Should I run straight water in my car?
07-08-2019, 01:54 PM
#1
Should I run straight water in my car?
I need to change the coolant in my RX-8 and I bought a few bottles of the FL-22 Mazda coolant/antifreeze. But I've been doing some reading and I'm thinking it may be better to run straight distilled water and Royal Purple's Purple Ice to achieve lower temperatures. I bought his car primarily for tracking usage and I live in Georgia where it rarely gets below freezing. If it does, I wouldn't drive the car anyways and it'll sit in a garage otherwise.
I did my first track session the other day and I was hitting 215-220 temps consistently (about 90 F outside). It runs 180-190 normally on the street.
Any opinions and advice is much appreciated.
I did my first track session the other day and I was hitting 215-220 temps consistently (about 90 F outside). It runs 180-190 normally on the street.
Any opinions and advice is much appreciated.
07-08-2019, 02:06 PM
#2
Straight water shouldn't be necessary. And I wouldn't do it, no idea how well Purple Ice lubricates and protects against corrosion.
Let me copy a post from Steve Dallas on the subject:
From this thread
In short, your temps sound pretty normal to me. If you are really worried about it, there are plenty of ways to truly help you cooling system than swapping to straight water.
Let me copy a post from Steve Dallas on the subject:
From this thread
Here is a re-post of my thoughts on overheating from another thread:
Quote:
I need data logs to remotely diagnose your situation. What you are saying about the temp gauge is troubling, however. It doesn't move from the center until you are already very hot (235F if memory serves). That points to overall inefficiency in your cooling system that could be due to one big failure or several small failures combined. My coolant temp never rises to more than 215F on the track in the hot Texas summer. Under normal spirited driving around town, it never rises much over 195F.
Fans
The fans in this car are known to weaken (slow down) over time. Yours are 12 years old, so they are worth testing for RPM and current draw.
Water Pump
The early water pump design was known to suffer from cavitation at high RPM. Mazmart solved this with their aftermarket Remedy water pump, and Mazda redesigned their pump at some point. So, again, at 12 years old, yours is worth looking at, as it could be the early inefficient design.
Radiator Foam
The radiator should have some heavy foam on the bottom and light foam around the top and sides. The foam is designed to force more air through the radiator at low speeds and allow some air into the engine compartment at higher speeds. Some guys advocate stuffing more foam all around the radiator to force as much air as possible through it. It will lower your coolant temps when the car is moving, but it will also raise your engine compartment temps, which is not good for the rubber and plastic in the engine bay. If everything else is working well in your cooling system, this treatment should not be necessary, IMHO.
Radiator
The proximity of our radiator to the ground means it gets dirty faster than radiators otherwise do in other cars. I have found back-flushing the fins with clean water to be worthwhile. Clean the oil coolers while you are at it. And, be sure to straighten all the bent fins you find in the process.
Thermostat
In a 12 year old car, the thermostat may not be opening completely. It is an inexpensive part that is relatively easy to change. You also have the option of buying an aftermarket 170 degree thermostat that will begin to open 10 degrees sooner to help combat heat soak.
Catalytic Converter
What? Seriously. The cat is prone to clogging and preventing heat from effectively escaping the engine. This can put additional strain on the cooling system. It should be inspected.
If it were my car and my wallet, I would bite the bullet and refresh the whole cooling system just to be sure. I would replace the radiator since it is partly made of 12 year old plastic (an OEM style replacement is only $90), replace the water pump with an OEM unit, replace the thermostat with an OEM or Mazmart 170 degree unit, replace the accessory belts, and flush and replace the coolant with genuine Mazda FL22. I would test the fans and replace if necessary. I would also inspect the cat for any signs of clogging.
I like to run a mixture of FL-22 coolant that works out to 60% distilled water and 40% coolant. You need a certain amount of coolant to lubricate the water pump.
Be aware that this car requires coolant that is lacking certain additives that damage silicone seals. It is best to stick to Mazda FL-22, which doesn't really cost much more than Prestone or whatever anyway.
Quote:
I need data logs to remotely diagnose your situation. What you are saying about the temp gauge is troubling, however. It doesn't move from the center until you are already very hot (235F if memory serves). That points to overall inefficiency in your cooling system that could be due to one big failure or several small failures combined. My coolant temp never rises to more than 215F on the track in the hot Texas summer. Under normal spirited driving around town, it never rises much over 195F.
Fans
The fans in this car are known to weaken (slow down) over time. Yours are 12 years old, so they are worth testing for RPM and current draw.
Water Pump
The early water pump design was known to suffer from cavitation at high RPM. Mazmart solved this with their aftermarket Remedy water pump, and Mazda redesigned their pump at some point. So, again, at 12 years old, yours is worth looking at, as it could be the early inefficient design.
