Lower engine and IAT2 temps with free mod...
- Thread starter fullboogie
- Start date
:-D +1
Even if it is drawing air in through the back of the cowl, it could very well be forcing more hot air out of the vents due to increased pressure at the bac of the bay. Regardless of the "string", if the temps are lwoer without the seal then it is helping with cooling.
Just make sure you still have an oring on your coil covers. Getting those wet can ruin them.
A real test would be to do them back to back not have it one way and then 10 days have it another. When ever i do any testing like this i repeat the teat at least 4 times just to verify the tests were correct. I am currently doing h/e tests. I take the car to different tracks for one. I also do a 25 mile drive each way and record the temps etc. The drive consists level ground, some elevation changes from 1800ft to almost 4100ft and some city driving. The days have been about the same temps. On level ground the temps have all been about the same but the difference while climbing the hills is where you the big difference is at. One h/e restricts so much that my engine soared to 225* while climbing one of the hills.
This mod seems to be ok while cruising and in city traffic the true test will be higher speeds that put a load on the engine. I would bet that if you did the test day to day the temps would be much closer than you think.
I think you need to re-read; the OP said he tested for ten days straight, not waited 10 days to test.
OP great job with your testing and datalogging.
I agree with this. That extra air coming in has to exit somewhere. But I also agree with stkjock (I believe) in that the air coming in would be dispersed by the engine and other parts under the hood so as not to create any effective lift. Perhaps it forces more air out of the heat extractor? One thing's for sure, it has to be creating more drag. OP, have you been logging fuel consumption compared to having the weather strip in place?
You guys are hilarious :rolling:
Are you serious? Logging fuel consumption after removing a piece of weatherstripping? I had to look at the top of the page to make sure I wasn't on corvetteforums.com.
Oy. :facepalm: Did you even read my post or did you just jump to the end with blowtorch in hand? You know drag affects fuel consumption, right? You're not coming from Camaro5 are you?
Yes, I read your post GT Premi. I couldn't give a damn about increased drag or fuel consumption, nor does anyone else using their car as a daily driver - which is the entire purpose of this thread. It has nothing to do with increased lift, increased drag, or taping strings to your hood.
And for what little drag/mpg may be affected, I'd then say the mod is effective at scavenging heat from the engine bay, wouldn't you? In any case, you've mucked up a thread with issues that nobody cares about.
And for what little drag/mpg may be affected, I'd then say the mod is effective at scavenging heat from the engine bay, wouldn't you? In any case, you've mucked up a thread with issues that nobody cares about.
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I'm gonna take a different approach here. We have two facts. 1-Fullboogie removed his weatherstrip and his car ran cooler. 2-I showed that the base of the windshield is a high pressure area and it's unlikely that hot air is exiting there.
Maybe our conclusions on how this is happening are wrong. On a standard old grocery getter, where does engine compartment air go? Out the bottom, probably drawn out by air rushing under the car. But what displaces this hot air? More air coming through the radiator and whatever other air leaks there are. It can only remove as much as is equal to that coming in. In other words, it's sucking against resistance. Now, you remove your weatherstrip, the high pressure air comes rushing into the engine compartment, relieves some of the resistance to air getting sucked out the bottom, more hot air gets sucked out, and the car runs cooler.
Maybe our facts were right but our conclusions wrong.
Steve
Maybe our conclusions on how this is happening are wrong. On a standard old grocery getter, where does engine compartment air go? Out the bottom, probably drawn out by air rushing under the car. But what displaces this hot air? More air coming through the radiator and whatever other air leaks there are. It can only remove as much as is equal to that coming in. In other words, it's sucking against resistance. Now, you remove your weatherstrip, the high pressure air comes rushing into the engine compartment, relieves some of the resistance to air getting sucked out the bottom, more hot air gets sucked out, and the car runs cooler.
Maybe our facts were right but our conclusions wrong.
Steve
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Could I talk one of you GT500 guys into trying this string test with the hood weather strip removed?
Though it is certainly not needed a go-pro camera on the dash would just be a nice bonus, you could call out the miles per hour as you increase speeds for reference.
I don't have an 05-13 Mustang to try this on. I am none the less very interested because if the aero of that body is that much different that than a SN95 or new edge car, guys that track 05-13 cars can benefit from that information as being a valid cooling mod. If I ever pick up a used Boss or GT or GT500 it will be good to know.
I would like to clear up one other thing, air entering the engine bay from any area that is not through the radiator, is going to increase the air pressure in the engine bay, which will decrease the pressure differential between the air in front of the rad and the air behind the rad. The exception would be where it is directly ducted to the engine air intake and ingested into the engine.
This will result in less air flow through the rad.
Engines do not get cooled by blowing cooler air on them, they get cooled by coolant removing heat from the inside.
Hood vents are all about the air pressure differential, they maximize the difference between rad inlet air and rad exit or engine bay air.
Lowering engine bay air temps makes practically no difference.
