Noob with swap questions. NEED HELP FROM THE EXPERTS! S5 to S4T
07-02-08, 01:41 PM
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Noob with swap questions. NEED HELP FROM THE EXPERTS! S5 to S4T
Hi everyone. I'm currently building my first RX7 and have run into some snags.
The car is a 1990 GXL and I am in the middle of swapping what I thought was a JDM S5 Turbo II engine into the car. While rebuilding the engine I discovered that it is actually an S4 turbo II engine. It also came with a tranny still attached.
Here is what I have:
S4 Turbo II engine complete with JDM RHD harness with ECU. It came with the TB and everything. It's all there save for the intake hose and MAF.
In prep for the swap I have purchased:
1. S5 USDM TII engine harness
2. S5 Turbo II MAF meter
3. Turbo II pressure sensor (passenger side strut tower)
4. Mazdatrix hybrid drive shaft for turbo tranny to NA rear end.
5. New hoses and block off plates for emissions removal.
6. Other small misc things like a FMIC, etc......
Here's my question:
I know that to swap an S5 motor into an S4 the S4 harness will not plug into the S5 guage cluster harness. I assume that the same is true when going to S4 from S5.
What parts do I need to swap in order to use my S5 Harness with my newly rebuilt S4 engine?
Obviously I'll need an S5 ECU now. What about the Throttle body and will I need to swap the solenoids in the rat's nest?
Please guys I've searched all over and can't quite get a clear answer. Any help will be very much appreciated.
The car is a 1990 GXL and I am in the middle of swapping what I thought was a JDM S5 Turbo II engine into the car. While rebuilding the engine I discovered that it is actually an S4 turbo II engine. It also came with a tranny still attached.
Here is what I have:
S4 Turbo II engine complete with JDM RHD harness with ECU. It came with the TB and everything. It's all there save for the intake hose and MAF.
In prep for the swap I have purchased:
1. S5 USDM TII engine harness
2. S5 Turbo II MAF meter
3. Turbo II pressure sensor (passenger side strut tower)
4. Mazdatrix hybrid drive shaft for turbo tranny to NA rear end.
5. New hoses and block off plates for emissions removal.
6. Other small misc things like a FMIC, etc......
Here's my question:
I know that to swap an S5 motor into an S4 the S4 harness will not plug into the S5 guage cluster harness. I assume that the same is true when going to S4 from S5.
What parts do I need to swap in order to use my S5 Harness with my newly rebuilt S4 engine?
Obviously I'll need an S5 ECU now. What about the Throttle body and will I need to swap the solenoids in the rat's nest?
Please guys I've searched all over and can't quite get a clear answer. Any help will be very much appreciated.
07-03-08, 05:20 PM
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i did the the s5t into an s4 n/a swap and let me tell you, it is a BITCH!
so much splicing... and rewiring... i eventually got it running but decided to go stand alone once i got it running. I HIGHLY HIGHLY recommend going stand alone. your basically playing with fire with different series ecus. the s4 ecu is programmed for lower boost and lower compression then the s5 ecu.
when i went to a shop 3 cars were actually sitting waiting for a rebuild due to the series swap.
the s5 injectors are high impedance injectors and the s4 are low.
In my case i used to the s5 injectors in my s4 car which cause me to bypass my solenoid resistor.
also the s5 uses an electric OMP when the s4 uses oil injection. you have to swap the OMP to the right series for the car which in return cause you to fab a pully for the OMP.
you also have to change the front cover which will cause you to change your turbo oil return tube.
you also have to use the series throttle body.
you really shoulda paid attention to your series motor when you got it cause the series swap is major $. and is def not for n00bs. As for a straight forward answer on how to do the swap from people, youll never get one. its all up to you now.
there are never any clear answers to this swap.
as for me i did a s5 turbo motor into an 86 GXL. and it turns out the 86 wiring is actually different then the rest of the s4's such as the 87-88 so must of the wiring i did was a guesstimate. talk about a pain in the ***!!!!
i highly highly highly highly recommend going stand alone. itll cost as much as the parts do to actually do the swap. Ive done it personally and am not trying to bullshit you im trying to save you money, tears, and a pain in the *** of a swap.
pick up a haltech e6k for like 1400$ and make your harness from the wiring they give you, its simple. and will clean up your engine bay. itll also let you get rid of your goddy air flow meter.
