.
Anyway, the commercial "grounding mod" packages seemed like overkill to me. I changed the battery terminals and added 3 or 4 ground straps which together linked the battery to the intake manifold, engine block, and then to the firewall very near the ECU.
I don't know if all of these were necessary, I'm just reporting what worked for me.
07-30-2003, 11:43 AM
#9
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Thanks 2stroke, that's very helpful. Just FYI for anybody reading this thread, I filled up with 100 octane the other day. I'm going to run this tank through, fill it with 100 again, then go back to 91 afterwards.
My initial impressions after driving it with 100 for a few days now is that timing is no longer getting pulled out. The car feels ***** to the wall strong now, and very responsive even at very low RPM, i.e. below 2k rpm. It feels like the timing is very advanced now judging by the off-boost responsiveness and willingness to move at low RPMs.
However, I still have some hesitation issues. it's seeming more and more like what 2stroke described, a grounding issue. It feels like what some of my other cars have felt like when their maf was going bad or needed to be regrounded. I'm sure a lot of you know what it feels like - You get on the gas, it hesitates for a second then starts moving, pulls strong then power drops off for a second then comes back on... etc. I've noticed it does this more in lower gears than higher ones.
Aside from that though, the car is quite a bit stronger than it was before the 100 octane went in, and I suspect it's all due to the timing being advanced and not being pulled out constantly. I'll verify this after I go back to 91 and note the difference in driveability.
I'd fill up with 100 every time, but it's $5.50 a gallon. Ouch. My wallet still hurts.
My initial impressions after driving it with 100 for a few days now is that timing is no longer getting pulled out. The car feels ***** to the wall strong now, and very responsive even at very low RPM, i.e. below 2k rpm. It feels like the timing is very advanced now judging by the off-boost responsiveness and willingness to move at low RPMs.
However, I still have some hesitation issues. it's seeming more and more like what 2stroke described, a grounding issue. It feels like what some of my other cars have felt like when their maf was going bad or needed to be regrounded. I'm sure a lot of you know what it feels like - You get on the gas, it hesitates for a second then starts moving, pulls strong then power drops off for a second then comes back on... etc. I've noticed it does this more in lower gears than higher ones.
Aside from that though, the car is quite a bit stronger than it was before the 100 octane went in, and I suspect it's all due to the timing being advanced and not being pulled out constantly. I'll verify this after I go back to 91 and note the difference in driveability.
I'd fill up with 100 every time, but it's $5.50 a gallon. Ouch. My wallet still hurts.
07-30-2003, 08:38 PM
#10
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Join Date: Jul 2003
Location: 03 WRX Wagon Southern California
Posts: 42
Car Info: 2003 WRB Wagon
My car runs MUCH stronger on 93-94 octane than on 91. It makes a big difference between 2000-3500 rpm.
I was buying 100 octane Unocal at first, but it didn't take long before I started looking for more convenience and lower cost.
A net search and a bunch of reading led me to start adding toluene and/or xylene to my oxyegenated 91.
They are 114 and 116 octane respectively, IIRC, and are available at finer paint stores nationwide. Xylene is available at home depot in socal. You don't need both, either one will do.
For me, toluene is preferable, as it's already a component of gasoline, and it's less toxic.
I use a gallon with every fill-up. I find myself filling up at 3/8 of a tank just so the octane ends up higher. I like to end up around 93.5 - 94, but even 92 is an improvement you can feel.
The calculation is straight arithmetic:
(gallons of gas* 91) + (gal. of tol. * 114) = "combined octane"
"combined octane" ÷ total gallons = average octane.
I was buying 100 octane Unocal at first, but it didn't take long before I started looking for more convenience and lower cost.
A net search and a bunch of reading led me to start adding toluene and/or xylene to my oxyegenated 91.
They are 114 and 116 octane respectively, IIRC, and are available at finer paint stores nationwide. Xylene is available at home depot in socal. You don't need both, either one will do.
For me, toluene is preferable, as it's already a component of gasoline, and it's less toxic.
I use a gallon with every fill-up. I find myself filling up at 3/8 of a tank just so the octane ends up higher. I like to end up around 93.5 - 94, but even 92 is an improvement you can feel.
The calculation is straight arithmetic:
(gallons of gas* 91) + (gal. of tol. * 114) = "combined octane"
"combined octane" ÷ total gallons = average octane.
