Building a Dinan 540iA


1996-2001 540i (E39) Performance Engine Software

 Dinan Performance Engine Software improves acceleration and fuel economy by reprogramming the fuel  mixture  and ignition  timing parameters of  the engine  management system. Furthermore, the software safely  raises the  factory rev-limit from 6100 to 6400 rpm.   A  higher rev-limit  gives  your  BMW  a broader power band and greater road speed in each gear.  During part throttle or "cruise" conditions, the Dinan software actually improves fuel economy.   You will also notice that significant power gains were achieved at part throttle, as well as full throttle. That means extra power is available where you spend most of your time driving. The Dinan software also removes the factory top speed governor.


Peak Horsepower Gain:

9 hp @ 4500

11 LB/ft @2500 rpm

Rev-Limit Increase: +300 rpm


December 2, 2001 headed for EL Centro out of San Diego.  Wanted to see what she could do after both of these mods. 

I had the needle pegged at 1??mph in 4th gear doing 5500 RPM.  Didn't take long!

Dinan Free Flow Exhaust

Dinan's new Free Flow Exhausts for the 540i provide power gains without the excessive noise associated with typical "performance" mufflers. Dinan's exhaust systems feature rigid and durable muffler cases, manufactured from 20 gauge 304-stainless steel for optimum corrosion resistance. Internally, the systems feature Dinan's Tuned Resonance Chamber technology which provides the optimum balance between maximum power gains and a civilized, yet sporty exhaust note. The Dinan exhausts also provide substantial weight reduction compared to the stock mufflers. The 540 system weighs in at 18.5 lbs. vs. 34 lbs. The dual 3 inch diameter polished stainless steel exhaust tips have been designed to be visible on the 540i, giving the cars a tasteful performance look. The Free Flow Exhaust is50 State Emissions Legal.

Peak Horsepower

Peak Horsepower Gain: 7 hp @ 6400 rpm

Peak Torque Gain: 6 lb/ft @ 6400 rpm

540 1996-2001 (E39)

High Flow Cold Air Intake

The High Flow Cold Air Intake System develops horsepower and torque gains for faster acceleration and improved throttle response. The performance intake systems have been designed to provide improved intake airflow at the lowest possible temperatures, for greater engine efficiency and resulting power gains. When combined with Stage 2 Performance Engine Software, power is increased by as much as 20 horsepower and 20 LB/ft torque. The system is currently 49 State Emissions Legal*.

The High Flow Cold Air Intake Systems replace the factory air box with a large cylindrical K&N filter and 4 inch diameter mandrel-bent aluminum intake pipe. The filter is relocated to a separate compartment behind the front bumper and below the headlights in order to insulate it from engine compartment heat and maximize exposure to cooler outside air. Stage 2 Performance Engine Software is required which optimizes the fuel mixture and ignition timing for maximum power gains. If you already have Dinan Software in your car, it will be upgraded at no charge when you purchase the High Flow Cold Air Intake System.

Click on the image for a larger view


Dinan Transmission software comes in three different versions for the 1999-2003.  The 1st version if designed for Stage 1-3 engine software and the 2nd version if for Stage 4-5 engine software and finally the 3rd stage if for the Supercharger.  It is very important your Dinan dealership verify the correct version is installed to match your current Stage of engine software.

Dinan Automatic Transmission Software raises the shift points to a higher rpm for faster acceleration in both the "Sport" and "Economy" modes, allowing you to carry more road speed in each gear.

The software also provides firmer and quicker shifting, further improving acceleration. Shift pressures are increased by up to 25% depending upon how the car is being driven (light loads vs. high loads). The increased pressures provide for more rapid shifting, resulting in faster acceleration. The transmission software will typically shave 0.1 seconds off of 0-60 mph times and 0.3 seconds to 100 mph. The software provides the same benefits in both the automatic and manual shifting modes.

