A8L_New_England

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There's been discussion around the stock intake and exhaust / downpipes being adequate for a stage 2 tune, but I've been wondering what I'd end up with using only stock turbos also. Does this even make sense (or does "stage 2" imply larger turbos or other hardware)? Can I even get an S8 type tune in an A8? Is there anyone here who has this sort of setup? I'll give APR a call at some point, but mostly want to hear from anyone who has done something like this. I'd do it if it were safe and produced a measurable performance boost. I guess I'm looking for the best performance boost on top of an APR Stage 1 without getting into major hardware upgrades.
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2turbos4rings

Historically the stages of tune looked something like this (power mods only, not including support mods)

stage 1: tune

stage 2: tune + exhaust

stage 3: tune, exhaust + forced induction addition or upgrade

There are some subtle differences with superchargers getting bigger pulleys in stage 2, but basically that’s it.

with stage 2 receiving exhaust upgrades (downpipes being by and large the most meaningful component) the tune will reflect the freer flowing air and include additional changes.

The factory 4.0T downpipes are a mess, narrow, restrictive and take up a lot of space. If you replace them with open pipes you will be very happy with the results, regardless of what psi and timing the tune you choose gives you.

APR has long been a really popular tuner because they give off the shelf easy tunes with good performance and you can see the promise of power and it takes 30 minutes… an APR stage 1 tune is the McDonald’s of the tuning world, you know exactly what you’re going to get and exactly what it’s going to cost, no mystery. But there’s many many more options out there for getting more power and catering to your personal goals for the car. DS1 has been quite a game changer for the 4.0T and gives owners the flexibility that a full custom tuner can give but at a nicer price and the ability to continuously make changes as you change hardware.

If you want something simpler though and the off the shelf option sounds better to you then Unitronic offers a nice stage 2 tune. Been a while since I tuned one but it was maybe around 550hp and added like 190lb-ft. Whatever it is it’s a healthy increase. The torque curve wasn’t disgusting like it is on some 4.0T tunes either, thanks to the smaller, fast spooling A8 snails. My biggest beef with the RS 7 and S8 for the street is waiting until 3,500rpm for peak torque that immediately starts to taper.

If you’re considering going stage 2, do it! Downpipes are easy enough to do if you’re handy and like to tinker for a Sunday afternoon and you can DIY the flash as well

2turbos4rings

Also, VW products have generally never suffered intake bottlenecks, thanks to super restrictive exhaust 95% of the gains are to be had on the back end and not the front. Factory airboxes take the coldest air possible from the front of the car and neatly deliver it. For you I would consider stock S8 twin airboxes, but I wouldn’t lose any sleep over your factory intake. My gut is that you’re only leaving a few hp on the table

Tree57

I believe I read that due to CARB aftermarket exhaust crackdowns APR won’t even offer stage 2 anymore. DS1 only requires SRM intakes for stage 2, DPs are optional. That’s true for S8, S6, etc. check out page 15 of “The time has come…” DS1 thread on AZ where John from DS lists Tune, Intakes, then DPs (in that order) of realized gains. The intakes themselves are fine, it’s really the turbo inlet pipe on the 4.0ts that’s the bottleneck.

A8L_New_England

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One says downpipes, one says intakes... I don't get the feeling that either would yield much improvement without bumping the turbos up. At least, that's the scuttlebutt.
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The original question still stands... Are there any meaningful gains to be had from additional/alternate tuning without hardware upgrades? Any way to get an APR Stage 2 tune on an A8? DS1?
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Has anyone here had any personal experience with this? Can anyone compare APR Stage 1 to a DS1 tune on a stock setup? I want to continue to run 93 octane.
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2turbos4rings

He’s right about the charge pipes, an oversight on my part. The precats are still the biggest bottleneck. The air is the hottest and most expanded and it’s trying to be shoved through the cat media. I disagree wholeheartedly that turbos need to be upgraded to see meaningful gain. It’s not only how much power a setup gives you but also how it’s delivered. Just because you don’t see huge power numbers on stock turbo cars doesn’t mean they’re not making meaningful power that you can feel. Idk what the factory turbos on the A8 boost to but it’s probably less than 9psi. APR’s stage 1 tune might peak in the upper teens? In actuality you could probably crank them up reliably into the mid-20s or beyond, if you don’t beat on them, warm and cool them properly.

These are just round numbers but they paint a picture.

Big turbos = a higher bragging number and more steam at the top end, but longer time to spool

Factory turbos = fast spool time and flatter torque curve and will run out of steam at the top end

all depends on end goal and driving style and preferences.

