Removing the Hood Fire Blanket....Bad Idea?

[tjkj2002]

EDIT:


I re-read your entry and have some questions. At 60 yr. old I think of "older" cars as a '60 model. I don't see a difference in a '90 and a similarly equipped '06 vehicle with respect to under hood heat generation and retention. I still have questions about the baking process as to when that started. I have a friend that runs a body shop. As soon as I get a chance I'll get his input.

I'd also like to know what temp. reading would be on a dark colored hood that is sitting in the midday sun in the south in August for comparison. I certainly can't touch them. hummmmmm ........

Sometime in the early '90's is when they switched to the 2 stage paint system.

Not all body shops bake the paint when they re spray something. Far as I know factory paints are indeed baked.

None around here bake but they should know about the process, when it started, how it is effected by the direct under hood temps, etc.

I'd be finding one that does since most newer paints need to be baked for longevity.Those bodyshops must have terrible turnaround times for there work without a bake booth.Heck my home town of 15,000 people all the bodyshops have bake booths in all the bodyshops,the dealership I worked at has 2 bake booths.

 

[Redbone]

That damages the hood too. Heat is heat, doesn't matter where it comes from. I can't say whether or not the heat will destroy the hood, I just know I've owned a few cars where the hood was noticably oxidized and peeling where the rest of the car was still in decent shape.

I'm pretty sure the paint they put on cars is better than the stuff they were putting on the cars I'm remembering, but if the manufacturer put on a large heat resistant blanket, I'm going to assume it was there for a good reason. My guess is, the manufacturer isn't 100% confident that their own paint will stand up to direct engine heat over time.

Again, I doubt anyone's going to see anything noticable in even five years. But if you keep the vehicle for its lifetime, the one without the blanket will probably suffer some kind of paint failure before the one with.

NOTE: I'm not flaming or argueing. Just a discussion comparing info.

That being said and out of the way, you are right about changes of paint quality. For a while, late '70s & most of '80s you could store the cars in a controled temp. garage and the paint would oxidize. Silver was the worst.

I'm still hung up on the reason for the blanket. My '02 Trans Am Does not have one as did my '98 and the '94. My '03 GMC does have one. I don't think GM would have a confidence problem with one and not the other.

I do agree that whatever the reason for it no problems will show up very soon. I've removed several without a problem todate. HOWEVER I always remove the rear weather stripping too. This will lower underhood temps considerably.

 

[tjkj2002]

HOWEVER I always remove the rear weather stripping too. This will lower underhood temps considerably.

I'd rethink that one on a KJ,not a good idea to have water constantly(if raining and such) to be dripping right on the PCM/TCM.

 

[Redbone]

I'd rethink that one on a KJ,not a good idea to have water constantly(if raining and such) to be dripping right on the PCM/TCM.

It's a Jeep. Should be tight as a ducks butt - waterproof.

 

[tjkj2002]

It's a Jeep. Should be tight as a ducks butt - waterproof.

More like weatherproof at best.

 

[Redbone]

I have looked at this on my KJ and other vehicles. There is evidence of water getting on almost everything under the hood when driving in the rain. I/we were doing this all the way back to a time when vehicles had points. Only had one problem and that was waaaaay back then. GM had that handy little sliding door on the distributor cap. It sure was convienient to adjust points gap but didn't seal worth a crap.

As I said, nothing but a poor man's cowl induction.

 

[tjkj2002]

As I said, nothing but a poor man's cowl induction.

To bad for what you want it to do it is the total opposite since air is force into that area instead of drawing the hot air out.

 

[Redbone]

Yeah, I've proven that to others using ribbons. My main goal is to get air moving to cool underhood temps. Direction is unimportant.

 

[tjkj2002]

Yeah, I've proven that to others using ribbons. My main goal is to get air moving to cool underhood temps. Direction is unimportant.

It is when your moving forward,unless you drive around in reverse all the time it's defeating the whole purpose.

 

[Redbone]

It is when your moving forward,unless you drive around in reverse all the time it's defeating the whole purpose.

I'm . If air is traveling out it is hot air escaping. This would be replaced by air from the front. Even air having passed through the radiator would be better than stagnant air. If air is traveling in at that point it is cold air. Obviously this would be good.

Another point I would make is if you are correct a lot of people have wasted money on a lot of cowl induction hoods .... including us. I thought this induction system had been proven.

 

[tjkj2002]

I'm . If air is traveling out it is hot air escaping. This would be replaced by air from the front. Even air having passed through the radiator would be better than stagnant air. If air is traveling in at that point it is cold air. Obviously this would be good.

Another point I would make is if you are correct a lot of people have wasted money on a lot of cowl induction hoods .... including us. I thought this induction system had been proven.

