Helpful Acronyms:
VAG - Volkswagen Aktiengesellschaft
180q - 180hp quattro model
225 - 225hp quattro model (all 225s are quattros)
BT - big turbo kit
SMIC/FMIC - side-mount/front-mount intercoolers - there is one SMIC on the 180, and two SMICs on the 225
TIP - turbo inlet pipe
DV - diverter (dump) valve; recirculates vented boost
ARB - anti-roll bar (also called a sway bar)
N75 - solenoid that controls boost; VAG made several versions
N249* - solenoid that regulates the DV
N80* - solenoid that controls the EVAP (evaporative emissions) system
SAI* - secondary-air injection (pump, hoses, kombi, N112 valve) - used to ignite cats at cold start-up for emissions control
* deletable for engine cleanup

-GENERAL

• What different submodels are available?

There are four common submodels of the Mk1 TT: the 180hp FWD model (1.8L engine with k03s turbo), the 180hp quattro model (1.8L engine with k03s turbo and Haldex AWD), the 225hp quattro model (1.8L engine with k04-022 turbo and Haldex AWD), and the 250hp quattro model (3.2L VR6 and Haldex AWD). In 2002, Audi switched its Bosch ME7 ECU to a CAN-BUS system, and in 2003 the 225 gained VVT, both of which matter if getting tuned.

• How does the 225 get more power than the 180?

The 225 has a k04-022 turbo, which is larger than the 180 k03s. To support the bigger turbo, it has two side-mount intercoolers (rather than one), bigger fuel injectors, a dual-outlet exhaust, thicker connecting rods, different ECU programming, the compression ratio is 9:1 instead of 9.5:1, and the K04 produces 14psi, versus the K03, which runs at 11psi.

• How do I tell the difference between a 225 and a 180 quattro?

The 225 only comes with a 6-speed transmission, while the 180 quattro comes with a 5-speed manual or automatic (Tiptronic). Also, the 225 comes with a dual-outlet exhaust, but it's not a good idea to use this as a distinction criteria, since it's so common for people to put aftermarket exhausts on their car. The 225's intake manifold has its throttle body on the driver's side, and also has a pipe on the passenger side of the engine cover (easily seen under the hood) that leads to the passenger side intercooler.

• What is special about the 3.2?

The 3.2TT with its 24v VR6 was released in 2004, and was only available with the DSG (later S-tronic), or direct-shift gearbox. All quattro models share their suspension with the MkIV R32, so the parts are interchangeable, even the 6spd manual if you have $ laying around. The 3.2 is heavier than a 1.8T, and has slightly different suspension settings as a result.

• How/why is the quattro system on the TT different from the quattro system in other Audi cars?

The TTq, like the Volkswagen R32, uses an AWD system manufactured by a Swedish company called Haldex, rather than the traditional TorSen (torque-sensing) quattro system used in other Audi models. The Haldex is basically a control unit that uses a prop shaft off the rear of the transverse gearbox (02M, DSG) to control how much power the rear differential uses. Both cars are effectively FWD until sensors throughout determine that power needs to be sent to the rear, which, in stock form, happens with hard acceleration or loss of traction. The Haldex system on average distributes about 80% of the power to the front wheels and 20% to the rear wheels. In normal driving and highway cruising, the TT quattro is essentially a FWD car; when handling becomes an issue, the Haldex system wil send power to the rear wheels, but it will never go beyond a 50/50 split. TorSen, on the other hand, can send almost all its power to the rear wheels, depending on modifications.

If you want a more constant 50/50 power distribution, you can purchase a Haldex Performance controller... they sell for $900 new or around $600 used. This part will give you a more aggressive power distribution, and will allow more power to go to the rear wheels in any conditions, not just after front tire slippage. There are two replacement parts for the Haldex system, in the form of either a Blue or Orange controller; with the Blue controller, more power is sent to the rear wheels earlier, but the controller unlocks once the gas is released, or if the clutch or brake pedals are pressed. The more expensive ($1000+) Orange controller, however, stays locked. What this all means is that the Blue is good for improved street driving because of a more neutral power distribution, whereas the Orange is more track-oriented because a locked AWD system is always applying power, which takes away a safety net on the street. Ultimately, an Orange controller will understeer more than a Blue, but its negligible. Here is my Haldex Blue thread with install and driving impressions.

