If A/C works in s13 why not S14
If A/C works in s13 why not S14
I was thinking that if the A/C can be made to work with the S13 with a RB but does not work with the s14 A/C...how come we can not put the s13 A/C system into the S14, seems like it would work that way. Just wondering what you guys thought of my brain storm.
Whoever said A/C does not work in S14 with RB?
As for putting s13 A/C system into an S14, I assume you mean putting the RB compressor into an S14? There is no reason why this will not work, but you should of course change the receiver/dryer and flush the system if you plan to use R-12. If you are using R-134a, then of course you can use the RB compressor with nothing more than an oil change.
Wiring is cake, btw.
As for putting s13 A/C system into an S14, I assume you mean putting the RB compressor into an S14? There is no reason why this will not work, but you should of course change the receiver/dryer and flush the system if you plan to use R-12. If you are using R-134a, then of course you can use the RB compressor with nothing more than an oil change.
Wiring is cake, btw.
I was talking with a shop and they said it does work in a s13 but in a s14 it will come on but will not turn off, so the compressor will go out. You have to piggy pack the KA computer with the RB computer to even get it to work. There is alot of threads on here about the s14 A/C and the RB motors being almost impossiable to make work. At least I think that is was they meant.
There are zero, ZERO, threads on here that mention someone putting A/C in the S14 and not getting it to work. The reason nobody has A/C is because they either did not want the hassle, or, like me, they wired for it and decided that the compressor mounting, electric fan/FMIC/radiator/condenser mounting, and custom A/C hoses are too much trouble. Maybe I'll change my mind when it gets hot this summer tho...
Actually, I would like to see someone make the piggyback work. That sounds like pure bs to me (although, yes, I have heard that theory before).
Actually, I would like to see someone make the piggyback work. That sounds like pure bs to me (although, yes, I have heard that theory before).
Wulfgang wrote:There are zero, ZERO, threads on here that mention someone putting A/C in the S14 and not getting it to work. The reason nobody has A/C is because they either did not want the hassle, or, like me, they wired for it and decided that the compressor mounting, electric fan/FMIC/radiator/condenser mounting, and custom A/C hoses are too much trouble. Maybe I'll change my mind when it gets hot this summer tho...
Actually, I would like to see someone make the piggyback work. That sounds like pure bs to me (although, yes, I have heard that theory before).
Care to share some insight on how to wire a/c in a s14? All of the stuff I've seen says they are pretty much incompatible. I'm fairly determined to get it to work also. Six years of cars without a/c is enough for me
i asked McKinney about this too. they say that the pigy back will not work properly. the cycling of the compressor is all wrong. I dont quite understand that though. if you use the KA computer for the A/C, use the KA compressor, and keep all your interior stuff the same, there is no reason why it wont work. i am thinking the volumes of the r134 might be important, but i could be wrong. spmeone has got to get it to work right for me to understand what is going on.
what about using the skyline's A/C controles and compressor? any thoughts. i know i need A/C as well for GA/FL. iam a baby, but i like to have it anways.
Ryan
what about using the skyline's A/C controles and compressor? any thoughts. i know i need A/C as well for GA/FL. iam a baby, but i like to have it anways.
Ryan
First of all, do some searching. I have posted how to do the wiring at least 3 times on this forum and there are websites with that info as well, so I won't go into that again here.
As I understand it...
If you have an S14 with R-134a, you should probably use your stock setup. The compressor is a pretty good design and is matched to the evaporator and condenser cores. You will need to modify your compressor mount to make it fit the RB. I have taken a quick look at this, but have not made a mount up myself yet. The mounting holes on the block are offset, which may mean that all we need is a spacer, but I'm not sure about pulley alignment yet. I believe this is the best way to go, though, IF the compressor can be mounted.
But you could also use the RB compressor. It is designed for R-12, but with an oil change and retrofit kit for R-134a, it should work fine. You would of course need the hose ends from the Skyline to make custom hoses, but that's pretty cheap. If it is too hard to get the KA compressor on there, then this is what I will be doing (hopefully the RB compressor I have still works).
The third option is to use the RB compressor with R-12. If you have the stuff lying around, this would be the coldest option by far, especially with a condensor/evaporator designed for R-134a. Still need the custom hoses tho.
Actually, no matter what way you go, you'll probably want a custom low pressure hose. The S14 has it routed right by where the turbo sits, which is probably a bit too hot. Better to make it a bit longer and run it closer to the frame rail.
I guess Dekand and I have both decided to put A/C back in before this summer hits, so someone should have this working within a few months.
As I understand it...
If you have an S14 with R-134a, you should probably use your stock setup. The compressor is a pretty good design and is matched to the evaporator and condenser cores. You will need to modify your compressor mount to make it fit the RB. I have taken a quick look at this, but have not made a mount up myself yet. The mounting holes on the block are offset, which may mean that all we need is a spacer, but I'm not sure about pulley alignment yet. I believe this is the best way to go, though, IF the compressor can be mounted.
But you could also use the RB compressor. It is designed for R-12, but with an oil change and retrofit kit for R-134a, it should work fine. You would of course need the hose ends from the Skyline to make custom hoses, but that's pretty cheap. If it is too hard to get the KA compressor on there, then this is what I will be doing (hopefully the RB compressor I have still works).
The third option is to use the RB compressor with R-12. If you have the stuff lying around, this would be the coldest option by far, especially with a condensor/evaporator designed for R-134a. Still need the custom hoses tho.
Actually, no matter what way you go, you'll probably want a custom low pressure hose. The S14 has it routed right by where the turbo sits, which is probably a bit too hot. Better to make it a bit longer and run it closer to the frame rail.
