Heat extraction hoods.. why?

[TooManyFords]

Everyone is carping about needing "Heat Extraction" for a hood. My question is simple...

WHY?

What is under there that you're afraid of melting?
(nothing)

Will your car run faster? (no)

You'd all do better to run a duct from the intake to the lower front if you want your car to run faster! Cowl Induction hoods actually had a purpose on the Chevy's when there used to be an air cleaner that was tied to it. It would pop open and fresh air would be sucked into the air cleaner. Otherwise it was nothing more than a styling cue.

Now, if you tell me you just want a cowl hood because you like the looks of them, that's one thing. But please show me the science behind wanting one for any other reason!

John

[sailsmen]

If you are running a turbo. I had a turbo on a Mercury and the heat toasted everything under the hood.

I installed 2 NACA ducts and cut a hole in the front facia but the heat damage had already been done.

Even the windshield washer reservoir was toasted!

[snowbird]

TMF,

I've got an IAT gauge and in some conditions, the temp is raising quite a bit. On light loads, it hover about 30 degree above ambiant but:

1- On a red light or in a traffic jam, it is rising 50 to 90 above ambiant very fast,
2- When taking off the OD on the highway, (to be ready to accelerate briskly), it will raise 50 -60 degree above ambiant before i even start fooling around.

Meth injection on boost will cool things off but you can only use it with a clear ahead road for obvious reasons !!

I admit it is nothing out of the extraordinary and maybe (probably) i'm worrying too much !

[2ndMDRebel]

I'm getting one just to help lower temperatures overall a bit in the engine compartment, or at least try to anyway. Yes, I like the looks (same one as gMDJoe's on his GothVic) too so its a win-win. He also checked with one of those laser temperature reader thingies and he was running a bit cooler on some of the component surface temps. Besides, "heat extraction hood" just sounds sexy!

[juno]

Uhhh, why not???? If you are going to spend the money on a new hood, why not get something functional?
Any heat you can remove from the engine compartment is good. Especially those of us living in SFL. I also will be running a turbo and that is some serious heat.

[magindat]

If I indeed got a hood, it would, in fact, be for the same reason Chevy had it!

[Zack]

Heat only builds up when you are standing still.
This was easily proved on one of my cars when I left the autometer Ambient Temp gauge under the hood in various locations
Within 1 minute of constant movement, the underhood temp was within 5 degrees of the outside temp.

[magindat]

Heat only builds up when you are standing still.
This was easily proved on one of my cars when I left the autometer Ambient Temp gauge under the hood in various locations
Within 1 minute of constant movement, the underhood temp was within 5 degrees of the outside temp.

I've been watching IAT's as well. For the street, that's fine. At the track, especially, here in FL, an 80 degree IAT is 14.3 while a 140 degree IAT is a 14.8.

Just reciting what I've experienced. No flames, my IAT's are high enough!!!

[TooManyFords]

If you are running a turbo. I had a turbo on a Mercury and the heat toasted everything under the hood.

I installed 2 NACA ducts and cut a hole in the front facia but the heat damage had already been done.

Even the windshield washer reservoir was toasted!

This was on your Marauder?

[TooManyFords]

The IAT of a boosted car doesn't count people. Just because your compressor of choice is raising the IAT temp doesn't mean that having a cowl hood will lower them. It won't.

Still don't see any science....

John

[TooManyFords]

If I indeed got a hood, it would, in fact, be for the same reason Chevy had it!

So, you want to put a Quadrajet on your 32V and run a vacuum operated Cowl Induction hood on your Marauder??

let me know how that works out for you, ok?

Still no science!

john

[magindat]

So, you want to put a Quadrajet on your 32V and run a vacuum operated Cowl Induction hood on your Marauder??

let me know how that works out for you, ok?

Still no science!

john

John, gimme a break. I said for the same REASON, not the same method!

I would build an intake box into the cowl and suck cool air all the time. The details are irelevant at this point since the hood doesn't exist. The science is suck cooler air. Typically for an NA car 10-12 degrees rougly means 1% HP. In Florida, on a 90 degee day I can pull 90 degree air or 200 degree air. Which would YOU rather?

Further, on a supercharged car, the heat of compression is fixed ata given boost level. Therefore, (again in Florida where I LIVE and DRIVE) if one pulls air that's roughly 100 degrees cooler, then when the heat of compression is added, the charge would start 100 degrees cooler and allow one to run more timing. There's HP in that (slightly) denser air and in that timing!