•--> If you have installed a Haldex controller, you should lower the fluid change interval to 15k for the Blue and 10k for the Orange.

-BUYING A TT

There are a few things one needs to look for when buying a mk1 TT. The most important thing is to check as to whether or not the timing belt has been replaced. The factory service interval is stated as being 100,000 miles, but it is well-known that the 1.8T's timing belt is THE major weak point of the engine, and that it should be changed by about 60,000 miles. If you are looking into buying a TT with under 60,000 miles, you should be aware that you should definetly change out the belt by the recommended 60,000 mile mark; if you are buying a higher-mileage TT, make sure it has either been replaced or that you don't mind taking on that responsibility. The two ways to take care of the timing belt is to take it to a dealership, in which you will pay dealer prices and service rates for convenience, or to pick up a timing belt kit from one of the several companies that make replacements. ECS is the preferred company, as they provide a complete kit for this swap, which includes a water pump with a metal impeller (to replace the earlier OEM plastic one), and you have the option of either a lightened or under-driven crank pulley. The reason replacing the timing belt is so important is because if the belt fails, engine destruction will almost surely be the result. If you happen to be covered under warranty, you may choose to not worry about this issue, because if the belt does fail, Audi will have to provide you with a new engine. That being said, there are fewer and fewer Mk1's under warranty, so be smart about your car. It will cost about $300 DIY or $900 at a shop, but in either case its cheaper than a new engine. Two good timing belt DIYs: 1.8T Timing Belt DIY and 225 Timing Belt DIY

Aside from the major timing belt issue, the TT has a few other little problems. The instrument clusters are known for being buggy, and may either have problems or fail, in which case you will need a rebuild or a new cluster. The glovebox latch is also problematic, as they can get stuck because the mechanism fails, or the entire latch can simply pop off. The fixes are pretty easy, and have been detailed on both this forum and AudiWorld's TT forum. Another issue is that the manual transmissions (especially the 6spd in the 225) are known for having slow synchros and some grinding issues, especially in the 2-3 upshift. A common solution is to replace the stock fluid with Redline 75W90 transmission fluid, or the newer (arguably better) OEM fluid. The Redline is cheaper, and many TT owners have done this and reported that it cured the grinding issue, along with improving shifter smoothness. Another known issue is rust on the two roof strips (NOT the actual roof, which is part of the double-galvanized unibody), which can come off for the roof racks that Audi sells. Taking care of the rust only requires removal of the roof strips and a respray. Some TT owners complain that they have noisy suspension, and the majority of the time it is due to squeaky sway bar bushings. If you hear a strange creak when you hit a bump, you probably need new bushings. Generally, 2000-2002 are more finicky than the 2003-2006 model years. Finally, make sure that the Haldex has been serviced every 20,000 miles, with fresh fluid and a new filter.

In addition, here are some other things to look for:
* Driver seat left bolster for excessive wear
* Under the front and rear bumper for damage from curb stops
* Door sills for damage from people climbing in and out of car
* Speaker grills and bottom of door card for same damage
* Correct function of windows
* Missing lines on gauge info display, correct gauge function, etc
* Correct function of the radio, all speakers and 6 disc changer
* Sufficient torque - this can be checked with VAG-COM. From the factory, the TT has certain torque ratings (170 - 210 depending on model). When there is a significant drop in this number, the car will not perform as it should. This is caused by excessive carbon buildup in the head, or similar issues. Carbon buildup IS a common problem, so be wise before making a purchase as it is NOT covered by any warranties!

