Mythbuster: Under hood heat shield or fire blanket?

[Rice Over Wheat]

Let's confirm or kill this "myth" once and for all. I did a search and found two threads on that foil under hood cover. In both cases, Defiant says it's a myth and is only there to save your sheetmetal/paint from high engine bay temps. Then there's a wiseman or two that says no, it's for smothering fires when the plastic tabs melt. Which is it? Is it both?

http://www.dsmtuners.com/forums/showthread.php?t=93018&highlight=heat+shield

Reason I am asking is because I just finished my GreyforestGST hood mod. I tossed the under hood cover without even thinking first...now I'm wondering if I should head straight to Mitz dealership for a replacement or cut an evo one to fit. I felt my hood and it did feel pretty damn hot without one.

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[1stGenRocks]

its just a heat sheild. My friend actually had one catch fire on his 1g after he had a nasty oil leak.

You should get one though otherwise your paint may start to crackle

 

[Rice Over Wheat]

I also think it's just to guard the hood from engine heat. My EGT sensor popped out once and I was shooting 1400* exhaust into that shield. The foil peeled away and it got charred. Didn't catch fire though.

I'm heading to Mits tomorrow to see if the evo one might work when cut. Might not though since the evo has those vents all over.

 

[sheldon]

I also think it's just to guard the hood from engine heat.

that is correct...eventually the outside of your hood will get start turning a faint brown

 

[denniegst]

but since you now have air flow into the engine bay the paint might not faint, however i would get one anyways.. better safe than sorry

 

[steve]

I haven't looked that closely on a 2G but on a 1G it's held in place by metal spring clips so clearly it's not intended to drop down on anything. It's there to protect your hood from the heat.

Steve

 

[PieEyedPiper]

Agreed. Just by looking at it too though one can decern that it would be a pretty terrible fire supressing utility.

 

[Boosted98gsx]

That's a pretty spiffy hood mod.

 

[Rice Over Wheat]

^^^

Yeah, greyforestGST is a f'ing genius:

http://www.dsmtuners.com/forums/showthread.php?t=109404

Agreed. Just by looking at it too though one can decern that it would be a pretty terrible fire supressing utility.

...no kidding. Tomorrow I have to go dumpster diving and see if I can recover my hood cover before the garbage man gets there.

 

[Defiant]

but since you now have air flow into the engine bay the paint might not faint

Until you park.

Note that the insulator is made with a shiny, reflective finish. Just like the inside of your other heat shielding should be, if optimized.

 

[ryno]

Yes just get the sheild and cut your vents out in it also. By the way your car looks really good!

 

[DGajre777]

Mitsubishi calls it (3) insulator not heat shield or fire blanket.

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According to www.dictionary.com
in·su·la·tor (ns-ltr, nsy-) Pronunciation Key
n.
A material that insulates, especially a nonconductor of sound, heat, or electricity.
A device that insulates.

And (as Defiant said) the grey forest mod is good only when the car is parked. When the car is motion the vents make air go IN the engine bay instead of hot air coming OUT. There needs to be a scoop or cover before the vents to make air come out when the car is in motion.

 

[mavisky]

We tell everyone at the dealership when we sell cars that it'll magically supress fire if there's an engine fire, but its total bs. The thing could't put out a flaming marshmallow. It's simply there to protect the paint on the hood from all the heat underneath the hood.

 

[dr1665]

It's simply there to protect the paint on the hood from all the heat underneath the hood.

--ding!--

 

[Rice Over Wheat]

We tell everyone at the dealership when we sell cars that it'll magically supress fire if there's an engine fire, but its total bs. The thing could't put out a flaming marshmallow. It's simply there to protect the paint on the hood from all the heat underneath the hood.

Funny thing is, I just got back from the Mits dealership and the parts dept guy told me the same thing. I told him that's crap.

Anyway, the crooks want $65 for a new insulator and $1 each for those shitty plastic tabs. I told him I'll think about it. It can't be hard to fab one myself, I just have no clue what kind of material to use. Aren't there similar materials for ovens? I know I've seen that stuff before somewhere.

 

[mavisky]

My carbon hood and all the others I've seen don't have one. With the added venting you have now it should be fine. I'd check junkyards or other 2g's with carbon hoods to see if they have theirs laying around somwehere. I think mine's up in the attic. I hung on to it figuring I might find another use for its heat reflecting abilities. Said use has yet to show itself.

 

[spyderturbo007]

The thing could't put out a flaming marshmallow.

That's funny sh$t right there........

 

[DSMunknown]

It's simply there to protect the paint on the hood from all the heat underneath the hood.

--ding!--

I have had personal experience with this. I had my "insulator" off for about 6-months-to-a-year and the middle of my hood started flaking off the paint. I had the hood repainted and put the insulator back on, and haven't had hood paint problems like that since.

FYI it was a couple years ago when I had the hood repainted, but I have had the car for about 6 years now. For some reason I decided to take it off one day, and it cost me.

 

[staticbrainwash]

I was going to put some DIY heat shield up on my CF OEM style hood (just haven't ### i'm lazy). But what i did find was some good sheet shielding on summit. Buschur also has some.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=THE-14120&N=700+115&autoview=sku

There's also some cheaper stuff on summit.

https://secure.buschurracing.com/ca...d=775&osCsid=b5c1038a3c3e85ea60aeb10a3d91015a

Just to give you an idea if you still wanna fab up a section.

At least you still have mounting points though, i have to figure out how to mount it on the CF hood once i get around to it.

 

[Ludachris]

Now just wondering - what would happen if you just used a bunch of foil duct tape under the hood instead of the Mitsu piece? Wouldn't that help reflect some of that heat?

 

[staticbrainwash]

Haha, i don't know if it has the reflective properties as a true heat shield would. But to be cost effective, for a while i was thinking about buying a bunch of extra heat wrap when i do my manny and o2 and just run a bunch of strips of it on the hood.

I figured it'd look tacky though. So i opted to spend a little more for the real thing, just have to shape it.

 

[Rice Over Wheat]

Looked around the net myself...here's 3 ft x 3 ft for $10!

http://www.competitionproducts.com/prodinfo.asp?number=SH3603

$17.41, shipped! I'll let you all know how this stuff works out...

 

[wishihadatalon]

I would recommend the summit stuff because it actually has the insulation behind it like every car come with.

As for the c/f hood why couldn't you just drill the holes in the same spot as before? Or find some heat resistant adhesive and glue some tabs to the under side of the hood.

I took mine off because it was pealing back and rubbing on my timing belt. I will probably buy a new one from the stealership this winter.

 

[staticbrainwash]

At the time i didn't want to deal with drilling. I got REAL lazy after the debacle my hood was to get on period. But it's not a bad idea.

I might pick up the real stuff from mistu and hang it in a similar location. Then just drill holes large enough to use the stock metal retaining clips.

But enough about me.

I'd go with the summit stuff too. There's others on their site for cheaper that has the insulation and foil. I just linked to that one as an example.

 

[Defiant]

Now just wondering - what would happen if you just used a bunch of foil duct tape under the hood instead of the Mitsu piece? Wouldn't that help reflect some of that heat?

If the adhesive didn't melt and drop the tape down onto the manifold and catch fire, you'd still not have the ¼" of insulation the factory panel has. It would reflect some energy, but I have doubts it would reflect enough.
Set a nice, shiny wrench out in the sun for ten minutes on a summer day. Then try to pick it up. As you're relieving the blisters, reflect on how well it kept itself cool.