Stealth TDI
Pre-Forum Veteran Member
Hi,
I offer the following points/observations:
1) While the hardware issues presented above seem plausible, I fail to understand how it can still be considered a possibility if the car drives almost perfectly with RC3 loaded into the automatic file location (S001). If hardware was the issue, I believe the car would ALWAYS have a problem.
2) You didn't get shudder during your test drive of my car because we were flogging it, testing for smoke, and taking VAG-COM plots. Ask Oliver what he thought of my shuddering. I'm not exaggerating when I say it's BAD. Hot-coffee drinkers beware! <joking> The intensity of the shudder is proportional to the amount of fueling delivered by the program (eg, RC2 is worse than UP2, RC3 is worse than RC2, RC3+ is worse than RC3...) or the size of the injector nozzles.
3) I hardly consider autocross as the type of "racing" that would require the pulling of the head from time to time. Quite frankly, a morning of VAG-COM logging is more stressful on the engine than 4-minutes of cumulative cone-dodging in a weekend, especially if you recognize that my foot is in the floor for only 20-30 seconds of all of that. If anything is being abused, it's the chassis, suspension, and wheels/hubs.
4) I agree with 'Meister in that I do not believe I'm laboring the engine. The shudder occurs when I'm NOT laboring the engine... light climbing, slow acceleration, or while pulling my 500-lb trailer.
5) I'm not sure if we're talking about the same "slow down shudder." Imagine nearly any ground speed at which one is driving below 2000-rpm. Yes, I know some prefer driving at 2800-rpm in third instead of 1800-rpm in fourth. But I'll cruise through neighborhoods at 1800-rpm before choosing to rev through quiet neighborhood. FWIW, I cruise at 1800; but not 1500. Anyway, my slow-down shudder isn't just about when coming to a stop. It happens through the normal, minor fluctuations of speed such driving at 1800-rpm, but minor grades or turns require lifting off the pedal a touch to maintain speed. I'm not talking about letting up all the way... I'm referring to letting up 1/8-inch. The engine doesn't necessarily shudder, as in the type to vibrate the car. Instead, it sounds like it's "missing" in these scenarios... perhaps TINY pulses felt in the car. If Aligator can fix this and maintain the highway manners, they've found GOLD.
Now that I know progress can be made via software, I'm just BARELY interested in blowing precious time and $$$ by pulling the head just to take a look. I have 570-psi on all four cylinders, Oliver ensured the injectors were balanced, and the IP and ECU are new. I haven't found a mechanic yet who thinks the head should come off knowing those things. The only other thing I can consider is the possibility that one or two of my intake ports have more caked soot than another (from pre-EGRectomy days). I'm not talking about a huge difference... perhaps 1/16-inch... just enough to see it. But that could be a bit of a stretch. HERE'S A PHOTO.
I tend to believe that OEM tuning may not be the best route in light throttle conditions since the injectors are not OEM. Perhaps Aligator has reduced fueling in light throttle conditions to compensate for the extra fuel flow. I'm not sure. I'd like to see some comments from DI and/or Aligator.
Take Care,
Scott
I offer the following points/observations:
1) While the hardware issues presented above seem plausible, I fail to understand how it can still be considered a possibility if the car drives almost perfectly with RC3 loaded into the automatic file location (S001). If hardware was the issue, I believe the car would ALWAYS have a problem.
2) You didn't get shudder during your test drive of my car because we were flogging it, testing for smoke, and taking VAG-COM plots. Ask Oliver what he thought of my shuddering. I'm not exaggerating when I say it's BAD. Hot-coffee drinkers beware! <joking> The intensity of the shudder is proportional to the amount of fueling delivered by the program (eg, RC2 is worse than UP2, RC3 is worse than RC2, RC3+ is worse than RC3...) or the size of the injector nozzles.
3) I hardly consider autocross as the type of "racing" that would require the pulling of the head from time to time. Quite frankly, a morning of VAG-COM logging is more stressful on the engine than 4-minutes of cumulative cone-dodging in a weekend, especially if you recognize that my foot is in the floor for only 20-30 seconds of all of that. If anything is being abused, it's the chassis, suspension, and wheels/hubs.
4) I agree with 'Meister in that I do not believe I'm laboring the engine. The shudder occurs when I'm NOT laboring the engine... light climbing, slow acceleration, or while pulling my 500-lb trailer.
5) I'm not sure if we're talking about the same "slow down shudder." Imagine nearly any ground speed at which one is driving below 2000-rpm. Yes, I know some prefer driving at 2800-rpm in third instead of 1800-rpm in fourth. But I'll cruise through neighborhoods at 1800-rpm before choosing to rev through quiet neighborhood. FWIW, I cruise at 1800; but not 1500. Anyway, my slow-down shudder isn't just about when coming to a stop. It happens through the normal, minor fluctuations of speed such driving at 1800-rpm, but minor grades or turns require lifting off the pedal a touch to maintain speed. I'm not talking about letting up all the way... I'm referring to letting up 1/8-inch. The engine doesn't necessarily shudder, as in the type to vibrate the car. Instead, it sounds like it's "missing" in these scenarios... perhaps TINY pulses felt in the car. If Aligator can fix this and maintain the highway manners, they've found GOLD.
Now that I know progress can be made via software, I'm just BARELY interested in blowing precious time and $$$ by pulling the head just to take a look. I have 570-psi on all four cylinders, Oliver ensured the injectors were balanced, and the IP and ECU are new. I haven't found a mechanic yet who thinks the head should come off knowing those things. The only other thing I can consider is the possibility that one or two of my intake ports have more caked soot than another (from pre-EGRectomy days). I'm not talking about a huge difference... perhaps 1/16-inch... just enough to see it. But that could be a bit of a stretch. HERE'S A PHOTO.
I tend to believe that OEM tuning may not be the best route in light throttle conditions since the injectors are not OEM. Perhaps Aligator has reduced fueling in light throttle conditions to compensate for the extra fuel flow. I'm not sure. I'd like to see some comments from DI and/or Aligator.
Take Care,
Scott
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