Mk1 TT production (body style/number produced):
- Built in Gyor, Hungary

• 1999 (Europe only): 52,579 (Coupe 44,022, Roadster 8,557)

• 2000: 56,776 (Coupe 31,064, Roadster 25,712)
TT only a 180hp coupe, with either FWD or quattro
Optional packages:
Comfort - heated seats
Audio - Bose sound system
Performance - 17inch alloys and xenon headlights

• 2001: 39,349 (Coupe 22,078, Roadster 17,271)
225-bhp quattro edition w/ 6 speed manual released, 18" wheels optional
Roadster becomes available, manual or power top - Europe also had a rare, optional hardtop
Baseballs stitched leather convertible option
FWD/quattro available on 180-bhp coupe model
ESP becomes standard, ducktail spoiler added, and alignment changed
Comfort and performance packages combined into premium package
GPS audio navigation optional

• 2002: 34,711 (Coupe 21,488, Roadster 13,223)
Standard audio system becomes a CD player instead of cassette player
ALMS special edition (a 225 app. package, to commemorate Audi's victory in the ALMS series and Le Mans):
-18 inch Audi 9 spoke RS wheels
-Misuno Red with Silver Nappa leather, or Avus Silver Pearl with Brilliant Red Nappa leather
-Door cards, knee bolster, seats and steering wheel had matching leather

• 2003: 32,337 (Coupe 20,807, Roadster 11,530)
180-bhp available only in FWD Tiptronic (automatic)
225-bhp available only in quattro/6spd manual

• 2004: 23,605 (Coupe 14,753, Roadster 8,852)
3.2 6cyl version released, coupe or roadster, only available with DSG and quattro. 225/180 continue
S-Line appearance package optional

• 2005: 12,307 (Coupe 8,368, Roadster 3,939)
3.2, 225, and 180 auto

• 2006: 23,675 (Coupe 21,461, Roadster 2,214)
3.2, 225, and 180 auto
TT SE (special edition) released, available in several colors, all with a black roof - only on the 3.2

•--> Interior and exterior colors varied through the TT's production, with more options available later - AW Paint Code list

-MODIFICATIONS

• How does a performance "chip" work? Which one should I buy?

Performance chips will significantly increase your horsepower and torque. They do this primarily by advancing engine timing, adjusting air/fuel ratios, and, in turbocharged vehicles, increasing boost beyond factory limits. The major manufacturers are APR, REVO, GIAC, and Unitronic. With all four of these manufacturers, you can expect to pay around $600 for a chip/flashtune. These tunes are all different, but the general verdict is that you should just get whichever one has a dealer closest to you so that problems can be easily fixed should they occur. If you feel the need to save some money, you can consider InMotion Tuning, who sells their chips for $200 each; although they aren't as well-established as the big 4, they have gotten good reviews. In the end, don't be cheap with your tuning, because not only will your car benefit from a better tune, but it may save you a headache down the line.

If you plan on chipping your car, there are some things to consider: a turbo-back exhaust isn’t needed, but is definetly recommended, as is a TIP. You may need new silicon boost hoses (Samco, APR Forge), because the stockers can collapse under increased boost, you should have at least a boost and oil temp gauge to monitor your modified engine, and 4-5k seems to be the agreed-upon oil change interval, regardless of the factory service bulletin. You will also NEED to gap your spark plugs to .028 (as opposed to the stock .032). Along with this, better brakes will help you slow down after you start hauling more ass then before.

• Who makes a good cat-back or turbo-back exhaust system for the TT? What kind of gains can I expect with either?

It seems that the general consensus on the forum is that the downpipe is the most restrictive part of the 1.8T exhaust, and will produce the most gains when replaced. Neuspeed makes a 180 downpipe (the Neuspeed piece is the exact same as a GTI piece, because the cars are the same aside from looks), and APR and 42 Draft Designs both make a 225 downpipes, but only 42DD makes a 180q DP. For a cat-back, you can go custom or go to Borla, Jetex, Remus, Blueflame, and some others. APR makes a full turbo-back exhaust for the TT, but it's certainly not cheap, and arguably unnecessary unless running a BT set-up. Gains of around 10hp from a downpipe, and around 5-7hp from a catback, are common. The torque gains for each are usually about double the horsepower gains. Intakes, while nice, are somewhat useless on the 1.8T, whereas the 3.2 gets more out of an intake, with or without a chip, because it is naturally-aspirated, and the colder intake air goes directly into the engine, not through the turbo system.

