4.2 vs 3.0T

[Audimatic777]

What's everyones thought on the 4.2 vs 3.0T? Been looking for a 3.0T but found a good deal on a 4.2. About half the price. 124k but runs well. Super clean for 6k. Most 2009+ 3.0T are still north or 12k here.

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[NickLim]

4.2 is less reliable and less powerful

V8 sound is indeed better, and clearly the price is as well for you

So with that information it's up to you to decide

Personally I would just go 3.0t and do it right the first time if I was you

[NickLim]

Unless you really like the sound of a V8 I would say that it is unwise to go with a 4.2 from a long term financial stand point as well as performance

[se.farrell]

Go with the 3.0 for longevity.
From what I understand, it is going to be more reliable.
Plus, the real reason for me is that it has way more aftermarket support. There is not much you can do to the 4.2. But the 3.0 has much more optionality, both performance and styling.

[Audimatic777]

Correct me if I'm wrong but isn't the 4. 2 engine in the A6 belt driven and not a chain like what's in the S4?

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[Kevin1]

Correct me if I'm wrong but isn't the 4. 2 engine in the A6 belt driven and not a chain like what's in the S4?

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The 4.2 engine in the C6 is chain driven. It is also the major weakness in the engine. The timing chain guides and tensioners become a real problem once you pass the 9 year/135k mile marks.

[Audimatic777]

The 4.2 engine in the C6 is chain driven. It is also the major weakness in the engine. The timing chain guides and tensioners become a real problem once you pass the 9 year/135k mile marks.

Got cha. For some reason I thought it was belt driven. My bad. Maybe it's the older version?

Anyways, I guess I should not do the 4.2 then.

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[NickLim]

Got cha. For some reason I thought it was belt driven. My bad. Maybe it's the older version?

Anyways, I guess I should not do the 4.2 then.

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Go for the 3.0t bro the c6 a6 3.0t is the most undervalued car RN

[Nollywood]

My choice would be the 4.2 V8.

[Nollywood]

The 3.0T and 3.2 N/A are also chain-driven, similar set-up to the 4.2 079-series.

Same strengths and weaknesses in terms of timing gear.

The 4.2 V8 079-series is more reliable than the 3.0T.

[NickLim]

The 3.0T and 3.2 N/A are also chain-driven, similar set-up to the 4.2 079-series.

Same strengths and weaknesses in terms of timing gear.

The 4.2 V8 079-series is more reliable than the 3.0T.

I read the 3.0 is based off the 3.2 and that the repair for the timing chain is much different than the 4.2

With the 3.0t as I understand it the job can be done without pulling the engine

Whereas with the 4.2 you have to pull the entire thing and drop the tranny

[MSq5]

I know little about the 4.2. I can say that the 3.0 TFSI engine can be bumped up to over 400 horsepower with one 30-45 minute pulley swap and a stage 2 tune. If you don't go crazy on the pulley ratio it remains uber reliable.

[Spaceme1117]

Skip both the 3.0T and the 4.2 V8. You really want the 5.2 V10.

[Nollywood]

I read the 3.0 is based off the 3.2 and that the repair for the timing chain is much different than the 4.2

With the 3.0t as I understand it the job can be done without pulling the engine

Whereas with the 4.2 you have to pull the entire thing and drop the tranny

The procedure is exactly the same. The chain on the 3.0 TFSi / 3.2 FSI is at the rear of the motor, same as the 4.2 079-series. How can the chain be replaced with the engine connected to the transmission??

[Nollywood]

I know little about the 4.2. I can say that the 3.0 TFSI engine can be bumped up to over 400 horsepower with one 30-45 minute pulley swap and a stage 2 tune. If you don't go crazy on the pulley ratio it remains uber reliable.

Very true.

But the 3.0T lacks the displacement of the 4.2 V8. The V8 will ultimately produce more power than the 3.0T. There’s just no substitute for displacement.

[NickLim]

Very true.

But the 3.0T lacks the displacement of the 4.2 V8. The V8 will ultimately produce more power than the 3.0T. There’s just no substitute for displacement.

The V8 will ultimately produce more power than the 3.0T - u sure?

