scottacus

I agree. ADS is simply a combination of adjustable suspension and dynamic steering (and on the S5, the sport differential). It does not change engine operation at all. (The sport program does change throttle tip-in but the hardware is exactly the same as on non-ADS cars).

Again, ADS has absolutely no effect on engine management, and adding a larger intercooler won't interfere with ADS electronics.

As previously mentioned the issue has to do with physical fitment. I'm a bit surprised to hear it's a second oil cooler that's the problem, but it's possible that the dynamic steering requires relocation or reconfiguration of some components near the engine and a second oil cooler made the most sense.

Old Dog

The reason for joining AW for me was simple: to learn. This was my first Audi at age 60 and wanted to get informed on the various aspects of the car, good and not so good, and all the related systems. Systems that include acronyms for most of the alphabet, like: MMI, ADS, ECU, VAG, ECS, ECM, TCM, SVM, FMIC and many, many others.

Yes, I was one of the ones that appreciated Moviela’s post and was appreciative of his efforts to explain FMIC etc. However, I would have even been more appreciative, and I’m sure others as well, if B8aruba would have kindly been more specific as to what was not 100% accurate and what are the right facts on how it works IHO. Of course, B8aruba and others are under no obligation to do so, but it would have been nice for guys like me.

I hope I haven’t ruffled any feathers, if so, I apologize.

need_TQM

I'm sitting in the airport with not much else to do, so for what it's worth, here is my take on this - sorry if this is basic to some, and I hope I don't talk below everyone's level.

The use of a turbo (or supercharger) on an engine to compress the intake charge has a harmful side-effect of creating higher temperature air. This is one reason that forced-induction cars typically run at a lower compression ratio than a naturally aspirated version. For example the 2.0T runs at 10.5 compression ratio if I recall correctly, while the NA 3.2 runs at 12.5 (?). Both use direct injection, and as the fuel is injected directly into the combustion chamber the evaporation cools the charge a bit (the evaporation process takes energy, and this energy is taken from the air, thus the drop in temp). Thus DI engines can run a bit higher compression ratios than NA engines.

So, Audi fitted a FMIC to help reduce the temperature of this intake air. It's basically a heat exchanger - hot air from the turbo flows inside and hopefully cold air from the front of the car flows through/around the outside and the metal transfers the heat from the charge air to the outside air. Exactly like the radiator, except that both internal/external fluids are air in this case, where the radiator uses liquid coolant as the internal fluid. Front mount takes advantage of the forward speed of the car to drive air through the engine -- top mount intercoolers do the same except through a hood scoop (usually) to drive air through them.

AWE has done some testing and has seen that the stock FMIC is marginally sized for the stock level of boost etc. and if you push the car hard it doesn't have the capability to remove enough heat to keep the inlet air temperatures where you (they?) would like them to be. If you add an aftermarket ECU program that uses higher levels of boost (more compression = more heat and more power=more hot air to cool) the situation would be worse. Of course AWE is trying to sell products, so take their statements in context, but the principal is sound.

The engine control unit (ECU) measures pressure/temperature/and air flow rate (amonng other things) and will adjust timing, fuel delivery, etc. to "optimize" the engine performance. If the inlet air temp is very high, the fuel/air charge is more likely to detonate prior to the ignition event (referred to as ping - pre ignition detonation) - this is very bad as the piston is not yet travelling down, and in extreme cases might still be moving up -- either way power is reduced and stress on the engine is much higher.

A larger FMIC likely won't make the engine "safer" except in extreme cases (the ECU will compensate) but it will allow it to make more power since the charge air will be cooler - thus it has more oxygen and can burn more fuel = more power - and in addition the lower temp will allow optimial ignition timing to maximize power while still preventing ping.

The things Moviela said that I questioned (not saying they are wrong, but have heard conflicting evidence).

1) ADS ECU behaves differently than a "stock" ECU.
2) the 2.0T in the B8 has "low headroom" in the fuel system - several tuners have said the EA888 pump/injection system is a large step up from the B7 engines (EA113?)

Plus I'm sure everyone that is considering a FMIC would have bought the RS4 if it were the same cost, but relatively small changes like this FMIC and a ECU tune (at least small relative to the cost difference between an RS and a stock A car) can improve power considerably at relatively low cost - even relative to the cost difference from the 2.0T to the 3.2 (at least when it was offered).

Disadvantage : You are operating the engine/drivetrain outside of the range Audi intended it to. If something breaks, or wears prematurely - you are on the hook for it.

Old Dog

Thank you very much for this need_TQM. Glad it killed a bit of time for you at the airport. I do have a clarification on your second paragraph and one small question when you have time.

In your second paragraph you say, “This is one reason that forced-induction cars typically run at a lower compression ratio than a naturally aspirated version. For example the 2.0T runs at 10.5 compression ratio if I recall correctly, while the NA 3.2 runs at 12.5 (?).” Then in the last sentence it says, “Thus DI engines can run a bit higher compression ratios than NA engines.”

Should this read, “Thus DI engines run a bit lower compression ratios than NA engines”?