Lowering engine bay air PRESSURE makes all the difference in the world! difference.
Van@RevanRacing
Active Member
I was one of the first to open track a GT500 as many of you know. I experienced heat soak and attacked the problem. That was the beginning of Revan Racing.
I spoke with a Ford Racing employee, now employed elsewhere, about this very subject. I removed the weather stripping and open tracked the car with and without. Now open tracking is a lot more heat and abuse. With that said the removal of the weather strip does help to remove engine bay heat which decreased IAT1 which subsequently decreased IAT2 modestly. However the car was still heat soaked and that's when I got started with the radiator and the heat exchanger most of you all know today.
The weather stripping does allow for cooler operating temperatures on the street and track.
Down sides to removal:
1. If you wash your or your car is exposed to rain, water will get into the engine bay. For those that are complete neat freaks about an engine bay this will represent a problem.
2. If you wash your car or it is exposed to rain even a heavy down pour you can and will accumulate water in the valley of the motor. It runs down the back of the motor and collects in the valley underneath the intercooler pan. Then you freak out when you pull into the garage and there is water under your car because it sloshes around and it is dry out. You will think your radiator is broken
3. If you wash your car or it is exposed to rain and you have not adequately and properly secured your coil pack covers and gotten the gasket placed correctly in the back by the fire wall your rear coil packs can and will fill up with water. I've seen it a lot. This can cause a CEL and spark plug failure and detonation. FYI. Super Snakes have aftermarket hoods with no weather strip. I've worked on quite a few Super Snakes with water in the rear coil packs. Even from just giving the car a wash.
In short, if you're going to open track the car or your car never gets wet, go for it. I would only suggest this modification if you plan to open track the car or participate in something that creates excessive engine bay heat.
I spoke with a Ford Racing employee, now employed elsewhere, about this very subject. I removed the weather stripping and open tracked the car with and without. Now open tracking is a lot more heat and abuse. With that said the removal of the weather strip does help to remove engine bay heat which decreased IAT1 which subsequently decreased IAT2 modestly. However the car was still heat soaked and that's when I got started with the radiator and the heat exchanger most of you all know today.
The weather stripping does allow for cooler operating temperatures on the street and track.
Down sides to removal:
1. If you wash your or your car is exposed to rain, water will get into the engine bay. For those that are complete neat freaks about an engine bay this will represent a problem.
2. If you wash your car or it is exposed to rain even a heavy down pour you can and will accumulate water in the valley of the motor. It runs down the back of the motor and collects in the valley underneath the intercooler pan. Then you freak out when you pull into the garage and there is water under your car because it sloshes around and it is dry out. You will think your radiator is broken
3. If you wash your car or it is exposed to rain and you have not adequately and properly secured your coil pack covers and gotten the gasket placed correctly in the back by the fire wall your rear coil packs can and will fill up with water. I've seen it a lot. This can cause a CEL and spark plug failure and detonation. FYI. Super Snakes have aftermarket hoods with no weather strip. I've worked on quite a few Super Snakes with water in the rear coil packs. Even from just giving the car a wash.
In short, if you're going to open track the car or your car never gets wet, go for it. I would only suggest this modification if you plan to open track the car or participate in something that creates excessive engine bay heat.
Well Jimmy, there goes my latest theory.
Fullboogie, since your weatherstrip is already out, why don't you do the string test on your way to work tomorrow. Freeway speeds should be enough to determine what happens.
Steve
Fullboogie, since your weatherstrip is already out, why don't you do the string test on your way to work tomorrow. Freeway speeds should be enough to determine what happens.
Steve
Will do, Steve. Your theory may be correct - that maybe there is something else indirectly causing this effect. All I know is that after ten days of logging with the strip in place, my engine temps were consistently in the mid 180's and IAT2's were in the mid to upper 110's every single day at the highway offramp. With the strip removed, I got the temps displayed in the original post. Same weather, same humidity. I'm happy with the results and plan to keep the strip removed. But I'll do the string trick and report back. I just question whether the mild venting affect will even show up with all the turbulence that area will see at highway speeds. I don't expect to see the strings flying backwards at 70 mph.
Rather than all this bickering, I just wish someone would take five minutes to remove theirs and log temps. It's too damn easy not to try it.
Rather than all this bickering, I just wish someone would take five minutes to remove theirs and log temps. It's too damn easy not to try it.
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You know what, maybe i too was going about it the wrong way too. My perspective was people saying the hot air exiting the rear of the hood. I proved that wrong years ago. I never thought about what if you let more air in the engine compartment it would run cooler. My ait1's aren't going to be any lower since i have the jlt cai.
Thanks guys.
Another test to find out answers to.
Thanks guys.
Another test to find out answers to.
Yes, when I changed my spark plugs it appeared that water had run down the harness and under the coil cover on each side at the rear. I also noticed that when SA installed the different spark plugs for my KB upgrade, the seal for the coil covers had not been properly seated in the channel/groove at the rear of each cover, allowing water to get under the cover more easily.
