cruiserdan said:
I'm not sure how you are coming to that conclusion. I'd like to see that fan on my truck for comparison sake.
ABC'S of 80's Cooling Part IV - Hood Vents
- Thread starter SUMOTOY
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I'm not sure how you are coming to that conclusion. I'd like to see that fan on my truck for comparison sake.
IdahoDoug said:
Probably right on a good powerwash and flush ect. I'd say that a cooler engine bay translates into better cooling by the radiator. The heat from the radiator has to go somewhere, the bigger the temperature delta to the surrounding air the more heat is going to be transfered. We all know that the temp of the air coming in the front of the radiator makes a difference. Why wouldn't it make a difference on the fan side? I'm stuck somewhere between the fact that the air in the engine compartment isn't going to effect the radiator cause the fan is blowing hard enough to keep it all going one direction, and just thinking, well it's got to.... Where did that heat transfer book go??????
- Thread starter
- #63
general comments
Guys:
I'm all up for good discussions. The theory part of all of it doesn't excite me much anymore, cuz the subjective difference in my truck with vents installed was major. It's quite possible I haven't taken the proper measures, used the proper tool to do so, or even went after the proper data. Fire away at it, it's only observed data, and it's a set of numbers. Debate them, refine them, toss them, critique them. Matters not to me, I'm working thru the issues with my Supercharged Truck as I have identified in Parts I-IV. Ending with Part V when I make the jump to electric fans.
To date, I have no regrets on the 'how', and really none regarding the data I supplied. If it only makes us all *aware* of numbers, or even presents us all with agreement on the ones that are significant, great. In the meantime, I take my IR temp gun and zap away. The conclusion that my truck runs better for it is noticeable every day since I put the vents in. I *need* no more debate or discussion, my truck runs noticeably better. Period.
Certainly the Supercharger adds extreme environment to the nacelle of the 80. 20 years of my life was spent in turbo cars, I'm well seasoned to underhood trapped heat. Way back in 1985 my GLH turbo had a hood vent from the factory, as did every single 2.2 turbo application for years. I've installed them in a wide variety of cars and trucks since, from offroad to track. It doesn't matter to me if no one else does them. I have extensive experience with them in the performance arena, and they have worked well for me every time.
I enjoy reading the banter, the *controversy* over me sacreligiously porting my 80 hood. All theory, controversy, opinion and other 'experiences' so noted, I concluded within a day that this was the best mod I've done to date next to the Supercharger itself.
Does it mean a non supercharged truck will yield the same benefit? Not sure I really care, I'm pretty selfish about mods, I have only a passive interest in even doing the reports on it. Right down to the PITA of stopping mid cut, to take a pics of my butchery. My best hope is that the definition of "80 Tech Forum" might change for the better because of what and how I approached my ABC's. Nothing to date has indicated to me that my results and conclusions are tainted by my attempts at posting data. I have followed to the letter, my goals and targets for my truck, as I identified areas of improvement in regards to heat management the factory delivered.
I also understand completely, when some might take an askance look at my primitive reports and data, and want to demand more: Data, theory, opinion and methodology. Occasionally I think why bother, but I've also learned over the years, most folks know the tech from the BS generated because of it.
I've now btdt on the hood vents, and my conclusion of their benefit stands as reported. In Part V, I'm going after electric radiator cooling fans.
Scott Justusson
QSHIPQ Performance Tuning
Chicago
94 FZJ80 Supercharged
Guys:
I'm all up for good discussions. The theory part of all of it doesn't excite me much anymore, cuz the subjective difference in my truck with vents installed was major. It's quite possible I haven't taken the proper measures, used the proper tool to do so, or even went after the proper data. Fire away at it, it's only observed data, and it's a set of numbers. Debate them, refine them, toss them, critique them. Matters not to me, I'm working thru the issues with my Supercharged Truck as I have identified in Parts I-IV. Ending with Part V when I make the jump to electric fans.