What is meant by “low headroom” in the fuel system? Is this the optimum point at which fuel will/should ignite?

Have a pleasant and safe flight .

Thanks again, Garry.

need_TQM

Gary. So forced induction engines typically have higher inlet air temperatures because the air is compressed by the turbo. You could loosely equate that to the very first little bit of the compression stroke once the air was in the cylinder. Higher temperature means that forced induction engines (turbo/super charged) typically run at lower physical compression ratios - referring to the amount the piston compresses the air in the cylinder (10:1 would mean the air in the combustion chamber is taking up 1/10th of the space it did at the start of the compression stroke). Turbo engines probably run higher total pressures than naturally aspirated engines, but the compression ratio of the piston/cylinder is lower.

The above is assuming the injection method is the same and the only thing you change is the induction type (forced or natural). Direct injection (DI) engines can run higher compression than a non-direct injection engine because the evaporative cooling effect of the direct injection lowers the temperature slightly - thus you can increase the compression ratio slightly before the compression effect gets the fuel/air charge to the same temp it would have been without direct injection.

Hope that makes sense.

As for "headroom" - I think what Moviela meant was that in the past, the fuel pump and injectors were close to being maxed out for the stock levels of horsepower etc, but you would have to ask him to be sure.

If you wanted to put a big turbo etc. on the amount of fuel the stock system could deliver quickly became the factor that limited the amount of power you could get. Some of the tuners (both GIAC and APR if I recall correctly) have made some comments leading me to believe that the B8 2.0T fuel delivery system is not running as close to being maxed out as previous generations when generating stock power.

B8aruba

need_TQM, thanks for taking the time to post a more accurate explanation of what, imo, needed to be corrected from that previous post. It's good to have the facts straight, less misleading to those who are learning about their cars. I just returned to an area with wireless service (yes, we have a lot of dead zones this far north), and was happy to see Old Dog got his questions addressed properly. I didn't have time to compose the info at the time of my first post, nor did I want to jump all over Moviela that quickly when all he was doing was trying to help folks understand.

I do believe you are correct. From what I've studied and gotten from speaking with APR directly, the latest 2.0T engines utilize an FSI approach, the fuel system (pump, rail, FPR, and injectors) has quite a range of capacity over previous injection systems. This means tuners are able to match fuel with even higher increased boost levels, all using the stock fuel management setup. Obviously, you can only go so far before you'll run out of the good stuff, but it sounds like there's a good amount of room to play with already.

ItsDubC

Tuned B7s have been known to experience fuel cut issues, even ones that aren't running big turbo / Stage III setups. I have yet to hear of a single instance of fuel cut on a tuned B8.

There has been some very heated debate between B7 tuners regarding the necessity of fuel delivery upgrades w/ turbo upgrades on that platform. The B8 is still in its infancy, so no news on that yet AFAIK.

Old Dog

I took the time to re-read both your posts several times need_TQM and, yes, it all makes sense. My only understanding of turbos initially was - they rammed air into the fuel mixture. Didn’t know what was going on behind the scenes like: they created higher inlet air temperatures; a FMIC is needed to bring the air temp down for a better air/fuel mixture; there is an ECU to control a few variables to make sure engine performance is optimized; there are limitations on what the stock fuel systems can deliver to obtain more power.

So, yes indeedy, the Old Dog came away with more than I started with thanks initially to Moviela and B8aruba, and then yourself need_TQM, and for this I thank each of you for exporting some of your knowledge North of the border. I hope others come away a little more enlightened as well.

I once, as a younger guy, messed around with cars quiet a bit, long before engine management systems and long before on board computers. Used to do all my own car repairs and had the opportunity to do a complete engine rebuild on my 1947 Pontiac at the time. There are some pics in my album showing that old flat-head six. Had a hand in swapping two other engines as well during this period. However, those days are long gone. The engines today are too sophisticated and so computer oriented I’d be asking for trouble if I tried anything.

However, this shouldn’t stop me from understanding what some of the systems are about and, if and when something does go wrong, maybe I can at least recognize the symptoms and narrow down the problem area(s).

Today, all I do is check my oil and other fluids, look for any signs of leaking fluids and check the condition of the engine belt after I do my weekly or bi-weekly car wash. Checking the oil the “old-fashioned” way is now history with the B8’s. Hate this idea of no dipstick .

Thanks again to all for your patience.

Garry

euroboost

I took a pic today of the available space behind the front bumper and couldn't find the steering oil cooler anywhere, it looks like the FMIC could be fitted with no issues, I don't have dynamic steering so it might have something to do with it, but would appreciate if some of you ADS guys could take a shot of your own car.

cazeluf

I don't have a picture, but I took a peek through the front grille on my ADS car with Dynamic Steering, and yes, there is an additional radiator which is not present in your picture. It is not a block type radiator, such as the stock intercooler, but is essentially tubing with fins. It would definitely conflict with a taller intercooler. Couldn't tell for sure, but it does seem the supply hoses run back to the steering rack.

So, it seems that cars without Dynamic Steering are fine for a taller intercooler, but those with Dynamic Steering will have to wait for a solution.