No, I'm not a tuner. I'm regurgitating info you already know.

Please don't be an LV and flip out over something that doesn't even exist yet. If folks like it, let 'em buy it. Just sit back and shake your head if you don't agree.

Take it easy. :D
Rich

[TooManyFords]

John, gimme a break. I said for the same REASON, not the same method!

I would build an intake box into the cowl and suck cool air all the time. The details are irelevant at this point since the hood doesn't exist. The science is suck cooler air. Typically for an NA car 10-12 degrees rougly means 1% HP. In Florida, on a 90 degee day I can pull 90 degree air or 200 degree air. Which would YOU rather?

Further, on a supercharged car, the heat of compression is fixed ata given boost level. Therefore, (again in Florida where I LIVE and DRIVE) if one pulls air that's roughly 100 degrees cooler, then when the heat of compression is added, the charge would start 100 degrees cooler and allow one to run more timing. There's HP in that (slightly) denser air and in that timing!

No, I'm not a tuner. I'm regurgitating info you already know.

Please don't be an LV and flip out over something that doesn't even exist yet. If folks like it, let 'em buy it. Just sit back and shake your head if you don't agree.

Take it easy. :D
Rich

Fair enough Rich. To rephrase your Science, the cowl hood does nothing until you also build a special intake box to change where the intake is getting air. And would you agree with that without the custom air box you would not get the benefit of the cowl?

People, you can want a cowl hood and it is OK. I'm just trying to prove a point in that you'll probably improve your track times with the lower weight of a regular fiberglass or carbon fiber hood than any "heat extraction" feature you may imagine is possible. So, until someone proves this with science I'm playing the BS card.

My personal opinion? I think Cowl induction hoods look tacky. The Marauder is just too big of a car to have one that looks like it belongs on the car. I realize some of you HAVE to have something done because your motor now sticks out of the hood. So does mine, but you should have thought about that before putting the motor in. And please don't take that the wrong way either! I'm all for making motors stick out of the hood. DUH! So for a couple of you this will have to be done and you have very good reasons. But "heat extraction" ain't it and that's my point.

Cheers.

John

[O's Fan Rich]

Anyone notice the flat louvered grilles on the hood of the H2?

It's black!

[pantheroc]

If underhood temp is a concern, wouldn't a temperature controlled relay to the fans be enough?

[Zack]

Heat only builds up when you are standing still.
This was easily proved on one of my cars when I left the autometer Ambient Temp gauge under the hood in various locations
Within 1 minute of constant movement, the underhood temp was within 5 degrees of the outside temp.

John, was this not Science enough?

[TooManyFords]

John, was this not Science enough?

Plenty and it proves my point.

;)

john

[magindat]

If underhood temp is a concern, wouldn't a temperature controlled relay to the fans be enough?

Marauders already have that and it's variable speed to boot! Trouble is... fan control is not based on IAT, but is controllable in tuning. That air needs a place to go if you blow it on the motor. Heat rises. Cowl hood allows the blown fan air to escape along it's natural path of rising.

Functionally, a cowl hood isn't gonna do a dayum thing without doing something else to utilize it. Either build an intake box, close it off and add gauges, change your fan speeds and temps in tuning, put on a high rise intake (needing clearance), 5.4 heads or whole 5.4 motor, bigger twin screw s/c, even just clearancing a trilogy pully, whatever. Just the hood itself serves little if any function. It allows all kinds of other things to be done, though!

So, in a way, John and Zack are definately right. JUST A HOOD DOES NOTHING. It's how you use it that counts.

Of course, bling is king and many will simply like the looks!

No judgement here, just helping satisfy John's need for SCIENCE!!!!!

[TooManyFords]

We just need a factory light-weight fiberglass hood and then everyone can graft on whatever they want AFTER they receive it. I'm not sure everyone realizes they're going to incur another $400-$500 charge for a bodyshop to actually "finish" that hood you want, regardless of what it looks like.

You're dreaming if you think you're going to get a "prime and paint" hood! They will have to mud it, sand it, straighten it, clean up the highs and lows and after 20 hours of labor, THEN they can prime and paint it. That hood will go from $500 to $1000 before you can blink.

