Lockie-rx8

ok this is my first post, I have done some reading on engine swaps and ecu flashes. now after doing all that. is the easiest thing to get a say salvage 2004 with like rear dmg? to flash the ecu rebuild the 2004 engine how I would like. mainly will the 2004 ecu work in a 2006 base with only nav. and if so could I use other controls if it had dcs and such? thank you for you help, just looking for some feed back before I do anyting

RIWWP

iTrader: (2)

Your understanding isn't quite up to where it should be before you start tackling this. You are currently way overthinking it. You do not need a separate ECU if you just want your ECU tuned.

Read the section on ECU Tuning, Chips, and the AccessPORT here: https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/ (starting at the end of post #2 and continuing into the beginning of post #3)

If you are swapping an engine, then the only time another ECU will be needed is if you are going from a manual transmission to an automatic or vise versa. Or if you are putting the Renesis into a different car entirely. Replacing your current engine with another compatible engine will use your current ECU.

Lockie-rx8

oh I was under the impression the only year the immobilizer would be removed is the 2004 (racing beat) ecu. first time dealing with obdii so I dont plan on messing with ecu myself.

RIWWP

iTrader: (2)

The immobilizer is standard on all RX-8s. If there is a method of removing it on a 2004, it will work equally well on all 2004-2008 ECUs.

One way the immobilizer would cause problems is if you are transplanting the entire RX-8 drivetrain into another car and are not retaining the immobilizer. The easiest method of doing such a swap is to have a donor RX-8 that you can move literally everything from, including the keys, key cylinders, immobilizer module and components, ECU, wiring harness, etc... If you find you missed something, just go over to the donor car and grab it.

If this is all with the same car, the immobilizer will only cause you problems if you replace the ECU with another one and don't have a dealership pair the ECU to the immobilizer. It doesn't sound like your current ECU is fried however.


If your RX-8 is working fine and this is all with the same RX-8, and all you want is an ECU tune, see the thread I linked, post #2 and #3. No additional ECU or mess with the immobilizer is required.

Lockie-rx8

mostly, I want the things mine doesn't dcs mainly then stupid things like heated seats, possably radio if it has cd changer home link rear view... then have the other engine and everything for rebuilding on the stand. have done a couple builds on 80's 300zx as well as a 88 vette. all the computer stuff makes me iffy. thank you for your helping reading that post atm

RIWWP

iTrader: (2)

Ah, ok.

If you want to gain DSC, I am pretty sure that you will need more than just the ECU. It might not even be the ECU that controls it, but a separate ABS control module. That will probably need pairing with the ECU. I'll have to poke around to see if the ECU and the ABS control module are separate for the RX-8 or joined. I don't know that answer already.

The other items have nothing to do with the ECU. All RX-8s actually have the heated seat wiring harness, you just need the leather seats and center tunnel trim with the buttons, and plug everything in. No 'control' to it, just simple circuitry

The head units are not involved with the ECU to my knowledge, you just have to find a head unit out of an RX-8 with the 6-cd changer, or buy a changer head unit from the dealership.

Lockie-rx8

yes other things are simple. mostly dcs and engine. but you help a lot so I know what donar car to get. hoping the car will have dcs and all that so should have all parts. and looking for a good factory service manual atm. it's in planning phase now, want to know what i'm looking for before doing anything that may cost me at the end

RIWWP

iTrader: (2)

Have you considered trading your current RX-8 for a GT trim RX-8?

The cost difference between the two is going to be less than the donor car by itself, not to mention the time and trouble getting everything working, the space problems, two cars with neither running for a while, dealing with the left-overs, transporting the donor car around, etc...

Lockie-rx8

I have room, really like to keep the one I have now with work already done. donar car would be from the salvage auction here. but one went for $1200 last week gt didnt have nav was rear ended and started and everything. I know its not the best place to get one, and I enjoy doing the work. just to have something you put the time into. I might be nuts though haha

RIWWP

iTrader: (2)

Alright.


I would agree with the nuts part. It makes me wonder why you didn't just buy the car you wanted to begin with, and that it isn't too late to correct that.

Very few people will agree with you on what you are doing, but, your time, your money.

j9fd3s

for some reason the DSC cars have the HID lights and the suspension position sensors, so a donor car might not be a terrible idea. the HID's are a nice addition

i'm really not sure either what controls the DSC, except for the suspension sensors, and the switch in the dash there is no additional hardware, so it must be software, but i'm not sure which box! i have a suspicion its not the ECU, but i don't know.

to me buying another 8 to get heated seats seems like a fine idea, but i've got 4 rotary cars they are like potato chips, one is a bad idea

Lockie-rx8

donar car would be cheap, and get all the little things i wanted out of it, not sure about the dcs looking into it. big thing is want a fresh engine built on a stand and what not as spare parts

RIWWP

iTrader: (2)

From an engine perspective, a donor car isn't a bad way to go.


I did some digging through the Mazda shop manual, and it looks like the DSC module is attached to the block that all the ABS hard lines feed into, and is not connected to or related to the ECU. There is no mention of if the module has an electronic pairing with the ECU however. It very well might have such a pairing (Mazda tends to do that). I do not know if this module also controls ABS or not. The shop manual on fexed actually doesn't have any ABS component articles, and Mazda's OE dealer site isn't responding at the moment.

You will also need the "combination sensor" located on the transmission tunnel under the trim between the two rear seats, the switch wiring, and the steering wheel position sensor and it's wiring. Just from a parts perspective. Getting it all working together is a different story

j9fd3s

there must be at least one wire to the ecu to tell it to cut power...

and LMAO, Mazda must the be the only company in the history of the internet to shut its servers down on sundays...

RIWWP

iTrader: (2)

The DSC system does not cut throttle. It uses the ABS only. TCS is entirely within the ECU, and will only cut the throttle (lots of play time with the differences). Typically though, when DSC is engaged, you will start getting overspin on the rear tires, so TCS also triggers.


That being said, it does bring up a good point that if both TCS and DSC are handled via the same button, they have to have a common point in 'a' control module somewhere, and it makes sense that it's the ECU, with the ECU having a pass-through over to the DSC module on the ABS block.

j9fd3s

lmao! i actually thought it was one system, that explains a lot!

my thinking is that since DSC/TCS is an option, and the only hardware difference is the switch... it must be an option in the software somewhere, but i don't actually know, and since i live where people need a cayenne S to merge onto the freeway @37mph, DSC/TCS just isn't needed.