I know this is a topic that has been discussed before, but has anyone actually done it with success?, and have any photos of how they did it.
This would allow better airflow into the Radiator
My idea is to lay the A/C condensor down flat on the under tray ( Alloy undertray ) and allow it to vent out the bottom through a mesh grill, and then mount a fan on top of it to blow air down through it.
I realise this involves a bit of new pipe work for the A/C system and having to regas it as well.
This would be useful for people who use their car on the track and or are turbocharged.
From what I see so far, most people seem to be happy to either add an extra radiator or look at V mounting or other setups, but as yet I haven't actually seen anyone move the A/C condensor.
I look forward to your views.

Rotaman

 

Ok
Looks like no one has done this modification or is not prepared to comment.
So I went ahead and did this modification myself.
First I removed the aircondensor off the front of the radiator,( as I personally think the most restrictive part of the cooling system of the RX8 is the angle they have mounted the radiator/aircondensor and the fact that the aircondensor has very small fins and doesn't allow good airflow into the radiator.)
I then made up some mounts so I could lay the aircondesor flat on a new alloy undertray that I made out of 2mm alloy sheet.
I had to get one new hose made, thats the one that goes to the aircond pump. The other smaller solid pipe I just reshaped to make it fit.
I also had a air deflector made up to mount off the back of the intercooler, so it would direct air straight up into the radiator. This gives the radiator a more direct flow of air.
I mounted two ten inch fans onto the face of the aircondensor and they blow air down through and out via the bottom under tray.
At the moment the fans come on when I turn the aircond on. But I think I will mount a temperature probe on the face of the aircondensor so the fans come on only when the aircondensor reaches a set working temp, which I'm lead to believe is around twice ambient temp.
Anyway you will see by the photos, what I have done.
So far everything seems to be working well, infact I will probably have to replace the 76c thermostat that I have currently been running and fit the factory 82c thermostat back in place. As sometimes its running too cold.
At a later stage I will still probably replace the alloy radiator that I'm currently using with a better quality one, just so if I decide to use the car on the track at all, it will help keep the temperature stable for longer.
















Hope this is helpful for anyone that might be interested in doing the same thing.

Rotaman

 

Looks like it should work OK....only problem is the reciever is along the one side and it might not like being horizontal? How does it work? That's basically the proof

 

It seems to work pretty well, and I talked with the air conditioning specialists first, and they didn't seem to think there would be a problem having the aircondensor laying flat.
I guess the real test will come when summer comes around again.
But so far so good.

Rotaman

 

you know the problem is actually the size of the condenser and the GARBAGE R134a that we use.

 

I'm guessing you mean the size of the condenser is too big to allow good flow into the radiator?
And I must admit I don't know what R134a is?, but I guess its the gas that is put into the condenser.

Rotaman

 

very neatly done and congrats.
I have also spoken about how I think that thing is very restrictive. It has to be.
I did move mine out away from the radiator approx 1 inch and that --I think--actually helped a little.
Fans pull better.
Again nicely done. results in coolant temp differences?

 

olddragger
I'm sure you are right about fans pulling being better, but unfortunately there isn't that much spare room to mount them anyway else.
As for coolant temp differences. On average about 5-10 degrees C ( 41-50 F ) lower at normal open road conditions.
So far I've seen the temp as low as 74C ( 165.2 F ) which I think is too cold, this was under no load going down hill, and as high as 96C ( 204.8 F ) which I still think is a little warm, and this was under boost going up a long hill.
The average temp seems to sit around 80-86C ( 176-186.8 F ) on the open road, thats with ambient air temp sitting around 18-20C ( 64.4 - 68 F ).
Although I did find once the ambient air temp dropped down to 16C ( 60.8 F ), I struggled to keep the cars temp above 76C ( 168.8 F ).
Our season over in NZ is now Autumn ( Fall ), so our temperatures are starting to drop a little. I will really have to wait until summer comes around again to really see how well this setup works.
Ideally I would like to be able to have the car run at between 85-90C max ( 176-194 F ) and I think I will be able to achieve this once I replace the radiator I'm using at the moment, with one I'm going to have made. Only I'm lacking some spare dollars at the moment.
Hope this is helpful

Rotaman

 

Bravo, and well-done! Benefits both systems.

 

yep, r134a is the refridegrant inside the system. some people calls it a freon but thats just wrong.

someday i going to clean everything and recharge the system with something else, maybe freeze 12 kind of thing, it requires less pressure and cools better. dunno yet. for those who dont know freeze12 is a mix of gas, majority of it its still r134a but it cools way better. well this is not on the top of my mods list so ...

 

How did you go in the summer months with this mod?

I would have thought that venting the under tray would have given a path of least resistance for the air to flow through. Thus less air through the radiator.