In fact, everyone that is interested in a fiberglass hood should go out to their local bodyshop and get an "estimate" for finishing, painting and installing said hood and then report your findings back here. Please, do this if you want a hood. Let's find out what the -rest- of the story looks like.

John

[TooManyFords]

fan control is not based on IAT, but is controllable in tuning. That air needs a place to go if you blow it on the motor. Heat rises. Cowl hood allows the blown fan air to escape along it's natural path of rising.
Fan control is set in the PCM to keep the coolant at the optimum temperature for efficient combustion of the factory motor.

But the rest of that makes me laugh!
:lol:

Of course heat rises but the air will only escape through a cowl when you're sitting still. That would be like saying you're racing on jack stands and I know that's not true. Air escapes under the car as soon as you start moving regardless of how hot it is... Ask Zack.

So far, the only true heat extraction exception might be Big Joe P's side-vent mod he did. That was a novel approach and would actually vent air out the side. But I believe he did that mod for aesthetics, nothing more...

John

[Power Surge]

Why?..... Why not?

Hot underhood temps serve no benefit that I can think of, so why not keep things cooler under there?

Lower underhood temps can help lower overall engine temp, lower exhaust temp and EGTs, and of course lower air intake temps, depending on the vehicle of course.

If someone is gonna plunk down 500-700 bucks on an aftermarket hood, it might as well do something other than look pretty.

Just my take on it.

[merc]

Sal, if you get the hood made sign me up on the group buy.

[Zack]

I say we just trade the MM in on an Impala or Hemi product.
They make hoods for those cars

[merc]

I say we just trade the MM in on an Impala or Hemi product.
They make hoods for those cars

Are you proposing a group Trade-in ?:lol:

[magindat]

Fan control is set in the PCM to keep the coolant at the optimum temperature for efficient combustion of the factory motor.

My point exactly. The fan speed is NOT for reducing IAT's. Although, you could change the tuning to 'help' IAT's.



Of course heat rises but the air will only escape through a cowl when you're sitting still. That would be like saying you're racing on jack stands and I know that's not true. Air escapes under the car as soon as you start moving regardless of how hot it is... Ask Zack.
Of course, ask me, too! You both have one of my air dams made to do just that!!! As a matter of fact, the cowl will only pass air OUT while sitting still. Upon moving, the bernouli effect will actually cause air to be suck IN. This is the basis of COWL INDUCTION.


So far, the only true heat extraction exception might be Big Joe P's side-vent mod he did. That was a novel approach and would actually vent air out the side. But I believe he did that mod for aesthetics, nothing more...

John
So, what's wrong with a hood for aesthetics?

Again, and to bring my discussion together, I see very high IAT's while waiting in line at the track for my run. I raise my hood while parked and let 'er cool. I load up when called and I idle while I wait my turn behind 10-15 cars. In that time, my IAT's will go from ambient to 120-140 degrees. To me, that's 30-50 above ambient or 3-5% HP (brake) or 10-15 HP. The IAT won't drop to ambient 'till about 1000'. That's at the tall and of 2nd gear. So I shorted myself 10-15 HP just by waiting in line.
We often see Dodge folks (without the PCM speed controlled fan) taking over their fan control. Upon discussion with the smarter of them, not only does it help with heat soak while waiting, but also with IAT's building while idling.
So, in summary, a cowl hood still DOES NOTHING until you do something with it. My point is, many things CAN BE DONE WITH IT that would be at least mildly beneficial.

[magindat]

Excellent thread. Good exchange of ideas, a little ribbing, a little joking and good, hearty discussion!

[TooManyFords]

So, what's wrong with a hood for aesthetics?

So, in summary, a cowl hood still DOES NOTHING until you do something with it. My point is, many things CAN BE DONE WITH IT that would be at least mildly beneficial.

I totally agree. I just think that there are a lot of people on the forum that might be misled by this mod. I've already said that if you like cowls, it is OK.

My point is that if we all started with a generic factory hood and then purchased whever form of mod for it, be it cowl, scoop or ram-air, or in my case none, that we'll get more people to buy than trying to argue out what the hood should look like. We're all going to pay that extra fee to finish the hood at the bodyshop. Adding whatever dongle to it will be minimal at that point and everyone benefits.

That is my opinion.

