Home Page
Articles and Profiles
Z of the Month
Z Car Photos
The Garage - DIY
Discussion Forum
Women Who Drive Datsun / Nissan Z Cars

Click for a larger image

Aeromotive DFMU/EFMU

Click for a larger image
Bosch wideband O2 sensor,
left cat at flange to header
Click for a larger image
Wheel actually turning in 5th
gear at redline - fast camera

How to Install
ATI ProCharger (supercharger)
on a 350Z ('03 or '04)

Tuning Phase

Before doing any tuning, it's best to get a thorough understanding of just how the EFMU/DFMU works. A good place to start is to join 350Z Frenzy Forum, do a search for the username "jesseenglish", and read all his posts concerning the ATI ProCharger. You will find excellent explanations of how everything works and a checklist with photos of crucial items to check when installation is complete (even if someone else does the installation, you can still check everything out)!

If someone else does the installation and/or tuning, make sure they know how the Aeromotive DFMU works in conjunction with the 350Z's ECU! Just because someone has tuned an ATI supercharger on a Mustang or Vette, doesn't mean they can do it right for a 350Z! If you do anything, err on the rich side! Lean = detonation = destroyed engine. Tuning MUST be done with a wideband O2 sensor. Jesse's information is a must read for tuning the ProCharger!

Here is a very informative e-mail Jesse received from Brett Clow, Aeromotive Tech Department, that explains exactly how the Aeromotive DFMU works.

How the Aeromotive DFMU Works

The DFMU scale is set by ATI before shipping for a 7 psi boost. The scale controls the range of boost for each slider. Each slider on the DFMU should activate at the following boost levels for the 350Z application.

  • First slider covers 0 - 1.3 psi
  • Second slider covers 1.4 - 2.7 psi
  • Third slider covers 2.8 - 4.1 psi
  • Fourth slider covers 4.2 - 5.5 psi
  • Fifth slider covers 5.6 - 7.0 psi

You can verify the scale adjustment with a low pressure source and regulator. The 5th slider light should activate at 5.6 psi.

This presumes that you are achieving the full 7 psi boost, so after rough tuning the DFMU, you may want to take a max boost reading at redline. If it doesn't read 7 psi, you'll need to check for leaks or restrictions in the intake plumbing, check your PCV/vacuum lines for leaks, make sure the bypass valve is working properly, and make sure your serpentine belt isn't slipping.

If after checking everything out, you can fine tune the scale by taking the maximum boost you are achieving at redline and divide it by 5, then multiply the result by 4, and that number is the number at which the 5th slider should activate. You can make your scale adjustments with a low pressure source and regulator. For instance, if your max boost is 6 psi, the scale increment becomes 1.2 and the 5th slider should activate at 4.8 psi.

Once the scale is set, you can proceed to fine tuning the air/fuel ratio. Here is where you need to map the A/F with a wideband O2. Your target A/F at the activation of each slider should be about 11.5 (slightly rich) so that it does not exceed 12.5 just before the activation of the next slider. Mine actually holds around 12 from 3,600 rpm to 5,000 rpm, and then a steady 11.6 with a slight upswing to 12 at redline. Remember that these A/F settings are done at WOT (put the pedal all the way to the metal).

Tuning is usually done on a dyno, but make sure your engine doesn't get heat soaked. About three pulls, and then let things cool off for a bit. A heavy duty, industrial fan helps to keep air flow around the engine and aid cooling. If you decide to do the tuning on the road (typically less accurate), you'll need a method to record the rpm and wideband O2 data (boost recording would be good too), and a good, safe, straight track for running at WOT.

I highly recommend a wideband O2 gauge, boost gauge, and fuel pressure gauge as minimum equipment to monitor the health of your system. It's reassuring to know all the time if your system is happy.

An additional piece of safety equipment to consider for any FI installation is the J&S Ultrasafeguard, it's a bit expensive, but a lot cheaper than rebuilding a destroyed engine. Here's a link to their web site:


Some people with the ATI ProCharger have their systems set up with various combinations of larger fuel injectors, the TechnoSquare ECU flash for an FI application, and the Apexi S-AFC II. Check the major 350Z forums for information on these setups.

Do it right, and enjoy all that horsepower safely!

Phases (click on a link):

Word document of entire text of the
ATI ProCharger Install Article

Click on photos for a larger image

Back to The Garage

Have some mod installation tips
or you-fix-it help?

E-mail info to


Click for a larger image

Digital Wideband O2
Air/Fuel Gauge
Click for a larger image
Strapped onto the dyno
© 2003 Z Chickz
Last updated: Sunday, January 14, 2007 8:45 AM