The cowl area gets high pressure air coming in,why many carb'ed engines get a benefit from "cowl induction" hoods since cool air is forced into that area when traveling forward.Now when you are traveling forward you also have air coming in from the front(radiator area) which is heated from passing through the radiator,add the "cowl induction" the hot air and cold air meet and is forced down under the vehicle which is where you do not want it to go since hot air wants to raise and you take any cooling effect the colder air rushing under the vehicle does for the trans,t-case,and F/R diffs.Plus that added air under the vehicle messes up your "drag" causing worse mpg's also.

What you are trying to do with "cowl induction" does more harm then good.Put hood vents in and replace that rubber molding in the coal area to prevent shorting out the PCM/TCM in a KJ and get better/cooler underhodd temps.

 

[Redbone]

The cowl area gets high pressure air coming in,why many carb'ed engines get a benefit from "cowl induction" hoods since cool air is forced into that area when traveling forward.Now when you are traveling forward you also have air coming in from the front(radiator area) which is heated from passing through the radiator,add the "cowl induction" the hot air and cold air meet and is forced down under the vehicle which is where you do not want it to go since hot air wants to raise and you take any cooling effect the colder air rushing under the vehicle does for the trans,t-case,and F/R diffs.Plus that added air under the vehicle messes up your "drag" causing worse mpg's also.

What you are trying to do with "cowl induction" does more harm then good.Put hood vents in and replace that rubber molding in the coal area to prevent shorting out the PCM/TCM in a KJ and get better/cooler underhodd temps.

O.K.

 

[jnaut]

It's a Jeep. Should be tight as a ducks butt - waterproof.

I think the legal term would be "Weather Resistant".

 

[HoosierJeeper]

I think the legal term would be "Weather Resistant".

x2....

 

[Redbone]

Now when you are traveling forward you also have air coming in from the front(radiator area) which is heated from passing through the radiator,add the "cowl induction" the hot air and cold air meet and is forced down under the vehicle which is where you do not want it to go since hot air wants to raise and you take any cooling effect the colder air rushing under the vehicle does for the trans,t-case,and F/R diffs.Plus that added air under the vehicle messes up your "drag" causing worse mpg's also.

Here is whats bothering me. I could debate the effect on the running gear as it is fact that colder air would be better for it. BUT this writeup doesn't appear to be rooted in fact. Please direct me to where this theory has been tested. In the mean time I must take exception to the idea that any possible negative effect would be large enough to be measurable.

I'm going to have to stick with the my theory that the existing hot air from the radiator, radiant heat from the engine, and the cooler air from under the front of the car will mix with my added cool air from the cowl area. This cooler air moves around the engine compartment and under the vehicle cooling everything a little more than prior to no cowl air. I would put forth that under typical driving conditions the air from the engine is moving at a rate of speed so as to take the rise of hot air out of the equation.

In the end I can't prove my cooler engine compartment = greater performance either but I figure I can slip the rubber gasket back in place for trade in purposes much easier than repairing holes in the hood. I suppose I'll just leave the seal out for now.

 

[oddball]

After a couple of years mines still good but then I installed hood louvers as well

Copycat.

(or would that be the other way around?)

 

[Redbone]

HOLD THE FRICKIN PHONE ......
My son used my computer. He saw the thread and answered this like it was serious. Sorry tj. :-&

Redbone

Originally Posted by tjkj2002 View Post
Now when you are traveling forward you also have air coming in from the front(radiator area) which is heated from passing through the radiator,add the "cowl induction" the hot air and cold air meet and is forced down under the vehicle which is where you do not want it to go since hot air wants to raise and you take any cooling effect the colder air rushing under the vehicle does for the trans,t-case,and F/R diffs.Plus that added air under the vehicle messes up your "drag" causing worse mpg's also.

Here is whats bothering me. I could debate the effect on the running gear as it is fact that colder air would be better for it. BUT this writeup doesn't appear to be rooted in fact. Please direct me to where this theory has been tested. In the mean time I must take exception to the idea that any possible negative effect would be large enough to be measurable.

I'm going to have to stick with the my theory that the existing hot air from the radiator, radiant heat from the engine, and the cooler air from under the front of the car will mix with my added cool air from the cowl area. This cooler air moves around the engine compartment and under the vehicle cooling everything a little more than prior to no cowl air. I would put forth that under typical driving conditions the air from the engine is moving at a rate of speed so as to take the rise of hot air out of the equation.

In the end I can't prove my cooler engine compartment = greater performance either but I figure I can slip the rubber gasket back in place for trade in purposes much easier than repairing holes in the hood. I suppose I'll just leave the seal out for now.

My belief is tj's ideas are correct. I resealed my hood. tj reminded me that hot air rises. The hotter the air under the car the more it pushs up on the car. This makes the car lighter and I get better mpg.

 

[jnaut]

HOLD THE FRICKIN PHONE ......
My son used my computer. He saw the thread and answered this like it was serious. Sorry tj. :-&





My belief is tj's ideas are correct. I resealed my hood. tj reminded me that hot air rises. The hotter the air under the car the more it pushs up on the car. This makes the car lighter and I get better mpg.

Ahh, the old 'remember me' checkbox. Gets 'em everytime.