I was thinking of getting the Performance Stage 3 Software for my 2004 325xi. I have a Dinan Intake, Throttlebody, and Exhaust.

My question is how come this software doesnt seem to produce any hp or tq compared to others out there? In addition how does installing this software affect my gas mileage afterwards? Can you quote me a service charge? I tried Dinan of Mountain view but they were going to charge me $130 for 10 units of labor, but I saw on the website that the software is 5 units of labor for my 325xi (01-06)

Thanks for the question.
The power claims that other companies are making are not possible. Horsepower gains from software are decreasing over time. Software has changed dramatically over the last 20 years as well as the hardware it runs on. Just think back to the hardware and software that you were running on you home computer over the last 10, 15, or 20 years. When electronic fuel injection was first used on BMW***8217;s in the early 80***8217;s the hardware, sensors and software were quite primitive by today***8217; standards. To give a perspective this is about the time that the commodore 64 was released! All this means that the system was quite crude and the OEM know that they had to be conservative. If they truly tuned the car for premium fuel and a customer used regular it would likely cause damage to the motor. This was not a good option for the car companies, and incidentally it was much more sophisticated then the system it was replacing, carburetion. The aftermarket tuners took up this safety margin understanding that their customers knew that they had to use supreme fuel.
At this point 10-15 % gains could be made by software. As the technology of the hardware, software and sensors progressed the OEM began to add knock sensors, adaptive engine timing, and adaptive fuel mixture control. What this mean to the consumer is the factory could make cars that would adjust right to the edge for the fuel quality, weather conditions and driving style and they no longer had to leave a large safety margin. The systems are so good now that the system will prevent damage to the motor by adjusting to all the aforementioned variables. The computer adjusts for the quality of the fuel. In fact we ran a test where we compared HP of an E46 M3 running on 91 vs. 93. The motor made an additional 10 HP on the 93 octane. Look at your home computer today and compare it to what could be done 10 years ago. This also explains the large variability that can be seen on the dyno, especially without adequate cooling (http://www.dinancars.com/whitepapersFile.asp?ID=9)
The bottom line is it makes sense that power increases from software will diminish over time. If a tuners HP claims do not do likewise I would be suspicious. Hey BMW has more money, resources, and test facilities than any aftermarket tuner and in the case of software they can have their cake and eat it to now!
Of course when a hard part is changed the software needs to be changed to account for that, and additional power over just the hard part can be gained by properly recalibrating it for the new hardware.

Theoretically the mileage will increase, but because the variability caused by driving styles is much larger than the change and when people get new stuff they always drive it harder, the net change is usually for less MPG not more.
Cost quoting is done by the service departments. If you have a question call them and ask, or call Dinan sales and they can answer those questions.
Cheers

so basically software can only do so much on the sophisticated engineering on cars now a days that hp gain is not obtainable on my car and other companies advertise false information? And that even our car can put down more hp if we have a higher octane fuel even with the stock ECU?? If thats the case I'm glad u came into the spot light I wouldve saved myself $200 from buying custom tuned software.

I've just heard that many aftermarket tuners claim that the reason why BMW software or Dinan software produces no power is due to the fact they have to consider a safety margin. Like the example you gave about it being tuned to 91 octane and any other lower grade would result in motor damage. (If this statement is true i'll make an appointment with DINAN asap). But other than that most aftermarket tuners claim they produce that much hp because the tune it specifically for 91 and expect u to run nothing but 91 octane.

I don't think this is an entirely satisfactory answer. First, software tweaks will still increase HP some, but at the cost of MPG and with more pollution. BMW (and other manufacturers), try to balance performance with efficiency and the proper post-burn mixture for their catalysts. After market software will interfere with this.

Second, I don't think most intake and exhaust hardware that will not affect vehicle street legalality will make any appreciable difference until you get forced induction. Your answer appears slanted in the direction of hardware changes (which Dinan sells), but not software changes (which Dinan doesn't sell). These days the hardware tweaks deliver almost imperceptible gains in HP and torque for a lot of money. The advances in material sciences in the last 20 years are almost as remarkable as the advances in computer sciences.

Any BMW owner who has a car with, say 330 HP, who drops $3500 (inclusive of installation) and gets a 7-10 HP gain and a little less of a torque gain is either a who wants to show off his "bling bling" or a moron .

Any BMW owner who has a car with, say 330 HP, who drops $3500 (inclusive of installation) and gets a 7-10 HP gain and a little less of a torque gain is either a who wants to show off his "bling bling" or a moron .