A/C condenser Questions
 

I'm trying to find out whether I can change my car's a/c condenser for a slimmer version.

Here's the reason: After much hassle with the coolant temps I'm at a point where I'm totally satisfied with my car's coolant temps when the a/c is not in use. The only thing that messes with this total bliss is when I turn on the a/c my coolant temps begin to climb. That is totally due to the hot air blowing from the condenser so I'd like to get a slimmer one. Does anyone have any suggestions about where and from what brand of vehicle I could buy one?

Thanks

You can run any condenser you want for the most part. Of course it will also impact the efficiency one way or another. When you say thinner, you actually mean shorter? The Miata condenser is quite thin, but I don't know that I've seen any thinner (or thicker for that matter).

What I'm really wondering is why you have this problem, and I haven't seen anybody else mention overheating when the AC is on. Or have I missed it? I mean- if you're not in boost, then the only thing impact your exchangers is the air flow blockage of the intercooler- correct? Because the car comes stock with a radiator (which your's is upgraded) and the condenser. And it didn't overheat before the intercooler, correct? Just trying to get an idea of what's really causing the problem.

duct your heat exchangers and the problem will go away.

It's that crazy Caribbean heat.

Thanks for the help Rob. Let me try to clarify what I'm saying.

I do mean shorter. Not thinner.

The car tended to overheat before I even thought about boosting it. In fact, I blew 2 head gaskets due to overheating.

The thing is: the car doesn't overheat even when in boost when I'm not using the a/c. This leads me to believe that the overheating (I think it's not really overheating, rather running hotter than normal) is due to the extra hot air coming through the engine bay which is blown in by the a/c condenser when the a/c is on.

Another thing Rob; fwiw, I'm running the car without a thermostat. I've been doing so for over 4 months now. Artie is dead on about the oppressive heat down here. My autometer gauge reads a constant 180 to 190 degrees at all time. As soon as I turn the a/c on it starts to climb. When it reaches 210 degrees I shut the a/c off. I have also logged the coolant temps in my AEM to confirm the temps and they read the same as those I mentioned before.

Another thing that happened yesterday is what lead me to start this thread. I'm using a pair of flex-a-lite fans. One of them broke and immediately I started seeing coolant temps at around 195 to 200 (without a/c on of course). This lead me to conclude that the fans where doing the job (meaning they were really taking out the heat as they are supposed to do) and the higher temps are due to the additional hot air being blown into the engine bay by the a/c condenser. If I'm correct, then maybe I need a shorter condenser (I mean one that doesn't block off most of the radiator). I've also been thinking about changing the angle of the next condenser so as to try to blow that additional hot air towards the ground (I'm thinking about placing it at a 45 degree angle facing downwards).

Thanks for your input. It's always much appreciated :bowdown:

Try Hustler's advice first, as it involves the least hassle and is the least expensive option. Make sure your undertray is in place and then block off any exit that air entering the mouth of the car can take that isn't through all the heat exchangers.

If that doesn't work, you can try a coolant reroute (http://www.flyinmiata.com/index.php?...0%20%201990-93). I'm not sure if you're still running a stock radiator, but if so you can also try changing that out for a bigger aluminum unit.

You should be able to get the problem licked without resorting to changing our your condenser.

Here in Ontario, Canada we have to run a front license plate. I've found on highway runs in mid-summer with high humidity on any kind of an uphill my 6psi boost supercharged 2000 overheats with AC on. I have no IC either. My plate was in the mouth and moving it removed the problem.

We don't have to have the front plates down here and I'm using the Racing Beat Type II front bumper so I have plenty of air coming through but your problem sounds similar to mine. Your issue may also have to do with the a/c condenser blowing additional hot air into the engine bay.

Hunter; thanks for the help.

I don't have an undertray (the guys at the shop where the turbo was installed lost it). I can't find one locally.

I have an aluminum radiator. Actually, this one is the second one. I had a PWR that took a crap and now I have a Mishimoto.

I have the coolant reroute. I'm happy with how it turned out. What really bugs me is the fact that my car is running perfect temps when I don't use the a/c! :bang:

I'm 56 years old and average temps down here (during the day) are around 90 degrees with very high humidity all year round. If I have to drive a car without a/c I'd rather sell it.

