BMW E46 3-Series Intake System R&D, Part 2: Power and Sound Testing
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Mishimoto BMW E46 Performance Air Intake
After completing our initial prototype it was time to strap this E46 to the dyno and make a few pulls. We would be evaluating power output, monitoring vital engine sensors such as AFR, and collecting sound clips for comparison against the stock intake system.
Time to make some pulls! Check out the dyno video below.
The video shows the changes our setup made in intake noise. This is likely a result of our open-element filter residing within the engine bay. Although closing the hood seals off the airbox portion of the intake, it is still more audible than the stock unit. The stock airbox is designed in a way to reduce noise and create a more drivable experience for non-enthusiasts. That said, this creates a numbness among car folk and leaves much to be desired.
So we’ve managed to improve engine sound with our intake system. How did we make out in the power department?
First up, our horsepower plot.
We were not expecting massive gains with this intake system. For our setup, we are using the stock MAF housing. Intake gains are typically achieved by modifying the diameter of the housing to lean the mixture slightly. If this is designed carefully, precisely, and properly tested it can be very beneficial.
The gains we are seeing with this vehicle are likely because of the improved airflow from our filter and lack of restriction. The stock airbox is likely impacting flow in a negative manner (although only slightly), so we are able to take advantage of this by removing it.
We saw maximum gains around 4,600 rpm to the note of around 4 whp and peak gains of 2 whp at 6,000 rpm. If you look at the plot, you will see that we make 1-3 whp throughout the entire rpm band, which is fantastic.
One additional note is in regards to the data we collect. Each plot represents an average of 3 consistent runs with each individual setup. We could easily select the highest Mishimoto run and lowest stock run to compare and promote bigger gains. We do not do that at Mishimoto. These are the results you can expect, they are not mind blowing, but we are pretty pleased with what we saw.
Next up, a look at torque output.
Although intake systems are generally characterized by horsepower gains, we should not forget torque as an equally important measurement of power. The plot above depicts the improvements we saw with our intake installed compared to the stock setup. Maximum gains were achieved at 3,500 rpm to the tune of nearly 5 wtq. Peak gains at 4,750 were right around 2 wtq. Both numbers are very respectable for an easy bolt-on intake system.
These gains aren’t comparable to strapping a Holset to your M54, but for a bolt-on intake system these gains are pretty respectable.
Intake Kit Information
Check out a few 3D models of our final intake setup!
The black portion of the model depicts our intake shroud that will be constructed from powder-coated black steel. We will also be using the weather-stripping noted earlier in this series to seal the box and reduce the chance of any vibrations on the edges.
The blue hose in these models is our silicone intake hose, which leads from the MAF housing to our air filter. We will also be using one of our oiled air filters, which is completely serviceable allowing for years of service.
Now that we have completed the testing and full design of our intake, we need to construct a final prototype for an official test fit.
We are also likely launching a discounted presale prior to actual release of this intake for those who are interested.