A8L_New_England

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Aware and agreed, for the most part. Remember that the focus of this thread is "how much can I safely wring out of stock hardware with a tune". And again, can anyone compare APR Stage 1 to a DS1 tune on a stock setup? Has anyone gone down this road before?
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I'm not much for stoplight-to stoplight racing with my luxo-barge, so slightly larger turbos may be in the future. ...but right now I'd like to explore its potential with only a tune - bumping up the pressure.
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DallasDave

I don't know if this helps, but a few fellow members and I recently had our cars dyno’d.

Mine is a 2016 S8 Plus with the APR Stage One tune (that’s all, no HW changes). I was using Costco 93 octane fuel and here is the result: 586hp & 674 ft-lb of torque.

Randy’s is a 2016 S8 Plus with the APR Stage Two tune (downpipes and using 100 octane fuel map). His result was: 661hp & 674 ft-lb of torque.

Here is a link to APR’s website specifically for a 2013 A8 4.0: https://www.goapr.com/products/softw...U-40T-EA824-A8

The horsepower will jump around 110 over stock, but the torque jumps 185 ft-lbs. This will DEFINITELY push you in the seat when the throttle is matted! My recommendation is get the APR Stage One tune (it’s only $799) and see how you like it. If it is still not enough, then move to Stage Two.

2turbos4rings

I misunderstood, I thought you were asking how much performance you could get with stock turbos, not a stage 1 tune alone.

DS1 is not a tune, it is tuning software, there is an infinite amount of possibilities with DS1. You can use their baseline tunes or other user’s programs written for DS1. If you’re knowledgeable you can also log with it and write your own tunes. I do not recommend this unless you first have extensive knowledge because it is not user friendly and you can easily lunch your block

A lot can be done for cheap on the A8.

-if you don’t want to change anything then an OTS tune is the best you’re gonna do. paying extra from custom software with zero hardware upgrades will be less gain for equal or more money than just moving to stage 2, no stage 2 tune will work for a car with stock dps and charge pipes. Do not be fixated with APR, they are not the only company that offers OTS tunes for a reasonable price, look around, compare dyno graphs and not just peak gains. The graph will tell you how the car will drive

-if you’re not happy with stage 1 or you’re willing to throw a bit more money at it then stage 2 is still exceptionally drivable and affordable for great power. DPs and OTS tune. Easy peasy (as long as you’re not in a CARB state) not only is the jump similar to stage 1 from to stock, but it’s better for the turbos, less heat soak. DPs are the first to go, then charge pipes. You do not need to think about cooling, fueling or intakes

Stage 1 and 2 are dead easy, very reliable- if you take care of the car and treat it well- and very affordable

MP4.2+6.0

FWIW and just staying at altitude, post author is A8 4.0T. Here and there thread occasionally drifts to S8 (or RS7 brother). Focus is closer to staying closer to stock hardware wise as I read it.

So, note the subtle but obvious: In move from A8 to S8 factory tune level, most obvious change is the turbo set and then the boost levels. And from S8 to Plus or straight RS7 to Performance, it really seemed to come down to a slightly more aggressive factory tune (and where APR re levels playing field for either). S8/Plus does have the twinned air boxes, but then RS7 even at Performance step still has the single box set up. There are secondary changes from A8/S7/S6 to S8/RS7/RS6 like compression ratio, at least one added cooler, somewhat bigger mains, and so on. But those logically are more to deal with the consequences of more power rather than generating it.

Net, think thru anything A8 to S8 for where the factory went, and why. When these were designed, they probably had more dino juice powertrain engineers and budget than probably everyone else on the tuner planet combined. Also subtle, but if you stay in that track of relating it to S8 or RS7 and especially at "stock" parts for them, you may find pricing advantages.

For a variant for parsing it through, also consider 2.0T in its pumped up forms and how the factory gets there. Specific output per liter of the stock Mk 7 Golf R or counterpart TTS is at basically same level as an S8+ or RS7 Competition, and 2.0T has a variety of engines at lower state of tune, like the 230HP class in a couple flavors (including GTI) that is the analog to a 430-450HP A8/S7/S6 class 4.0T. Not that you will ever use either a 2.0T or even its hardware, but it perhaps has 10x the number of units out there and maybe 100x the tuning following, experimenting and so on--especially in tweaking from GTI state of stock tune upward. 2.0T's problem and relatively early limitation for both factory and tuners seems to be the drivetrain's (DSG or clutch) ability to handle it, while ZF slush box (especially torque converter) gives 4.0T more latitude for D4 scenarios.