Radiator Foam
The radiator should have some heavy foam on the bottom and light foam around the top and sides. The foam is designed to force more air through the radiator at low speeds and allow some air into the engine compartment at higher speeds. Some guys advocate stuffing more foam all around the radiator to force as much air as possible through it. It will lower your coolant temps when the car is moving, but it will also raise your engine compartment temps, which is not good for the rubber and plastic in the engine bay. If everything else is working well in your cooling system, this treatment should not be necessary, IMHO.
Radiator
The proximity of our radiator to the ground means it gets dirty faster than radiators otherwise do in other cars. I have found back-flushing the fins with clean water to be worthwhile. Clean the oil coolers while you are at it. And, be sure to straighten all the bent fins you find in the process.
Thermostat
In a 12 year old car, the thermostat may not be opening completely. It is an inexpensive part that is relatively easy to change. You also have the option of buying an aftermarket 170 degree thermostat that will begin to open 10 degrees sooner to help combat heat soak.
Catalytic Converter
What? Seriously. The cat is prone to clogging and preventing heat from effectively escaping the engine. This can put additional strain on the cooling system. It should be inspected.
If it were my car and my wallet, I would bite the bullet and refresh the whole cooling system just to be sure. I would replace the radiator since it is partly made of 12 year old plastic (an OEM style replacement is only $90), replace the water pump with an OEM unit, replace the thermostat with an OEM or Mazmart 170 degree unit, replace the accessory belts, and flush and replace the coolant with genuine Mazda FL22. I would test the fans and replace if necessary. I would also inspect the cat for any signs of clogging.
I like to run a mixture of FL-22 coolant that works out to 60% distilled water and 40% coolant. You need a certain amount of coolant to lubricate the water pump.
Be aware that this car requires coolant that is lacking certain additives that damage silicone seals. It is best to stick to Mazda FL-22, which doesn't really cost much more than Prestone or whatever anyway.
07-08-2019, 02:45 PM
#3
^^ +1
Upgrade the rad (not just to improve cooling performance but avoid the stock plastic endtanks cracking and turning the track into a slid'n'slide adventure) + make sure your airflow to the radiator is well managed and you have all the original undertray and other ducting.
How fast is the track you're running? If it's all low-speed turns and traffic, the cooling system has to work harder. Nice long high speed straights help cool things down.
Upgrade the rad (not just to improve cooling performance but avoid the stock plastic endtanks cracking and turning the track into a slid'n'slide adventure) + make sure your airflow to the radiator is well managed and you have all the original undertray and other ducting.
How fast is the track you're running? If it's all low-speed turns and traffic, the cooling system has to work harder. Nice long high speed straights help cool things down.
07-09-2019, 05:34 AM
#4
RX-Heaven
iTrader: (6)
I agree on upgrading the radiator. I have a Mishimoto radiator in my Brilliant Black 04 6sd and have never had any issues with the cooling system. Running the original Mazda FL-22 coolants should be fine with an upgraded radiator. I have not used the Royal Purple stuff so I can't comment on how well it works and how efficient it is.TO be fair, I have always used the standard FL-22 coolant and a bottle of BG Super Cool. I drain and fill the cooling system every 2 years as preventative maintenance.
07-09-2019, 07:56 AM
#5
Water Foul
I have not tried this in my RX-8, (have always run FL-22 and distilled water with enough glycol to protect to 0F, lubricate the seals, and prevent corrosion), but I run D water and MoCool in my Miata and BWM. I have done this successfully with the Miata for 3 years with no problems, however it requires you to flush the system yearly. I bought the Bimmer from a friend, who started using MoCool around the same time I did, and that car also has a clean cooling system and healthy water pump. As for as helping keep temps down, I have no data to support whether it works or not. The product may or may not do anything, but running a higher concentration of water is known to work, so the combination probably does work. Whether it is safe for the seals inside the Renesis is unknown to me--I have not looked into it.
FYI, the water temp on my RX-8 often peaked at 218F on track in the summer, and I eventually lost a coolant seal. If I were to ever track the car again, I would take the necessary steps to keep it closer to 205F.
FYI, the water temp on my RX-8 often peaked at 218F on track in the summer, and I eventually lost a coolant seal. If I were to ever track the car again, I would take the necessary steps to keep it closer to 205F.
07-09-2019, 03:12 PM
#7
I have not tried this in my RX-8, (have always run FL-22 and distilled water with enough glycol to protect to 0F, lubricate the seals, and prevent corrosion), but I run D water and MoCool in my Miata and BWM. I have done this successfully with the Miata for 3 years with no problems, however it requires you to flush the system yearly. I bought the Bimmer from a friend, who started using MoCool around the same time I did, and that car also has a clean cooling system and healthy water pump. As for as helping keep temps down, I have no data to support whether it works or not. The product may or may not do anything, but running a higher concentration of water is known to work, so the combination probably does work. Whether it is safe for the seals inside the Renesis is unknown to me--I have not looked into it.
