Hello everyone!

I'm new to the forums and am also a new owner of a beautiful black 2006 S4. I absolutely love the car. I've been reading around and just have a pretty simple question. What would it take to get my car to do 0-60 in under 5 seconds? I know that the RS4 and the S4 use the same engine so what exactly sets it apart? Thanks!

 

S4 and RS4 dont use the same engine, they actually have alot of differences they just share the same displacement. The s4 has 40 valves, the rs4 and s5 have 32 valves, compression ratio is vastly different

These come from the Audi 4.2-liter V8 FSI Engine Self-study Program, its S5 motor vs RS4, but theres even more differences between RS4 and s4

The main technical differences between the base Q7/S5 engine and the high-revving engine lie in the following:

* Crankshaft/connecting rods/pistons
* Timing gear
* Cylinder head
* Oil supply
* Engine cooling
* Intake path
* Exhaust system
* Engine management


The cylinder crankcase of the high-revving engine was machined to higher specifications due to the higher stresses in this component. To minimize warping of the cylinder manifolds, the crankcase is honed under stress. For this purpose, a honing template is attached to the crankcase before the honing process in order to simulate the warping of the bolted-on cylinder manifold.

Modifications to High-revving Engine
At very high engine speeds, axial vibration occurs due to the unbalance in the single-mass damper. This can cause the crankshaft to break.

To avoid this vibration, a dual-mass damper without unbalance is employed in the high-revving engine. To compensate for unwanted engine vibration, heavy metal inserts are integrated in the first and eighth crank journals by way of unbalance.

Connecting Rod
Cracked connecting rods made of 36MnVS4 are used in the basic engine, while the conventionally split connecting rods in the RS4 engine are made of 34CrNiMo8, for strength.

In addition, the geometry and tolerances of the
connecting rods were reduced on the high revving version of the 4.2L V8 FSI engine.

Bearing journals diameter: 54 mm
Bearing bushings: 1.4 mm thick, 15.25 mm wide
Length of bushing: 0.20 mm diameter rolled
Connecting rod length: 154 mm

Piston
For strength reasons, forged pistons with a slightly higher weight than conventional pistons, are used. Both engines have the same piston geometry.
Piston weight without rings: approximately 290 g (10 oz)
Piston pin: 0.20 mm x 0.11.5 mm x 40 mm

High-revving Engine

* 3/8" simplex sleeve-type chains are used here. Their advantage is their reduced wear and higher stress resistance at high engine speeds. In this case the idler gears have 38 and 19 teeth. The camshaft sprockets have 25 teeth.


Different Features of the High-revving Engine

* To match the higher engine power output and RPM, the following cylinder head components were modified:
* Intake ports are charge optimized (based on larger cross-sections)
* Intake valves are chrome-plated hollow stem valves (for weight reduction)
* Valve springs are made of a material with higher tensile strength and also have higher spring force
* To meet the higher fuel requirements, the injectors are designed for higher flow rates.
* Roller rocker arms are more robustly designed, with peened rollers for higher strength
* Camshafts have different timings and larger opening lengths
* Intake valve opening angle 230 crank angle degrees
* Exhaust valve opening angle 220 crank angle degrees
* The lifters were adapted from the 3.2L V6 engine found in the TT and A3. They have a larger ball stroke which, in the course of testing, proved advantageous for the high-revving engine (with regard to the inflation of the hydraulic valve clearance compensation element).
* The cylinder head has a modified water jacket which circulates coolant to the area between the intake port and the injector, thereby reducing the temperatures in the cylinder head combustion chamber plate.
* Due to a modified camshaft drive reduction ratio, the camshaft adjuster has 25 teeth for the chain drive, as opposed to 30 teeth in the basic engine.

In the more highly stressed high-revving engine, an additional oil-air heat exchanger is used to minimize the oil temperature even at high engine load. This additional heat exchanger is operated in parallel with the heat exchanger via a thermostat.

Audi RS4 Sump
A reliable supply of oil in all driving situations is critical, especially in a sports car such as the RS4. The oil supply system in the high-revving engine was designed for racing applications in which it is subjected to lateral
acceleration of up to 1.4 g. To ensure this, the sump in the RS4 has an additional system of flaps.

Design
Four flaps, whose axis of rotation is parallel to the longitudinal axis of vehicle, are arranged inside a housing. Each of the flaps opens toward the inside of the intake end of the oil pump.

