RB Run HOT HOT when AC is turn ON

[BlackRB]

Hey yall, recently follow the AC thread here ( zerothread?id=267002 ) from 300plus to hook AC on my S14/RB25det NEO. Everything work perfectly, AC On when AC button is press, AC run cold, Colling fan kick in when AC On. Nothing really seen to go wrong, but some reason my motor run really really hot when AC is ON. On highway goind 70+mph it will get really really hot in about 10mins. Here is what i have done exactly like 300PLUS threat and the follow is not. Same:AC switch buttons at dash and AC Relay wires from S14 F4 plug direct connect to RB ECU AC Switch wire without any other wire interfere in between. Different:1. I wire my Fan AC switch to the + wire at AC relay Switch INSTEAL of the Triple pressure sensor (it kick in everytime when i hit the AC button). Flex fan manufacture AC wire is + not -, so i have to do that way.2. Triple pressure switch is not cut.3. I have no service valve at the High pressure gas line (only pump and vacuum at the Low pressure gas line). Work Cold!4. Dont have the muffler between the Low pressure gas line.

I hope the picture below will help you guys understand what im talking about. Thank alot yall.
Modified by BlackRB at 2:15 PM 6/23/2009

[krayton]

sounds like your ac works.

engines will run hotter with ac, thus cars have an "ac fan" to help cooling the car.

if you have a temp gauge and your overheating. it sounds like your problem is on the cooling side of the engine, not the ac

[Darius]

I think everyone that ends up running AC on their RB-powered cars will have to abandon the stock oil-to-coolant cooler for an external oil cooler. This will relieve a LOT of load on the radiant cooling system and free up some capacity for the AC condenser to absorb.

...or if you're a real hardcore ricer, run an AC duct to help cool the condenser/radiator Has anybody seen the kid with the honda that ran his CAI into the side window so he could blow cold air into it from the AC vent?

[krayton]

^lol...sort of.

i always wondered about using the ac and make a freon type cooler for intercooler.

u know? instead of water to air, r134 to air cooler

[BlackRB]

I have dual 12" fan on my car now and without AC ON I can run the car all day long without heating it up and stay normal at all time. So really thing more like the compressor. BTW when the AC kick in, i can hear it kick it with kinda loud click noise follow ZZZZZZ (4-5second) sound than it stop. So can it be my compressor have LOW or HIGH refrigerant or OIL on it. Please tell me if im wrong. Very new to this stuff.
Modified by BlackRB at 2:10 PM 6/23/2009

[krayton]

your wrong.

the freon u have in your ac system doesnt go into the engine or have anything to do with it.

turning the ac on puts tension/stress on your engine making it work harder because it has to turn the ac compressor. unless your ac doesnt work, then your compressor is fine.

your gonna need to improve your cooling system

keeping the ac system is gonna require a good cooling system. not only does the engine have to work harder to spin the compressor, but the condenser also blocks air flow to the radiator

[BlackRB]

Perfect, I totally agree with you. That is what i was thinking too, if my compressor is bad than it make the motor work harder and overheat easier. BTW NEW UPDATE i just put more lubricant oil in the AC and it immediately eliminate noise that i was describe earlier "i can hear it kick it with kinda loud click noise follow ZZZZZZ (4-5second) sound than it stop". So hope that will fix the problem. But coolant system if def needed too, i agree. Thank alot KRAYTOM.

[BlackRB]

BTW so it is okay not having the service valve on the High pressure gas line?

[Darius]

When you add refrigerant, you need to also check to make sure there is enough oil in the compressor and lines too. krayton - I think this is the "OIL" he was referring to. I don't know how much is supposed to be added with each service, but I think that's part of why the system is vac'd before refrigerant is added. It is to pull all the crap out of the lines including the old lubricating oil.

BlackRB - Yes, it is perfectly fine to go without a high pressure service port. It isn't going to change the way the system operates.

However, it still doesn't make sense that the engine is overheating when the AC is on. The small load that the compressor puts on the engine is negligible... It has to have something to do with your cooling system not being able to handle the additional heat load of the condenser or the AC is running at too high of a pressure. Do you hear the compressor engage and disengage when it is sitting there idling? You said it turns on when you push the button, but does it ever turn back off again?

[BlackRB]

Yes Darius-- I can hear the AC engage and disengage, and i can turn it OFF and ON. It does it job very well just like it suppose to, FAN and AC. I think this is my problems is that i DONT have OIL cooler, HAVE stock radiator, only have it the Flex Dual 12" Fan to cool of the motor. BTW Does is matter if i dont CUT any wire from the Triple Switch. My Fan AC wire is positive not negative, so i connect to the AC relay and it work perfect, turn on every single when AC button is press. SO i leave the AC Triple Switch along without cutting it. Please let me know. Thank

I didnt cut anything of from the triple switch. I dont know if the black wires in it needed to be ground it or what.

[krayton]

ac puts a good amount of load on the system. when i had mine it overheated at first too.

but who did your freon? i do acs and theres a set amount of oil and freon that you need to put in your system. not doing it right can F your system. and not putting oil or the wrong amount will damage the compressor

also did you evac and vacuum the system and what not? a good ac place can properly set up your system. alot of procedures you have to follow. and im confused, do you not have a shredder valve on the high pressure side?

[krayton]

and is your guys wiring like pressure switch all hooked up correctly? the ecu neds to be able to turn the compressor on and off so it doesnt destroy itself

[eh?]

What kind of oil did you service it with? I think nissan uses some version of pag but which kind I don't know for the r33.