-mitch
so much splicing... and rewiring... i eventually got it running but decided to go stand alone once i got it running. I HIGHLY HIGHLY recommend going stand alone. your basically playing with fire with different series ecus. the s4 ecu is programmed for lower boost and lower compression then the s5 ecu.
when i went to a shop 3 cars were actually sitting waiting for a rebuild due to the series swap.
the s5 injectors are high impedance injectors and the s4 are low.
In my case i used to the s5 injectors in my s4 car which cause me to bypass my solenoid resistor.
also the s5 uses an electric OMP when the s4 uses oil injection. you have to swap the OMP to the right series for the car which in return cause you to fab a pully for the OMP.
you also have to change the front cover which will cause you to change your turbo oil return tube.
you also have to use the series throttle body.
you really shoulda paid attention to your series motor when you got it cause the series swap is major $. and is def not for n00bs. As for a straight forward answer on how to do the swap from people, youll never get one. its all up to you now.
there are never any clear answers to this swap.
as for me i did a s5 turbo motor into an 86 GXL. and it turns out the 86 wiring is actually different then the rest of the s4's such as the 87-88 so must of the wiring i did was a guesstimate. talk about a pain in the ***!!!!
i highly highly highly highly recommend going stand alone. itll cost as much as the parts do to actually do the swap. Ive done it personally and am not trying to bullshit you im trying to save you money, tears, and a pain in the *** of a swap.
pick up a haltech e6k for like 1400$ and make your harness from the wiring they give you, its simple. and will clean up your engine bay. itll also let you get rid of your goddy air flow meter.
-mitch
07-03-08, 05:24 PM
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oh yeah i forgot to mention, you also have to rewire you fuel pump resistor relay since yours is an s5 for constant volatge which you will find is a bitchhhhh
07-03-08, 05:30 PM
#6
There are a lot of differences, especially since you're trying to use parts from 3 different models/years.
Using a TII EM harness in an NA car requires rewiring the front harness to EM harness connector. Swapping the front harness with one from a TII really isn't an option since it goes behind the dash, into the engine bay & all the way around the front of the car. Modifying the NA EM harness is much easier.
On the engine side, get a S5 TII TB and TPS, get S5 TII injectors and a S5 TII front cover and OMP. Use the S5 TII AFM & boost sensor. You would basically just be using the S4 TII block, manifolds and tranny. All the sensors should stay S5 to avoid making new plugs & running new wires. You really will want to keep all the electronics S5, and use mechanical only parts from the S4 motor. Also, keep the PS pump and AC from your S5 NA setup.
Lookup the threads on using an NA harness on a TII motor to get the details, as well as downloading the FSM wiring diagrams.
Using a TII EM harness in an NA car requires rewiring the front harness to EM harness connector. Swapping the front harness with one from a TII really isn't an option since it goes behind the dash, into the engine bay & all the way around the front of the car. Modifying the NA EM harness is much easier.
On the engine side, get a S5 TII TB and TPS, get S5 TII injectors and a S5 TII front cover and OMP. Use the S5 TII AFM & boost sensor. You would basically just be using the S4 TII block, manifolds and tranny. All the sensors should stay S5 to avoid making new plugs & running new wires. You really will want to keep all the electronics S5, and use mechanical only parts from the S4 motor. Also, keep the PS pump and AC from your S5 NA setup.
Lookup the threads on using an NA harness on a TII motor to get the details, as well as downloading the FSM wiring diagrams.
07-03-08, 05:38 PM
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There are a lot of differences, especially since you're trying to use parts from 3 different models/years.
Using a TII EM harness in an NA car requires rewiring the front harness to EM harness connector. Swapping the front harness with one from a TII really isn't an option since it goes behind the dash, into the engine bay & all the way around the front of the car. Modifying the NA EM harness is much easier.