The transmission software also provides the driver with Dinan's version of a "manual mode". The stock manual mode programming has been designed to upshift into a higher gear whenever the normal shift point is reached, even when the manual mode has been selected. The stock program will also allow the car to downshift automatically in the manual mode whenever the vehicle's speed drops below 25 mph in fifth gear or 15 mph in fourth gear. The Dinan program eliminates the automatic upshifts and downshifts unless the driver activates the accelerator "kickdown" switch intentionally. This allows the driver complete control of gear selection and shift points whenever the manual mode is selected. As an added convenience, the Dinan software will return the transmission to first gear from any other gear whenever the vehicle is brought to a complete stop. I found this to be the case, however, when the vehicle is going  less then 5 mph and in the sport 2nd gear possition the transmission will return to 1st gear.

Available as a software download for cars produced after 12/96 or as a replacement chip for earlier production vehicles.

Dinan 3.15 Differential

For standard models the differential features a shorter final drive ratio for faster acceleration. The 3.15 final drive gearing takes advantage of torque multiplication, lowering the stock 2.81 gearing for a 12.1 percent increase in torque delivered to the ground. The improvement in acceleration comes only with a minor increase on engine speeds at cruise and no effective reduction in top speed. The specific gear ratio has been selected in order to enable the cars to attain a speed of at least 60-mph, without introducing the need for a second to third gear shift.

Dinan High Flow Throttle Body

Dinan's High Flow Throttle Body for 9/98 and later 540i Sedan and Sport Wagon models improves intake air flow for additional horsepower and torque gains. The internal diameter of the stock throttle body is increased by 3mm, for a 8% increase in air flow area. The resulting increase in air flow area provides more horsepower and torque throughout the rpm range. with noticeably quicker throttle response.


Dinan Stage I Suspension

The Stage 1 Suspension Systems consist of a matched set of performance tuned springs along with custom rebound adjustable Koni front struts and rear shocks. The Stage 1 System dramatically reduces the pitch and roll associated with the stock suspension while maintaining a nicely dampened ride. The custom externally adjustable Koni front struts feature user adjustable rebound dampening via a knob located at the top of the strut for quick and easy adjustment of ride comfort and handling characteristics. The Koni rear shocks are also rebound adjustable, requiring removal for adjustment. The springs are available separately and actually work quite well with the M5 and 6 speed 540's Motorsport shocks and struts, although the best possible handling is achieved with the more aggressive valving provided by the Konis.  Click on the Link to see a comparison picture.

Dinan Strut Brace

Dinan Strut and Shock Tower Braces help to maintain the structural integrity of the towers over the life of the vehicle, as well as providing sharper handling by reducing flex under hard cornering conditions. The Braces can be installed in conjunction with each of the Dinan Suspension Systems or with the stock components. The braces are manufactured from 6061-T6 aluminum for light weight and superior strength; and the brushed finish and carbon fiber inserts make for an attractive addition to the engine compartment and trunk. The Eng. brackets are machined for precise fitment over the existing strut tower reinforcement for a clean and solid installation. Rear braces are not available on the 540i Sport Wagon.  See the Pic below!


Dinan High Flow Air Flow Meter

Dinan's High Flow Air Flow Meter for the 540 compliments the Cold Air Intake System by further opening up the intake tract for increased power and quicker throttle response. The Dinan Air Flow Meter features a larger internal diameter and is manufactured from aluminum, as compared to the smaller plastic stock unit. The Air Flow Meter is designed to accommodate the stock electronics and comes with all of the components necessary for a clean and simple installation. The Dinan Cold Air Intake System is required when installing the Air Flow Meter, as well as specially tuned Dinan Stage 4 Engine Software. If you have already installed Dinan Engine Software, the original purchase price will be credited toward the purchase of the Stage 4 version. Here is a comparison picture of the oem meter and Dinan's meter. Click here..

Dinan High Flow Intake Manifold

The replacement intake manifolds feature larger diameter "runners" for improved engine efficiency at higher engine speeds (rpm), resulting in increased horsepower and torque. When installed in conjunction with fully matched Stage 5 Engine Software, the Cold Air Intake System, High Flow Throttle Body and Air Flow Meter, peak horsepower is increased to 321 @ 5700 rpm, for a 40 hp gain (with a peak gain of 48 hp @ 6500 rpm) over the stock rating; torque is up by 39 LB/ft @ 6000 rpm. The result is faster overall acceleration, with the car feeling noticeably more willing right up to the rev-limiter. Not available for cars produced prior to 9/98 because they already have larger intake manifolds, mass airflow meters and throttle bodys..