ABC'S of 80's Cooling Part IV - Hood Vents (1 Viewer)
- Thread starter SUMOTOY
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SUMOTOY said:
An IR temp gun has nothing to with air temps, they do a descent job of estimating surface temps on some surfaces. You got "a *massive* reduction in airbox temps" who cares what the can measures? I thought air temp was the key to horsepower?
SUMOTOY said:
OK, so your all of that and a bag of chips. What is the improvement? Before and after temps of, intake AIR, coolant temp, A/C vent idle and speed, fan output AIR, underhood AIR, A/T temps, did any of them change? I am sure you measured them in your systematic analyses, why not post them? Is there any improvement that matters or are you recommending everyone cuts holes in their hood to lower the can temp? How would this affect a stock truck or do we have to follow the exact same "upgrade path" to take advantage these "massive" benefits.
- Thread starter
- #43
Tools R Us said:
Always intrigued by those that ask for other numbers, because the one's given aren't good enough. Kevin, what causes the air filter temps to increase above ambient? If it's the oven temp surrounding it, can't we draw a direct matrix to oven temp vs air temp for a specific test parameter (say idle at 95F)? I like IR Temp guns, because they are simple, and are data, quick, fast and replicable data. Let's get the data, enough of it, draw the matrix of airbox to air filter vs ambient vs rpm.
What matters to you Kevin? What matters to me right now as I stated in my Part IV, is that hot trapped heat is bad for engine performance. I appeared to have addressed that well, albeit not measured optimally in your opinion. 10 degree variance? Test conditions, humidity, good gas, etc. 70F variation? I think the temp gun is fine.
Regarding affects on a stock truck? What I've observed so far: Hot start is much easier, A/C efficiency, reduction in airbox temps (er, I make the connection to air filter temps), noticeable improvement in hot idle, better tip in throttle response, lower underhood engine bay temps, noticeable and measureable heat release thru the vents (I conclude means more effective radiator heat exchange). All good things *in my opinion*.
Part V will take those heat exchange improvements and add the final step of electric fans. I expect plenty of challenges on that as well. I'm pretty convinced that steps I-IV have done well by me, and that Part V will complement steps I-IV. Stay tuned Kevin, in the meantime I look forward to you removing the fan shroud and putting up the measures. IR temp gun is fine...
Cheers
Scott Justusson
'94 FZJ80 Supercharged
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SUMOTOY said:
I beleive that I was on this forum, but that was based on the idea that Toyota had optomized the cooling ability of the system already. It appears they didn't and hot running engines can be addressed with a simple clutch mod.
I personally won't be doing any of the mods that you are suggesting unless I'm strong armed into it by an issue with the truck that can't be resolved any other way.
Right now I'm completely content with that 1 simple change.
- Thread starter
- #45
landtank said:
We completely agree "that it appears that they didn't optimize the cooling ability of the system already." That simple clutch mod proved risky for me. And I might venture that if Mr T overlooked a fluid change, a few more compromises to 'optimal' might be present.
I look forward to your continued reviews of my systematic and documented approach in optimizing heat management of the 80 series truck.
Scott Justusson
Dusty said:
Dusty what part of the county are you in and what are the summer temp like?
- Thread starter
- #47
Dusty:Dusty said:
Sounds like a hot running truck to me. What were the temps you measured (oil/water). Is your VC fan working properly?
Mr. turbo dude... What are your air inlet temps, or even what is your air can temps? I suspect you have really high underhood temps. If that's the case, I expect that blowing more air on the condenser probably adds to underhood temps. It sure did for me.
A test for you. Pick a spot to measure temps, preferably on the PS or at the airbox. Heat soak the truck at idle, a/c on, but aux fan off. then add the aux fan back into the equation. What I noted was a dramatic increase in airbox temps with the aux fan installed. I read that to mean that underhood temps are spiking with the extra flow negating the benefit of the aux fan.
Is your aux fan mounted to the condenser and sealed? Where is the intercooler? (you can just point me to the engine bay pics if you like). Edit found the cooler... Dusty, as a rule I use 25row coolers minimum and 36 row coolers in the turbo cars I tweek. Yours appears to be much smaller (13row?). Here going big can't hurt if your temps are really high. What are your overall temps (water and oil) vs ambient. Remember, turbochargers increase water and oil temps both, and pretty significantly. You may be out of capacity, and/or you are out of exchanged heat release. You have added a radiant heat source (turbo hot side), an additional convective heat generator = turbohcarger centerbearing water/oil heater, and an additional heat exchanger = oil cooler (didn't see IC, but that would make 2 additional). I see just my stock supercharger maxing out the cooling capacity. You have exponentially taxed it. Take the hood off?!?
