Port Injection Supplemental Fueling for the Mazdaspeed

This has been something I have wanted to do for quite a while now. I had to put it on hold until the intake manifold was on the market, I just couldn't take on 2 projects at the same time. I talked to several techs (that are much more knowledgeable than I am about AUX fueling) about fuel injector options, fuel rails, hoses and sizes that would be able to handle the amount of fuel I need. The guys at Ballenger Motorsports ? High Performance Electronics were by far the most versed at setting this system up. After talking to them for almost 45mins we decided that these were the best injectors to run. Home » Shop » Fuel » Injectors » Siemens DEKA IV ( DEKA 4 ) Mototron 60lb/hour High Impedance Injectors ( Short Style ) These are 60 lb 4 orifice 30° spray pattern high impedance injectors. 43mm in length, with an installed length of just under 24mm, this is a plus when installing in the tight confines of my engine bay.

Next, I went to Dash 6 Fuel Rail Extrusion - Ross Machine Racing for the fuel rail and bungs. These are high quality pieces, and best of all they are cheap, probably the cheapest part of the install. Now I have a blank fuel rail, I needed to cut o-ring ports for the injectors. The injectors are a standard domestic 14mm o-ring. For those of you that are into machining will appreciate how difficult it is to accurately cut an o-ring port. But never fail RmR has a beautiful tool already modified to cut a perfect o-ring port, It is pricey, but to me, worth every penny. 14mm Injector Port Tool Now I have all the components to start modifying the intake manifold, by far the most nerve racking part of this install. I stopped by my buddy's machine shop since he has the proper fixtures to set this up properly. The angle of the injectors is 40°. We started off by cutting the bungs at the proper angle and length, which the length ended up being .620" on the short side at 40°. The next step cooked my noodle for a minute. The manifold was bolted to the table upside down and backwards. I struggled with what angle the table was to be set. At first, I thought this will be easy, I need a 40° on the injector, so the table has to be set at 40°. Wrong answer, it has to be set at the other half of 90°, so the table has to be set at 50°. Next was to figure out where the long side of the bung would hit on the runner. I wanted to hold off the head plate .950" to give the most time to let the fuel atomize and also to hold the spray off of the divider in the head. Normally doing something like this on a 90° cut to the plane would be a simple calculation of the total of distance plus half the diameter of the cutter to achieve the center line. Well, when you throw an angle into the equation it gets a little more complicated. There are formulas to figure this out, but my cave man brain could not figure it out. So, I called my buddy over (knowing that I was in over my head) and asked him. He mentioned that there was more to this than a hard and fast calculation. He implemented some Kentucky windage, more to allow for tool flex on a longer cutter than anything. We used a 1/2" end mill first just in case something was not right with his set up. He was able to hit it the very first time, sigh of relief!!

Next up was an undersized 3/4" end mill. The injector bungs actual measured .743".

Now I have a pocket in the runner to help orient the bungs for welding. Fits like a glove!!

Fuel rail was next. Pretty much self explanatory.

I was still worried about keeping everything lined up with the heat from the welding process. I was not going to put the injectors in the rail and in the bung while I had the bungs tacked welded in place, I felt that is was too much heat for my liking. I made some dummy injectors.

Mocked up in the car with injectors. I need to trim the rail down about .750" on each end. That is the least of my worries after cutting holes in a perfectly good manifold.

Cut one inch of the fuel rail off each end, made brackets for the rail itself, and had everything welded together by a very talented welder (not me..lol). Tapped the rail for 9/16x18 thread, cut a chamfer for the -6 o-ring fittings. Made up a return line for mock up purposes. The return line fitting just clears the power steering hard line.

Alright...so I did do some work on the car this past week end. Not much though, mounted the controller, and routed and connected the wires. I am up to the fuel pump and regulator install, not sure which route I am going, but I have to make up my mind before the weather changes since I do not want to be stuck in the garage working on this while the weather is nice..

I installed the FPR behind the small battery box I fabbed a while back; the bracket is bolted to the stock mount for the OEM battery box. I only have a mechanical gauge to set base pressure right now; my next step is to install an actual in cabin pressure gauge so I can keep tabs on the fueling. I have a boost pressure switch installed on the pre-I/C side of the piping to pull in the fuel pump relay. I put it pre I/C because that pipe will see the boost before the intake manifold will, in turn activating the pump with enough time to pressurize the system. I also installed an LED in the dash on the output side of the relay just to let me keep tabs on the pump circuit. The boost switch is made by Design Flex, it is a very robust high quality switch with a 10 million cycle life, and it can be end user adjustable. It has a burst pressure of 300psi and can be set to engage from 1 - 25psi.

Fabbing up the bracket for the cell. I used the mount for the spare tire and built a battery box type clamping device to hold the cell in place. I used all 1/8" angle and lined it with a rubber gasket to keep everything isolated from vibrations.

Built a false floor and a simple wooden box around the exposed fuel cell. Not sure if I like this, I might end up forming up some aluminum sheet metal and then covering it with carpet, but it will do for now.

Dropped the lines to bulk head fittings through the trunk floor, added a fuel filter. By using the bulk head fittings it keeps the lines tucked up close to the under body.

The filter breather on the vent line.

It has been a while since the last update. I have completed the install, and have driven about 100 miles and went wide open about 6 times with this. For a base line rich map in the AIC, this is one nice set up. I should have done this before ever installing the meth injection. Although water/meth has its place in a turbo application, this is a far superior fuel delivery system. For tuning right now, I pulled 3° of timing out of the ignition tables until I get the AFR's ironed out with the PI. I am also running pump gas in the cell right now until I make sure everything is right with the system. I am going to the speed shop this week to pick up some 112 octane and I will slowly bring the tuning back up to where it was with the 1100cc's of meth.