• Should I get an aftermarket suspension?

Good basic mods are the Haldex upgrade, a rear anti-roll bar, and a different alignment. Neuspeed makes a 19mm street and 25mm dry/track-only rARB, H&R makes a 21mm, and Autotech produces a 22mm. A front ARB will also help, but the front subframe needs to be dropped for installation, a major PITA.

Coilovers will make a world of difference, but cost more and can compromise ride quality. Koni, H&R, and Bilstein PSS9 seem to be the most popular if money is no object, but the H&R does not allow ride-quality adjustment. VMaxx coilovers are the cheapest and seem to still be a good value for the money. According to most of the popular feedback, Vogtland and VMaxx coil-overs are a good compromise if you're looking for decent ride quality and performance for less money than the PSS9's. Some people like to get the HPA coils (which promise good handling without sacrificing ride quality), but the HPA suspension is the same thing as the Koni V1. If you don't want to spend the money for coilovers, you can get shocks/struts and springs, and any of the companies mentioned above should also have that option. Front and rear sway bars are a popular mod, and will serve the same purpose that they do on any other car. The TTq can take any of the same suspension mods as a VW R32. Also, along with suspension, many people also use spacers to "finish" the look; here is the AudiWorld offset/spacer calculator

• What should I consider if I want a bigger turbo in my 1.8T?

If you have a 180, you could get a K04-001, which will bolt right up but not really increase performance; its is only about +20hp over a K03, and +5hp over a K03s. The K04-022 from the 225TT can make decently more hp than the 001, but IS NOT A BOLT ON, as it requires a new manifold, injectors, MAF housing and software. Either TT can use an ATP eliminator kit, but it is not favored because some question its quality issues, high price, and increased lag from the OEM KKK manifold; use quality BT parts. With a BT you will NEED new rods because the stockers cannot handle the increased torque. The bottom line is that if you want the engine to make a significant amount of hp over stock, i.e., if you want the upgrade to be worth the time, money, and effort, you need to rebuild it. You should also only expect the maximum performance from the set-up with a dyno tune, because although companies make BT tunes, but you could be giving up power and driveability because of the "generic" program - they are not bad, but they do give something up to a "parts-tuned" ECU. Expect to spend a few hundred dollars on a dyno session. See the VWVortex 1.8T FAQ, and the AudiFreaks Big Turbo and High Performace post. Another common procedure with a BT is a wideband o2 sensor conversion, which allows for better/safer tuning. Basically, do a lot of research and be patient before spending money, it really is the better option and you will skip the half-ass/"learn along the way" problems you'd encounter otherwise.

If you're putting a bigger turbo in a quattro, you'll need a custom downpipe to get around the Haldex system. If you're putting a bigger turbo in a 225, you'll need to consider that you have a different intake manifold/intercooler setup than the 180FWD/Golf/Jetta, so those parts won't fit your car.

Finally, the quattro models use the 02M transmission, so the clutch isn't interchangeable with the 5spd Golf/Jetta. Both the Audi TT quattro models require a specific 02M clutch, which is the same as the one for the 6spd Golf/Jetta/R32. The Haldex system is good for about 550hp, but your engine won't be able to go too far beyond 350ft-lb of torque without needing stronger connecting rods, which is about where you will be with a GT2871R. You will break a lot of other things before you break the Haldex

-------------------------------------------------

-->EVERY TIME YOU HAVE AN IDEA OR QUESTION YOU WANT TO POST ON THE FORUM, PLEASE SEARCH FIRST

This FAQ was complied from these posts: It's about time for a TT FAQ... TT BUYERS GUIDE Any suggestions or additions will be noted and edited into this FAQ; thank you to all who helped and to those that will continue helping.

