Pros and cons between the 2.7tt and the 4.2.

[Knives1010]

Hello,

My A4 was recently totaled because of a drunk driver striking me at a stop light. I know I want a c5 Allroad for my next vehicle, I'm just unsure as to which engine will best fulfill my needs. As a result I thought I would ask the gurus, what the pros and cons to each are.

[Arsenal2012]

Im interested in this...
Gas mileage
Easy of mods
Weight
Drive ability
Brakes
Amenities
Etc....

[A Stupid Turtle]

The allroad came with a chain driven 4.2l.... as much as I love the 4.2l, the chain driven shenanigans scares me... for that reason alone I would go with the 2.7tt...
2.7tt only has 9292838484ie9w948383% more mods out there too.

[n8henn]

When I bought mine, I looked at it like this. If you are not going to modify the car, the 4.2 is an option. However I wanted to modify and insisted on a manual 6-speed car then the 2.7tt is your only option. Not much tuning potential for the 4.2 and as others have said, the chains will fail at some point. Oh and no 6-speed 4.2 AR.

[rollerton]

Yeah. If it's an Allroad specifically you want you're probably not going to find a huge number of 4.2 fans in here. Personally I don't have a problem with them, but since you can buy an S6 so cheap I could never see a reason to buy a V8 AR.
Here's that V8 in the allroad. Look like fun?

http://www.nogaroblue.com/cars/s4v8.jpg
Here's some discussion about them:

http://www.audizine.com/forum/showthread.php/414598-B6-B7-S4-Timing-Chain-FAQ-Information-Discussion-Thread

They're kind of cool since they're so uncommon..but otherwise I'd take the turbo maintenance over the liability/ potential trouble of that V8.
Now...if you want to compare it to the C5/ BBD S6 V8 you've got a whole different deal. And we don't need to start that.

[n8henn]

WOW!!!! That's insane!

[Knives1010]

I was unaware that the AR had the notorious chain driven 4.2 that makes my mind up right there.

[mr_dave]

2.7T would be my only choice in an AR. Much more options for tuning, available manual transmission, and there's no way I'd want to deal with the timing chain mess on the rear of that 4.2L. I'd much rather change timing belts.

[LINDW4LL]

I was unaware that the AR had the notorious chain driven 4.2 that makes my mind up right there.
Yep. I'd go for an S6 if you want the V8, or else be prepared to do chain service.

2.7T is the bomb. The K03s are somewhat failure prone at higher mileage, especially when tuned, but the engine is just asking to be upgraded anyway. This engine with K04s is a beautiful thing.

Find a 6MT, too.

[Nollywood]

I would go with a 4.2 V8, each and every time. If I really wanted an Allroad 4.2 V8, I would replace the pesky chain-driven 079 series V8 with the much more robust (and proven) belt-driven 077 series.

[alistairogrady]

Do you not get the 2.5 V6 Tdi Allroad in the USA?

Alistair

[Knives1010]

Nope, we also don't get irsh green pearl which I would love

[Scotty@Advanced]

Do you not get the 2.5 V6 Tdi Allroad in the USA?

Alistair

No

[happy2B5]

When I bought mine, I looked at it like this. If you are not going to modify the car, the 4.2 is an option. However I wanted to modify and insisted on a manual 6-speed car then the 2.7tt is your only option. Not much tuning potential for the 4.2 and as others have said, the chains will fail at some point. Oh and no 6-speed 4.2 AR.
Meh, just supercharge the 4.2 and do a 6mt swap [emoji41] [emoji4] . Lol!

I think the timing component job/issue is overblown. Sure it is a very real consideration and spending coin on preventive maintenance without power gains is a bummer. That said, how many 4.2 ar timing failures/issues have we seen? Once done, it is done.

Also, when you add up the real world cost to replace turbos (engine pull), clutch upgrade (when going bigger turbo), fueling, tune, etc...multiple timing belt jobs, it adds up quick. BUT, you have one badass audi at that point imo. So, I like both options frankly (currently own a b5 s4 2.7tt avant and 4.2 ar).

Following the jhm performance recipe for the b6/7 s4 with exhaust, tunes (ecu/tcu), intake mani, lwcp, lwr, and the 4.2 ar can be a fun formidable option, too.

[Scotty@Advanced]

Meh, just supercharge the 4.2 and do a 6mt swap [emoji41] [emoji4] . Lol!


Actually just the 6mt swap is awesome. It totally transforms the car. I'd wager that the 6mt swap will best an automatic with a blower.

[happy2B5]

I doubt the zf 5hp19 can handle a blower [emoji6]

If it could, I don't understand why that would be case though?

[Scotty@Advanced]

I doubt the zf 5hp19 can handle a blower [emoji6]

If it could, I don't understand why that would be case though?

The automatic is horribly inefficient. I had a customer do an AR dyno before and after a 6mt swap and gained a significant amount on the after dyno.. and that is not counting the 150 lb weight savings.

[happy2B5]

Ah. Nice

[A6C5V842]

Scott,

Is the weight saving only 150lbs?

My first C5 was a 2000 auto and around 200k on it. I drove that one for over 6 years and knew it intimately.

This one is a 2001 6MT with 100k on it. The weight difference feels significant to me. Plus the lack of torque converter etc makes a massive difference in performance in every way. Instant power and torque in places the auto was useless. Also the handling is improved dramatically because the chassis is under power and therefor much more controlled and controllable. I have to admit, I did doubt the 6MT guys claims a little until I got this one. It really is a B6 S4 for adults!!!

PS, I'm talking about the 4.2 sedan here of course.

[rollerton]

Scott,

Is the weight saving only 150lbs?


I can tell you that the 5hp24 weighs about 370 metric tons. The 01e is pretty light and the 2/3/4 gears are pretty awesome with a V8. The speedo outruns the tach any time you get on it. I can never get to the end of a gear before I start worrying about jail time.....and the torque? It's basically an auto if you leave it in 3rd.

[A6C5V842]

^^ Exactly.

3rd is pretty much auto. I can pull away without so much as a mumble in 2nd and then hit 3rd and drive around town all day. That engine was built and tuned for a manual box and it really shows.

First time I drove it I was stunned, literally, at the difference.