Hey all,

After initially looking at the 2.7T because of the potential for major power with an ecu upgrade I am now leaning towards the 4.2 based on my actual needs and wants and have a few questions.

Now I am looking at the 4.2 and BMWs 540i with 6 speed manual. I dont have to drive on a daily basis and will mainly be using the car on the weekends for getting to the golf course, heading up to Tahoe for skiing, and taking weekend trips up the coast. With the Audi my main questions are:

-Am I looking at significantly raised maintenance costs over the 540i? After speaking with my mechanic (had a 535i before college) he said he loves the idea of me getting a 2.7 or a 4.2 because I will be making his wallet fatter and encouraged me to look at the 540i. I have somewhat of a hard time believing that a well maintained A6 is going to be any less reliable than a 540i but im a bit spooked now.

-Are there any items specific to the 4.2 that i need to worry about when looking at cars? I know to make sure the timing belt and cooling system have been replaced/upgraded when looking at a car with 80k or above miles? My mechanic mentioned that 4.2s require special tools for some maintenance and can be somewhat of a pain to work on overall with the electrical systems requiring even more f-ing around that most Audis/Bimmers.

-I am looking at 2 cars with less than 100k and wanted to know about what kind of warrantee's are available and/or recommended for a car that has underk 100k miles and has had the timing belt changed, the cooling stystem upgraded, and is generally in a state of good repair.

-Finally, is an ecu and transmission software modification recommended for the 4.2? I have seen that APR advertises a chip for the 2002 4.2 in the AllRoad but not the 4.2 in the 2000 A6. Would an ecu upgrade yield an additional 40 hp and be worth the expense?

Thanks in advance for any and all responses,
CalLax

 

Audi and BMW are generally pretty comparable dealership to dealership, BMW is probably slightly more. Audi tends to be a bit more complex due to the systems involved so if the car has been serviced by an independent that doesn't know Audi well there could be more issues arising due to the mechanic's inexperience. Personally I wouldn't worry about a well maintained A6 being any less reliable than a well maintained 540i.

Timing belt/waterpump is the major service. The only other thing that often seem to go wrong is the control arms and front suspension end links. Valve cover gaskets can also seep. The transmission is generally very strong and the 4.2 benefits from a significantly beefier tranny than either of the V6's. Other than that, most of the rest is just standard maintenance for an older car which you'll run into regardless of the make.

There are some aftermarket ECU programs for the 4.2L which are meant to increase power and sharpen the transmission shift points. Will they yield an extra 40hp? I doubt it, but I'm always skeptical of power gain claims from a just a chip on a NA engine.

Is it worth it? For my money no. The 4.2L has more than enough power and torque in it's OEM programing to handle any situation and 40hp more is not really significant enough a gain for the money and potential extra stress on the the engine. My take on it is if you're going to modify a 4.2L then don't waste your time on an ECU upgrade, just go straight to the various low boost supercharger options from the start. Those can bump you up to 400 - 450hp depending on the kit and options which is a worthy upgrade.

Basically the 2.7T is the choice for the person who is willing to accept a more finicky platform with the higher maintanence needs of a forced induction engine as a trade off for the ability to modify it to produce significant power output. The 4.2L is not a particularly easy base platform for modifications but it does produce significant power as stock with the lower maintenance requirements that come from being naturally aspirated. In my case I went with the later choice because I've had several modified cars in the past and, while they were a lot of fun, they did eventually become maintenance headaches and this time around I just wanted something I could keep at stock spec and still have fun in.

My only regret about the 4.2L is the lack of a manual gearbox but the tip gate alleviates that issue to a degree. I find that 2nd gear is usually perfect for driving around on surface streets and that keeps me in the power band so I don't have to deal with kick down lag. 3rd or 4th is great for spirited driving on the freeway however there I usually just stay on the auto gate

 

Hey Mithril - thanks for the detailed response.

