Lexmex

Most of you are away from seeing my cardomain page what the modifications to my cooling system are:

1) Tom's Radiator Cap
2) TRD Thermostat
3) Use of 100% coolant as opposed to mixture with water
4) Use of Redline WaterWetter
5) Removal of plastic cover on top of radiator
6) Removal of rear rubber seal on back of engine near air inlets for the passenger compartment

Result:

Notice my vehicle speed in the attached picture as this was taken this afternoon on a toll road. Notice the temperature indicator is below the half way notch. It sometimes even gets very close to the next notch down at night.

CivicFerio

Nice cooling mods you have. Have you had cooling problems before?

I have a question on the coolant you are using, is it a premix 50/50 or 100% glycol? According to the redline watter wetter website, Glycol isn't the best thermal conductor and plain water is. That is why they recommend you use a 50/50 mix. Check out the report here
http://www.redlineoil.com/whitePaper/17.pdf

I heard that some radiator shroud actually creates a low pressure behind the radiator while the car is in motion, manufacturers do wind tunnel testing on this. So be careful with what you remove it may do more harm than good.

Running the engine cooler than specified may cause uneven wear on cylinders. When they designed the engine, they have to comphensate for thermal expansion, so running it cooler might cause problems in the long run. I think cooler by 10-20°F shouldn't hurt it though.

One more thing is there is an optimum opertaing temperature for most engine is between 180°- 200° in general. At this range combustion temperature is kept high enough for a complete burn of the fuel. Cooler than 160°F usually fools that ECU that the engine is still cold thus it will dump more fuel.

Good luck! It looks like your car is ready for the summer!

Lexmex

You bring up some good points.

Only time I have some issues were with the K&N filter oil getting on the MAF.

For coolant I am using the same Toyota coolant you would pick up at the dealer. There is a sport coolant I am aware of from TRD.

My uncle is the one that suggested I go to 100% coolant. He has been fixing cars as long as I can remember and not one ever encountered a cooling problem afterwards.

I worried about that radiator cover at first, but I have seen no difference. I though actually their might be an air dam. Without the the rear rubber seal near the passenger air inlets, I can actually feel the hot engine air when I take the recirc mode off when I am doing 1/4 mile runs. My 1/4 mile times were faster after this.

At this elevation, the car is probably going closer to sea level performance but not quite with all of the modifications so I am not worried too much about the cylinders. The real test will come when I go to sea level. There is about 23 to 25% less oxygen up here.

With the lousy Pemex gasoline here, you need every mod you can get to get the gas to burn.

Grumpa72

There is a very good reason to mix water with coolant in a 50/50 ratio. Go with the scientific testing versus what your uncle says. I am sure that he is a great guy but a test from one individual, without scientific data that is reproducible, is pretty much that - a test of one. That is why you see magazines like Consumer Reports as well as the manufacturer's tests that are not only valid tests, they are reproducible. Think about it - if Toyota could get you to buy two gallons of antifreeze versus one gallon plus water, don't you think they would do that? Same thing with the shroud you removed. Don't you think that if Toyota could save $2 on a piece of plastic that they would? It is there for a reason and it usually means it is directing or controlling air flow for better and more efficient cooling.

The problem with most of the mods that we do to our cars is that most of don't have access to properly tested and calibrated testing tools and methods to determine if we are doing our car any good. I would venture a guess that most of the mods that we do to our cars is actually detrimental to either performance, drivetrain longevity, or reliability.

I once bought an old pickup from a farmer for hauling junk to and fro and when I asked when the last oil change was he said (with a VERY heavy Arkansas accent) "My daddy says if it ain't broke don't fix it." Needless to say every fluid in that truck got changed and it ran quite well. Oth, I paid $500 and drove it for two years hauling my dog and hunting gear everywhere.

Just my two cents.

Gary

bizzy928

Another thing is that runing your vehicle for extended periods below normal operating temperature can do more harm than good.

