Driving in Extreme Heat with Heavily Modified Rig (Heavy)

[PrinceValorum]

Thats a unique idea. But I feel it wouldn't really help, as I feel the water would just simply, fly through the radiators fins going highway speeds. If somehow the fins of the radiator would somehow capture the moisture and let it absorb somehow, I can see something there.

That's an interesting point you bring up. I suppose it would depend on how finely the sprayers atomized the cooling water, and how densely packed the fins were. If the mist passes through the rad without touching it obviously that doesn't help, but if it is in contact with the rad before getting blown off by the incoming air while driving, it will pull heat out of the rad with it, ie. evaporative cooling.

I typed 'mist radiator' into youtube and found several videos, to my mild surprise. The ones about radiators didn't really have much in the way of hard data, but this quick vid by Might Car Mods showed some numbers for their Miata spraying the intercooler with water. There would be a lot more heat to pull out of a radiator vs an intercooler because water has more than 4x the heat capacity that air does, but the temperature delta will be much greater between a radiator vs ambient air compared to their intake air vs ambient air, which would assist in cooling a radiator.

Ambient air was 86F during their test, and with 104F IAT, the sprayer took it down to 97F, giving a temp delta of 7F. When they had the car under higher load and intake temps were 118F, the sprayer brought temps down to 104F, giving a temp delta of 14F. Not insignificant improvements.

https://www.youtube.com/watch?v=O0MY0diHo4U


As several of the people who installed the radiator sprayers mentioned, there are some pretty significant drawbacks, including limited reservoir capacity, having to refill the tank frequently due to the limited capacity, the potential for mineral deposits if you don't use distilled water, and the fact that this is kind of a big bandaid fix in the first place, etc, etc. Still pretty novel idea, imo, especially if you just need it for a few sections of climbing in a trip vs needing it for the entire trip.

 

[Brian.]

I think I will probably go with an aluminum radiator, probably the Koyo because I don't want to deal with the fitment issues of the Champion.

FWIW, the only "fitment issue" I had was that the ears that hold it up while you line it up for bolting it in just won't work. 30 seconds with a hacksaw and a file make that problem go away. That's it.

Sleepydad had some bad rivnuts, mine were fine. By drilling his out and just using nuts on the backside, his fit fine ~ mine needed a couple washers on one corner (but I know my 4r has been in an accident too, so it's likely a little twisted) to sit right.

The potential issues with the Champion are minor, especially when you consider that the Koyo is twice the price... though I "get" that $200 means less to someone with a $200k/year income than to someone like me with a $30k/year income, so it may be a non-issue from the finances standpoint.

 

[HiluxSurf SSR-G]

the stock air intake system is a "COOL AIR" intake because it sources the air from the inner fender, not from inside the engine bay. I would prefer this over some aftermarket air intake systems that call their intake system as "COLD AIR". COLD AIR is a misnomer because the intake air isn't COLD and in fact some of them, like the pod-type air filters, source the intake air from inside the engine bay which is actually HOT AIR.

No cold air intake. I have the stock set-up.

 

[Hopeless Diamond]

Get a Desert Water bag like they use to use. The canvas actually allows water to seep out, which then aids in cooling the radiator through evaporation.

 

[Hopeless Diamond]

My feeling is the re-gearing will probably provide the best results, assuming there isn't some underlying issue with the motor. A heavily loaded vehicle with probably minorly compromised airflow from the armor has to work a lot harder. Add in the increased ambient temps and you don't have a good way to extract all that extra heat.

Just like running trails in 4Lo, the engine/trans, etc has less work to do so it's not putting more heat into the system. The lower (probably more correct for the tire size, etc)gearing will probably also net a little better fuel economy, once you do the mileage/speed corrections.

 

[D'arce]

It sounds like you may be pushing the 4Runner platform to its limit with all the bolt on armor, gear, tires, etc. I'm all about the 4Runner but if I was going to drag all that gear and people into the back country it may be safer, more comfortable and more reliable in a heavier duty platform to start with. Just my .02.

 

[RedRunner01]

Working in transport refrigeration, when I see high engine temps I immediately start with with a radiator/condenser wash-out to see if that corrects the issue. These are engines that run for hundreds of hours at a time in temps from -30F to 120F+, sometimes higher. If dirt, dust, and bugs are clogging the airflow, you're not getting efficient heat loss.

