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Old 12-04-2001, 03:35 AM   #1
ImprezaRSX
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Location: Lake Stevens, WA
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4 domtuned subys

Question Slower @ Wot?

First the mods:
PDM intake (ganz-flow knock off)
UR Power Pulley
K&N filter in stock box
Magnecore wires
Borla Headers (3rd Gen)- wrapped to clear CEL
Intmd pipe and Stromung SS Dual Tip
Autometer A/F on rear O2 (not knowing it was the rear O2.... long story)

Then the symptoms:
When reducing throttle position from WOT, car pulls harder.
I first noticed this one day when some guy in a 328is was messing with me on the freeway. @55 I double clutched and downshifted into 3rd... went WOT.. shifted to 4th.. hit about 102 still WOT.. shifted to 5th carried to about 110 or so still WOT.. BMW was hanging about one car length back until about 105. So I began to then back off the throttle.... as I passed through 90% throttle (appoximately) the car began to accelerate more. I was actually pushed back a bit into the seat (just a bit).

Now the tests:
I did this again to test for repeatability. I tried it at different speeds, gears and RPM ranges.
Results:
Pretty consistent. In high gears @ approx 4kRPM and up car will accelerate more with less than WOT throttle positions.
However, A/F didn't show any significant changes with throttle position during the tests (80%-WOT) It read in the first two green rich lights through most of the accells.

My theory:
This kinduv makes sense to me. At WOT the car is open loop running on pre-programmed fuel maps without input/feedback from various engine sensors (O2 mainly) and therefore isn't able to fine tune the mixtures to a more optimum value. At less than WOT the engine takes input from those sensors and adjusts.

My questions:
1. Does anyone else have similar symptoms?
2. Could it be the nature of my mods?
3. Does an S-AFC affect WOT? or just closed loop operation?
4. Any suggestions to getting the most power from my car. CLEARLY I'm not getting the power I should if I'm creating more power with less air. I'm deeming the A/F results pretty inconclusive due to the fact that its running off the rear O2.

Thanks,
Dominic

BTW- Just because I drive like an idiot @ speeds in excess of 100 MPH doesn't mean I think everyone (or even myselft) should. Please be smart and safe. Straight, open, clear roads with no traffic are the safest, but still illegal.
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Last edited by ImprezaRSX; 12-04-2001 at 03:45 AM.
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Old 12-05-2001, 11:34 AM   #2
skidplatez
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I've noticed the same sort of thing! But interestingly enough I have two different hypothesis about why this might happen.

1) at WOT the car runs a little richer because of full fuel being applied to not much more(than 90%) air. And we all know a little lean is more Hp

2) or At 90% there is a little more turbulence/tumble past the TB and it mixes the fuel/air better in the intake charge. This typically produces more hp/torque if you maintain air speed.

So I don't know what it is either but I have noticed it occasionally and those are my guesses.
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Old 12-05-2001, 08:34 PM   #3
FatCatTurbo
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yea, it'd def. something to do with ure a/f ratio...mess around with it more, i know the autometer gauges aren't exactly precise, but just do ure best to try and solve the problem.

g'luck


Kevin
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Old 12-06-2001, 01:03 AM   #4
DoodieHead
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I have had similar symptoms with my car. What I did is pull the car out of gear and feather the gas a couple times, then put it into gear. It seems to get rid of the sluggish WOT. I noticed that you have the Magnecor wires. I also have them, but I refuse to use them. If you are of the experimental type and have your stock wires still, put the stock wires back in an reset the ECU. I did that and every since, I have had little issues with WOT response. I kept getting a critical CE light with the magnecor wires (blinking CE). Just a suggestion.
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Old 12-06-2001, 03:34 AM   #5
XT6Wagon
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Sounds like the ECU map for WOT is messed up. My SHO ran BAD at wot after some of my mods, but was VERY VERY wicked at 3/4 throttle. The ECU map was running ultra rich as it turns out. I think 12:1 was common and it went lower on a couple syno runs.
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Old 12-06-2001, 10:38 AM   #6
FastPorsche
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I know this is not helping much But I have to agree with these guy's Your car is most likely fat(rich) at wot. Why? Posibly the Intake, or ignotion wires. I have virtually no mods and my car runs confused at 4000 when I roll into the throtle, it might be in the software from SUBY. If you have the time remove each component one at time replace the stock part a test the car. Then tell everyone what your results were so we dont go down the same road HEHE. You might consider a Piggy-back EMS like Uni chip to correct the problem if you dont want to surender any of your mods.
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Old 12-06-2001, 10:45 AM   #7
ImprezaRSX
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It is surely running rich. Throughout the entire RPM range.

Does an SAFC affect WOT? I'm not sure it does.
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Old 12-06-2001, 07:25 PM   #8
JulianH
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Quote:
Originally posted by ImprezaRSX
It is surely running rich. Throughout the entire RPM range.

Does an SAFC affect WOT? I'm not sure it does.
If you set it up right it will. Set the Hi throttle setting to 80% and it will control WOT. Also the S-AFC is only effective over a long period of time at WOT, since the ECU can compensate for changes while in closed loop mode.

JulianH
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Old 12-07-2001, 10:38 AM   #9
FastPorsche
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I think you can use a UniChip to correct the issue, you can adjust the map every 400 RPMs in 12 different throttle positions. Works best when tuned on a dyno, the unit blows away the APEXi and is only $595.00 retail.
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Old 12-07-2001, 10:54 AM   #10
ImprezaRSX
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Join Date: Oct 2001
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Location: Lake Stevens, WA
Vehicle:
07, 06,01,93 I have
4 domtuned subys

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can't get those in Hawaii; no dealers, no 4 wheel dynos.
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Old 12-07-2001, 12:54 PM   #11
Puckaveli
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I have noticed this also. I have been analyzing results with the obd-2 software. I have to research some more but I can remeber the timing changing after the tps passes 90%.
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Old 12-07-2001, 02:10 PM   #12
inpreza kid
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the problem with the unichip is you can't tune it yourself. you probably have to pay a unichip dealer to do it. might get costly. if your in the market for a programable ecu AEM and greddy will have something affordable.
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