Supercharger Performance and Engine Performance Parts

Posts Tagged ‘BMW’

How do you go about modifying a car that is truly a benchmark in its own class ?

The M3 has always been the top of the line street performer. With cheetah like reflexes, jaguar like top speed, and the growl of a lion, the M3 leaves nothing to be desired in the world of daily driven sports cars.

So how does one go about improving something that is truly best in class (5 seconds faster per lap in this video!), and something that is without a doubt the best that the OEM *and BMW is not any plain old OEM* had delivered?

Most enthusiasts would quiver at the idea of modifying a German car, let alone the M3. However, Sammy, the owner of the car in question here went ahead with a surgical strike buildup.

In trying to improve an already stout performer, the approach always has to be two fold:

The plan to upgrade this M3 was to play up it’s strongest inherent qualities : it’s balance, it’s poise, and it’s engagement.

To make the care more exciting and engaging, Sammy has chosen to upgrade the engine with the utilization of Akrapovic Titanium Exhaust and a Gintani Supercharger kit.

The exhaust is a beautiful titanium piece that is a direct bolt on to the old cat-back exhaust system and features a built pre-catalyst balance tube (H-pipe) as well as a post-catalyst X-pipe for better engine scavenging and cylinder bank balance. The titanium construction not only reduces the car’s running weight, but moreover titanium exhausts have a nice ‘resonance’ to them where they help amplify and meld the timbre of the exhaust sound into a more exotic and sinister sound.

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The Gintani Supercharger boost the power output of the M3’s V8 using a vortech V2 supercharger, a custom Gintani intake manifold complete with a built in air to water intercooler, and a matching software tune. The use of a centrifugal supercharger enhances the linear and controllable performance of the M3 , while the choice of a short air path air to water intercooler (rather than a long path front mounted air to air) maintains the quick response of the naturally aspirated V8 engine that is typical of M3 performance. After all is said and tuned, the prototype Gintani Kit delivers over 480 rear wheel horsepower at 8.0 psi of boost.

What is great to see on this specific application is how a well designed exhaust system can dramatically improve the performance of a supercharged car. Sammy’s car is only running 7.5psi of boost meaning that the exhaust system has relieved the engine of 0.5 psi of exhaust back pressure. With this freer flowing exhaust and freer breathing engine combination the supercharger package when all is said and tuned delivered 512 rear wheel horsepower at a lower 7.5psi of boost!

In other words, the exhaust system (and a matching tune) on this application is worth 32 rear wheel horsepower. Considering the stock M3 delivered a respectable 315 rwhp on the same dyno, the combination here is worth 197hp which is surely going to enhance both the excitement and the engagement of this car.

With close to 600 crank hp on tap, Sammy then turned his attention to making the most of this power. A set of KW Variant 3 with adjustable rebound, compression, and compression rates allows the car to put down the power through the rear wheels and maintain its poise on high speed canyon runs. Sammy says they “feel amazing, smooth as hell, soak up bumps very well, especially thru the canyon, keeps wheels planted. Daily driving is fine, feel like its on the middle setting of the stock 3 settings.” which is a testament to the performance and the quality of the KW V3s.

Keeping the car’s stability at triple digit speeds is a new body kit from 3F engineering (not a body kit manufacturer but rather an engineering firm). The kit comprises three important components to help reduce the car’s drag and increase it’s down force at high speeds. A front and rear carbon fiber diffuser accelerate the air’s motion under the car creating a low pressure front under it for better road hugging and more controlled high speed cornering, while a carbon fiber low drag low profile rear spoiler adds down force to the rear end.

The front splitter / diffuser also guides generous amounts of air to the front mounted air to water heat exchanger for the intercooler system as well as to the massive brake ducts feeding now upgraded 380mm / 6 piston front and 345mm / 4 piston rear Brembo rotors. These massive units are the only thing that would qualify as an ‘upgrade’ on a car as stout as the M3 and they just “STOP -- thats what happens when [you] hit the pedal now, but consistantly and [don't] feel any fade.”

Last but not least in this exotic transformation are supercar sized 20X9 front and 20X10 Rear Agio sport wheels. The wheels are wrapped in Falken FK-452: 245/30/20 and 285/25/20 tires which are hard pressed to keep the power down in the first two gears.