I have no idea where you'd go for a car or truck, we use a wide-spray pressure washer and Hydra-Brite acid solution on most models.

It's only been in the high 90's here, 2002 auto on 33's, front and rear ARB, Sherpa roofrack. Seeing 184 at 65 mph, 188 at idle. Both with AC on.

 

[ch1966]

What were your transmission temps doing Tim?

I received my OBDLINK MX+ yesterday.
I made an 1 1/2 hour trip in 96* degree weather (~105* intake temp. ). Lots of uphill/downhill on the interstate with the cruise set @ 81mph and AC on. I found that the trans temp would spike when the calculated load hit 65-70%. I actually hit 249* at one point when I exited the interstate and my airflow over the radiator dropped down. My water temp never went past 210*.

I came home early this morning when it was 20-25* cooler. Running no AC and doing 77 MPH. Trans temp didn’t have any major spikes.
I was shifting OD OFF both ways when the calc load hit 65% on the uphills.

I learned what I long suspected - I need a trans cooler.

My 2001 rig is basically stock with 32 inch MTs and 99 tall springs.

 

[Pyral]

How susceptible to heat is the 4 cylinder engine assuming stock configuration

 

[PrinceValorum]

I learned what I long suspected - I need a trans cooler.

My 2001 rig is basically stock with 32 inch MTs and 99 tall springs.

Holy crap, I gotta get a trans temp gauge.

 

[phattyduck]

The radiator and cap were replaced 20k ago so I wouldn't suspect an issue with the cap. I think I'll follow your suggestion and go to a 40/60 coolant/distilled water mix.

Nevermind then! I know the rest of your cooling system is in tip-top shape.

Speaking of 117*F... That's the only time I've seen a working Toyota cooling system have troubles (on my Camry with a giant 3-row Koyo). A bit disconcerting to have your gauge look like this:

Not even 20 minute track sessions got that car to overheat - then 115*F with the AC blasting on the freeway to sudden traffic did it... Luckily I was about 2 miles from the house and I was able to turn off the AC and limp home.

-Charlie

 

[clearock]

The auto transmission temps r the the major contributor to the engine temp increase with the heavily (weight added) modded runners, getting heat-soak from said that is transferring to the engine. I believe may peeps r not understanding the difference between overdrive and T/C lock up. The amount of heat being introduced to the system when the auto trans is not locked is massive and when U add hills and weight to the vehicle they can quickly overcome the cooling ability of the OEM and modded cooling system if not monitored. There R any # of things one can do to help cooling (ie increased air flow, larger amounts to fluids, fans, decreasing weight, etc, etc.) After modding my 4runner (adding large amounts of weight) one of the best mods I did was to add an idiot light to show lockup, this taut me how to drive said and lower my temp massively. Removing the trans lines from the radiator and running a standalone cooler removed the trans temps being added directly to the engine coolant, the trans "cooler" on the bottom of auto rads were places there to help warm the trans fluids and bring them quickly to operating temps the trans fluid required (depending on what fluid is used these operating temps can be significantly lowered). By watching lockup my trans temp run 120-130degs on the hwy normally.

The trans lock timing and be altered by running diff gearing, with dual tcase (4.7 in one) I could get the system to lock up at 9mph on the trail.

 

[JZiggy]

The auto transmission temps r the the major contributor to the engine temp increase with the heavily (weight added) modded runners, getting heat-soak from said that is transferring to the engine. I believe may peeps r not understanding the difference between overdrive and T/C lock up. The amount of heat being introduced to the system when the auto trans is not locked is massive and when U add hills and weight to the vehicle they can quickly overcome the cooling ability of the OEM and modded cooling system if not monitored. There R any # of things one can do to help cooling (ie increased air flow, larger amounts to fluids, fans, decreasing weight, etc, etc.) After modding my 4runner (adding large amounts of weight) one of the best mods I did was to add an idiot light to show lockup, this taut me how to drive said and lower my temp massively. Removing the trans lines from the radiator and running a standalone cooler removed the trans temps being added directly to the engine coolant, the trans "cooler" on the bottom of auto rads were places there to help warm the trans fluids and bring them quickly to operating temps the trans fluid required (depending on what fluid is used these operating temps can be significantly lowered). By watching lockup my trans temp run 120-130degs on the hwy normally.

