MrJoshua
MrJoshua UltimaDork
4/27/22 1:19 p.m.

We bought my son a 2000 Audi TT at auction a while back and now its time to get it nicer.  

 

It ran when we got it-like a lawnmower. We replaced one dead coil and it settled into a decent running machine. It's current list of woes includes:

  1. Vibrations at idle. It has a cone filter intake, an open blow off tube, and some shrink wrap repaired coil wires.
  2. Terrible terrible front shocks. As bad as I've ever driven. It turns small bumps into sweet jumps and slight potholes into smashing impacts that feel like you've bent a wheel. The rear may be shot as well, but the front is really dramatic about it. 
  3. Clutch master didn't like being ignored for so long and got lazy. The pedal rests comfortably on the floor now instead of springing back up like a good clutch master/pedal. 
  4. Amusing 1990's style dash warning lights that I think are warning me of an active volcano. 
  5. Lots of play in the front end. 
  6. A few new wrinkles in the front and rear bumper covers from my 15yo learning to drive by using My 4 runner as a cue, the TT as a cue ball, and knocking the 8 ball (wifes WRX) of of 4 jackstands onto its transmission. 4Runners a beast, TT's are tough, Bellhousings can slice car floors if they land on them. Props to the kid-She's wrecked approximately 1 car per mile driven. 

Questions for the forum:

  1. Any thoughts on what to chase for the idle vibration? It doesn't seem like a dying dual mass flywheel vibration, and I didn't see poly mounts.
  2. What do you like for shocks? It will be 99.99% daily driven, and maybe autocrossed a few times in its lifetime. 
  3. Who's your favorite parts supplier for easy stuff like clutch hydraulics?
  4. Is the rear-front A-Arm bushing the go to for front end play? I will get under there and look around/push on some stuff, but It looks like an easy culprit.

Thanks in advance!

RossD
RossD MegaDork
4/27/22 1:24 p.m.

http://Briggs & Stratton 19200 Tachometer,Black https://www.amazon.com/dp/B0044AV5VK/ref=cm_sw_r_apan_i_YHRH3MC7990SYRR6JZBT

This can help chase vibrations. Might have to do maths on pulley size ratios vs the crank and engine idle speed.

 

Teh E36 M3
Teh E36 M3 UltraDork
4/27/22 1:39 p.m.

Check this youtuber's page out. She went full out on her to but it is awesome. 
 

https://www.youtube.com/playlist?list=PLmhNtwDcrRxEf7TWOFeAy-k5UexHlVYmF

Noddaz
Noddaz GRM+ Memberand UberDork
4/27/22 9:12 p.m.

If the car has lots of miles the upper strut mounts and lower control arm bushing are probably shot.

I just installed poly strut mounts on my 97 Jetta and wow are they harsh.  The TT uses a special rear control arm bushing which can be had pretty cheap.  The Audi bushing does not have slots in it like the Golf/Jetta bushing.  I understand that the poly rear control arm bushing are too hard and unforgiving.  

This is what the bushing you want looks like.

 

versus this:

And I want an Audi TT.  Have fun!

Placemotorsports
Placemotorsports GRM+ Memberand HalfDork
4/28/22 8:00 a.m.

Is the idle low to match the vibration or just rough idle in general?  If idle is normal replace the PCV valve.  It's cheap and probally needs done anyway

MrJoshua
MrJoshua UltimaDork
4/29/22 1:18 p.m.

That's a scary choice of graphic to use for low washer fluid!

MrJoshua
MrJoshua UltimaDork
4/29/22 1:24 p.m.
Placemotorsports said:

Is the idle low to match the vibration or just rough idle in general?  If idle is normal replace the PCV valve.  It's cheap and probally needs done anyway

Not sure, maybe a little low. It feels slightly better at idle than a little higher RPM. The vibrations are worse around 1k during fast idle. Its a really fine vibration-very small amplitude, more buzzy than shaky. I will do the EGR.

MrJoshua
MrJoshua UltimaDork
4/29/22 1:29 p.m.

The factory front  A-Arm rear bushings seem pretty shot. They look like they may be like they are the holey design you posted Noddazz. sad

I am definitely getting into the front and rear suspension. Suggestions for Struts/shocks and springs? No cheap or expensive aftermarket coilovers required.

Tk8398
Tk8398 HalfDork
4/29/22 3:13 p.m.

Bilstein HD shocks/struts.  The TT ones are different than the golf/Jetta/beetle because the sway bar mounts different.  There are some heavy duty upper strut mounts from some euro performance car (I could be wrong about this but Seat Cupra R sounds right) that would be worth getting too.

MrJoshua
MrJoshua UltimaDork
4/30/22 9:30 a.m.
Teh E36 M3 said:

Check this youtuber's page out. She went full out on her to but it is awesome. 
 

https://www.youtube.com/playlist?list=PLmhNtwDcrRxEf7TWOFeAy-k5UexHlVYmF

Yeah, thats a fun rabbit hole to watch, but a scary foreshadowing of what may be ahead. surprise

She's an amusing doofus. Cool to see people succeeding by building fun stuff. It's like what a kid thinks growing up a being a mechanic will be. Ooooooh-reminds me, checked out Nivlac/Calvins new vid.

