Hey there hows it going with all of you? Just wanted to drop a post and introduce myself. I am thinking about gettin a 2001 S4, but not for probablly 6 months, so i found this website and am starting my research. Already found great information that will help me in my purchase, keep up the good work everyone....[sm=smiley20.gif][sm=smiley20.gif][sm=smiley20.gif][sm=smiley20.gif]

 

Feel free to ask any questions. The 2001 is a confusing year for the S4. A few changes here a few changes there - depending on the release date. I hope it all works out for you. Keep us posted and be sure to post pics when you get the S4.

By the way: Welcome. Don't forget to read the "Start Here" post that is at the TOP of this forum.
Here's the link... Start Here:

 

hey imolas4 thanks for the welcome, im pretty familiar with the start here section just because i know how frustrating it can be to read the same question 10 times when its already been talked about.

anyways, hopefully everything works out so that i can get the S4 in a bit but until then i will be spedning alot of time here, thanks again

 

Are you in the States?
What have you found out about the S4 so far? Any questions?

 

Yeah i live in California.

Basically I have been looking around the forum just to see what normal problems there are with used S4's. THe one thing that kinda makes me feel uneasy is a blown turbo, but hopefully a blown turbo isnt a normal issue. I am sorta new to turbo engines so i am not to sure about what all goes into maintaining a turbo so that it lasts.

As fo question i have, i was just wondering, you mentioned that there were chages between the 2000 and 2001 S4 depending on build date. i was just wondering what the differences where and which, in your opinion, should i be looking at to purchase?

thanks imola, i apprecate all the help..

 

Well... you'll get more people telling you that the latest version is always the best, because all of the "kinks" were worked out by then.
But.... you'll get a few select people that will claim the early version is best.

Now let's look at it objectively....

2000 S4 has and has nots:
Has (smaller) classic S4 badge.
Has an f-hose.
Has the Bosch MAF.
Has the "A" box ECU for manual 6 speed (considered to be the most aggressive of all the ECU boxes).
Does NOT have ESP.
Is about 60lbs lighter than the later versions.

2001 S4 has and has nots:
Has (smaller) classic S4 badge.
Has an f-hose.
Has the Hitachi MAF.
Has ESP.

2001.5 S4 has and has nots:
Has (larger "S") new S4 badge.
Does NOT have an f-hose.
Has the Hitachi MAF.
Has ESP.
Note S4 Avant arrived at this point, too.

2002 S4 has and has nots:
Has (larger "S") new S4 badge.
Does NOT have an f-hose.
Has the Hitachi MAF.
Has ESP.
Has larger turbo oil lines.
Has "AA" or "T" ECU boxes which are considered the most sophisticated of all others (except 2000 A box is strongest in performance).

So... read through the above and see what you think.

Secondly, consider this for any model year S4:
The DV's should be upgraded - especially those that get chipped.
The TBB is a weak link on all S4's, too. It should be upgraded with a better unit or a redesigned unit like the APR Bi-pipe kit.
The coolant sensor should be upgraded with the latest OE sensor (a $5 fix).
The control arms should be inspected for wear on a regular basis.
The oil should be changed to synthetic oil, if it hasn't been already, and it should be changed frequently.

As far as turbo failure... it is rare but it happens occasionally. If it happens, it happens more to those engines which have been chipped and even more so to those that are chipped and abused. It is a risk we all take with turbo engines, but most of us agree it is worth the risk. Many of the conservative thinkers (albeit aggressive drivers) will plan for the inevitable; they start a savings account that's earmarked for new turbos! But in reality, if you take care of the engine and turbos with disciplined maintenance and keep your abusive driving to a minimum, the chances are pretty slim that anything will happen to the turbos. Lastly: The most common turbo failure is the passenger side turbo and the reason for that failure is that the turbo oil line's proximity to the exhaust manifold on the passenger side is too close. The overheated oil may break down and cause sludge to build up on the main turbine bearings of the passenger side turbo. Eventually this will cause the passenger side turbo to fail. To this date, there is no preventative modification or upgrade that seems to remedy the potential problem - other than cooling down the engine before turning off the ignition after a spirited drive. By the way: I know a guy who has a chipped S4 with over 150k miles on the original turbos - no problems.

Let me know if any of this is confusing or you have any other questions.