[NickLim]

For whatever reason I also don't think the timing chain is as big as a problem as on the 4.2

I basically never hear about anyone doing that repair - whereas with the 4.2 I hear about it all the time

[JamessHalpert]

Skip both the 3.0T and the 4.2 V8. You really want the 5.2 V10.

I came in to say the same thing lol.

[MSq5]

Very true.

But the 3.0T lacks the displacement of the 4.2 V8. The V8 will ultimately produce more power than the 3.0T. There’s just no substitute for displacement.

How much money and what hard parts mods would you have to do to produce more power than a Stage 2 or 2+ 3.0T Would the labor be more than 30-45 minutes to swap out a pulley and belt and flash a tune?

Oh yes, you can get there with APR's Stage 3 supercharger kit for only the modest of sum of . . . $13,000. But, wait, price notwithstanding, that is displacement AND forced induction, and does not count the considerable labor cost involved.

[BSIX-SFOUR]

What's everyones thought on the 4.2 vs 3.0T? Been looking for a 3.0T but found a good deal on a 4.2. About half the price. 124k but runs well. Super clean for 6k. Most 2009+ 3.0T are still north or 12k here.

From someone who has now owned both, let me put in my 2 cents. I owned a B6 S4. Great car! Quick, agile, and that 4.2 really sings with a decent exhaust(not AWE). The biggest Achilles heel to that platform is undoubtedly the chain driven timing. As one of Audi’s first(if not THE first) production vehicles to feature a chain driven timing system, there was bound to be some problems. I’ve heard of guides and tensioners failing as quickly as 60k Miles. Unfortunately, it’s a rather labor intensive and expensive problem to have. Mine came with a 3rd party warranty, and to my surprise they covered the whole thing (totaling just north of $10k at my local Audi dealer). Even though I used JHM timing components (which I had to pay out of pocket for but was later reimbursed). The warranty cost me $3500, and it was money well spent in this scenario. I now own a B8 S4... when I purchased it was at 69k and I shelled out a little over $18k for it. It has the APR stage 2 single pulley upgrade and TCM flash which according to APR’s dynograph makes right around 455 hp and 395 ft lbs of torque. To put this in perspective for you, people have bought the JHM supercharger kit for the 4.2, had the block sleeved, done all forged internals, added titanium valve components and STILL don’t make that amount of power. The supercharger kit is $8000 on its own, then to have JHM completely do the bottom end is another $10,000, plus the cost of the car, and the $3000 for upgraded valvetrain. In my mind, it was a no-brainer. Plus with the B8, you get way better creature comforts. Although the B8 does sound like shit compared to the B6/7. Lol I always laugh when people say there is no replacement for displacement. If that’s the case, then why can a 3.5L Nissan RB28 make as much or more power than a twin turbo 5.2L v10? More cylinders doesn’t necessarily mean more power. The b6/7 s4... or even RS4 don’t hold a candle to a B8 S4 in the bang for the buck department.


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[lumberwood]

Amen.

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[Mrads]

From someone who has now owned both, let me put in my 2 cents. I owned a B6 S4. Great car! Quick, agile, and that 4.2 really sings with a decent exhaust(not AWE). The biggest Achilles heel to that platform is undoubtedly the chain driven timing. As one of Audi’s first(if not THE first) production vehicles to feature a chain driven timing system, there was bound to be some problems. I’ve heard of guides and tensioners failing as quickly as 60k Miles. Unfortunately, it’s a rather labor intensive and expensive problem to have. Mine came with a 3rd party warranty, and to my surprise they covered the whole thing (totaling just north of $10k at my local Audi dealer). Even though I used JHM timing components (which I had to pay out of pocket for but was later reimbursed). The warranty cost me $3500, and it was money well spent in this scenario. I now own a B8 S4... when I purchased it was at 69k and I shelled out a little over $18k for it. It has the APR stage 2 single pulley upgrade and TCM flash which according to APR’s dynograph makes right around 455 hp and 395 ft lbs of torque. To put this in perspective for you, people have bought the JHM supercharger kit for the 4.2, had the block sleeved, done all forged internals, added titanium valve components and STILL don’t make that amount of power. The supercharger kit is $8000 on its own, then to have JHM completely do the bottom end is another $10,000, plus the cost of the car, and the $3000 for upgraded valvetrain. In my mind, it was a no-brainer. Plus with the B8, you get way better creature comforts. Although the B8 does sound like shit compared to the B6/7. Lol I always laugh when people say there is no replacement for displacement. If that’s the case, then why can a 3.5L Nissan RB28 make as much or more power than a twin turbo 5.2L v10? More cylinders doesn’t necessarily mean more power. The b6/7 s4... or even RS4 don’t hold a candle to a B8 S4 in the bang for the buck department.