Regarding water temps, I'm not really sure I care what those are until I get to part V. The Aux fan is to cool the condenser, I have never seen it as an additional radiator fan. The radiator temps will vary significantly, and you won't be able to stabilize them because the variance in VC intervention will be huge. As will the variance in acceptable temp ranges of a idling truck. I only assume as a given that the overheat cutoff of the A/C hasn't been reached = radiator <226F. I'm passively interested in IAT temps, but probably have the best tool to gather them, so I'll try to get that data out when I can.
Scott Justusson
SJ
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SUMOTOY said:
Hold your breath
I might be reading this wrong, but it sounds (from a bystander's point of view) that some folks aren't exactly supportive of Sumotoy's efforts. I say let him run with this, don't discourage him. It's nice that someone is taking the time to not only mod some things but to explain his progress in detail. That's a lot of work to go through for the benefit of others. I for one am following the writeups, and will come to my own conclusions about what to take away from these threads. Not that there's anything wrong with questioning the methods or mods themselves, that's the beauty of the forum- 67 heads are better than one. Just please don't discourage the effort expended.
-Spike
-Spike
Dusty said:
I am with Dusty. A cooler air box doesn't mean 70F + drop in the air intake temp at speed or idle. Way too much air moving through the engine at higher rpm say 3000 rpm.
Do the calculations for the time that the air is in the system and the conduction coefficent of the air. I would be shock if at 3000 to 5000 rpm you see a increase of a couple of degrees in the air due to air box temperature. Likely, the air will cool due to the vacuum and moisture in the system being vaporized. That is why most throttle bodies butterfly valves are heated - to avoid icing during rainly days. The source of the incoming air is most important in terms of temperature and that is on the fender already not in the engine bay.
The pusher fans, interesting results. What temp are the fans set to turn on?
Waggoner5
SILVER Star
I have spent many a day checking the function and heat reduction from the engine bay. I felt hot air coming from both vents. They work. Hot air comes out. What they didn't do is lower the operating temp of the engine. 190* thermostat, 190* engine temp. They did lower the air temp going into the intake but with a heat sink like that it didn't take long for it to come back to the same temp. Also, as with the Mercruiser AIT sensor, the Toyota ECU understands that high IAT temp even as hot as it is, and runs the engine accordingly. When I fooled the IAT to think that the air was cooler than it was the engine leaned out, which increased the engine temp. My crude and unimaginative tests found that my Mercruiser engine runs at the thermostat rating, at normal altitudes that is.. When I subject the truck to high altitudes that the Mercruiser computer could not compensate for, I removed the hood completely. Engine ran the same temp. This is when I had the big revelation. Hood vents didn't do much on my truck.
Now on a friends stock 62 with the 3FE at high altitude the truck stumbled and acted like it was starved for fuel. It was vapor locking. Removed the hood, strapped it to the roofrack and wheeled for 10 days, never having another issue. Even being rained on.
Now on a friends stock 62 with the 3FE at high altitude the truck stumbled and acted like it was starved for fuel. It was vapor locking. Removed the hood, strapped it to the roofrack and wheeled for 10 days, never having another issue. Even being rained on.
seems like if a hot airbox was influencing the temp a simple wrap with some insulation would be as effective as anything else.
Waggoner5
SILVER Star
Agreed. The problem is that the IAT is designed to read the hotter temps. You would think that 150+ degree air would not be a good thing, but thats the temp inside the intake plenum even with cold air going to it. The IAT sensor is just looking at a value not the actual temp. When I fooled it, it just screwed things up.
Gary's "hood" observations are of particular interest to me at this very moment.
Without intending to, I discovered some interesting stuff this evening during an impromptu test.
I stopped at the next-door neighbor's house to chat for a couple minutes on my way home. He was grooming his horse and I stopped (transmission in drive, A/C on, standing on brake) and rolled the window down and visited for a few minutes. When I excused myself I noticed that my engine temp was about 210 degrees. The ambient temp was about 80 and the humidity quite high for us (~50%). I pulled into the yard and left the vehicle idling with the A/C cranking.
After about 10 minutes the engine temp had climbed to 215+ (I deliberately left the aux fan off.). I next kicked the Aux fan in and the temp stabilized at about 215 degrees. My next step was to kick the engine RPM up to 1,800 and hold it using the hand throttle. The temp dropped to 210 and held. My next change was to open the hood. I changed nothing else and the temp dropped to a bit under 190 in about two minutes.
This tells me that there is an enormous ammount of heat trapped under the closed hood. I wish there was an easy way to take the blower out of the loop to see what the identical vehicle would do without it being there.
D-
Without intending to, I discovered some interesting stuff this evening during an impromptu test.
I stopped at the next-door neighbor's house to chat for a couple minutes on my way home. He was grooming his horse and I stopped (transmission in drive, A/C on, standing on brake) and rolled the window down and visited for a few minutes. When I excused myself I noticed that my engine temp was about 210 degrees. The ambient temp was about 80 and the humidity quite high for us (~50%). I pulled into the yard and left the vehicle idling with the A/C cranking.