I guess Dekand and I have both decided to put A/C back in before this summer hits, so someone should have this working within a few months.
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IT could be made to work properly if some one wanted to but in the time to do it! The controls for the ac in the Engine computers are different. the US S14 has a different control system that the S13 and the JDM car''s and the Skylines also, but as I said above it coud be done. The piggy backing of the S14 computer is used by most to fix the problem, but it the idea having to use 2 computer that turns most people off. "rcodea" I must have told you wrong, as the use of the piggy back system will work most of the fuction for the ac, we just do not use it.. Making the system work does require the use of the JDM compressor or a custom bracket, custom lines and proper servicing, but if you need it...
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this is what Wulfgang wrote a few months ago:
Cycle the system? That is not done by the ECU at all. The thermo control amp cycles the system by turning off and on depending on the evaporator temperature. That is true for the RB20 and both the S13 and S14 as far as I can tell. The role of the ECU is to cut the A/C if the driver is demanding high load or if the engine is too hot.
So here's what I can tell. You need to do 3 things:
1. Connect S14 F3 pin 46 to pin 46 on the RB ECU. This sends the thermo control amp signal to the RB ECU.
2. Connect S14 F3 pin 43 to pin 9 on the RB ECU. This lets the ECU turn on the compressor relay.
3. Connect the powered side of the RB FICD to the S14 A/C compressor relay. The Skylines power the FICD thru a relay, but the S14 has it just connected in parallel with the compressor clutch. This connection could probably just be made directly to the relay in the engine bay.
Those pin #'s should be verified since the S14 FSM is riddled with errors, but this is gist of what I believe needs to be done. The triple pressure switch is already integrated into the engine room harness, so no need to worry about burning up the compressor if you make a mistake. The compressor will still shut off if something is drastically wrong.
The RB ECU may also want a signal from an ambient temperature switch. I still need to find out what this switch does, but I think it just shuts off the A/C if the outside temperature is too cold. The S14 has this switch, so that should be no problem if the RB needs it. The S13 does not have it, fwiw.
The S14 ECU also controls the cooling fans based on part of the signal from the triple pressure switch; however, since electric fans are needed anyway, this should not be an issue.
These are the mods I plan to make if I can get the S14 compressor to bolt up. Anyone know if it does?
Shane
So, according to this, and my understanding of what he is thinking about this, it IS possible to use the RB ECU to run the A/C. This would mean not having to use the KA piggy-back set-up that, from what people are saying, will work properly in the first place.
Mack, check on this and see if this makes since to you. as well as anyone that knows exactly how the RB ecu controles the A/C.
well, it seems that we know what is going on, just need someone to do it and tell us after that. Any takers?
Ryan
Cycle the system? That is not done by the ECU at all. The thermo control amp cycles the system by turning off and on depending on the evaporator temperature. That is true for the RB20 and both the S13 and S14 as far as I can tell. The role of the ECU is to cut the A/C if the driver is demanding high load or if the engine is too hot.
So here's what I can tell. You need to do 3 things:
1. Connect S14 F3 pin 46 to pin 46 on the RB ECU. This sends the thermo control amp signal to the RB ECU.
2. Connect S14 F3 pin 43 to pin 9 on the RB ECU. This lets the ECU turn on the compressor relay.
3. Connect the powered side of the RB FICD to the S14 A/C compressor relay. The Skylines power the FICD thru a relay, but the S14 has it just connected in parallel with the compressor clutch. This connection could probably just be made directly to the relay in the engine bay.
Those pin #'s should be verified since the S14 FSM is riddled with errors, but this is gist of what I believe needs to be done. The triple pressure switch is already integrated into the engine room harness, so no need to worry about burning up the compressor if you make a mistake. The compressor will still shut off if something is drastically wrong.
The RB ECU may also want a signal from an ambient temperature switch. I still need to find out what this switch does, but I think it just shuts off the A/C if the outside temperature is too cold. The S14 has this switch, so that should be no problem if the RB needs it. The S13 does not have it, fwiw.
The S14 ECU also controls the cooling fans based on part of the signal from the triple pressure switch; however, since electric fans are needed anyway, this should not be an issue.
These are the mods I plan to make if I can get the S14 compressor to bolt up. Anyone know if it does?
Shane
So, according to this, and my understanding of what he is thinking about this, it IS possible to use the RB ECU to run the A/C. This would mean not having to use the KA piggy-back set-up that, from what people are saying, will work properly in the first place.
Mack, check on this and see if this makes since to you. as well as anyone that knows exactly how the RB ecu controles the A/C.
well, it seems that we know what is going on, just need someone to do it and tell us after that. Any takers?
Ryan
Yep, that's why I think the piggy-back idea is silly. All the ECU does is to decide whether or not to let the thermo control amp turn on the A/C. So with a piggy-back, the ECU always thinks nothing is happening (it has no idea what the rpms are, the load, the engine temperature, etc). Therefore, it does nothing. It simply passes the thermo control amp signal right on through to the relay.
So.... why run a piggy-back at all??? If that is all you want, then why not run the thermo control amp signal straight the A/C relay, bypassing the ECU altogether? If signal buffering is what you are worried about, then put a buffer circuit in the line!
I just don't understand why people want the piggyback, and I have not heard any reasonable reason why it is needed.
So.... why run a piggy-back at all??? If that is all you want, then why not run the thermo control amp signal straight the A/C relay, bypassing the ECU altogether? If signal buffering is what you are worried about, then put a buffer circuit in the line!
I just don't understand why people want the piggyback, and I have not heard any reasonable reason why it is needed.
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