To date, I have no regrets on the 'how', and really none regarding the data I supplied. If it only makes us all *aware* of numbers, or even presents us all with agreement on the ones that are significant, great. In the meantime, I take my IR temp gun and zap away. The conclusion that my truck runs better for it is noticeable every day since I put the vents in. I *need* no more debate or discussion, my truck runs noticeably better. Period.
Certainly the Supercharger adds extreme environment to the nacelle of the 80. 20 years of my life was spent in turbo cars, I'm well seasoned to underhood trapped heat. Way back in 1985 my GLH turbo had a hood vent from the factory, as did every single 2.2 turbo application for years. I've installed them in a wide variety of cars and trucks since, from offroad to track. It doesn't matter to me if no one else does them. I have extensive experience with them in the performance arena, and they have worked well for me every time.
I enjoy reading the banter, the *controversy* over me sacreligiously porting my 80 hood. All theory, controversy, opinion and other 'experiences' so noted, I concluded within a day that this was the best mod I've done to date next to the Supercharger itself.
Does it mean a non supercharged truck will yield the same benefit? Not sure I really care, I'm pretty selfish about mods, I have only a passive interest in even doing the reports on it. Right down to the PITA of stopping mid cut, to take a pics of my butchery. My best hope is that the definition of "80 Tech Forum" might change for the better because of what and how I approached my ABC's. Nothing to date has indicated to me that my results and conclusions are tainted by my attempts at posting data. I have followed to the letter, my goals and targets for my truck, as I identified areas of improvement in regards to heat management the factory delivered.
I also understand completely, when some might take an askance look at my primitive reports and data, and want to demand more: Data, theory, opinion and methodology. Occasionally I think why bother, but I've also learned over the years, most folks know the tech from the BS generated because of it.
I've now btdt on the hood vents, and my conclusion of their benefit stands as reported. In Part V, I'm going after electric radiator cooling fans.
Scott Justusson
QSHIPQ Performance Tuning
Chicago
94 FZJ80 Supercharged
Last edited:
Waggoner5
SILVER Star
The IAT sensor was replaced with a resistor of value that fooled the ECU into thinking the air temp was lower than it was.Cattledog said:
I too understand how this works, only wanting to test the effects of a lower air temp reading to the ECU.
- Thread starter
- #65
Waggoner5 said:
BTDT on the water temp too, to enrich the mixtures. IME, fooling computers usually ends up with less than desireable results. IME, if you create more demand for air, you create more demand for fuel. Fuel is matching injectors, fuel pump, and fuel pressure regulators. I've followed this logic with the latest of OBDII systems, and created spreadsheets to help in calculating those increased demands in terms of sizing.
The only trick is what you do is based on 'actual' conditions of your specific vehicle, not marketing, or optimal dyno claims. On OBDII, you have +/-15% long term fuel trim correction ability with any mod before CEL. It's a great tuning tool IME.
Why fool any input? Either reprogram the ecu, or change the hardware to the capability of the engine. It's quite obvious to me that Mr. T allows a pretty wide ability to accomodate modifications. Up to and including bolting on another 1/2 atmosphere of pressure.
SJ
Waggoner5
SILVER Star
Mine was a test for Mercury Marine on a specific issue.
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SUMOTOY said:
Sorry, I wrongly assumed that more testing would be necessary to determine overall performance. A 67F drop in underhood temps is excellent and I would guess that it would greatly reduce the operating temps of all underhood systems, well worth cutting a couple of small holes in the hood.
- Thread starter
- #68
Tools R Us said:Sorry, I wrongly assumed that more testing would be necessary to determine overall performance. A 67F drop in underhood temps is excellent and I would guess that it would greatly reduce the operating temps of all underhood systems, well worth cutting a couple of small holes in the hood.
