Yesterday, I installed the Apexi engine grounding kit. It was actually bought by a fellow club member (Mazda6sMtx) for installation into his car. However, after struggling with the install for a while (none of the cables were long enough to reach the right locations), he quite disappointingly gave me his kit and suggested we try installing it in my car instead. He has the V6 engine and I have the I4. After the installation, which was a success in my car, he let me keep the kit. Paul, you're such a nice guy
The kit itself is the following one: http://www.apexi-usa.com/product_electroni...d=224&pageNum=1
Now, before I continue the review, I'd like to point everyone to a post I recently made over in the 2.3-I4 section: http://forum.mazda6club.com/index.php?show...ndpost&p=510265
Essentially, at a particular spot in the 1000 to 3000 range, my engine would feel quite sluggish... as if there wasn't enough air or fuel getting through to the engine. The whole thing manifested itself as a "hesitation" or sluggishness at a particular point in the above-mentioned range. I did the airbox mod, which seemed initially to have improved the issue. However, recently, the issue started re-appearing even with the airbox gutted (after a trip to a local dealer). Above 3500, however, the engine felt alive and well. This particular characteristic was present pretty much since the first day I had the car.
I need to also admit that, before the installation, I was a total skeptic when it came to engine grounding. I had read the numerous posts on this forum on how grounding the TB was pretty much just a placebo. I approached the grounding kit with the same belief but I figured, heck, there's no harm in installing it... its not going to damage anything by being there... and if it turns out that it actually improves performance, then fine and well.
So, the kit was installed... and I instantly felt a complete difference in engine character. The engine was extremely responsive, right from 1000 rpms all the way up through to 3000 and beyond. No more hiccups, hestitation, or sluggishness throughout this range. I drove around yesterday, after the install, and part of today in total amazement that my engine feels so much improved just due to the presence of a few extra wires. With this kit in place, the car seems to pull stronger and power seems to be available more readily.
Now, the kit isn't just a grounding kit. It includes a system that evens out voltage spikes and provides a constant voltage to all parts of the engine. Also, according to Mazda6sMtx, he read somewhere that this particular kit was installed on a Mazda3 (presumably the one with the 2.3 engine) and it was dynoed before and after the installation. There was a net gain of almost 10hp to the wheels.
Anyways... just wanted to report my findings and see what the more knowledgeable people on this forum have to say.
The control box. As you can see, there are 3 grounding wires coming out of the box. A 4th wire goes to the +ve terminal of the battery and a 5th wire is grounded to the body.
Closer view of the box, showing the red LED that continuously glows.
Grounding wire #1 disappears under the cover and attaches to a bolt on the valve cover on the right side of the engine.
Grounding wire #2 disappears under the cover and attaches to a bolt on the valve cover on the left side of the engine.
Grounding wire #3 is routed along the front of the engine bay, and around to the engine mount.