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I completely agree with all of this. I am also an owner of both platforms (b8 4.2 S5, B8.5 S4 with Stage 2, and now B8.5 S5). Before getting my most recent S5, I toyed with getting another B8 S5 and adding a supercharger plus the supporting mods. After looking at the costs, I went back to the V6T. The cost of a clean 6MT 4.2 and doing the mods simply didn't make sense. Getting to 450+ HP with the V6T is a fraction of the cost of supercharging the 4.2. I still miss the V8 noises but I don't miss the crappy 4.2 fuel consumption.



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[Nollywood]

For whatever reason I also don't think the timing chain is as big as a problem as on the 4.2

I basically never hear about anyone doing that repair - whereas with the 4.2 I hear about it all the time

Google 3.0T timing chain issues.

Already, despite the 3.0T being a relatively new engine, chain rattles have started. The 4.2 079-series is 15-years-old, so naturally you’ll hear more issue with them.

I’m an ex Audi Master Tech, and I still keep in touch with the boys at Audi. The 3.0T timing chain issues are starting in the same way they did with the 4.2 079.

The repair procedure will be the same, too.

[Nollywood]

How much money and what hard parts mods would you have to do to produce more power than a Stage 2 or 2+ 3.0T Would the labor be more than 30-45 minutes to swap out a pulley and belt and flash a tune?

Oh yes, you can get there with APR's Stage 3 supercharger kit for only the modest of sum of . . . $13,000. But, wait, price notwithstanding, that is displacement AND forced induction, and does not count the considerable labor cost involved.

You’re talking about a totally different issue here.

I chimed in, because reliability was mentioned, with the 3.0T being more reliable than the 4.2, which is strictly not true.

There are other ways to boost the 4.2, it’s just that most people take the easy way out. They want bolt-on power. Coming from an engineering background, I know how to extract more out of the V8, be it chain or belt-driven. And I will always start with the largest displacement I can commercially get hold of.

The 5.2 V10 would be my choice, once they become more readily available used, and more cars get written off.

It’s just a matter of time, and like the vulture sensing carrion in the distance, I’m patient.

[Audimatic777]

Thanks for everyone's input. I think what I am getting at is a 4.2 A6 could be had for significantly less. I found another one for 5k private party with 100k miles. The cheapest 3.0T I have found has been 9500 with over 100k miles. So buying a 4.2 and worst case happens, you're still all in for under 10k and the chain and tensioners are done.

I had a 2012 A4 stage 2 APR and loved it. I do get you can get more cheap power from the 3.0T. Just weighing the options. I have also been keeping an eye on V10 S6. Have found a few for same price as a 3.0T A6. I always have the false sense of better reliability with an n/a motor due to experience.

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[Nizmo]

S6 is great.

I see (30) 3.0T's a day.

[thierryfabrice1]

4.2fsi has been very reliable to me. About to hit 100k no problem. Timing chain is not an issue on 4.2FSI engine. Now speaking of bigger displacement. You can and will always extract more power out of bigger displacment vs smaller engine. In this case 4.2 vs 3.0. it is just a matter on how much money you are ready to drop in. The S5 is not tuner friendly because there is just no much room in the engine bay. Maybe A6 engine bay is a different story

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[NickLim]

I just tuned my 3.0t and bro the 3.0t is crazy.... This the engine you want.

[Nizmo]

If you get the S6, you need one with all the options. Carbon Interior, Solar Sunroof, Etc.

A tune on the S6 brings you right around 445-460hp, of course dependent on a few things like all other cars :) Maintenance is key not limited to an S6.

A symphony at your right foot.