TRU:
At some point I suppose I could unwrap one of my Davtron IC guages and put up better data. What is missing from your and other's critiques is any possible explanations regarding the subjective benefits. Specifically, tip in throttle, better hot idle, better SC response, better hot restarts, better A/C performance, and less fan clutch lockup.
We can always go back and pick the numbers that might be more optimal in terms of interpretive data. I say, my data is only as measured with the tool I used. I clearly identified both and the conditions and procedures under which I used them. Optimal? Don't care, only clearly identified and replicable.
What doesn't change regardless, is my subjective evaluation exclusive to changing a single variable within hours of install. I appreciate the fact you want to focus on the theory, I'm looking at 20 years of similar results of the practical application.
No need to apologize, I don't. What I'd rather see, is discussion on the conclusions I made, because that appears to defy a lot of educated opinion here. Yet they confirm for me, based on years of slicing up hoods, the benefits are consistent, again, in the 80 chassis. I claim based on my results, I didn't miss anything other than what a couple theoretical engineers are looking for to possibly motivate practical application.
Kevin, take the fan shroud off and put up some measures. I've gotten up to speed on the 80 pretty quickly in my rookie year. From Supercharger install tips, to radiator install tips, fan interference data, to using the pressure switch on the aux fan, even 10kcst fluid from the dealer I bought 1 week after my truck. I acknowledge my relative inexperience in the 80 chassis. What I'd appreciate you *acknowleging* and thinking about, is that me taking action and posting results, might have value to this 80 tech forum.
I have no personal issues with you or anyone else on this list. Sit back, and let the rookie do his thing. If any of it fails, you are welcome to say "I told you so" when I post it up.
Peace
Scott Justusson
94 FZJ80 Supercharged
Chicago
landtank said:
In order to make it a true apple on your vehicle you would also need a supercharger. You could install the smaller blade and space it out toward the radiator but you would not have the same "heatsink" and you would have different airflow through the engine compartment (around the supercharger).
I went into more detail privately Dan.
- Thread starter
- #71
WE:
All great points if I was writing an SAE paper, or was even getting paid for the trouble. I'm not. I have presented data, tear it up. Could it be better? You bet. Is the data and results I posted 'inconclusive'? Nope. Is it repeatable? Sure. I say it has validity and a confidence level. I also agree you could make it more so, but not for free!
I also say you could remove the hood, or just open it.
I'm absolutely fine with what I presented. No one here has offered to pay me to hook up expensive guages and give SAE type results. I've done it several times, understand how and what tools to use in measuring data. My major in College was statistical research.
Here, you got what you paid for. You don't have to accept or believe, and can opin away. I accept that those with higher level expectations might not be satisfied. Fortunately, that's the exact minority on this forum. The question you need to ask yourself in reviewing ABC I-IV, is, do they have any value?
Despite your demand for more for free, I suspect so. I also expect that if you want to challenge my findings, take the practical application in doing so, and put up the data *you* find relevent. I think you'll better understand my point.
Scott Justusson
All great points if I was writing an SAE paper, or was even getting paid for the trouble. I'm not. I have presented data, tear it up. Could it be better? You bet. Is the data and results I posted 'inconclusive'? Nope. Is it repeatable? Sure. I say it has validity and a confidence level. I also agree you could make it more so, but not for free!
I also say you could remove the hood, or just open it.
I'm absolutely fine with what I presented. No one here has offered to pay me to hook up expensive guages and give SAE type results. I've done it several times, understand how and what tools to use in measuring data. My major in College was statistical research.
Here, you got what you paid for. You don't have to accept or believe, and can opin away. I accept that those with higher level expectations might not be satisfied. Fortunately, that's the exact minority on this forum. The question you need to ask yourself in reviewing ABC I-IV, is, do they have any value?
Despite your demand for more for free, I suspect so. I also expect that if you want to challenge my findings, take the practical application in doing so, and put up the data *you* find relevent. I think you'll better understand my point.
