LaserSVT

So I am coming up on my 5th 8 class car and cant decide between an S8 or an S8+. I keep finding conflicting answers and even the search here has been....iffy. Even my guy at my favorite Euro company does not know. Is the power difference between the S8 and the S8+ only in the tune or is does the Plus have larger turbos. Also is either similar/better than the RS7 turbos? I do like the black optics of the Plus but I want a gray car so I could take or leave the black treatment. The ceramic pack is nice, love the CF bits but I wanna drive this car a lot and dont want to maintain ceramic brakes. I aint driving it at Laguna Seca.
I will get a tune and downpipes and have seen a modded turbo regular S8 make 820ish awhp on 98 (guess I would have to mix or order ACES again) and nearly 900 on race gas and I want similar numbers. If the Plus already has larger turbos I may be willing to drop the extra 25K (I imagine larger turbos are EXPENSIVE) and get it with the black optics and ceramic options.
But if they have the same turbos I would save the cash and get the color I want. Besides I have discovered its FAR easier to find a 2013-2016 S8 with a B&O system than an S8+ with one. I wont get another one without it.

MP4.2+6.0

Good luck trying to truly nail it down. My net take is it is all in the tune. You can back into it by looking at the APR site and quickly realizing it is the same end result whether you have an S8 or S8+. I recall some S8+ guys whose jaws kind of dropped when they found out you didn't get any farther up the post tune power chart, pre or post +. At factory tune level, S8+ has a higher redline where some of the final HP may be. But owning a pre-+, good luck using that real world, at least in more built up metro areas. Car just runs away when you get on it; mine almost never sees up close to redline. Also know that just about every test on the planet says stock S8 is more like 575HP, so Audi sandbagged it to try to differentiate some to the RS7 most likely. But, the few tests out there say S8 + is close to the rated number. So, stock to stock, the comparo is really 575:605, not 520:605. It in turn explains why it really is apparently just a slightly massaged factory tune tweak and the real tuner result from APR comes out the same on either one.

Equally hard to pin down the RS7 and 7 competition side. You get lots of "mine's better/bigger" and has an R and various blustering stuff on the forums, but when push comes to shove, not so easy to find documented differences. If anything, with the greater general under hood room, exhaust clearance, etc. plus the known twin air boxes on the S8 and S8 Plus, has always seemed yet more dubious. To be clear, both S8 (and +) and RS7 have the larger turbos, but it is relative to the "standard 4.0T" in the A8, S7 and S6. Both also have the beefier main bearings, more oil cooling and various other tweaks. Thus you will find true differences from std 4.0T to S8/RS7, some of which you really can't even mod like internal engine.

Make sure you keep in mind the now pretty well known and increasingly understood 4.0T turbo issues per other threads. If you are going to seriously mod, you would likely be in deep enough to change the relevant filter screens anyway. Otherwise, since I am both CPO and have a CARB/CA model with turbos' covered to 7 years/70K via the CA/CARB states emissions warranty, I plan to stay stock until then. That might be best argument for a Plus actually--better tune stock. If you get a very late (and very rare) one, it will apparently also have the TSB parts update already in it. Once you mod either one while in warranty, figure the $10K or so turbo set replace (or anything else drivetrain wise) is on you. Plan that it will routinely get strip searched now for any mod contraband when it comes to anything bigger bucks warranty in drivetrain.

LaserSVT

Thats actually a great point. I can actually have a warranty on a newer S8+ and enjoy tuned S8 power. Guy that bought my A8 a year ago also bought a warranty. For $50 they threw rebuilt trans in it and a pair of struts.

LaserSVT

As for known TT issues I was only aware of the PCV PITA. I am not worried about yanking one apart though. Doing the pipe from hell in an 07 S6 right now. 32 freakin hours to replace an o-ring. Pretty sure I can do it in half. We knocked out my RS6 trans in an afternoon/evening with many beers.

Mike911A8

Laser, I agree with MP4 that the turbos are the same for the S and the Plus, but that there doesn’t seem to any direct evidence available. BTW, since it seems as if you are new to this D4 thread, you will quickly find that MP4 is, in my opinion, the best source for technical info.

My opinion regarding turbo size is based more on circumstantial evidence. First of all, I had about six months to kill before my new Plus was built and delivered, and I read every article I could find, and by that time the Plus had been in circulation for over a year , so there were quite a few articles. While my first impression was that the Plus had substantial upgrades beyond a tune, after a more critical re reading of the articles, I got the impression that some comparisons may have blended in comparisons with the normal 4.0 , and that the author was paid by the word. I am confident that the S8 has serious bearing upgrades and heat removal systems. Some talk of connecting rod upgrades for the Plus, but I don’t know.

I believe the difference comes down to the tune because I seriously doubt Audi would have spent the development money on hardware changes such as larger turbos when there was no real need to do so, in particular since it was clear that this engine was coming to the end of its lifespan. I’m no engineer, nor have I given any serious thought to learning the ins and outs of tuning. But it’s my understanding that larger turbos tend to cause turbo lag issues, and I can attest that my Plus has no noticeable turbo lag. I believe strong evidence that a tune is the major reason for the performance of the Plus is the “overboost” which is triggered by throttle position , and this overboost shows up as a major increase in torque at high RPM. This torque difference may be the most significant difference between the S8 and the Plus. Incidentally, anyone considering a tune for a Plus should make sure that the overboost is preserved in the new tune. Mike

LaserSVT

Thank you for your input. After looking at several more pages including Silly Rabbit I believe the cars all have the same turbos with the only real upgrade being a $6000 ceramic bearing upgrade available. Couple that with pipes and tune and thats 10k to reach that 800ish awhp goal. Also seems the 2016-2017 were technically Plus cars already for America that has allowed me to open up what I am looking at. I have looked at the screen and cooling issues for the turbos so figure doing the upgrade makes more sense now so i can save a few bucks and get a 2015ish car but I also love the red stitching and want the heads up display but all the cars I have seen with that are 80k where as a Daytona Gray with Ebony guts and a B&O but at 520hp and no heads up is closer to 44k. Thats half price! LOL
How bad do I want stitching and a heads up? lol

Mike911A8

Laser, moving on to cosmetics, I considered the Black Optics option, and I would have gone with it if I had ordered a lighter color exterior. Sometimes I think I may have made a mistake; see my Avatar picture. My finalists for color were Daytona Gray and Moonlight Blue. One reason I went with the blue was that it did a better job of masking the crease lines of the car, which I am not fond of. I ordered the Arias Red Audi Design interior, which is exclusive to the Plus, and I love it!

as for your tuning plans, I hope you have a very big and empty road! Mike

LaserSVT

I live in Texas. Ive had my 2014 CL65 AMG (fully built) to 220 and my Vette has seen 230 in the Texas Mile. lol We have the roads.
Yeah I want blue or gray and like the black optics but not a deal breaker. B&O is and I really really want HUD.

dwboston

It's your $ but the HUD is a requirement for me now on any car. I've had it going back to my 2006 Acura RL and my subsequent 2 Audis and I refuse to go HUD-less again.

Kelzo

To me, it made the most sense to get a facelifted S8 (2015+) without paying the most premium for the S8+ as that'll still tank in value.

Mine has the HUD, the matrix lights but no stitching and no optics package (let's be real you can do this for literally hundreds of dollars).
As you mention, an APR stage and a couple of other pieces and you are laughing.

Good luck! Absolutely perfect car!

** To note.
I never use the night vision on my car.
As a $7k upgrade the B&O sounds great.....but nowhere near the price point. So don't be stuck on that.