The trans lock timing and be altered by running diff gearing, with dual tcase (4.7 in one) I could get the system to lock up at 9mph on the trail.

Manual transmissions sounding better and better!

That's a great idea of having an indicator to show TC lockup. How do you do that?

 

[clearock]

added and LED light to the cluster by splicing into the ECU lock-up command wire. I can also force lock up but I don't recommend said for most peeps as u can damage the T/C if not very careful

 

[ch1966]

added and LED light to the cluster by splicing into the ECU lock-up command wire. I can also force lock up but I don't recommend said for most peeps as u can damage the T/C if not very careful

Wow. Thanks for the insight. Still playing with my new OBDLINK MX+. Found the pid and added it to my ever evolving dash.
“Status of Lock Up Sol Off/On”

Here I am unlocked before getting on the interstate. Temps up a little.

On the interstate. Achieved lock. Temps fall.

Slowing down for merging traffic. TC unlocks. Temp rises.

Achieve lock. Temps fall.

I make my exit. TC doesn’t lock in the 45mph zone.
Temps rise. Quite a bit in a mile @45mph.

It locks back up after the speed limit goes up and cools back down and I arrive at my destination.

I now have my eye on it. Thanks for your idea.

 

[T4topher]

The auto transmission temps r the the major contributor to the engine temp increase with the heavily (weight added) modded runners, getting heat-soak from said that is transferring to the engine. I believe may peeps r not understanding the difference between overdrive and T/C lock up. The amount of heat being introduced to the system when the auto trans is not locked is massive and when U add hills and weight to the vehicle they can quickly overcome the cooling ability of the OEM and modded cooling system if not monitored. There R any # of things one can do to help cooling (ie increased air flow, larger amounts to fluids, fans, decreasing weight, etc, etc.) After modding my 4runner (adding large amounts of weight) one of the best mods I did was to add an idiot light to show lockup, this taut me how to drive said and lower my temp massively. Removing the trans lines from the radiator and running a standalone cooler removed the trans temps being added directly to the engine coolant, the trans "cooler" on the bottom of auto rads were places there to help warm the trans fluids and bring them quickly to operating temps the trans fluid required (depending on what fluid is used these operating temps can be significantly lowered). By watching lockup my trans temp run 120-130degs on the hwy normally.

The trans lock timing and be altered by running diff gearing, with dual tcase (4.7 in one) I could get the system to lock up at 9mph on the trail.

If this is the case that the auto trans is a major contributor to the engine temps then gearing will 100% help the most IMO. Will make the trans and engine work way less overall.

 

[HiluxSurf SSR-G]

You could have turned on the heater full blast and then opened the windows so you don't get steam cooked. Turning on the heater helps in dissipating heat from the coolant

...
Not even 20 minute track sessions got that car to overheat - then 115*F with the AC blasting on the freeway to sudden traffic did it... Luckily I was about 2 miles from the house and I was able to turn off the AC and limp home.

-Charlie

 

[19963.4lsr5]

Wow. Thanks for the insight. Still playing with my new OBDLINK MX+. Found the pid and added it to my ever evolving dash.
“Status of Lock Up Sol Off/On”

Here I am unlocked before getting on the interstate. Temps up a little.

On the interstate. Achieved lock. Temps fall.

Slowing down for merging traffic. TC unlocks. Temp rises.

Achieve lock. Temps fall.

I make my exit. TC doesn’t lock in the 45mph zone.
Temps rise. Quite a bit in a mile @45mph.

It locks back up after the speed limit goes up and cools back down and I arrive at my destination.

I now have my eye on it. Thanks for your idea.

Lockup occurs at 48mph in 4th and 42ish in 3rd on my 97.


Sent from my iPhone using Tapatalk

 

[ch1966]

Lockup occurs at 48mph in 4th and 42ish in 3rd on my 97.


Sent from my iPhone using Tapatalk

Thanks!
Mine will shift from 2nd to 4th under some circumstances.
I added a gear indicator.

I think I’d better drop the pan and put a new filter in it and get new fluid in it.
And add a cooler.
The prior owner put a new rad in a couple of years ago.

 

[Hopeless Diamond]

I do fair amount of driving over a couple of passes, which means turning off overdrive. Even if it's already kicked down into 3rd, when I turn off the overdrive, the converter locks up and the RPMs will drop by another 300 or so. Definitely part of the cooling plan, mainly for the trans, but everything ties together.