Scott Justusson
SUMO- I do think Walking Eagle has a point on the temp. readings, specifically this part:
"Take a couple of Thermocouples and put them under the hood at various places. Put one in the air box on each side of the filter. Then cover your vents. Drive down a 25mph road at 25, see what the temps are. Drive down the same road again (same direction to rule out the sun as much as possible), with the vents open. That will prove an effect. Do the same thing down a 5 or 10 mile stretch of interstate. That will also prove an effect. While your at it, measure engine temp if you can. I'm sure you could get the hoses to seal over a t couple and put one at outlet of radiator and inlet of radiator. Maybe even a couple well placed one in the radiator core."
I don't see any data on underhood, airbox, and rad. temps with hood vents vs. without. Without such data (not SAE-type results, just basic temp measurements), a very basic measurement of the effectiveness of this mod. is missing. Going by "seat of the pants" impression of the mod vs. before/after temp. data doesn't fit with the systematic approach you've described in earlier posts.
That said, I think I speak for a large majority of readers when I say I appreciate all the work you've put in so far, and have been reading your posts in the cooling thread with great interest!
"Take a couple of Thermocouples and put them under the hood at various places. Put one in the air box on each side of the filter. Then cover your vents. Drive down a 25mph road at 25, see what the temps are. Drive down the same road again (same direction to rule out the sun as much as possible), with the vents open. That will prove an effect. Do the same thing down a 5 or 10 mile stretch of interstate. That will also prove an effect. While your at it, measure engine temp if you can. I'm sure you could get the hoses to seal over a t couple and put one at outlet of radiator and inlet of radiator. Maybe even a couple well placed one in the radiator core."
I don't see any data on underhood, airbox, and rad. temps with hood vents vs. without. Without such data (not SAE-type results, just basic temp measurements), a very basic measurement of the effectiveness of this mod. is missing. Going by "seat of the pants" impression of the mod vs. before/after temp. data doesn't fit with the systematic approach you've described in earlier posts.
That said, I think I speak for a large majority of readers when I say I appreciate all the work you've put in so far, and have been reading your posts in the cooling thread with great interest!
Well,
Opening the hood makes a helluva difference in my case and as such I would have to speculate that any kind of hole(s) in the hood will drop the temp a bit.
I can also state (in my case) that the hot air is NOT having an easy time exiting my engine compartment when the vehicle is stationary.
Opening the hood makes a helluva difference in my case and as such I would have to speculate that any kind of hole(s) in the hood will drop the temp a bit.
I can also state (in my case) that the hot air is NOT having an easy time exiting my engine compartment when the vehicle is stationary.
To add a thought that doesn't seem to be adressed in this thread, underhood temps will affect more than just the engine temp. Heat kills rubber, electronics, and batteries. If the hood vents reduce temps in any way, be it engine intake air temp or just surface temps, it can't be a bad thing.
-Spike
-Spike
- Thread starter
- #75
alaskacruiser said:
****** BEFORE AND AFTER HOOD VENT TEMP DATA******
Combined from ABC Cooling Thread III and IV (pre and post hood vent temp data)
Raytek IR temp gun same spot in each test
A/C on fresh air (non recirc), Aux Fan on, 20minute heat soaked engine. Lift hood, zap temps within 10seconds.
Ambient temp 95F and 87F respectively
Actually, the data pre-hood vents is already logged as basic temp measurements. I'll repost from memory, but it's in my ABC's thread on Aux Fan install III post 1and in my ABC IV post 1. Here's the direct comparo between the two:
* Before my hood vents, I had 185-200F airbox temps with a heat soaked engine at idle and 95F ambient (a/c on - fresh air, aux fan off=185/ on= 200).
* After my hood vents, I had 125-135F airbox temps at 87F ambient (ac on - fresh air, Aux fan on)
Conclusion: 65-75F drop in measured airbox temps - (Note - offset 8F drop in ambient temp)
* Before my hood vents at 95F ambient (same conditions as above), I was measuring firewall temps on both sides of the motor of 160-180F.
