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RX8 ECU -> FC Renesis

Old 01-31-09, 11:14 AM
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RX8 ECU -> FC Renesis

So I've read a million times that you can't use the stock RX8 ECU when swapping a renesis into an FC.


Does anyone have picture proof of why you can't? I was talking to my buddy + his VW corrado has a passat ecu then another buddy has a BMW E36 w a different ECU in it as well. Help me understand why it won't work.
Old 01-31-09, 12:05 PM
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its a different setup, injector system, irons, etc.. oh and its 32bit.
you dont need "picture proof" to understand that the rx8 engines require different amounts of fueling .vs your FC.

but sure, wire in the sensors, wet injection, etc... hell just shoehorn that rx8 engine into your car with the harness & ecu. then it'll work just fine. otherwise, figure out how to flash it with your own cranking fuel and main fuel tables as well as ign tables - once you do that, you'll have undone millions of dollars of research.
-enjoy
Old 01-31-09, 12:13 PM
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I think it is more about how the ECU in the RX8 is looking for inputs from tons of things (wheel sensors, abs, traction control, instrument cluster ect ect) that you don't have on an FC. And without them it wouldn't work. That's what I was told at least.
Old 01-31-09, 01:15 PM
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I am just guessing, but I bet you could piggy back the rx8 ecu? I.E. run the harness piece from the RX8 ECU, wire up the essentiall functions it needs, and then keep the FC one for the main functions that are needed in the FC.

Again just a guess, don't know if it is worth it, or if it would even work, but it may be worth a try.
Old 01-31-09, 03:43 PM
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Originally Posted by hwnd
its a different setup, injector system, irons, etc.. oh and its 32bit.
you dont need "picture proof" to understand that the rx8 engines require different amounts of fueling .vs your FC.

but sure, wire in the sensors, wet injection, etc... hell just shoehorn that rx8 engine into your car with the harness & ecu. then it'll work just fine.
that makes no sense. what he said was put a renesis engine and ecu in a fc but it still wont work.

Originally Posted by Starfox07
I think it is more about how the ECU in the RX8 is looking for inputs from tons of things (wheel sensors, abs, traction control, instrument cluster ect ect) that you don't have on an FC. And without them it wouldn't work. That's what I was told at least.
now that is a logical explanation
Old 01-31-09, 07:54 PM
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Originally Posted by hwnd
oh and its 32bit.
That's all I really needed to know thanks.


Oh, there's already a guy 'shoehorning' a renesis into an FC.
Old 01-31-09, 08:13 PM
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But would the RX8 ECU work with the FC gauges?
Old 02-01-09, 12:45 AM
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The Rx-8 PCM communicates on a CAN bus (Controller Area Network, not a LAN but a CAN). A lot of the information (especially engine data like rpm) relayed on our ancient cars is now sent digitally on modern vehicles through a high speed and low speed serial bus. So instead of 0-5v volt signals and switched +12V signals, a lot of times it is communicated through packets of serial data, in the same way that your computer communicates with your router at your house.

It is a completely different way of doing things. That's why you can't put the Rx-8 instrument cluster in a 7. If you look at the wiring diagrams of the Rx-8, the vast majority of the information displayed on the cluster comes through serial packets on two wires.
Old 02-01-09, 12:51 AM
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You wanna use a rx8 ecu in a obd1 car? You should just go to standalone ecu, I'm running a haltech e8 in my fc.
Why would you want to run a rx8 ecu on your 13b engine, what gains would come of this?

All of the gauges work without the ecu except you need to run the wire for the temp gauge.
I also had to run a output to make my tach work.
Old 02-01-09, 01:25 AM
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Originally Posted by arghx
The Rx-8 PCM communicates on a CAN bus (Controller Area Network, not a LAN but a CAN). A lot of the information (especially engine data like rpm) relayed on our ancient cars is now sent digitally on modern vehicles through a high speed and low speed serial bus. So instead of 0-5v volt signals and switched +12V signals, a lot of times it is communicated through packets of serial data, in the same way that your computer communicates with your router at your house.

It is a completely different way of doing things. That's why you can't put the Rx-8 instrument cluster in a 7. If you look at the wiring diagrams of the Rx-8, the vast majority of the information displayed on the cluster comes through serial packets on two wires.
That is the best explanation I've heard. Thank you.

Originally Posted by lupin
You wanna use a rx8 ecu in a obd1 car? You should just go to standalone ecu, I'm running a haltech e8 in my fc.
Why would you want to run a rx8 ecu on your 13b engine, what gains would come of this?

All of the gauges work without the ecu except you need to run the wire for the temp gauge.
I also had to run a output to make my tach work.
I don't want to run the 8 ECU in my car, I want to put a renesis in my FC.

Does your e8 have signals for tach + speedo?
Old 02-01-09, 01:10 PM
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the simple (note that there is a difference between simple and easy) solution:

put the Renesis in the car and run it with a standalone. forget about the neo-**** PCM.
Old 02-01-09, 04:38 PM
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Originally Posted by diabolical1
the simple (note that there is a difference between simple and easy) solution:

put the Renesis in the car and run it with a standalone. forget about the neo-**** PCM.

Or run a carbed setup. More fabrication needed for this, but still doable.
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