[Bulti]

I read something on an Audi forum about a guy with similar problems. The idle was raised by only 40 rpm and apparently that was the sweet spot, no more vibrations! So maybe a tiny bit of extra throttle can make the difference.

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[ds968]

Checked out today to see where the sweet spot on my car is - 1100 rpm. Perfectly smooth at that point.

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[Bulti]

How many rpm did you have to raise the idle?

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[ds968]

[quote name='Bulti' timestamp='1390227073' post='154439']How much rpm did you have to raise the idle?[/quote]



About 250 . The car idles at just a little over the 800 line.

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[Bulti]

Glad it worked out with such a simple solution. Hopefully the vibrations stay away.

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[ds968]

[quote name='Bulti' timestamp='1390242756' post='154448']

Glad it worked out with such a simple solution. Hopefully the vibrations stay away.

[/quote]



uhh, I should have mentioned that I determined 1100 rpm to be the sweet spot using the gas pedal, not a solution by adjusting the idle slotted screw flash mentioned ..I have no idea how to get to it, but sounds like a PITA and that something or another may first need to be disassembled to allow access to that <img src="/forum/images/smilies/968/huh.png" class="smilie" alt="" />

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[kwikt]

I thought the idle can not be adjusted on these cars because of the dme along with the idle control valve.

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[flash]

it is adjustable, but the way it is set up stock, it's not easy at all, as it is pointing down, underneath the armature. i removed the throttle body, reversed the screw, and reinstalled, using loctite 242 when i was done.

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[ds968]

if the car is up on a hoist, is it any easier to get to that screw since it's pointing down ( and without having to mess with any of the throttle body or other hardware below or around it ) ?

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[flash]

nope

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[ds968]

It's all your fault Bob ! You made this car dead-quiet, so with 90% of the previous noise disturbances and distractions out of the way, the other 10% is exponentially more noticeable ! Ok, not ALL your fault.. Porsche is to blame for deliberately hiding adjustable parts in non-adjustable spots. <img src="/forum/images/smilies/968/glare.gif" class="smilie" alt="" />

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[ds968]

I checked the rpms again, and this time with a little more patience ( as opposed to the casual and brief one or two second observations I made previously ) . In neutral the idle is somewhere between 800 and the virtual 900 line, I'd say close to the middle spot between the two. When I put in in drive or in reverse it drops to 800, right on the dot.

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[Bulti]

[quote name='ds968' timestamp='1390262838' post='154464']... Porsche is to blame for deliberately hiding adjustable parts in non-adjustable spots. <img src="/forum/images/smilies/968/glare.gif" class="smilie" alt="" />[/quote]



I bet they put it the way they did it for some good reason. Maybe to stop people from fiddling with it? Maybe it's not supposed to be adjusted after the car leaves the factory except in very rare occasions.



Is there a way to determine the actual idle rpms? The rev counter can't be very accurate.

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[flash]

yup - that's because the ECU has an idle map, and will always try to return the idle to that. fiddling with the screw could cause some interesting symptoms

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[968cabx2]

Hate to be the new guy on the forums putting in my two cents, but the vibration issue is partially related to the fact that the torque tube is always spinning at idle on the tip cars.



Think of it, the flex plate connects directly to the torque tube and is always spinning. The torque converter is then driven by the torque tube.



With a 6 speed every time you depress the clutch you are essentially disconnecting the drive line right at the clutch and even if the clutch is engaged, the car is in neutral so there is a lot less rotating mass than when you are constantly spinning the torque converter. All this rotating mass causes vibration. When you "blip" the tach and find the sweet spot, you are just getting to a point where all that rotating mass vibrates the least.

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[flash]

probably on the right track, but odds are it's the flex damper assembly up front. after seeing it, i doubt it's balanced.

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[968cabx2]

That is an interesting thought. I guess to do it correctly, when replacing the flex damper, one would remove the "flywheel" and starter ring gear and bring that along with the new flex damper to a machine shop to have it all balanced as you would have a clutch, pressure plate and flywheel. I did not think of doing that when I did my flex damper replacement.

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[flash]

if and when i blow the damper in my tip car, i'll be addressing this one way or another. i will either balance that assembly, or replace it with a pressure plate/flywheel conversion idea.



crossing my fingers that doesn't become an issue anytime soon though.



it's also a reason i have not supercharged that car. i'm not sure how much beating the flex damper can take. i've seen them pretty ripped up. if i did supercharge it, i'd be sure not to thrash it very hard, and do so in smooth application. harsh acceleration at low and low-midrange rpm is what will rip them apart.

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[ds968]

[quote name='flash' timestamp='1400012168' post='157813']

it's also a reason i have not supercharged that car. i'm not sure how much beating the flex damper can take. i've seen them pretty ripped up. if i did supercharge it, i'd be sure not to thrash it very hard, and do so in smooth application. harsh acceleration at low and low-midrange rpm is what will rip them apart.[/quote]



Guess I'll have to be the guinea pig for that test ( I believe I still have the only D1R. SC'd tiptronic in the world ? ) Will keep you posted .

Tne flex damper was replaced prior to the SC and has only about 20k miles on after the SC install, so time will tell.

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[flash]

yup - you're it. kurt was willing to be the guinea pig. now that honor has been passed to you. i'd just try to avoid herky jerky power changes. stomping on it off the line, double gear drops, yada yada. that's what is going to rip it apart. it's just a big rubber disk that has to resist twisting. bad design from the get go. worse when we essentially double the power for which it was originally designed (944)

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