FYI, the water temp on my RX-8 often peaked at 218F on track in the summer, and I eventually lost a coolant seal. If I were to ever track the car again, I would take the necessary steps to keep it closer to 205F.
FYI, the water temp on my RX-8 often peaked at 218F on track in the summer, and I eventually lost a coolant seal. If I were to ever track the car again, I would take the necessary steps to keep it closer to 205F.
I'm assuming you had to either replace or rebuild the engine.
My RX-8 has an oversized Griffin/BHR radiator and an electric Davies Craig water pump. The system runs well and the temps recover very fast when at speed or when not driving too hard. But I still hit up to 220 on the hot track when it's 90 outside. I don't know how I could ever achieve 205 when driving hard on a hot day. The track is mostly tighter low speed turns BTW.
I'll plan to swap to FL-22 for now and avoid any potential issues by using DW alone.
Thanks y'all!
07-09-2019, 03:38 PM
#8
Yeah that'll definitely do it. 220F in that condition is not bad. Since you're running electric water pump, can you turn up the circulation speed? It's a less effective approach than, say, having an even bigger rad, but it's worth a shot.
Basically to reject more heat you need either more rad area, more airflow through it or more water flow (and all 3 are interrelated). You can try to have your fans running even at speed to get more airflow, but that'll need testing.
You could also open up the wheel well plastic behind the oil coolers and straighten the fins to flow more air through the oil coolers and reject heat that way.
Basically to reject more heat you need either more rad area, more airflow through it or more water flow (and all 3 are interrelated). You can try to have your fans running even at speed to get more airflow, but that'll need testing.
You could also open up the wheel well plastic behind the oil coolers and straighten the fins to flow more air through the oil coolers and reject heat that way.
07-09-2019, 03:43 PM
#9
Yeah that'll definitely do it. 220F in that condition is not bad. Since you're running electric water pump, can you turn up the circulation speed? It's a less effective approach than, say, having an even bigger rad, but it's worth a shot.
Basically to reject more heat you need either more rad area, more airflow through it or more water flow (and all 3 are interrelated). You can try to have your fans running even at speed to get more airflow, but that'll need testing.
You could also open up the wheel well plastic behind the oil coolers and straighten the fins to flow more air through the oil coolers and reject heat that way.
Basically to reject more heat you need either more rad area, more airflow through it or more water flow (and all 3 are interrelated). You can try to have your fans running even at speed to get more airflow, but that'll need testing.
You could also open up the wheel well plastic behind the oil coolers and straighten the fins to flow more air through the oil coolers and reject heat that way.
I'm still trying to learn about the Davies Craig unit, but I do believe I can speed up the flow by lowering the temp threshold.
When you say open up the plastic, do you mean cutting out a square piece behind the coolers? And what do you mean by straightening the fins? Do you know if there is a write up on this?
Is there any drawbacks to this, like debris flying from the wheel into the back of the oil coolers causing damage?
Thanks.
07-09-2019, 04:34 PM
#10
Yep exactly. You can cut out a square or enlarge the existing openings (which is what I did).
Put a half inch mesh screen in front and behind the cooler to keep debris out.
As for fin straightening, if your coolers have had road debris bend the fins, straighten then back into shape with a toothpick so air passes through better and carries away more heat.
Small word of advice on hot tracks like that: keep your own body cool. My brain got a little squirrely during an enduro in the heat on exactlt such a track.
Put a half inch mesh screen in front and behind the cooler to keep debris out.
As for fin straightening, if your coolers have had road debris bend the fins, straighten then back into shape with a toothpick so air passes through better and carries away more heat.
Small word of advice on hot tracks like that: keep your own body cool. My brain got a little squirrely during an enduro in the heat on exactlt such a track.
07-09-2019, 09:21 PM
#11
Water Foul
I see. I have a track like that near me. Try running your fans. At first, it seems counter-intuitive, because racetrack, but it works well on slower tracks with lower speed corners. Anything you might lose on the straights is more than compensated for in the turns.
You might also look into lower temperature oil cooler thermostats, as the oiling system accounts for much of the cooling in the Renesis.
And yes. I just had my engine replaced.
You might also look into lower temperature oil cooler thermostats, as the oiling system accounts for much of the cooling in the Renesis.
And yes. I just had my engine replaced.
11-09-2019, 09:37 AM
#13
REW Club
Well if it never freezes where you store the car, but like everyone else has said you need the ethylene glycol to lube the water seals.
I have been reading build threads and people get the aftermarket oil cooler t stats and it seems to really help keep oil temps down, but they’re FI.
Would probably help a little in N/A application with running the fans.
I have been reading build threads and people get the aftermarket oil cooler t stats and it seems to really help keep oil temps down, but they’re FI.
Would probably help a little in N/A application with running the fans.
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