Wow-kid went all production and mood on that intro. It was awesome!  Made an old GRMer who watched them grow up proud.

karplus2
karplus2 GRM+ Memberand Reader
4/30/22 9:49 a.m.
Teh E36 M3 said:

Check this youtuber's page out. She went full out on her to but it is awesome. 
 

https://www.youtube.com/playlist?list=PLmhNtwDcrRxEf7TWOFeAy-k5UexHlVYmF

She is my favorite YouTuber. She did a ton on that TT and she actually does a decent job detailing technical stuff (though not tutorial level) so should be a good reference.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
4/30/22 11:54 a.m.

Bad vibes at idle could just be sagged engine/trans mounts (all the NVH of stiff mounts without the reduced drivetrain slop) or it could be a dual mass flywheel going south.  Or someone swapped in a TDI single mass flywheel/clutch because it is cheaper to do all that than replace just the DMF.

MrJoshua
MrJoshua UltimaDork
4/30/22 4:03 p.m.
Pete. (l33t FS) said:

Bad vibes at idle could just be sagged engine/trans mounts (all the NVH of stiff mounts without the reduced drivetrain slop) or it could be a dual mass flywheel going south.  Or someone swapped in a TDI single mass flywheel/clutch because it is cheaper to do all that than replace just the DMF.

I saw some reports of motor mounts being the cause of vibrations. I'm hoping that's the fix instead of the Flywheel. Not in a hurry to drop the trans for a flywheel replacement.

preach (dudeist priest)
preach (dudeist priest) GRM+ Memberand Dork
4/30/22 4:18 p.m.

All of your rubber is pretty shot.

If you can deal with a lower car I'd go eibach springs and koni yellows. We did those on our 3.2 TT and it handled amazing. It was awfully low for New England winter roads though.

MrJoshua
MrJoshua UltimaDork
4/30/22 4:51 p.m.
preach (dudeist priest) said:

All of your rubber is pretty shot.

If you can deal with a lower car I'd go eibach springs and koni yellows. We did those on our 3.2 TT and it handled amazing. It was awfully low for New England winter roads though.

I found a Bilstein B8/Eibach setup for a few hundred cheaper than the Koni yellows and am considering going that route. I haven't read any negative reviews of ride. The crowd that seems to have these now likes to judge a suspension by how low it goes, so I am not sure I trust their opinions on ride. The amount of low from the Eibach setup isn't much of a problem here except for my son not having much respect for a relatives driveway approach angle. 

preach (dudeist priest)
preach (dudeist priest) GRM+ Memberand Dork
4/30/22 5:10 p.m.

No experience with the bilstien so I cannot comment, but I imagine they are on par with koni.

Adjusted the konis made the TT handle as well as my Cayman for the most part.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
4/30/22 5:18 p.m.

The consensus on the Audi forums I used to frequent is that Konis were great for lowered cars but Bilsteins handled and rode a lot better.

For some reason the Bilsteins made for the small chassis cars (4000/80/90/coupe) would blow seals out regularly, so people ran Konis.  Never saw this behavior in other chassis.  It might be related to the high mount steering rack putting a lot of side stress on the top of the strut.

I have had Konis and Bilsteins on RX-7s.  Bilstein B6 wins hands down.

Be careful lowering too far -- The other Mk4 platformed cars use TT lower control arms and knuckles as a swap to improve the suspension geometry when lowered, but that's only by 1-1.5" usually. The roll center drop shouldn't be as dramatic with the TT since you're starting with the best factory parts, but it is something to be aware of.

There was also a revision in handling that the TT received after its initial release, I think it was sway bars, maybe bushings? There were some publicized crashes where the rear end came around and Audi reacted. Anyway, the changes promoted more understeer and I recall reading some opinions that handling deteriated as a result. Worth looking into as an area to adjust for balance if your going for handling.

Also, the single mass flywheel that would be used in converting these is a VR6 flywheel from the G60 Corrado apparently. There's aftermarket copies for both the 1.8T and TDIs, the TDI ones obviously being heavier. The main advantage is that it takes a larger sized clutch disk, and is single mass. Converting away from the stock dual mass is pretty common on early 2000s VW / Audi products, and I have to say I like the single mass feel better myself. The vibration is almost certainly engine mounts, there should three of them: A left, right, and "dogbone" mount under the engine/trans. That last one is where I'd start. IIRC, the driver's side one will need to come out to do the timing belt, so don't do that one before doing the timing belt, unless you like doing stuff twice.

Keep up with the oil changes and only use oil that meets the relevant Audi spec. There were sludging issues when the 1.8T was newer, but that should be self selected for by now fairly well. The big thing with the oil changes is that it helps prolong the life of the oil driven solenoid in the back of the head that controls the variable valve timing. Timing belt is also important, these are interference engines. It's the usual routine, pay $250-$300 and replace everything in there, including the water pump, and there are some special tools involved.

Master cylinder should be a very easy job, I think I did one on my Mk4 Golf in 30min working slowly, the TT should be very similar. The clutch line has a plastic end with a clip -- do not lose the clip, do not tear the O-ring, and make sure it and the clip are fully seated (no, really) before you step on the clutch -- the line will pop out and brake fluid will squirt everywhere otherwise.

Parts suppliers: I like FCP Euro a lot, but they've recently been not stocking as many Mk4 bits. NAPA has been surprisingly reasonable for me recently, both in price and lead time. You may have less luck having a TT (one of the parts I got was a ball joint, the TT ones are different), but I was surprised I could get a clutch master same day for a decent price. German Auto Parts is in existence again for another place to price against, and RockAuto always has deals with the usual caveats. 034 Motorsport make some performance parts, but they can be really poor dollar value, and FCP seems to have stopped carrying them. They did have a silicone PCV system kit for the 1.8T that was pretty nifty, but that was years ago now.

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