With a buildup like this, other M3 (and in general German car owners) are always worried that the amount of power increase will negatively affect the rest of the car and especially the expensive high-tech manu-matic transmissions. In this situation there is nothing to worry about as “the DCT is running great… DCT still performs as it came, downshifts are perfect and fast as ever, and I love to hear the pssssshhhhh as i go to higher rpms and let off. From the outside you can obviously tell that the car is not stock , unless maybe I keep it at 2k rpm, otherwise you hear the air goin pshhhh! lol…it kinda makes me blush and feel like a giddy little kid everytime im in my car now.”

Technorati Tags: BMW, Centrifugal Superchargers, Intercooler, supercharger performance

From a technical point of view, throttle response can be measured by has your engine can build vacuum in its intake manifold i.e. via throttle pressure. The faster and higher peak vacuum is reached in the intake manifold, the higher the pressure differential will be between outside air, and your engine. This pressure differencial forces the air to flow from the area of high pressure (outside air) to the area of low pressure (the engine and cylinders), and the higher the pressure difference, the greater the pressure force, and the faster the air flow into the engine.

This is essencially how throttle response works. To improve throttle response several engine alterations can be used to achieve a higher peak vacuum in the engine or a faster change in vacuum per throttle input… some of these include:

1- Using undersized intake pipes and intake plenum runners to increase the airflow velocity in the intake system, making the engine able to suck all the air out of it faster and create vacuum sooner.

2- Adjusting intake cam timing to open the intake valve as peak vacuum is created inside the cylinder near bottom dead center.

3- Reducing the overall intake system volume, by using smaller manifolds, less vacuum lines, and more electrically operated (rather than vacuum operated) engine auxilliaries which means the engine has less air volume to clear from the intake system to create a vacuum in the manifold to force new air in.

4- Using cam seperation and cam overlap (when both intake and exhaust valves are open at the same time) to have the previous cycle’s exhaust gasses help pull in fresh intake gasses for the beginning of this combustion cycle.

and so on.

One interesting application of this concept is the G-Power supercharger kit for the BMW M3. The ASA supercharger powered kit focuses on response and effeciency rather than on astonishing peak power figures. The G-Power kit utilizes a very conservative boost supercharger by ASA giving a peak of only 4.4 psi of boost. Since the engine already very highly powered at 420hp, the addition of just 4.4psi of boost results in well over 500hp (as a conservative estimate) and as much as 560hp as a result of this combination.

The focus of the G-Power kit is not just power figures, as rather than just providing a supercharger kit for the M3, G-Power has designed a completely new intake manifold for the M3. The manifold although has higher volume than the original M3 manifold (for more peak power as this is now a supercharged car), does have a narrow profile that promotes high air velocities to improve throttle response. Furthermore, the new manifold has integrated individual runners for each cylinders complete with trumpet style inlets raised from the floor of the plenum, which has been proven through fluid flow simulation to reduce boundary pressure differencials, reduce the pressure drop inside the inatke manifold, and promote higher air velocities that lend themselves to higher peak vacuums and faster vacuum buildup inside the manifold.

Even though centrifugal superchargers typically show a linear boost curve with engine rpm, and thus produce little to now power gain in lower rpms, the combination of this supercharger with the redesigned intake manifold and new tune reportedly provides over 20% increase in torque at ALL engine rpms, and with increased response.

Here it is in G-Power’s own words:

Air duct: Sport air filter system, CAD-FEM flow optimized boost recooling system consisting of an air duct made from aluminium cast, high capacity air-to-air intercooler made from aluminium cast in the car’s front and a large volume air box made from aluminium cast, including 8 integral resonance induction pipes made from light polyamide, ensuring an optimal throttle response and a perfect torque curve; pneumatic controlled, engine load related boost control; boost level approx. 4 psi rel.

The G-Power kit comes in 3 power ranges corresponding to 4,6 and 7psi of boost. The 7psi kit with their full titanium exhaust is capable of peaking out over 580 hp with great response to match. Lat but not least the new G-Powered M3 is capable of  doing a 0-124 mph 2 seconds faster than a factory M3, which at those speeds is about 20 car lengths of distance between the two cars. Moreover the G-Power with its unlimited speedometer will keep pulling all the way up to 223mph!

Here is a video of the G-Power M3, notice the engine response and the speedo digital reading in the center digital readout. 10 to 200kph.

For more information:

G-Power.de

Technorati Tags: ASA, BMW, Centrifugal supercharger, G-Power, Intercooler, M3, Throttle response