Tell me about it. I actually added A/C to my car when I had the built engine/big turbo installed (Canadian cars generally didn't come with A/C in the nineties). Now I need to figure out why it only blows cold on fan settings 1 and 2 :vash:

I have an FM rad, the coolant reroute, a custom duct feeding air to the rad and an undertray. On my last road trip, driving through Montana with ambient temps in the 90s, my coolant was at about 200F with A/C off and 225F when on. My next step is to block off all air exits, but I haven't gotten around to it yet. Solutions to problems like this seem to require several detail steps that eventually get it licked.

You are confirming my suspicions. In your case; (as in mine) that extra heat being blown by the condenser is disrupting the temp balance inside the engine bay. I like the shorter condenser option. I'd like to hear Rob's take on this.

With regards to your fan settings: do settings 3 and 4 blow air at least? I ask because my wife used to have a Nissan Sentra which started showing a similar problem (hers would only work in settings 1 and 3) and she had to change the controller.

I can probably find you one Rafa, but how much would it be to ship something that large down there? The undertray has sides to it too which make it a little higher. Another option would be to get one of the beatrush skid plates to help with moving the air thru the engine bay better. It's not cheap, but it might help. And it's perfect if you decide to go out of the city =) http://www.gomiata.com/mibealunpa19.html

I dont remember, but do you have Turn Signal Intakes? Those can disrupt the flow of air too. What about the radiator cover on top? It goes between the bumper and the radiator? You're car should've came with one.

Also, how do you have ur cooling rerouted now? I remember there being a thread somewhere about it, but I'm really late to start work today so I dont have time to search. You dont have a heater core right?

If turning the AC on was causing the car to overheat stock (pre-turbo instal), then something else is wrong, probably with the AC system. Besides bursting risks, an improperly charged AC system can cause excessive heat. Have you had the AC system checked/serviced? Does it run hot at speed and at idle/stopped?

You could be right. It runs perfect most of the time. Sometimes it doesn't but there's no established pattern. I thought it had to do more with some heatsoak at the AIT sensor and the AEM readings. I'll doublecheck that.

I had the a/c system checked by a mechanic not too long ago because I had water accumulating inside the cabin (by the feet of the passenger). Of course that had to do with the draining. That was fixed and now it drains to the street.

Both threads about my coolant reroute: https://www.miataturbo.net/diy-turbo-discussion-14/yet-another-coolant-reroute-pics-23314/

and https://www.miataturbo.net/general-miata-chat-9/facing-temp-issues-need-some-assistance-36650/

Hey Artie! You're right about shipping being too expensive but I like the beatrush undertray pic. I think I can have someone local do something similar.

I do have both my OEM turn signal intakes. I'm missing the radiator cover too :bang:

I blocked off my heatercore portion.

Say hi to Paul from me.

You rock!

Yes, 3 & 4 blow air, just not cold air. I'm not that familiar with the A/C system, so where is this controller I should check?

I still think you should manufacture an undertray (the Beatrush skid plate won't easily fit with intercooler piping, I would think) and top radiator cover before going to the trouble of changing your condenser. Easy things first, I always say.

So the AC turned on causes it to overheat at speed and stopped/idling?

I just thought about that. I'll check and get back to you.

I've never used my AC since the turbo (blown fuse or something) but I have it and it's interesting to see other Canadians (and Rafa) with FI and AC are having the same ridiculous heat issues I am. I'm wondering if my car will simply melt when I get the AC working again.

Could the humidity have something to do with it?

I doubt it. Humidity makes things seem hotter to us since we depend upon the evaporation of perspiration to cool us down. Machinery won't care.

Do you guys have an extractor of any type in your hood? It worked absolute wonders for me both stopped and at speed- all in the cooper scooper thread.

get some good ducting in there, get the radiator cover up top, put an undertray in (OEM undertray not only protects the moving parts up front, it is also designed for, and is VERY effective at forcing more air through your radiator while moving) and make sure that both of your radiator fans are quality pieces and are working properly.

I don't know in the case of the Miata but in her car it was right behind the a/c buttons. I think your case is totally different because your blows air on the 3 & 4 positions. If I had to guess I would say your a/c is somehow disconnected when in those positions. It sure is weird.