 

thanks imola i appreciate the write up, i didnt expect that, but i appreciate it.

a couple question i did have after reading the post was the cost, you would think, for upgrading the DV and TBB. Just curious, and also do most poeple know about these neccesary upgrades or is it pretty rare that when purchasing a used S4 that these are takin care of?

Other then that no questions as of now, but im sure i will have plenty in the near future.

and...just wondering where you are located and what year your S4?

thanks again [sm=smiley20.gif]

 

Yes, those "in the know" or those that investigate S4's like you are doing, are well aware of these issues. They are not terribly big issues, but they are necessary to bring peace of mind. It is a gamble as whether the previous owners are aware. An example: All of the buddies I know with A4's and S4's all know of these issues, but I have a neighbor (a career Naval officer) who had no idea that the S4 has any of these issues until I mentioned them two weeks ago. The officer has had a 2001 S4 since new in May of 2001.

Costs for TBB and DV's:
An OE repacement TBB is probably around $35 (I really don't know because most of us do the upgrade), an upgrade TBB is about $55 and the APR BiPipe Kit is about $350.

As far as DV's are concerned, here's an article I wrote:
========================================
About BOV's, DV's and the Audi closed loop turbo system.
The Audi turbo system is a closed loop system by which all unused boost that is spooled during off throttle and gear shifts must be re-routed within the system; it cannot be vented to the atmosphere due to the dependence on the MAF and ECU to properly read and interpret air flow dynamics within the intake tract. Therefore BOV's (Blow-Off Valves) are not used because they create a rich air/fuel condition (i.e. less air to fuel ratio) which will damage the catalytic converter, create soot on the exhaust pipes, and cause occasional misfiring (due to the purged air) which will result in ECU miscalculated timing adjustments and other errors.

For Audi closed loop turbo systems, a BPV or DV (By-Pass Valve or Diverter Valve) is needed to recirculate the purged air and keep it within the intake tract.

At the time of this article, the following valves are available on the world market:
AmD Viper = Polished chrome version of Bailey DV with AmD logo, $$$ (see "Bailey" below)
Bailey = Probably the most popular, serviceable, $$$
Evolution Motorsports = Cosmetic, 4 color anodized choices, not serviceable, $$
Forge = Large (may have fitment problems), serviceable, $$
Forge 007 "A Line" = Same as standard Forge, flat top for better fitment, seviceable, $$
Forge Race = Larger than others (see above), adjustable, serviceable, $$$
GFB Stealth FX D-BOV* = Exclusive unorthodox design, externally adjustable, tight fitment, not serviceable, $$$$+
HKS SSQV BOV** = Dual stage pull-type relief valve, highly competitive for open loop systems, not for Audi turbo sysytems, $$$+
HKS Racing BOV Type II** = Single stage aluminum pull-type valve, same as SSQV but able to handle up to 43psi (3.0 bar), $$$$+
Hyperboost = Cosmetic package, not serviceable, $$
Hyperboost Adjustable = New, cosmetic package, may not fit S4, adjustable preload, not serviceable, $$$
Hyperboost HX = Newest, very cosmetic package, new internals, not serviceable, $$$
OE Bosch TT 710A = THE STOCK DV FOUND IN ALL (1997 AND UP) AUDI TURBO MODELS, Audi part # 034-145-710A OR 06B-145-710, $
OE Bosch TT 710N = Basic, popular & low-budget upgrade, maintains stock look, not serviceable, Audi part# 06A-145-710-N, $
OE Bosch Sport 110 = MTM upgrade, same as 710N with "better" internals, not serviceable, $$

$ = under $50 USD
$$ = $50 - $150 USD
$$$ = $150 - $250 USD
$$$$ = Over $250

* The GFB D-BOV is currently an unproven design; it is a hybrid diverter and blow-off valve; it is intended to act as a diverter valve while providing the cosmetic audible benefits of a blow-off valve; it is undetermined whether this design is effective for use on the Audi closed loop system or whether it may be causing long term damage.
** The two HKS BOV's are mentioned here because they have shown up on some highly unorthodox applications on the S4; they were not used properly and eventually removed due to poor recirculating feeds and other ecu errors.
========================================

I hope this helped.

Edit: DV list updated.

 

Damn...thanks for all the information i really appreciate the time you have taken to help me out. all this information, im sure, will help alot when its comes time to purchasing my S4.


thanks alot imola

 

No worries, I have these "articles" pre-written just for this very purpose.
Glad to help.