85gsl-12a

im doing a renesis swap into my first gen gsl. i have done my research but have not found anything on the throttle body needed. i know i need a manual throttle body and i want about 80mm. anyone know where i can get one for the rx8 motor? i think i can bum one off a mustang, but i dont know what year... thanks!

RGHTBrainDesign

Why not just do a drive-by-wire system with an Adaptronic ECU and leave the factory TB?

85gsl-12a

Well the car comes with a manual throttle body, I wanted to keep the swap as simple as possible. A drive by wire would work but would also require alot more work.

RGHTBrainDesign

No, the Rx8 comes drive by wire, which is why an aftermarket ECU with drive by wire capabilities could be easier (and seen as an upgrade) in your case. You'd just want to get a drive by wire pedal assembly and you'd be able to tune perfectly.

For a throttle body application, there's always Rotary-Works: rotary-works.com: Aluminum Throttle Body for Mazda Rx8 Renesis 04-10 Rotary engine

85gsl-12a

My apologies, I meant the rx7 comes with a manual throttle body. Is that other ECU as versatile as the Megasquirt?

RGHTBrainDesign

Megasquirt isn't plug and play. You said you wanted easy.

If you're doing your own harness you could go with anything from Adaptronic to AEM to Motec, but why bother when Adaptronic makes a plug and play for the Rx8? Just acquire an entire Rx8 harness and drop it in. You'll still have to figure out a few things with speed sensors/temp sensors, etc.

85gsl-12a

Hmm I didn't know that. I did a lot of research and heard the Megasquirt was best from what I want. I will be removing all emissions in the car. With the adaptronic still work?

RGHTBrainDesign

Okay, let's take a step back for a minute...

You plan to put an Rx8 swap into your FB. That's awesome. With that swap, you should get the ECU, Harness, 6 speed transmission, all the sensors, etc. There's absolutely no reason to delete all the emissions equipment, because you'll complicate the tuning process. If you just leave it all stock, you can just use a STOCK ECU. Deleting emissions won't gain you any power, just create more points of failure (new vacuum leaks are easy to come by!).

Okay, so once you figure out how you'll place that factory harness into your car (look into firewall connectors or leaving the ECU in the engine bay), the next step is going to be integrating the sensors to read on your factory gauge cluster or using an Rx8 gauge cluster mocked into your car (which all things equal, should be the easier route).

Now that you have an idea of how things are coming together, you should scan "Rx-8 Reliability Mods" and perform everything from fixing their temperature sensor accuracy to different types of gaskets/seals, etc. They have a bunch of suggestions in the Rx8 Community for reliability.

Run a better header/exhaust (mandrel bent 3") and use Rx8 OEM sensors wherever they came on that car.

85gsl-12a

Talk about complicating the process.... putting the 6speed in the car is very challenging. Along with that, if I delete the emissions and run a megasquirt or other ECU and delete emissions, all I have to tune is ignition and etc. Using all of the rx8 parts means alot of custom fabrication and challenges that are unnecessary. The 6 speed transmission also does not link up to the rear diff. properly. I'm not doing a rx8 swap into the car, I am doing a renesis swap. Only the motor.

RGHTBrainDesign

How is a complete rewire and retune easier than dropping in all functioning OEM parts/harness?

The transmission is whatever you want to do, it has nothing to do with the tuning side of things, and fitment is easy since you're already making your own motor mounts and **** at the front of the car.

Deleting all the emissions is going to be a HUGE hassle for getting the car to run right, and you need sensors to tune an engine, especially one as fragile as this. It's over complicating an OEM swap.

Simple things like intake, exhaust, fan, radiator, ignition, gauges, etc are all going to take more effort than you think. Megasquirt is a UNIVERSAL ecu, and a step in the wrong direction. If you want to tune yourself, get an Rx8 harness and plug in an Adaptronic and you're 80% there. You still need to have your gauges and sensors communicate back into the cabin at that point.

j9fd3s

iTrader: (3)

just to straighten a couple of things out.

1. the only emissions equipment on the Rx8 engine is the purge valve, air pump and cat. the whole reason they went to the side ports was so they could simplify the emissions system, and thus the 13B-MSP has basically the same setup as any other 2003 car.

1a. the air pump is just for cold starts, and thus can either be kept or deleted, up to you.
1b. i would keep the purge valve. it just needs a simple map to operate, rpm vs any kind of load is good enough.
1c. i would delete the cat until the car is tuned, i wouldn't want to damage it tuning the car. after its tuned i would put it back, or put a cat back on it

2. all of the valves on the intake also require outputs from the ECU. the stock Ecu obviously will just run everything, the other two will require setup and tuning.
2a. the stock ecu's are somewhat cracked, so you can do some tuning and turning off of some functions, but the stock ecu is WAY more complex and capable than either of the two aftermarket units so it requires more inputs/outputs, and it has 10x the maps/tables so tuning is a longer process, although it'll run ok out of the box.
2b. the stock ecu runs the gauges, and is networked to a bunch of other stuff in the car, so you need to decide if you want to run all the stock stuff, which is just a matter of getting it all in there, OR rewiring the whole engine and tuning a new ecu.

3. if you can fab the engine mounts to get the engine in the car, putting the 6 speed in is child's play.
3a. to keep the FB transmission you need the Rx8 a/t counterweight and an aftermarket flywheel, because the Rx8 uses the turbo sized stuff.

4. there really aren't any reliability mods for the Rx8, its the most basic rotary Mazda has ever made, all you need to do is change the oil, clean the CAS and check for spark once in a while.
4a. just to rephrase this point, the Rx8 guys will spend like $500 and a big chunk of time to re-engineer a $50 part that doesn't fail much, or their "mods" are really unproven at best.

5. plan on rebuilding the engine. these engines just wear out quickly, its a combination of small engine + heavy car + poor break in/zero maintenance + incompetent service.

RGHTBrainDesign

Thank you. It's not a simple bolt in procedure...there's a lot of fabrication necessary. See if you can get the entire front clip of an Rx8 and try to use as much of it as you can. Swapping in the gauge cluster and drive by wire pedal assembly from that car would be the way to go.