[BlackRB]

Krayton ---I follow the thread the post by 300Plus, by wire three wires together. AC button at dash and AC relay wires of S14 F4 direct to the ECU AC switch that all. The triple i leave them along, didnt not cut it or anything. FOR oil, i readed in the service manual of s14 not rb (i cant fine it in then FSM) and it need 2.5oz on compressor and 2.5oz on evaporator, but using PAG type oil. The guys the bump my AC did Vacuum the system out or already. I also double check the belt on the AC it seen to be VERY tight (this from the old Owner) so i'm untight it alittle and just but more oil and hole it work.

[BlackRB]

EH? thank for checking in. IT been a while i didnt get help from you LOL. YES EH? i use the PAG type hope is works.

[BlackRB]

Krayton---- My ECU didnt turn the AC ON and OFF by it self, i dotnt think. CAN YOU PLEASE show me to do that. THank ALot

[s14derrick]

stock radiator on an rb? maybe try upgrading to an aluminium radiator. add an air diversion panel maybe?

[Darius]

You dont have an upgraded radiator?!

[Carl H]

upgraded radiator is a must with these swaps, and fans capable of airflow is even more important...ideally if you're still on the stock radiator you should be able to squeeze the stock clutch fan in there...that will help out with cooling alot.it also sounds as if you're bypassing the ecu, which the ecu should be in command of the ac relay not the ac control...the ac head unit is for signal only, the ecu decides then to give the go/no go signal to the relay based upon throttle position and coolant temp, over 100*c water temp the ecu will cut the ac and at full throttle the ecu will cut ac.

[BlackRB]

No Sir Darius, I been running with stock radiator for about a 1-1/2 years now without a problem. Always stay normal temperature.

[BlackRB]

CARL H, i just follow the thread up here to hook up my AC. I dont have a knowlegde what so ever about AC. This is what I understand from our member, 300PLUS (sorry i'm not try to blamed anyone, I take consequence for my action), just connect the AC Dash Button + AC realy (to ECU) wires from the S14 F4 plug directly to the RB AC switch signal ECU without other wires interfere. The ONLY thing that i didnt do like 300+ advice was cut two wire out of the Triple Switch, that it. CARL H, i think you are right about ECU turn AC ON and OFF at certain temperture. Please help and show me how to rewire AC on my RB25 NEO motor im burning out there .

[Darius]

Buy a new radiator. The stocker is not able to handle all that heat. A regular old Koyo aluminum should do the trick for a couple hundred bucks.

[240z4u]

Yeah, you have had a stock radiator for 1.5 years but have you had a/c all of that time? I don't think you understand how much hotter the air is that goes through your radiator after it has hit the a/c condensor.

I did a mishimoto rad swap last year, and need one fan instead of two to manage the same coolant temps. Worth every damn penny!

[BlackRB]

I'lll try to work on that <Darius>, but i have this car as my hobby not for racing or competition and cannot affort that much now. MY stock shock blow out on me for few week now and still dont have money to fix it. I understand that if i dont get a good radiator in there than i might overheat my motor and that something I want to avoid. That for the advice.

[BlackRB]

100% agree <240z4u> i will try my best to work on it. thank

[BlackRB]

According to <Darius> is perfectly fine for not having the Service Valve at the High-presssure gas line. COOL perfect.

NOW, can anyone please help me on how to wire AC on my S14/RB25det NEO without having to bypass the ECU. I have use the three wire method that i have describe above. If anyone could please help find a way to wire the AC so it can control or signal by ACU to turn AC ON and OFF at certain temp or pressure. I would greatly appreciate. Thank yall

[eh?]

EH? thank for checking in. IT been a while i didnt get help from you LOL. YES EH? i use the PAG type hope is works.

I was wondering what you were talking about but then I looked up the previous thread

I was actually asking Krayton which oil he uses since he says he works with a/c. There are different pag oils and I'm not too sure if they are all compatible. I actually just did a compressor on another car and used ester oil and it seems to work well. I hope I didn't screw it up.

[BlackRB]

Eh? In the nissan manual just say that we need to use PAG oil with type S, type R ect... depend on what compressor you have, but i think you cannot get it in the nissan dealer. I have call several Nisssan dealer and they dont carry it, so they sent me to auto part to get that oil and told me that should use PAG 150 viscosity, but it ok if you have PAG 100 and MIX with 150 viscosity it just the weight different. i put Interdynamics OIL PAG MED VISCOSITY (100vscosity) and they ran out of the 100 at where i bought it so i add 150 to it. It does help alot on the noise that i had described earlier in this thread. I have confirm this to one other AC guys i know and them both told me the same thing. so according to the information i gather from the dealer and the AC guys, as long we use PAG oil for our condition we should be fine. I hope that would help Eh?

NOW please someone show me how to wire my AC correctly

[Darius]

I can't remember who said it to get you confused but the ECU does not control ANYTHING with the AC. Burn this into your brain.

The ECU simply responds to the grounding of the circuit at the AC button in the climate control unit.

The AC compressor and pressure inside the system are controlled by the triple pressure switch which is inline with the B/P wire and coil side of the AC power relay. When the system pressure is between like 50-300 psi, the tps closes the B/P circuit to ground which grounds the coil side of the AC relay and closes the relay for the 12V power to the compressor. When the pressure gets too high or low, the tps opens the circuit which opens the AC power relay and the compressor disengages. Does this make sense?

The temp in the cabin is controlled by the fan speed. I'm not sure what Ramius83 was talking about in the original AC thread from about 6 years ago, but I'll look into it. I'm almost certain that nothing will change with the way 300Plus and I have told you to wire it up.

[BlackRB]

Thank Alot for the help Darius. Yes I understand what you are saying now and YES i have wire the AC using three method exactly to what 300plus and you are using. The ONLY DIFFERENT about my wiring is that i DONT CUT tow of the TPS wire (one go ground and one go to fan). I have leave all that wire uncut. Do you think that might be the issue? Thank