Lexmex

Ever since I moved down here (or rather up here), the bad gas, high elevation and bad roads lead one to look at their vehicle in a whole different light.

Sometimes my uncle will tell me something and I won't believe him or it sounds screwy. However, when I talk to other mechanics, sometimes even my the senior mechanic at the Toyota dealer, I start to realize that this environment is unique for having a vehicle. For a while, I had a mixture of 50/50, but one thing I noticed was that I was having to add coolant and water every 3 months or so. I never had an issue except with the MAF sensor getting oiled up. On that day, the green paint melted on the engine cover (reason it is painted silver now).

When I switched to 100% coolant, gone was the coolant level problem.

The lack of oxygen here has a tremendous effect on vehicles here and until you experience it, it is hard to imagine. It ain't Colorado either, I have driven there.

Good example, I have a good friend who works at Mazda here in Mexico and they were all set to sell the RX-8, even showed it off at shows and you could see it on the street in demo models.

When it finally came time to get government approval turns out it wouldn't pass the California style emissions standards here due to gas and the low oxygen level here. They will now wait to sell it next year with the new, more powerful design. My friend's RX-7 would probably not pass either (though emissions here for foreigners are totally voluntary). I was surprised mine even passed with my exhaust work.

I am looking ahead to the day when I go back to the states and I have considered that I would probably have to alter some of my mods, especially toning down the air entries since I will have more oxygen.

However, up here I really need all the help I can get. The stresses on cars are much higher.

HarrierAWD

I also have coolant level problem. I have to add about a quart of coolant (50/50) every 3 months or so. Water boils at lower temperature at higher altitude, thus the loss.

When I moved from NYC to Colorado, I can definitely feel the loss of power and torque. I used to be able to get decent acceleration at 3,000 rpm, now I need 4,000 rpm.

I want that @#$% TRD Supercharger for my RX300!!! Toyota/Lexus are you listening??

Lexmex

Too bad that TTE Kompressor is underpowered and overpriced.

I PM'ed some of my racing buddies from the track and they also use either 100% coolant or a 70%coolant/30% distilled water mix. One guy in Chihuahua said he does do 50/50 mix but he heard about the problems at altitude. He was going to check with some buddies in Leon and Guadalajara that are also like 5,000+ feet up.

That air mod that scraps the air resonator really helps TunedRX300 and myself get up hills throwing in all that air. Before, I had RPM issues running up hills, even shifting down and using the PWR button still made the car go up the hill like a cow...not anymore.

When I get a chance to get to sea level, I will do a test keeping the coolant at 100%. Acapulco and Veracruz are not too far away but big time gas money. Maybe when I make a run up to San Antonio.

TunedRX300

Gary, a lot of what you say hold true. Just want to charm in to put my $0.02 in also...
People mod according to their needs, Toyota has a generic design. For example, intake resonator is meant for noise reduction than increasing air flow, who is to say the benefit of dB decreased could more than offset the performance loss? Toyota or individual owner?
Other mod to catch up on features. When RX first came out, HID and LED are not standard features. Technology change and cost decrease over time, people may find modding an existing car with aftermarket or OEM parts from wrecks cheaper and more satisfying than selling current car and buying a new one.
Last sometimes keeping the same practice, even those recommendated by Toyota, may not be the best. Remember Toyota's primary goal is to make $, not to serve you or me. This include drain and fill ATF only with Toyota T-IV, even though the practice change only a small portion of tranny's capacity and T-IV is unable to handle excessive tranny heat in AWD RX more than 15K. Few even think about the opportunity cost of not using a better approach and better fluid. We often point our finger to aftermarket companies such as K&N and Amsoil for overhyping their products but forget Toyota is every bit of guilty on promoting OEM filter and T-IV as another source of profit stream.

Fern

Hi Lexmex,

hey, I'm all for the mod minded person, but you have to weigh the consequences if any.