John

PS: I have an appointment to get my lower dam installed this week...
:banana:

[juno]

For some science read this thread, specifically starting at reply #9.
http://www.turbomustangs.com/smf/index.php?topic=47132.msg49364 1#msg493641

I hope the pics still work.

[2ndMDRebel]

PS: I have an appointment to get my lower dam installed this week...
:banana:

The Mach-1 one or is it custom?

[magindat]

The Mach-1 one or is it custom?

Not chin spoiler. lower air dam. See here: http://www.mercurymarauder.net/forums/showthread.php?t=31789

[RR|Suki]

to me the more heat you can get out while sitting still the better... temps sky rocket under my hood when sitting still, I am going to move my coolant res. to help this for right now since it currently sitts right next to the blower... I too have logged data from under the hood, and it doesn't take long for temps to cool off... but it takes longer yet for the internal temps to settle, I'm running ultra lite fans, a rather large snail and a lack of space to move the stupif coolant tank... I can see 220* easy in traffic, and to me if I could keep the temps mre reasonable at a stand still it would only benifit becasue temps would drop faster... that's what I think about that

[magindat]

I totally agree. I just think that there are a lot of people on the forum that might be misled by this mod. I've already said that if you like cowls, it is OK.

My point is that if we all started with a generic factory hood and then purchased whever form of mod for it, be it cowl, scoop or ram-air, or in my case none, that we'll get more people to buy than trying to argue out what the hood should look like. We're all going to pay that extra fee to finish the hood at the bodyshop. Adding whatever dongle to it will be minimal at that point and everyone benefits.

That is my opinion.

John

PS: I have an appointment to get my lower dam installed this week...
:banana:

I see your point and I mentioned similar in other threads that it would be mush easier and long lasting to mod fiberglass to fiberglass than FG to metal. I STILL think a LOW and BASIC 'cowl' or just rasing or the center section following existing body lines would be a great (better) place to start.

[High-C]

Of course, ask me, too! You both have one of my air dams made to do just that!!!

What is this Air Dam that you speak of???

[magindat]

For some science read this thread, specifically starting at reply #9.
http://www.turbomustangs.com/smf/index.php?topic=47132.msg49364 1#msg493641

I hope the pics still work.

Picty's no worky's.

Still a great read.
thanx

[magindat]

Not chin spoiler. lower air dam. See here: http://www.mercurymarauder.net/forums/showthread.php?t=31789


What is this Air Dam that you speak of???

I hate it when I quote myself!!!

[magindat]

The Mach-1 one or is it custom?


For some science read this thread, specifically starting at reply #9.
http://www.turbomustangs.com/smf/index.php?topic=47132.msg49364 1#msg493641

I hope the pics still work.


What is this Air Dam that you speak of???

The benefit which I measured on this mod is re-iterated in Juno's read. John this ain't a hijack, but an addition to your 'science'.

It'll take 9 takers at $100 a pop for another run.

They WORK.

[MarauderTJA]

I like the looks, but any heat that can be removed under the hood here in Florida, the better. No science here John:D .

[sailsmen]

The OEM turbo Mercury I had was an XR4ti.

Ford added a turbo to their 4 cylinder. Unfortunately they did not engineer the increased under hood temps.

Everything that was not metal cooked. Even the fan belts.

I modded it and it was fast and handle well, but was constantly replacing heat fatiged underhood plastic parts.:(

[gdmjoe]

2ndMDRebel - I'm getting one just to help lower temperatures overall a bit in the engine compartment, or at least try to anyway. Yes, I like the looks (same one as gMDJoe's on his GothVic) too so its a win-win. He also checked with one of those laser temperature reader thingies and he was running a bit cooler on some of the component surface temps. Besides, "heat extraction hood" just sounds sexy!
Temperature readings thread (http://www.crownvic.net/ubbthreads/showflat.php?Cat=&Board=performance&Number=1305132&page=0&view=collapsed&sb=5&o=365&fpart=1) <<<<< -click-

*Your mileage ( er, temperature ) may vary. :D

[GreekGod]

...I'm surprized no one mentioned the benefit of increased air flow through the radiator, with a vented hood.

Adding headers to an MM decreases exit area, for air getting out of the radiator. This is a common problem with big-block '68-70 Mustangs, which have very crowded engine compartments, even without headers.

NASCAR racers try to make the whole front end a big air dam, with the radiator air inlet as small possible.