dvs_dave

Popping over from my usual spot on the D3 board.

Anyway, mulling over the idea of an upgrade to a D4. I need LWB and the W12 and 4.0T's are currently more than I want to spend.

I'm guessing the stock 4.2i and 3.0T performance are pretty similar, and neither a huge leap over the D3 4.2i.

But I understand that with the 3.0T a simple supercharger pulley upgrade and ECU tune from the likes of APR can get you to into 450-500hp range.

I know plenty of folks here have tuned their 4.0T's, but not seen anything for the 3.0T's so any feedback and experience would be appreciated.

the_duke

Not sure what your budget is but 4.0t's can be had for high $30's to Mid $40's. 3.0t's seem to be about $5k cheaper. The 3.0t can be tuned to output high HP but you don't get the torque. According to APR's website the stage II 3.0t on 93 octane is 452hp and 387tq. The stock 4.0t on 93 is 456hp and 506tq. Plus you're looking at $1850 plus install cost for the APR tune on the 3.0t. It's well worth spending a few thousand more to get the 4.0t. If you haven't driven one yet you should. It truly is an amazing engine. And down the road if you decide to tune it the power gains put you at stock S8 levels.

Jack88

Ah, from personal experience the D4 4.2 is a big jump over the D3 4.2. Not in terms of power, but it's performance is comparable to a D3 S8. Thank the 8-speed. The 3.0t doesn't suit the A8, in my opinion, makes the wrong noise and gives you the sense it works hard to get the car around, even if the performance is comparable to a late D3 4.2. If you want the best of all worlds, I would agree that waiting until a 4.0t is feasible for you. No point in compromising on such a pricey car.

MP4.2+6.0

Yes, you could mod the 3.0T since same motor as in so many. Pulley obviously; you would have to ask the APR types if they actually have the tuning files for the D4 ECU.

4.2 is obviously highly refined from its cumulative years. As stated, it is really the 8 speed tranny that steps it up another notch over the D3. Having driven a low miles D4 4.2 though for a week when my D3 W12 was in for various warranty repairs, it did not have power at the W12 level and then presumably the similar D3 S8 though the torque curves vary some. But more than any of the D3 4.2's, whether older ports or the mid life FSI's. Mileage should tick up a notch too w/ the higher top gear.

The one you actually don't mention is the TDI. Hard to find just now with the scandal stuff, but at least before the debacle if I were thinking LWB like you mention and then considering a V6 gas, I would certainly look at a TDI. Also can be tuned.

dvs_dave

Seems that round my way, for a $5k difference it's a really nice 3.0T vs a bottom rung 4.0T. Similar age, miles and spec it's more like a $10k difference.

TDI's in NA market are so emissions restricted and even more complicated than the euro versions. Diesel is also way pricier and a pain to find. IMO they are a short lived curiosity at best and not well suited to market conditions, even if their real world performance is. Electric is even better.

Of course a 4.0T is preferable over a 3.0T, but like for like they carry a significant premium. So I'm interested to know how with a superior power to weight ratio (222 hp/ton) the performance of a stage II 3.0T compares to a stock 4.0T (197 hp/ton)? (450hp version is 2016 on and has 211 hp/ton).

4.0T is a torque monster in comparison, but with the 8 speed box, not as much of an advantage.

Anyone got any first hand experience with this comparison as on paper at least it's seems like fairly compelling case.

lennon31987

came from a d3 4.2, drove 3.0 first, slow....... TQ from the on demand power but felt the same as my d3 (with 140k on it).

go 4.0 or dont do it at all, save up your cash when you can afford the 10k difference. its pennies in a payment anyway over the life of it.


your gonna spend 2k plus on a tune and pulley and install so the difference isnt as large and not to mention these cars have tanked like rocks so you can absolutely find them

or hey, why not a d3 s8?

MP4.2+6.0

I thought about your original post a bit more. So, another idea. Do you really need the D4 now? Can you get by w/ D3 a bit longer? That is, my guesstimate is D4s may be down 30% in 12-18 months--plus you can look over market if anything special comes up at a compelling price configured just like you want. For example, what if by waiting, for whatever you would buy now, at a 30% drop in W12's (which drop fastest in both percentages and dollars) early on, would you do something like that over a current more loaded 4.2? Or get to a pretty well equipped S8 instead of a current 4.0T? Or probably easily get to a 4.0T instead of a 3.0T, and with a 4.0T a lot more likely to be better equipped just given the "entry" nature of the 3.0T? Not checking my math exactly on comparative values ,but you probably get the idea. Luxbarges are always a depreciating asset, and late in model run, a lot more so.

Your D3 is way more depreciated than any D4, certainly in terms of further annual hits. As D5 gets close, it will be the common bath on the current generation. Even now, I expect new buyers are much more likely to be looking at something less likely to be refreshed that (or as) soon--loaded S6's, S7's, RS7.s almost new design Q7's, etc. If I were running out of a lease now on a D4 , I would almost certainly be moving to something else besides another D4, especially if I were on a longer lease horizon. Not describing me--just half the buyers (and current holders) outright who would be on leases. And that is only half the market, let alone the owners.

Anyway, time is way on your side here--as long as you don't hear the D5 siren too much...

dvs_dave

You're right, I don't need a D4, and my D3 has plenty of life left in it. And I'd wait until the D5 is out before moving over to take advantage of the further value hit, as you say. Just beating the bushes as I think 3.0T's will become real bargains compared to the more sought after 4.0T's, yet still offer similar performance after some fettling.

dls911

I have an S8 now and love the smoothness and torque of the V8...but for a year or so before I upgraded.... I started out with an A8L 3.0 that I installed the Apr supercharger pulley and chip. It is relatively expensive but it completely transforms the car and in some ways made the car more fun to drive since the car was so much lighter in the front and smaller engine just rev'd more freely.... More like a 911 free revving motor than a smooth and powerful V8 like the S8. I do love my S8 though but more for the options like the B and 0, the upgraded leather... And the sound/smoothness of the V8 is excellent . Still... The 3.0 with the APR really transforms the car and I think that mod was worth every penny. Just my take on that mod.

dvs_dave

That's really interesting feedback, and a good point about the nose being lighter making the car more agile. Obviously the S8 is on another level performance wise, but did you sample a regular 4.0T? Did your tuned 3.0T feel outgunned compared to it, or was it's performance comparable?