I know the 2.7 is the tuners car of choice but for the same reasons you mentioned above (reliability mainly) I dont think I want to go that route. I also think I would be tempted to do stupid things on the road and with my wallet if I got a 2.7. I have always liked the results of ECU upgrades in the cars I have driven in the past so I figured if it would be possible to gain some extra power and improve the throttle response for a couple hundred buck it might be worth it (especially if the gain was actually 40hp rather than 10-15).

I love a well sorted manual transmission but since I live in San Francisco and would want my gf to be able to drive the car on occasions having the auto is almost a necessary evil. That coupled with the fact that I feel like the shift action in the A6 is relatively dull and numb leaves me feeling like the auto box is the way to go. Still, I dont like how "soft" the Tiptronic trans feels and that it wont hold a gear if you're revving the engine hard which is why Im interested in hearing about other folks experience with aftermarket transmission software.

 

The behaviour you're describing is the "new shift strategy" and can be changed via VAG-COM. It may have become the default program in later years and/or on the 2.7T and 2.8L models. In tip mode my '00 4.2L will hold every gear up to redline, it also doesn't auto-downshift until you drop to almost a full stop at which point it drops into 1st (about 10kph seems to be the threshold). It does auto-shift from first to second if you're not WOT of the line but the rest of the gear behave like a manual regardless of throttle amount.

Tip is still not a manual, and that 6spd manual mated to the 4.2L is a HUGE difference from tip, but it's still pretty if you are forced to accept an auto.

 

1-I agree with not wanting an MT6 in SF. I've visited quite a few times and in spite of most of my cars being manual, I could not imagine it on some of those hills and parking spaces.

2-I suspect the A6 may be a little more costly to maintain than a BMW bcause of the additional complexity of the quattro system. However, if you are going into snow country you will be AMAZED at what quattro can do. Otherwise both makes have the same over abundance of accessories, bells, and whistles that can fail and nickel/dime you to death.

3-Chipped my 2.7T at 75k, replaced clutch and flywheel at 85k, and have been driving it regularly since -- currently at 176k. Mostly highway driving however, and city driving, esp in SF, would be much harder on any vehicle. There's some very minor stuff wrong and regular maintenance that has to be done, but it has been a very reliable car and I do not hesitate taking off on a 2000 mile long weekend with it.

 

You can go to edmunds.com and read reviews from both owners of those specific cars. by the folks who own and drive them everyday. That's where I start when looking at models I'm unfamiliar with.

 

I think if you make the right decision when buying a 4.2 you can't really go wrong... but thats the hard part, finding one that hasn't been thrashed and has had all the major wear items taken care of. I have an 01 4.2 and my brother has an 02 4.2.

I've driven 540i sports and 2,7t's and I just like the 4.2. The 2.7t's are pretty spunky and with a little tuning are very potent. The 540i is awesome, I love 'em but the 4.2 suits my needs much better. It feels more luxurious and sure-footed, we had a nasty snow last year and everyone in the neighborhood was stuck but me. It made me really appreciate the car when all I see are four wheel drive monsters roaming around in the snow and the only car is mine. Plus it does huge doughnuts really well =]

Don't think that the 4.2 is just a regular a6 with a V8 stuffed in it, they are very different beasts.

My complaints would be greater if I didn't work on the car myself. The catalytic converters are super expensive, even more so in cali. I was quoted between 2500 and 3500 to replace em not too long ago, so I just "repaired" them (no downstream o2 sensors, yay!). Did the timing belt myself. It's a very logically laid out car, it's very easy to work as long as you have the bentley and pay attention.

I would honestly say the 540i is the more reliable, funner to drive car...if I had one I think I'd get a ton more tickets. A couple weeks ago I passed a 540i on the outside of a corner at very high speeds. We both were struggling, but then again I had 15mph on him and was still accelerating.

 

Dittos on what the rest have already said.

On the 4.2 Allroad the gains are greater because it is a timing chain instead of a timing belt.

With a 4.2 A6 I wouldn't do the ECU upgrade unless you're going to work on the exhaust to complete the process.

If you really want to press your luck you can try one of those PES Superchargers and let us know how that works out for you.

Good luck!

v/r,
Paul