* After the hood vents at 87F ambient (A/C on, heat soaked, Aux fan on) I measured 116-118F at the firewall both sides.
Conclusion: 40-60F drop in measured firewall temps - (Note - offset 8F drop in ambient temp)
And with this 'relief' I have observed better hot start, better hot idle, better tip in throttle response, better SC response at all speeds, and better A/C efficiency.
I'm sure others could do better measures, don't know, haven't see it yet. In the meantime, the above is data that hopefully puts up something for comparison.
Scott Justusson
Last edited:
Grench
SILVER Star
I have been following this thread for a while.
One of the early posts on this topic suggested lifting up the rear of the hood or removing the seal. This idea was put down because it would result in all the nasty fumes from the engine, oil leaks, etc... flowing over the windshield.
IMHO, cutting vents into the hood towards the rear isn't a whole lot better for the same reasons.
When I pop the hood after driving for a while I get a blast of hot air too. Cooling down the engine compartment is a pretty good idea.
What about going through the upper rear of the fenders with a 4" marine portal vent? Would this accomplish the need while keeping the fumes away from the windshield and cabin air intakes?
I haven't gotten to the vent cuting point in my cooling stuff yet. I'm still at the flush repeatedly before switching back to Toyota Red stage.
Edit...
Like this.
http://www.defender.com/product.jsp?path=-1|6880|45749|320599&id=46695
One of the early posts on this topic suggested lifting up the rear of the hood or removing the seal. This idea was put down because it would result in all the nasty fumes from the engine, oil leaks, etc... flowing over the windshield.
IMHO, cutting vents into the hood towards the rear isn't a whole lot better for the same reasons.
When I pop the hood after driving for a while I get a blast of hot air too. Cooling down the engine compartment is a pretty good idea.
What about going through the upper rear of the fenders with a 4" marine portal vent? Would this accomplish the need while keeping the fumes away from the windshield and cabin air intakes?
I haven't gotten to the vent cuting point in my cooling stuff yet. I'm still at the flush repeatedly before switching back to Toyota Red stage.
Edit...
Like this.
http://www.defender.com/product.jsp?path=-1|6880|45749|320599&id=46695
Last edited:
Stumpalama
Forum Junkie
Just cut two 10" hole in the firewall and run'em thru the truck and out the rear hatch (glass replaced by appropriate grade and thickness to avoid being blown out or having those nasty exhaust fumes roll back in).
Seriously though, well, maybe not, are we talking about driving a speed here or issues such as during wheeling, where air flow is controlled only by fan action?
'Cause all you have to do with an FJ40 is drive to get it up to temp, then shut it off and watch the temp gauge rise.
Seriously though, well, maybe not, are we talking about driving a speed here or issues such as during wheeling, where air flow is controlled only by fan action?
'Cause all you have to do with an FJ40 is drive to get it up to temp, then shut it off and watch the temp gauge rise.
SUMOTOY said:
I payed attention and sent a PM. The trouble I'm having is that in the same ambient temps Dan's truck doesn't maintain engine temps at idle and well as my truck did with a worthless fan clutch.
So why am I so concerned with his idling temps?
There is a york heading my way that will occupy the same spot as his SC. And I'm wrestling with how that install will effect my own cooling abilities.
The York will not take up as much room as the blower and it will not serve as a pre-heater for the intake air. It will have an effect on how air will flow through the engine compartment but I would not think it will impact you the way a blower appers to.
The only time I have a "problem" is when in induce it by making the truck sit at idle for a prolonged period of time with everything going. All I have to do is shut the compressor off or open the hood or kick the RPM up to bring the temp back down.
The only time I have a "problem" is when in induce it by making the truck sit at idle for a prolonged period of time with everything going. All I have to do is shut the compressor off or open the hood or kick the RPM up to bring the temp back down.