In your case I fear the coolant mix might cause restriction of the heat transfer capabilities, corrosion protection, and freeze protection. The concentration of freeze/boilover protection of the antifreeze mixture can be more harm than good if exceeding 70% coolant.

As for the rad shroud, have you considered airflow caracteristics being altered and wind diverted to radiator. I find it odd that Toyota would supply and install a part which in older times was not installed and now they do. Seams like it serves a purpose, which I would suspect is more than cosmetic.

Hey, look at decorative covers on the top of engines, there are some that say they are there for acoustics and others that say for thermal reasons, regardless, I think car manufactures don't normally install more than they have to.

Regardless have fun with the mods and monitor any adverse reaction the vehilcle may have.

Lexmex

Fern,

You help me bring up another point.

Before I had the radiator plastic cover, the radiator itself would heat up a lot after an hour run at the track (similarly if I was doing city driving for an hour). After removal, it is warm but not scalding hot. True, a little bit louder noise coming out of that area. My 1/4 mile times are slightly faster. It does look a little ugly there without out the cover if you look at my cardomain pictures.

One person emailed me from Guadalajara and also indicated they use 100% coolant and that the 50/50 mix doesn't help cool at all where he is. If my temperature indicator were going up higher rather than lower in this case, I would assume something is wrong. This has not been the case. I have to assume my uncle knows something about the effects of altitude and lower oxygen in the air or he would not have suggested it in the first place.

When I did have a 50/50 mixture, the temperature indicator would almost always be over the middle notch, now it rarely goes over except when it is over 80 F and then just sits in the middle for the most part.

Again, when I get back to sea level, let me run a test and see what the temperature gauge does at 100% coolant. This is probably an elevation-related thing.

The last thing I want is it being too cool and that was my first worry with the current modifications.

Lexmex

I would actually like to know from the RX group here what is the lowest temperature indicator position you have seen on your RXs.

mrogersii

I live down here in Mexico City with LexMex - I have a '93 Mazda RX7, modified to put out 400bhp. I do a lot of racing with it down here - both strip and circuit - and the altitude is a killer insofar as getting enough air to your engine and keep your car cool during circuit heats. I too am using 100% coolant, zero water, as the boiling temperature of water is lowered by approximately 15 ºF due to the altitude and barometric pressure.

I used to use a blended mix of water and coolant, but it just doesn't work here. 7,500 feet is a long way up and things definitely change insofar as cooling and proper air intake goes. Now with 100% coolant and WaterWetter, I no longer have heat issues. The car runs at normal temperatures thanks to the thermostat, so there are no issues about running the car too cool. What matters is that there is no fluid that will boil like water will at 199.3 ºF at this altitude. Here are some figures to consider (thanks to LexMex):

10%coolant:90%water = 213ºF boiling/ 26ºF freezing
20%coolant:80%water = 215ºF boiling/ 18ºF freezing
30%coolant:70%water = 218ºF boiling/ 8ºF freezing
40%coolant:60%water = 222ºF boiling/ -3ºF freezing
50%coolant:50%water = 222ºF boiling/ -21ºF freezing
60%coolant:40%water = 234ºF boiling/ -48ºF freezing
70%coolant:30%water = 247ºF boiling/ -93ºF freezing
80%coolant:20%water = 272ºF boiling/ -183ºF freezing
90%coolant:10%water = 347ºF boiling/ -453ºF freezing
100%coolant = 1704ºF boiling/ -5308ºF freezing

You can't beat 1,704ºF...

One thing I am considering to experiment with is Evans NPG+ waterless coolant.

Lexmex

Last Monday, I changed out the coolant and did a drain and fill on the tranny. 100% Toyota Red Coolant along with a bottle of Redline WaterWetter. I took a clearer picture at a slower speed. Yeah my D light has been out for ever, too.

2MCHPSI

It is widely known that 100 percent antifreeze has a lower heat transfer percentages, and even the antifreeze manufacturers say corrosion protection will be less also on antifreeze only setups. Personaly, I would drain at least 30 percent out and throw distilled water in it's place.