However, you cant argue that you have now freed up the radiator for better air flow. I do not have any issues in daily driving however, this mod will be useful at the track if I could block off the grill on the under tray for track days thus forcing all the air through the radiator.

 

Hi skc
Summer came and went and it all seemed to work pretty well. Certainly didn't have any problems with anything getting too hot. In fact I ended up changing the thermostat again, as with this setup the car was running to cold for daily driving.
Previously I had fitted the Mazmart thermostat, but I changed back to the factory one.
I have changed a couple of things and that is I have added a air deflector in front of the air condensor mounts, so that the air flow doesn't hit a turbulent object, and the airflow is directed up into the radiator area.
Also I have removed the air deflector from behind the intercooler, to see how much difference it makes.
I'm just in the process of fitting an intercooler spray system, which will be controlled by an intelligent control circuit, and will use a very small high pressure pump, able to pump up to 200psi.
I think your idea of blocking the undertray would be fairly easy to do, just make up another flat plate that covers the vented grill area, that can be bolted up and unbolted quite quickly.

Rotaman

 

This looks awesome! Good work!

This should be moved to the DIY or make it a new DIY thread with a few more details for easy searching. This will now be added to my FI list of things to do.

 

ITs a useless mod.

 

nycgps, you are welcome to comment, but if you have something to say, at least have the decency to back up your comment with some facts of why you think its a useless mod.

Rotaman

 

because it's not the front of the rad that's the problem, it's the back, there isn't much room to move the air away.

need me to take the airbox away to proof my point ?

I can get the stock coolant temp down to your level WITHOUT any mod,even lower in some case.

oh, there is a reason why I changed my radiator 3 times, played with different setups 6-7 times, and drain my coolant at least 20 times.

you are just so many years late.

You're more than welcome to keep trying, you might find something one day that I haven't yet try, friend.

but until then, it's useless.

a better idea might be to try to move the radiator forward, but there isn't much room. or just keep the condenser as stock and move the radiator to the lower part of the car. so the condenser gets more back room, and the rad will cool faster, but good luck trying to mount it.

 

I have run my car with and without the cover over the fan and not noticed any changes. Removing the deflectors caused the hot air to circulate through the engine bay and heat up my intake air.

However, I believe if you had a vented hood and a ducting shroud to direct the hot air out then it will be a worth while mod.

 

nycgps - you are just so many years late.

This isn't a competition, there is no time limit on how long it takes to achieve what I want to achieve.
I'm also quite aware of the limitations of air flow through out the engine bay of the RX8.
My aim is to keep the engine temperatures under control while being turbocharged and also keeping the engine bay looking standard, which is what I've done.

I'm sure there are better ways to achieve the same thing, but some of the other ways would mean my engine bay would not look standard anymore.

So all in all, it isn't a useless mod at all, it just doesn't serve the purpose of helping you obviously.

Rotaman

 

It makes sense to me that this mod will be beneficial . However , it would have been really good to have done some before and after tests under load ...................... So that the theory is backed up and we can all benefit .

 

With a larger, thicker dual pass rad this mod cannot hurt, especially for you guys running stock radiator fans. The larger FAL dual shroud was the best cooling mod I have purchased hands down. But the condenser has to be restricting flow to some degree.

But for me this would not be necessary since coolant temp problems are a thing of the past for me even in 95F weather being turbocharged.

 

Although I don't have any hard data, I have two large long hills that I have to drive up when I'm traveling to Auckland.
Prior to this mod being done, the water temps were getting up to over 100C (212F) going up these two hills.
Now after this mod, the water temp going up the same two hills is only getting up to around 95-96C (203-204F).
This is under load in any gear from 4-6th gear at over 100-120kph +.

I must admit that I still need to replace the radiator that I'm using with a better one.
A dual pass radiator is what I intend to use when I do change it.

9K what brand of dual fan setup do you have now?

Rotaman

 

I am running the FAL 420 dual fan setup, 2690 cfm IIRC, Hoss-05 is running the larger 3000cfm 440.

 

I can't find any difference between the 420 and 440, FAL website states they both are rated at 2500cfm, and are the same price.

Does anyone know what the difference is besides "maybe" different cfm ratings?

Thanks

 

Give them a call. The fan motors on the two are totally different and much larger on the 440. I'm not sure why many of the sites that have them for sale list the wrong pics and specs. Either way, I have the 420 and it works just fine and I am in south Texas and turbocharged. Even in heavy traffic in 95F heat for an hour with the AC on blast my temps never get above 215F even with driving hard under boost and then getting stuck back in traffic. My turbo is water cooled so it adds heat to my coolant as well.

480/490



410 (VSC), 412(Adj. Thermostat, A/C Relay), 420 (just fans, no comtroller)

 

isn't this somewhat similar to what the FC guys are doing / did back in the day with their V mount intercoolers? I remember the big thing was making sure you had proper baffling around the air inlets on the front splitter to help direct the air where you need it to go.