Rob, I haven't been able to check what you asked (I'm waiting for a spare spal set).

I spoke to a local drifter who races a Sylvia and he told me his car used to overheat and the hood scoop he installed has made all the difference in the world. He even told me he's going to install the thermostat back because his temps are too low.

One thing I'm noticing is that temps (even with 1 fan working only) are low. The only thing we did was take all the coolant out and put some coolant in and bleed the system thoroughly. I'm starting to think that part of my problem was air in the system.

I can't try the a/c yet but as soon as I put in the new fan I'll try it and get back to you.

Many thanks again for your assistance :bigtu:

I love my flex-a-lite fans. They've made all the difference in the world. BTW, those are the 3rd set of fans I try in my car.

I've tuned my car for coolant temps. What I mean is that even my spark map has been tuned for the lowest coolant temps possible and not for the most hp.

In my particular case, the undertray would be as expensive (maybe more) as a hood scoop. I'd rather try the hood scoop but thanks for your input.

BTW, I found out I do have the radiator cover on :bang:

Ok Rob, I just went out and tested it. It overheats at speed (the Autometer gauge will climb and read 210) and it goes down to 195 when stopped and idling for 3 or 4 minutes. It won't go down any further.

I think I have to try the hood scoop.

Then I think it's airflow/pressure. You need to make sure that the mouth is sealed up good and install a belly pan- which will reduce the underhood pressure at speed.

Sorry to ask but; you don't think the hood scoop would have the same effect?

BTW, as usual many thanks for your help :bigtu:

I owe you

The hood EXTRACTOR would- it would reduce pressure at speed AND vent the heat under the hood whether the fans were running or not. That's what I've seen. But I wouldn't start messing with a hood until you've addressed the sealing of the mouth and the undertray - if only in the interest of time/money. You might find that those two things fix the problem. The undertray is a BIG component in effective cooling at speed. I ran a stock Miata w/o it and at 100mph the started to look like it was ballooning. That's a lot of pressure on the wrong side of the exchangers, not to mention a big boat anchor to drag.

Got it.

Thanks Rob.

Running without a thermostat will cause the coolant to cavitate under high rpms. I bet you'll see steadier temps if you atleast run a gutted thermostat.

O RLY?

Define cavitation, then after you've looked it up you'll know why what you said doesn't make sense.

(hint, it has to do with speed of impellers, not water)

Edit: Granted, I'm certainly not saying that removing the thermostat is a good idea. I don't think it is. I just highly doubt the water pump is spinning fast enough to cause cavitation.

Hey, I could be wrong too.

A dentist can fix that cavitation.

So Rafa should just see his dentist and it should work itself out? :laugh:

I guess I should :laugh:

I'm not really sure what you don't understand about my statement but it sounds like the OP is having trouble with high temps at higher rpms and not at idle when the water pump is spinning relatively slowly. He could try gutting a $7 thermostat... or not. I'm not sure if it'll help, just trying to knock out the simple stuff first. I'm sure sealing every seam in the nose or getting a new hood/fabricating a scoop is easier though.

I would never run without a thermostat. A properly functioning thermostat will not cause a car to overheat.

An unsealed bumper mouth will contribute to overheating much more quickly. The sealing helps to keep the hot air from circling back around through the radiator again and again. It only allows cooler air from out in front of the car to enter the radiator and not hot air from under the car. The sealing also promotes a lower pressure area behind the radiator than in front of it which aids in airflow through the radiator when moving. Mazda didn't spend all of the money and time designing, building, and installing all of that plastic for no reason. They are far too cheap than to waste resources on something that wasn't necessary.

Sorry man; I think I did not make it very clear. I'm facing high temps issues not at higher rpms but at higher speeds and only when I have the a/c on. If I turn the a/c off temps won't go past 180 degrees at speed.

Thanks for your input anyways.

Shooter, you know I like your advice and usually follow it but in this case these past 4 months have been hassle free when it comes to coolant temps without a thermostat. Care to expand on the reasons for not running without a thermostat?

I hear what you say about sealing the front bumper of the car but I've read some threads about it and I'm not sure I could do a good job and I think the hood scoop will be easier to do (at least down here).

Thermostat keeps the water from passing through the radiator too quickly. Better cooling.