07-30-2003, 08:43 PM
#11
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Join Date: Jul 2003
Location: 03 WRX Wagon Southern California
Posts: 42
Car Info: 2003 WRB Wagon
And BTW, if you buy more 100 octane, mix it 50/50 with 91.
Our ECU's are only mapped for fuel up to 95 octane. Anything higher isn't going to improve performance over 95.
Our ECU's are only mapped for fuel up to 95 octane. Anything higher isn't going to improve performance over 95.
08-01-2003, 04:08 PM
#13
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Good info!, thanks! (and an off-topic question to 2stroke)
Originally posted by 2Stroke
And BTW, if you buy more 100 octane, mix it 50/50 with 91.
Our ECU's are only mapped for fuel up to 95 octane. Anything higher isn't going to improve performance over 95.
And BTW, if you buy more 100 octane, mix it 50/50 with 91.
Our ECU's are only mapped for fuel up to 95 octane. Anything higher isn't going to improve performance over 95.
The R's will drop, like, ridiculously far. It feels like a two-stroke engine (more on that in a bit) when you fall off the pipe.
But anyway, the car feels almost like someone hit the brakes...
nose dives even.
If -that- is the same bucking sensation everyone talks about, then I am only too ready to get a ground-kit and try that out.
Could it be that the ground issue is related to the car getting tweaked out of shape under power??... like the chassis is twisting just enough to open up some gap in some body-seam that otherwise makes contact?... and the ground-fix would fix this because it provides an alternate route? I've only just started reading up on this, so that is just flat-out swag (some-wild-***-guess, to the uninitiated).
I finally got to 1700 miles so I feel like I can really push it... and I'm seeing this only every so often. I run 93 octane gas (which is easy to get here in Houston, Texas). I don't hear any pinging, but I don't have the turbo gauge (just bought one today, will install tomorrow... Autometer 3301... hey, I can't see spending $200+ on one friggin' gauge!.. I just bought this car and I'm poor now! haha!)
Now, for the off-topic stuff:
2stroke... is that name in reference to two-stroke engines, like dirt-bikes or street-bikes? Reason I ask is I am a die-hard 'stroker fan and have a few 2-stroke street bikes (RZ350, RG500, TZR250), and I'm always happy to talk to other 'stroker pilots. You just don't see very many of 'em anymore, we're a rare breed!
-James
08-02-2003, 01:59 PM
#14
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Join Date: Jul 2003
Location: 03 WRX Wagon Southern California
Posts: 42
Car Info: 2003 WRB Wagon
It's mostly a reference to my dirt bike, a Honda CR500R. When I started using that nym, I had just got back from go-kart racing classes in 2-stroke karts, I was doing a lot of work on my 2-stroke bike, and everybody and their brother was raving about all the torque these new 4-stroke YZF426/CRF450 dirtbikes had.
So does anybody ever want to ride one of those torque monsters and race a CR500 on a big open track? I didn't think so.
But then, I don't do any supercross, either.
My real name is Steve. email is: 2-stroke@my_ISP.net, in which my_isp is earthlink.
So does anybody ever want to ride one of those torque monsters and race a CR500 on a big open track? I didn't think so.
But then, I don't do any supercross, either.
My real name is Steve. email is: 2-stroke@my_ISP.net, in which my_isp is earthlink.
10-27-2003, 07:27 AM
#15
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Join Date: Sep 2003
Location: Cincinnati, OH
Posts: 461
Car Info: 04 Java Black Sedan
I am experiencing the same bucking problems in my 04. Feels like misfire to me. I don't think it is the gas, I live in Ohio and normally fill it up with Mobile 93 octane. I used to only use Sunoco 94 in my Talon, haven't tried it in the Rex. I am going to try resetting the ecu tonight to see if that helps. I also have installed a MBC and have it tuned to a little under 16 psi, however it does not run consistant boost. It normally falls off a little in 2nd gear, 3rd and so on. I never holds at 16. It almost seems like there is a boost leak, but it will not drop below 13 psi. I have the line to the BOV T'ed which runs to the source plug for the MBC, then the other side of the MBC to the wastegate. This is different than I would have done it on my Talon, but this way was recomended. Anyone have any idea what might be happening.