On the engine side, get a S5 TII TB and TPS, get S5 TII injectors and a S5 TII front cover and OMP. Use the S5 TII AFM & boost sensor. You would basically just be using the S4 TII block, manifolds and tranny. All the sensors should stay S5 to avoid making new plugs & running new wires. You really will want to keep all the electronics S5, and use mechanical only parts from the S4 motor. Also, keep the PS pump and AC from your S5 NA setup.
Lookup the threads on using an NA harness on a TII motor to get the details, as well as downloading the FSM wiring diagrams.
Using a TII EM harness in an NA car requires rewiring the front harness to EM harness connector. Swapping the front harness with one from a TII really isn't an option since it goes behind the dash, into the engine bay & all the way around the front of the car. Modifying the NA EM harness is much easier.
On the engine side, get a S5 TII TB and TPS, get S5 TII injectors and a S5 TII front cover and OMP. Use the S5 TII AFM & boost sensor. You would basically just be using the S4 TII block, manifolds and tranny. All the sensors should stay S5 to avoid making new plugs & running new wires. You really will want to keep all the electronics S5, and use mechanical only parts from the S4 motor. Also, keep the PS pump and AC from your S5 NA setup.
Lookup the threads on using an NA harness on a TII motor to get the details, as well as downloading the FSM wiring diagrams.
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07-04-08, 02:27 AM
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Okay, I'm starting to wonder if this is above my head. I've done plenty of engine swaps but this rotary is pretty new to me. I ordered an S5 motor from the importer but got the run around when I tried to tell them they sent me the wrong engine because I had already started to crack it open for the rebuild.
I think I'll look into the Haltek like you guys said. But I have already sourced an S4 Harness. What kind of issues should I expect if I attempt to swap in the S4 motor with all of the S4 components, the S4 ECU and EM harness into my S5 car? I realize it won't be plug and play. Thanks guys.
I think I'll look into the Haltek like you guys said. But I have already sourced an S4 Harness. What kind of issues should I expect if I attempt to swap in the S4 motor with all of the S4 components, the S4 ECU and EM harness into my S5 car? I realize it won't be plug and play. Thanks guys.
07-04-08, 07:07 AM
#9
the biggest problems would probably be getting all the wires to mate up to the dash/"front" harness. Some of the s4 wiring is less complex than the s5, so I would think that an s4 into an s5 would be easier than an s5 into an s4.
I've never messed with s5 harnesses, but on the s4 there are 2 big plugs that connect to the "front" harness (which goes throughout most of the car). Since you will have an s5 front harness, and nonturbo to boot, you will probably have to cut off the plugs and solder 50+ wires or figure out some other way to make sure those two plugs match up.
But nobody uses the JDM turbo harness, it's too much of a pain in the *** because it is designed for a RHD car. You need a US spec s4 nonturbo harness, and then normally there is only a couple wires to modify to make it work on a turbo engine--but that's if you already have an s4 front harness. So you will have to mate an s4 emissions harness (that's the "engine" harness that has the fuel injector plugs etc) to an s5 "front" harness. You cannot swap in an s4 front harness, it won't work, and removing a front harness requires you to essentially gut the car.
I've never messed with s5 harnesses, but on the s4 there are 2 big plugs that connect to the "front" harness (which goes throughout most of the car). Since you will have an s5 front harness, and nonturbo to boot, you will probably have to cut off the plugs and solder 50+ wires or figure out some other way to make sure those two plugs match up.
But nobody uses the JDM turbo harness, it's too much of a pain in the *** because it is designed for a RHD car. You need a US spec s4 nonturbo harness, and then normally there is only a couple wires to modify to make it work on a turbo engine--but that's if you already have an s4 front harness. So you will have to mate an s4 emissions harness (that's the "engine" harness that has the fuel injector plugs etc) to an s5 "front" harness. You cannot swap in an s4 front harness, it won't work, and removing a front harness requires you to essentially gut the car.