--> If you have links you would like to share with the forum, please post any link to parts vendors, tech sites, or general/misc TT info as a reply to this FAQ. If you contribute, please keep it organized. Also, if you use Mozilla Firefox, you can download an add-on called CopyAllURLs which turns bookmarks into a text entry with a title and the bookmarked link.


Modified by l88m22vette at 12:57 PM 10-25-2009

I'm gonna call you out on this because I got called out on this misconception myself. Haldex can transfer up to 50% to the back in stock form, it uses EDL the same way as TorSen quattro does. The difference is TorSen is stuck on a 50/50 split the whole time until traction is lost, then it transfers torque, whereas Haldex is FWD until it sense slip and starts transferring torque.

Audi TT Mk1 Guide

The Loch Ness Monster

The Samco pipe isn't necessarily expensive, but I'm sure it's a PITA to install.

Quote, originally posted by l88m22vette »

I changed it to say that the controller will give a 50/50 split sooner and more aggressively

Awesome thread btw...bet 90% of newbies will still bypass it though.

I think we oughta add either a "buying a TT" section to this or a new sticky cuz I see that a lot too. i.e. list typical little problems to look for when buying.

Audi TT Mk1 Guide

Done and done

I'm one of the remaining 10%, then. I always did lurk in the upper percentiles.

In the modifications section, how about a brief explanation of the rear-biased Haldex mod? Since both my current cars are RWD, this mod will likely be the 2nd one I do when I get a TT (1st - chip).

Two things I'd add from my TT: leaky headlight washers (I've seen this problem happen to other people too) and my DV was toast when I got my car. Didn't realize until I drilled my airbox and heard surge instead of blowoff. DV can of course be replaced with 710N for cheap or aftermarket. Tracking down washer leaks is HELL took me forever to finally stop mine.

Audi TT Mk1 Guide

I did, check out the FAQ towards the bottom

Quote, originally posted by l88m22vette »

I changed it to say that the controller will give a 50/50 split sooner and more aggressively

I don't see a change

Quote, originally posted by l88m22vette »

The Haldex system, when engaged, distributes 80% of the power to the front wheels and 20% to the rear wheels; Audi's quattro system, meanwhile, is capable of a 50-50 split

And if you want to distinguish the systems , call them Haldex and Torsen , they are both quattro ..

Modified by 1.8Tabamoura at 8:50 AM 9-28-2007

http://forums.vwvortex.com/zerothread?id=3467969

Also here is the TTULL it is invaluable. We should Copy the links though. I dont know if UNEEK will keep it running as he is selling his TT.

http://www.straightfocus.com/uneekttlinks.htm

Kenneth

Modified by TREFTTY at 9:01 AM 10-1-2007

The Loch Ness Monster

Flirckr

Quote, originally posted by Buegie »

very well done write-up...it helped a TT noob like myself decide if I want to make the VW-Audi switch next spring, thanks

Good to hear it being put to good use

Everybody wants a bolt on turbo upgrade...for something directly drop in either they can get a K04-001 which will bolt right in but not really increase performance much. I read that it's +20hp over a K03 and +5hp over a K03s. K04-020 from the 225 TT which can make decently more hp IS NOT BOLT ON it requires new manifold, injectors, MAF housing and software.

Or they can get an ATP eliminator kit which IMO sucks ass because of its quality issues, high price and increased lag from KKK manifold etc.

If you want to make a significant amount of hp over stock (read=worth the money+effort) you'll have to go BT.

