I had a BMP intake on my cooper which wore a hole in my hood insulation - i removed the insulation - i now no longer am using the intake - would there be a benefit to putting the insulation back up? does it allow the heat to radiate better from under the hood reducing under hood temperatures? wouldn't lower temperatures be healthier for the engine? can cold weather harm the engine without the insulation - if the car is parked it will cool down faster - will it be too cold under the hood at night or while the car is running in the winter? will it harm my paint? i don't really buy the part about it putting out fires - if your engine catches on fire - kiss the car goodbye. does it keep heat from the sun out - is this really even an issue?
thanks!

 

I just yanked mine to install an OMP strut brace... I added a bit of felt to keep the windshield washer lines from rattling. So far, so good.

It's just a tad noisier in the car... From the look of the liner when I removed it, about all it's doing is deadening sound and protecting the underside from heat... Not sure of the long term effects, since I just pulled it off.

In the future, I may replace it with something much thinner for clearance...

 

FWIW, I've been running without the underhood insulation for about a year with no discernable effect.

 

Good to know! At autocross and track events, I normally open the bonnet to quicken the cooldown process, but was worried about it for daily driving...

Thanks!

 

Tony Nuzzo's race cars are minus the liner as you might guess, and with the kind of heat generated during the GrandAm events (2+ hours of racing), heat, and blistering of paint has not been an issue, at least to my knowledge. I suppose it couldn't hurt to ask him... I'm sure it does muffle noise a bit...

If one has an aftermkt intake with a shield or box that is meant to snug-up against the liner, then this would impact the ability to keep warmer air out...

 

Maybe its to keep hood from becoming to hot to the touch on the outside

...back to my nap.

 

I've been running wihtout one for some time on the race car, with no issues. I'm not sure if I would recommend it on the street, mostly for noise. I can't see any blatant problems that would arise however.

Hope that helps!
Randy

 

ok, this is hearsay or an urban myth, but i recall reading that modern hood liners, attached with plastic fasteners, are intended to smother an engine fire by draping down over the engine after the platic fasteners melt.....but us motor noiseheads don't care about that anyway. and besides it's too late then anyway.

 

That sounds pretty neat, but I would think for all the plastic to melt away the fire would have to be burning pretty hot and for a good amount of time. Doesn't seem like it would do much.

 

And there are a couple of metal screws in there too - cool theory though!

Randy

 

Its for noise.

 

Agreed. Direct sunlight heats the hood much more than radiant engine heat would, so the paint protection idea doesn't really fly.

 

Maybe also to protect the various lines behind the liner, like for the Xenon washers...

So, this in the Performance forum... I suppose for weight-reduction reasons then. What are we talking about here, 2 pounds max?

 

Yeah. I weighed my hood liner for somebody in another forum who asked the same question and with all the screws and fasteners it's about two pounds.

Approximately the same as either driving barefoot or skipping lunch.

 

hey, let's have a mythbusters show: does the liner stop the fire? will the paint crack over time without a liner? does the sun heat the hood more than the engine?

 

Spunky, that was me... I initially forgot, then remembered your response, but still proceeded, I guess just for confirmation I suppose. Thanks again.

 

Paint protection.

 

Oh, OK. I didn't remember who it was. I did remember what it weighed, though, which at my age is a stupendous achievement.

So, so far no paint blisters, no boiled washer fluid for headlight washing, no apparent genetic mutation, no change in my ferociously leftist political opinions, no deterioration of my eyesight, my hearing, no sizzling, no sagging, no false neutrals, no visits by the UnderhoodStuffPolice, but as far as I can tell it hasn't enhanced my attractiveness to women, made my breasts perkier, nor has it returned to me the lost idealism of my youth.

So from my point of view it seems like pretty much a non-event.

 

...and I was just going to tell you that you were looking perky today.

 

will having the hood insulator void my warranty?

 

The one thing that wasn't covered in this thread is that the hood insulation also seals the two compartments at the back of the engine bay. That's the only place where I have left it, the rest has been cut off.

 

^^^ Ding, ding, ding....we have a winner.

 

I recently removed mine, and I noticed the same... that the rubber strip around these cowl areas now will not seal against the liner, keeping heat out. However, I was also thinking that now engine bay heat will have an exit path over these walls then out the MINI cowl vents.

Heck, maybe another good idea for this M7 Aerogel stuff... to simply wrap or protect these items...

 

The exit for the engine heat makes sense, but I have a Dinan air box that relies on the drivers compartment being sealed off.(for now)

 

Given the Dinan air box, that makes sense to keep it in tact, at least in that area...

I just removed the rubber stripping that goes around the cowl areas, leaving a larger gap for engine bay air flow back, upward and out...