07-04-08, 04:00 PM
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Okay. So this is as big an issue as I initially thought. What about stand alone? Haltek uses it's own harness I take it? I see Mazdatrix sells it for around $1450. I see how that will run the engine, What about the dash and everything else? Would it make sense to pull the dash and fabricate my own guage cluster? I'm no stranger to that.
07-04-08, 04:44 PM
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naw, if you go haltech, you just work with the wiring they give you, its pretty simple. no new dash harness needed.
not to mention youll get better gas mileage, more power, and youll be able to tune via laptop whenever
not to mention youll get better gas mileage, more power, and youll be able to tune via laptop whenever
07-04-08, 04:48 PM
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Excellent Haltech it is then.
LOL Anyone need an S4 or S5 Turbo II EM harness?? If it simplifies things so much, why doesn't everyone go with Haltech for thier swap?? I see a lot of RX7s on Craigslist and such with a Turbo II swap half done.
And myersprostatus, When you say there is no need to swap dash harnesses when using the e6k, Does this mean I won't need to mess with the front harness from the driver side firewall? In your opinion should I just leave the S5 NA front harness in the car and use the S5 breaker box etc...?
My last tuner was a 511hp STi so this really is a new animal to me. Sorry if I sound needy but I am at this point. Obviously I'll do some reading tonight.
LOL Anyone need an S4 or S5 Turbo II EM harness?? If it simplifies things so much, why doesn't everyone go with Haltech for thier swap?? I see a lot of RX7s on Craigslist and such with a Turbo II swap half done.
And myersprostatus, When you say there is no need to swap dash harnesses when using the e6k, Does this mean I won't need to mess with the front harness from the driver side firewall? In your opinion should I just leave the S5 NA front harness in the car and use the S5 breaker box etc...?
My last tuner was a 511hp STi so this really is a new animal to me. Sorry if I sound needy but I am at this point. Obviously I'll do some reading tonight.
Last edited by Turbocharged94; 07-04-08 at 05:16 PM.
07-05-08, 06:46 PM
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i believe you can drive it to get it tuned, but do not step on it.
im still using my N/A harness and although im still in process of installation everyones tellin me i can use the n/a harness so im pretty sure youll be fine.
but then again I am using an E8, if you want all the info down to the slightest detail there is a haltech forum on this site. its under engine management systems.
im still using my N/A harness and although im still in process of installation everyones tellin me i can use the n/a harness so im pretty sure youll be fine.
but then again I am using an E8, if you want all the info down to the slightest detail there is a haltech forum on this site. its under engine management systems.
07-08-08, 02:18 AM
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Okay here's where I'm at. Since splicing an S4 TII harness into an S5 NA car is rediculously complicated I did some searching and found a Mazda salvage place that has a complete set of S4 Harnesses uncut already removed and ready to go. Everything except for the EM harness wich I already have.
Would it make sense (Since my car is almost completely gutted already) to just rewire the car as an S4? I realize how time consuming this will be but even with Haltech it seems like the splicing of the EM harness into the front S5 NA harness is just asking for problems and an engine fire.
What do you guys think? The price for all the harnesses is pretty reasonable in my opinion. 300 for everything right down to the dash harness and rear lighting harness. Everything is there.
Would it make sense (Since my car is almost completely gutted already) to just rewire the car as an S4? I realize how time consuming this will be but even with Haltech it seems like the splicing of the EM harness into the front S5 NA harness is just asking for problems and an engine fire.
What do you guys think? The price for all the harnesses is pretty reasonable in my opinion. 300 for everything right down to the dash harness and rear lighting harness. Everything is there.
07-31-08, 01:06 PM
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Okay guys I've run into a new problem.
I have aquired all the S4 Turbo II harnesses I will need including all complete front harness and resister pack, etc...
While installing the S4 TII EM harness I realized there is no plug for the crank angle sensor. However it does exist on the engine electrical harness. The thing that has me confused it that the origional JDM EM harness that came with the engine has the CAS plug bundled into it and it does not exist on the engine electrical harness.
Does this make sense to anyone?
I have aquired all the S4 Turbo II harnesses I will need including all complete front harness and resister pack, etc...