After about 10 minutes the engine temp had climbed to 215+ (I deliberately left the aux fan off.). I next kicked the Aux fan in and the temp stabilized at about 215 degrees. My next step was to kick the engine RPM up to 1,800 and hold it using the hand throttle. The temp dropped to 210 and held. My next change was to open the hood. I changed nothing else and the temp dropped to a bit under 190 in about two minutes.
This tells me that there is an enormous ammount of heat trapped under the closed hood. I wish there was an easy way to take the blower out of the loop to see what the identical vehicle would do without it being there.
D-
Waggoner5 said:
This is strange.
How did you fool the IAT?
As I currently understand IAT sensors, the sensor is cooled by the air passing by in the intake and compared to the coolant temp value by the ecu. That is why the IAT sensors are hooked into the coolant system in some cars. The temp value of the IAT is a weighted/corrected value in the air density calculations based on location and sensor design. The corrected IAT temp and MAP sensor are the values used to calculate the air density by the ecu. Please correct me if the 80 calculate air density differently in th 95 to 97 models. A value of 150F at the IAT doesn't mean you have air in the system at 150F but that the sensor is at 150F not 190F
Dusty said:
Sumotoy - you skipped over this - why are you using IR? And How? And please don't abreviate my name in your response, it's annoying.
cruiserdan said:
For me Dan, that says there is a lack air flow. I'll have to check the thread on my under hood temps but I think my truck in a similar situation had under hood temps of around 144*F. And I didn't have that high of an operating temp. It would be good if you could get your under hood temps as well for comparison.
EDIT: I checked and it was 90*F and 78% humidity on that day. But there was no AC on.
landtank said:
Agreed,
The "lack of airflow" results from the non-original fan-blade required by the blower drive assembly and the altered fan-blade operating plane, as well as the addition of the blowercase and manifold.
Dan,
While reducing the temp from 215 to 190 could be considered a universally good thing, it does not necessarily follow that any benefit was achieved. In other words, it could well be that the engine's output was within a couple HP at either temp for a statistically zero change since the engine can easily operate at either temp and adjust its own parameters accordingly. Temps at idle with zero vehicle movement don't translate to temps of the same vehicle at the same ambient air temp while the engine's working up and down the rev range and moving through the air.
I think that the whole "cooler engine bay translates into a cooler operating engine" thought process is over rated. Airflow randomly puffing around the engine bay does very little to impact the engine's cylinder environment - the area where the engine's output and other parameters are determined. I'd go so far as to say that powerwashing out typical dusty radiator fins would yield greater benefits from cooling than hood vents. Or a cooling system flush and new thermostat. Or new fan belts. Or an additional external oil cooler.
Why? These kind of things directly affect internal engine heat transfer - the motherlode of cooling. Hood vents reduce the temperature of the air around the external engine where there is no heat exchange designed into the engine's surface - heat loss is kinda random and unknown. Sure, IR readings are showing some changes to the various surfaces, but that is not a benefit in and of itself other then the "universal good" concept.
So, I remain unconvinced of the hood vent benefit though I appreciate Sumo's data, work, insights and continued efforts in pioneering a multi-front battle on engine heat. Great stuff, and keep it up - you are clearly making progress. Secretly, I also think hood and fender vents look tasty - that Sport Rover's fender vents always drag my eyes around when one drives by...
DougM
While reducing the temp from 215 to 190 could be considered a universally good thing, it does not necessarily follow that any benefit was achieved. In other words, it could well be that the engine's output was within a couple HP at either temp for a statistically zero change since the engine can easily operate at either temp and adjust its own parameters accordingly. Temps at idle with zero vehicle movement don't translate to temps of the same vehicle at the same ambient air temp while the engine's working up and down the rev range and moving through the air.
I think that the whole "cooler engine bay translates into a cooler operating engine" thought process is over rated. Airflow randomly puffing around the engine bay does very little to impact the engine's cylinder environment - the area where the engine's output and other parameters are determined. I'd go so far as to say that powerwashing out typical dusty radiator fins would yield greater benefits from cooling than hood vents. Or a cooling system flush and new thermostat. Or new fan belts. Or an additional external oil cooler.
Why? These kind of things directly affect internal engine heat transfer - the motherlode of cooling. Hood vents reduce the temperature of the air around the external engine where there is no heat exchange designed into the engine's surface - heat loss is kinda random and unknown. Sure, IR readings are showing some changes to the various surfaces, but that is not a benefit in and of itself other then the "universal good" concept.
So, I remain unconvinced of the hood vent benefit though I appreciate Sumo's data, work, insights and continued efforts in pioneering a multi-front battle on engine heat. Great stuff, and keep it up - you are clearly making progress. Secretly, I also think hood and fender vents look tasty - that Sport Rover's fender vents always drag my eyes around when one drives by...
DougM
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