Been a while since I’ve been on here, got more progress done, just been too lazy to make a post. Trying to decide how much detail I want to put into this stuff. I took lots of photos of this step so I’m going to try a slightly more in depth post about building something, and see how it goes.
The throttle pedal seems like such a simple thing, just toss it back in and done right? Well it’s not quite that simple. I spent a lot of time trying to figure out the wiring on the factory throttle pedal, and for the life of me I couldn’t figure it out, and neither could my friend who’s really good at the complicated wiring stuff. For normal e pedals there are 2 separate tps sensors inside the pedal for redundancy, and these are very easy to meter out on a multimeter as it’s just a change in resistance. The throttle pedal in a speed is something strange that does not use an obvious 2 separate tps sensors. I only had 2 wires that even seemed like they were connected inside the pedal somewhere. Now I’m not going to pretend that I’m the smartest guy when it comes to electronic things, so this isn’t saying that there isn’t an obvious way to make this pedal work, but for me it was simpler and more fun to use a known good e throttle pedal out of a different car.
Now I’m sure you’re wondering at this point why this even matters. Just plug it in, there’s no reason to figure out how it works. I haven’t posted on here a full plan of what I’m doing to the car because things could still change, but I’m going to be running on a traditional standalone (most likely haltech because me and my friend are both reasonably knowledgeable on haltechs as both our rx7s were/are on haltechs).
So the easiest thing in my mind being an rx7 guy, was to use the rx8 throttle pedal. It’s a commonly used throttle pedal for rx7s, and the wiring is very simple and I have a wiring diagram for it. I also happened to part out a rot box of an rx8 about 2 years ago so I had an rx8 pedal just sitting in a box in my basement. Obviously this requires an adaptor bracket to bolt into the car. The rx8 pedal is also a funky shape, and the pedal doesn’t land anywhere near where the stock pedal landed. Mine is also the plastic pedal as it came out of an auto so it doesn’t match my other pedals at all.
Factory vs the rx8 pedal.
The easiest way I’ve found to build something like this pedal, is to first make a jig of the important parts of the factory pedal. I welded some nuts to a piece of 1x3 steel, and then bolted the pedal to the steel
Then I made a sort of “frame” around the factory pedal, to capture its location and also its angle. This is so much easier than trying to make something that floats in open air, also makes test fitting basically pointless. As long as it bolts to the nuts I have welded in the plate, and the pedal falls inside the frame I built then it will bolt right into the car and sit in the exact location as the stock pedal.
Since the rx8 pedal is all plastic I chopped the pedal arm off to allow me to make a new arm that fits where it needs to. I made a super quick adaptor bracket that allows the pedal to bolt to the factory bracket. This wasn’t supposed to be the end result, just a quick bracket that allowed me to build the arm, but it ends up becoming permanent because while it doesn’t look super pretty it works well and has zero flex.
Next step was to make a plate that would allow me to bolt the factory aluminum pedal cover to. I traced it out on cardboard first, then transferred it to 1/8 steel, and then put a curve in it to match the factory pedal shape. Easiest way to do the next step was to tack this steel plate directly to the jig, allowing me to just connect the dots to get the perfect new pedal.
I made a little bracket that would bolt to the nub of the rx8 arm I had left, and then bent up a piece of steel rod to bridge between the rx8 pedal and the new steel pedal plate I made. To get this shape I just bent up a piece of filler rod, and then transferred it to the steel rod.
Now it’s just as simple as bolting the bracket to the rx8 pedal, and then welding the rod to the new pedal. Everything lines up perfect because of the jig.
Now this could very easily be done, but I wanted to add a little gusset between the pedal plate and the rod, just in case I get a little excited and stomp the pedal super hard. Don’t want it to have any chance to break off.
Now it’s just the normal powdercoat, and then bolt into the car. It looks great, there’s no way to even tell it’s not the stock pedal without looking under the dash, and it feels awesome too. Exactly the same as the factory pedal. Now the wiring is simplified and I can make this work with hopefully no more hurdles. Let me know if you want to see more in depth posts like this, or if you prefer the quicker overview posts.
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