While installing the S4 TII EM harness I realized there is no plug for the crank angle sensor. However it does exist on the engine electrical harness. The thing that has me confused it that the origional JDM EM harness that came with the engine has the CAS plug bundled into it and it does not exist on the engine electrical harness.
Does this make sense to anyone?
07-31-08, 04:22 PM
#19
To directly answer your question, you would plug the electrical/engine harness into the front harness and the EM harness into the front harness at the two big plugs I mentioned. Look at the wiring diagram for the ECU in the s4 FSM, it shows how the CAS wires are routed. Forget about anything JDM. your JDM harness is useless except if you need to cut some connectors off it or something.
And honestly, I don't understand why you would rather take apart the ENTIRE CAR to swap in s4 harnesses when you could have just done the Haltech and figured out the wires to splice near the ECU and such. Besides, you're going to want a standalone eventually anyway if you plan to make any power with this build. The fact that you are asking this type of question about the CAS instead of easily seeing this from the s4 FSM is a bad sign.
Personally, I would rather sell my vehicle and buy an s4 car than do what you are doing. First, you risk breaking much of the interior by pulling it apart. That would bother me, as I hate hunting down interior pieces for a 20 year old car. You will still have to double check many of the wires. You think everything is going to mate up? For example, you may have to figure out injector impedences issues (who says you need a resistor pack? what injectors are you running again?). Plus the idiot cluster pinout is different depending on the model, the radio wiring may be different, the rear harness may mate up but some pinout is probably not the same... the list goes on. You see where this is going? You're in over your head man. I can't predict what electrical gremlins you will encounter going down this road. It may be a lot, it may be a few, but it's not worth risking your sanity... But for your sake I hope I eat my words.
And honestly, I don't understand why you would rather take apart the ENTIRE CAR to swap in s4 harnesses when you could have just done the Haltech and figured out the wires to splice near the ECU and such. Besides, you're going to want a standalone eventually anyway if you plan to make any power with this build. The fact that you are asking this type of question about the CAS instead of easily seeing this from the s4 FSM is a bad sign.
Personally, I would rather sell my vehicle and buy an s4 car than do what you are doing. First, you risk breaking much of the interior by pulling it apart. That would bother me, as I hate hunting down interior pieces for a 20 year old car. You will still have to double check many of the wires. You think everything is going to mate up? For example, you may have to figure out injector impedences issues (who says you need a resistor pack? what injectors are you running again?). Plus the idiot cluster pinout is different depending on the model, the radio wiring may be different, the rear harness may mate up but some pinout is probably not the same... the list goes on. You see where this is going? You're in over your head man. I can't predict what electrical gremlins you will encounter going down this road. It may be a lot, it may be a few, but it's not worth risking your sanity... But for your sake I hope I eat my words.
Last edited by arghx; 07-31-08 at 04:34 PM.
08-03-08, 09:25 AM
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Well like I said this is my first ever mazda let alone rotary. I'm so used to Honda and Subaru swaps that I figured tackling this one wouldn't be too bad. I gutted the interior out in order to change the color and replace the carpets in the first place. I have a complete black interior and new carpets and seats ready to go.
As far as my grogress I have the entirety of the S5 NA wiring out and the S4 TII harnesses almost completely in. Most of my wiring questions I sorted through.
The engine is just about back together, emissions removed, all new fuel and vac lines, new clutch, new motor mounts and drive shaft. The only thing I'm waiting on are the new injectors. (Rebuilt and flow matched stock).
We'll see what happens. I'll see how it runs (If it runs). Then I guess I'll worry about stand alone.
As far as my grogress I have the entirety of the S5 NA wiring out and the S4 TII harnesses almost completely in. Most of my wiring questions I sorted through.
The engine is just about back together, emissions removed, all new fuel and vac lines, new clutch, new motor mounts and drive shaft. The only thing I'm waiting on are the new injectors. (Rebuilt and flow matched stock).
We'll see what happens. I'll see how it runs (If it runs). Then I guess I'll worry about stand alone.
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