1.8T reliability at 200 hp - HELP!

["Bruce, Erik (erdb)" <ERDB@chevron.com>]

Help, all you turbo-boost experts!   There's been an on-going debate on
JET's A4 bulletin board about the reliability of the A4's 1.8T engine
when chipped up to 200hp (with chips such as the .8 bar or 1.0 bar
Wetterauer, TAP's, Hoppen's or others).  

Many of the "facts" that have been posted are conflicting, so I'm
confused.  I certainly don't want to damage my new A4 just for some
cheap thrills (well, then again....)   I figured if anybody knows the
truth it's you guys (all of you running 2.0 bar boost in your turbo
rockets!).  I'm not an engine expert, so I can't tell which arguments
are valid.

Here's a summary of some of the points on both sides of the debate.  Let
me know which hold water (or boost pressure):

THE CASE AGAINST CHIPPING:
1.  Audi carefully engineered the 1.8T to run at 150hp, and anything
higher will cause excessive stress on the engine internals and reduce
engine life. 
 
2.  The turbo/ engine design was carefully thought out by Audi, and 7
lbs is where the turbo should be running (150 hp).  Getting 12 or 14 lbs
boost pressure from the turbo (200 hp or more) is too much for this
engine if you want it to last more than 75,000 miles or so, or certainly
too much for the poor little turbo.  

3.  If you're going to raise the boost pressure, you should change other
things such as the air inflow (filter), exhaust, perhaps intercooler,
etc.  It's not safe to just up the up the boost pressure. 

4.  200 hp from a 1.8T is a very high hp/ liter ratio, getting into the
very highest range of production cars, including high-end sports cars
such as the Porsche 911 turbo S.  There must be a reason that few auto
builders sell production cars with this kind of power/ liter ratio (and
that reason is reliability).

5.  Contrary to popular belief, the TT roadster's 1.8T engine is NOT the
same as the A4's, so the fact that the TT gets 215 hp is apples and
oranges.  Audi didn't just de-tune the engine management system and
reduce turbo boost in the TT's engine for the A4.  The compression ratio
is different, so the engine internals are slightly different.  This
indicates that Audi feels the 1.8T needed to be strengthened for the TT
roadster to withstand 215 hp.

6.  If it can be done safely, why didn't Audi do it?  Insert general
distrust of any "aftermarket" tinkering here.


THE CASE FOR CHIPPING:
1.  The reason the 1.8T is tuned at 150 hp is marketing.  How would Audi
sell the 2.8 if the 1.8T could outperform it (or the TT roadster for
that matter)?  They have positioned the 1.8T as a step below the 2.8 and
so it is tuned down to a less threatening hp level.

2.  The turbo's manufacturer says the turbo unit can withstand more than
14 lbs. boost pressure, and can run troublefree at 14 lbs. max., so quit
worrying.

3.  The TT roadster has a 1.8T that gets 215 hp, and it is not
dramatically different in design.  Audi would not have a totally
separate re-tooled engine line just for the TT's 1.8T, since it is very
limited production.  Perhaps the intercooler has been upgraded, and
maybe pistons, but the engine is basically the same.

4.  200 hp is not anything near the engine's upper limits of stress.
You can tune this little superstar engine way above 200 hp - check out
Ivor at Total Audi Performance for his options - 240 hp, 300 hp, racing
engines at 500 - 600 hp!  Yes, the much higher hp ranges have some major
mods, but it is still much the same little powerplant.  
 
5.  Audi itself has considered (or already has done so in some
countries) allowing dealers to sell chips as dealer upgrades, under full
Audi warranty.  Does this sound like they think extra ponies will hurt
the engine?

6.  The REAL factors in engine life are maintenance and how you drive.
These factors dwarf any affect extra boost pressure might have.

7.  A stock 150 hp engine may be flogged much more to get it to perform
well, while a chipped engine performs better at lower rpms and isn't
punched all the time to get the car moving quickly.

8.  If the stock 150 hp engine can go at WOT on the Autobahn for a
couple hours straight (the common use in Germany that it was designed to
handle), isn't that less stressful than a 200 hp version driven under
real world conditions -  mostly in the 2-4000 rpm range with only
occasional hard driving?

9.   Audi has a long history of turbo engines, with many people fooling
with the turbo boost.  They designed the A4 1.8T as an enthusiast's car
with the full knowledge that it could and would be chipped up, so they
designed it to last under higher boost levels.

10.  Hey, live a little!  Stop worrying.  200 hp in this car is such a
rush, it totally transforms the car!  Who cares what happens "down the
road"?   (I had to throw that argument in).


Thanks for whatever help you can offer.  My gut feeling (as yet
unproven) is that the extra stress of higher hp is real in some sense
(more power has to affect the engine), but at 200 hp it isn't
significant enough to affect engine life, assuming proper maintenance
and good driving habits.  Is this just wishful thinking?


***************************************************
Erik D. Bruce
Hazardous Waste Specialist
Hazardous Waste/ Drum Storage Teams
CREMCO Facilities Management, Richmond Technology Center
(510) 242-4385    e-mail:  erdb@chevron.com
***************************************************