Modified by Murderface at 1:45 AM 10-4-2007

Modified by Murderface at 1:46 AM 10-4-2007

Audi TT Mk1 Guide

Amulet Red: LY3C
Avus Silver Metallic: LY7J
Brilliant Black: LY9B
Brilliant White: LY9F
Denim Blue Pearl: LZ5W
Desert Green Pearl: LZ6W
Aviator Gray Pearl: LZ7W
Nimbus Gray Pearl: LZ7X
Raven Black Pearl: LZ9V
Lake Silver Metallic: LY7W
Misano Red Pri Metallic: LZ3M
Venetian Violet Pearl Effect: LZ3W
Moro Blue Pearl Clearcoat: LZ5J
Nero Blue Pearl Clearcoat: LZ5S
Imola Yellow Clearcoat: LY1C
Papaya Orange Metallic Clearcoat: LY2B
Ocean Blue Metallic Clearcoat: LZ5C
Goodwood Green Pearl Clearcoat: LZ6X
Dolomite Gray Pearl Clearcoat: LZ7J
Glacier Blue Metallic Clearcoat: LZ7K
Dakar Beige Metallic Clearcoat: LY1Q
Quartz Gray Metallic Clearcoat: LY7G


Modified by TREFTTY at 12:43 PM 2-1-2008

The Loch Ness Monster

Quote, originally posted by TREFTTY »

Yes, your car is falling apart. This is just one of the plethora of things that are now going to start breaking on your TT. The glove box handle has broken on practically every TT on this forum. I think what happened to you is that the little gear that makes one side pull right and the other side left has broke off of its pin. SO now it wont hold it shut. It sounds like your handle is still on, correct? Then your windows will squeel as they go down, such a charming attribute of the high dollar car. (There is a fix for this on Jeff Bipes page.) Next will probably be your cluster, whether it be a guage not working right, or perhaps the center display will have lines start failing. (Uber annoying) Then, Your windows will probably start going nuts(rolling up and then down then up again, when you hit the switch. Then your turn signals will start going nuts when you use them (This will be your hazard relay causing this problem). Then your fog lights will start acting up ( When you turn the headlights on they will be on no matter what. You will lose the ability to turn them on separately when the headlights are on. Then (my personal favorate) the two doors in the back seat area will stop staying closed. They will pop open whenever you hit a bump. And I am sorry to say that I have not left the interior yet. Now to the engine bay (The engine is actually a pretty solid engine) Coilpacks go way to often (When one goes bad, just replace them all) MAF's fail quite a bit (Alot of times cleaning will fix this) Secondary Air injection System will start causing a squeel on startup. The engine is just noisy, which will probably drive you nuts. And it will sound different whenever it feels like it just to make you think there may be something wrong with it (which there probably will be) You should install a "catch can", so your intercoolers dont fill with oil. Suspension/Exhaust This car is without a doubt the noisiest car I have ever owned (And there have been many) This car has more noises and rattles then I think it has parts. The suspension creeks, the exhaust rattles(even the stock one). And I know that there are fixes for all this ****, but should we all really have to replace all of our bushings with Poly? Couldnt they have just done that from jump street? This seems like a new one lately, Wheel bearings at abnormally low mileages. What a bitch these are to replace yourself. And annoying as hell to have to listen to. All of the above things happened to me on my 2002 TT in the short less then 2 year ownership I have had. I am sure that I missed some things but you get the gist of it. If you can look past all of these problems, then I guess the TT is a really fun car to drive. But I simply cannot. There is not enough money in the world for me to afford to own this car. I am entirely to picky. I have done every maintanance and then some and kept her so shiny that you could go blind if you looked at her the wrong way, and for all this she still hates me. But it looks hot as hell though, doesnt it? Inside and out, a work of art within itself. It is a shame that they concentrated on that one aspect when they built it.. Thanks fingy, for opening the door for this one. I really needed to vent some frustration. This car keeps me awake at night calling "Kenneth, come fix some more broken ****". And thats just really ****ed up right there, I dont care who you are.

Audi TT Mk1 Guide

The Loch Ness Monster

Thank you very much for the FAQ, it is really helpful.

Audi TT Mk1 Guide

Are there any hidden differences that someone trying to sell an revised TT as a revised TT wouldnt change and I could find out about?

Thankx.

And before telling me to ready the FAQ, I've read the FAQ and still cant see where that is.