R
Ok, here's my results of Steve's "string test" at idle. I've not had a chance to do this at speed, and I'm not sure I will be able to do so safely.
First up, video of the rear of the hood with the weatherstripping in place:
[youtube_browser]NPCvpr3QHuw[/youtube_browser]
Now with the weatherstripping removed (notice the venting effect even with the engine off?):
[youtube_browser]EDHLDE6txO0[/youtube_browser]
Keep in mind that this tested only about at 10" width of the rear hood surface. I'd say this proves the venting effect quite convincingly, at idle. I suspect the same is true at at any speed.
Regarding Van's concerns about rain coming through the rear of the hood, I will have to respectfully disagree with my bro. First, the seal is tucked at least 1/2" under the rear lip of the hood. Second, if you look at that area where the seal meets the plastic wiper cover (for lack of a better term), there is a huge valley that is at minimum 3" deep. In order for rain, or any other water, to flow into the engine compartment, there would have to be zero drainage and it would have to pile up at least 3" to overflow into the engine compartment:
And lastly, I did a little experiment in which I checked the temperature of the cowl area with an infrared gun both with the weatherstripping in place, and then with it removed, each after 10 minutes of idling:
First, weatherstripping in place:
Then with the weatherstripping removed:
I hope the above videos and pictures prove the venting effect of removing the weatherstripping beyond any doubt. If I can get a video at speed, I will. But I doubt I will be able to do so safely. Even so, according to the pressure differential theories in this thread, wouldn't the venting effect be even greater at speed - even more so than what is seen in the videos? Put another way - if there is this much venting at idle, wouldn't the "pressure differential" talked about be even greater at highway speeds, thus causing even greater venting effect?
Thoughts and comments welcome...
First up, video of the rear of the hood with the weatherstripping in place:
[youtube_browser]NPCvpr3QHuw[/youtube_browser]
Now with the weatherstripping removed (notice the venting effect even with the engine off?):
[youtube_browser]EDHLDE6txO0[/youtube_browser]
Keep in mind that this tested only about at 10" width of the rear hood surface. I'd say this proves the venting effect quite convincingly, at idle. I suspect the same is true at at any speed.
Regarding Van's concerns about rain coming through the rear of the hood, I will have to respectfully disagree with my bro. First, the seal is tucked at least 1/2" under the rear lip of the hood. Second, if you look at that area where the seal meets the plastic wiper cover (for lack of a better term), there is a huge valley that is at minimum 3" deep. In order for rain, or any other water, to flow into the engine compartment, there would have to be zero drainage and it would have to pile up at least 3" to overflow into the engine compartment:
And lastly, I did a little experiment in which I checked the temperature of the cowl area with an infrared gun both with the weatherstripping in place, and then with it removed, each after 10 minutes of idling:
First, weatherstripping in place:
Then with the weatherstripping removed:
I hope the above videos and pictures prove the venting effect of removing the weatherstripping beyond any doubt. If I can get a video at speed, I will. But I doubt I will be able to do so safely. Even so, according to the pressure differential theories in this thread, wouldn't the venting effect be even greater at speed - even more so than what is seen in the videos? Put another way - if there is this much venting at idle, wouldn't the "pressure differential" talked about be even greater at highway speeds, thus causing even greater venting effect?
Thoughts and comments welcome...
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I can only add this to the discussion regarding the back of the hood being a low pressure/high pressure area:
It's been raining heavily here in North Florida every afternoon and the tree i park under has been dumping a ton of leaves on my shelby. I hop on I-10 West and head home at 80ish and all of the leaves promptly leave the scene except for any that are on the back 1/4 of my hood (toward the windshield). They will sit there (and I'm not talking flat leaves suctioned to the hood from a membrane of water; I'm talking curled up leaves that have no business sitting stationary on a vehicles hood at 80+ mph) for the entire ride unless i get buffeted by the wind coming off a semi as i pass him in the slow lane or when i pass a large oncoming vehicle on a 2 lane...
For what it's worth...
It's been raining heavily here in North Florida every afternoon and the tree i park under has been dumping a ton of leaves on my shelby. I hop on I-10 West and head home at 80ish and all of the leaves promptly leave the scene except for any that are on the back 1/4 of my hood (toward the windshield). They will sit there (and I'm not talking flat leaves suctioned to the hood from a membrane of water; I'm talking curled up leaves that have no business sitting stationary on a vehicles hood at 80+ mph) for the entire ride unless i get buffeted by the wind coming off a semi as i pass him in the slow lane or when i pass a large oncoming vehicle on a 2 lane...
For what it's worth...
Van@RevanRacing
Active Member
Leave your car outside during a Florida torrential downpour and you will quickly discover that water will get in there. Ask me how I know? LOL
I am not theorizing I am speaking from experience. It happened to me.
:beer:
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