Function
When the vehicle is cornering, the oil flows inside the sump toward the outside of the corner. The two flaps facing the outside of the corner close and hold the oil in the sump intake. At the same time, the two flaps facing the inside of the
corner open to allow additional oil to flow into the intake. This ensures a sufficient supply of oil to the oil pump.

The intake system of the RS4 engine was designed with emphasis on maximum flow control. Pressure loss is minimized by a large cross-sectional areas in the Mass Air Flow (MAF) Sensor G70 and air intake pipe in combination with a 90 mm diameter throttle valve.

To ensure a sufficient supply of air to the engine at high RPM, the power flap in the air filter is opened at engine speeds higher than 5000 RPM and at road speeds higher than 200 kph.
The power flap is opened and closed by a vacuum
actuator which is map-controlled by the ECM via the Intake Air Switch-Over Valve N335.

The sand cast aluminum (should be magnesium) intake manifold was designed specifically to match the sporty characteristic of the engine. In contrast to the basic engine, maximum torque is produced at higher engine RPM. At this engine speed, the intake manifold changeover valve would be switched to the short path for higher power output.

Spark Plugs
In contrast to the Audi Q7, spark plugs with a higher heatrating (colder plugs)* are used because the RS4 engine is subjected to higher thermal stresses.
* applies to NGK spark plugs

Injectors
Due to the higher fuel demand and the shorter window of time available for injection at very high engine speeds, the RS4 engine is fitted with larger injectors than the Audi Q7 engine.

 

Now back to the question, your options are more HP or less weight, the car is pretty close as it is mid 5 seconds i think. You could get lightweight rotors and wheels, these help alot on acceleration because the weight is unsprung, you can also remove sprung weight by removing the spare, getting a lightweight battery, lightweight seats etc anything you can think of helps

As far as power goes without getting too in depth you can buy any number of chips and full exhausts, these wont get you a ton of power though. JHM is making long tube headers and allready has RACE gas tunes which make more of a difference. the AWE/VF supercharger is one of the only forced induction options available at the moment.

I cant say exactly what it would take but a combination of mods and weight reduction would certainly help out

 

the ole' race saying every 100lbs is a .10 of a second. Just pour some slim fast in everytime you fill up.

 

Great info all around. Reducing weight seems like a good option. Replacing wheels and rotors with lighter ones seems easy enough. Although I don't know of many places that tell you how much a wheel weighs (how much do the stock wheels weigh?). Are there any suggestions on places to buy/models to look at? Same goes for rotors.

In reading around about chips I was really intrigued. I read that some chips have selectable programming and that a good chip can improve the overall engine compression and driving ability. I'm definitely all for that even if the hp improvement isn't huge. What kind of exhaust systems are good for the S4? Someone told me that forced air intake would help quite a bit. I assume this is what you're referring to when you say that the supercharger is the only available option at the moment.

Pardon my ignorance for this last point but who is JHM and what exactly is a long tube header and gas tune?

Thanks again for all the great points.

 

Enkei RPF1's are pretty light, any wheel under 20lbs is pretty decent. Rotating mass is more important than sprung weight, removing 5lbs per wheel is like removing 80 pounds of sprung weight and it will really show in acceleration

JHM is JHmotorsports.com owned by jason harbinson. Lately hes been doing alot more RnD of parts for the V8 models, currently cars withhis parts and file hold the b6/b7 1/4 mile record

As far as horsepower per dollar the chip isnt a bad investment, the gains arent huge, but every little bit helps. JHM makes racegas tunes for the 4.2 meaning its designed for like 104 octane and the power increase will be more than a chip designed for 93 octane. I wouldnt reccomen driving around daily with race fuel but switching to a race file and race fuel when you want to race is allways good. GIAC and other chips are also just fine

You get less horsepower per dollar gained from an exhaust, but thats because most full exhausts for this car are really expensive. Exhaust will free up some power and make it alot nicer to listen to. As far as the long tube header, its a common performance mod for v8's. The stock exhaust header is just a cast log style manifold, JHM seperates each runner for as long as possible then merges them much farther back, its a more advanced design and will yeild more power replacing your manifolds and downpipes.

JHM also sells the brake discs

Im not really sure onthe intakes, im sure some are better than others. Sime are mostly for show. If you have a manual a ShortShifter would be a better way to spend your money (JHM makes the most kick *** shifter FYI)

the VF/AWE supercharger replaces the intake manifold, its a twin screw roots type IIRC only runs a few pounds of boost but it will bump you up to like 500chp with a full exhaust all for like $12,000 or soemthing. MTM sells a blower too but its like $20-$30k last time i checked, i predict the VF/AWE one will become more available and more popular this year