Hood Insulation - BMW Forum

93 325i · 11-22-2004, 01:05 PM

Im installing a new hood and just want to know if I need to transfer the old insulation liner to the new hood. Would it hurt anything not to have the liner?

Brian325i · 11-22-2004, 01:17 PM

Has been discussed before, there are both pros and cons to having and not having it. Try a search.

93 325i · 11-22-2004, 01:59 PM

alright thanks..didnt even think this would have been a raging debate in the past.

B_w. · 11-22-2004, 05:06 PM

you will hear your engine much more at WOT. I believe there is an m3 made without the hood lining. if you have an intake with heat shield you will need a new heat shield to seal the compartment properly.

B3M2W5i · 11-22-2004, 09:09 PM

Quote:

Originally posted by B_w.@Nov 22 2004, 05:06 PM
you will hear your engine much more at WOT. I believe there is an m3 made without the hood lining. if you have an intake with heat shield you will need a new heat shield to seal the compartment properly.

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whats WOT?

Autotechnica · 11-22-2004, 09:44 PM

WOT = Wide Open Throttle, when the throttle body butterfly is completely open.

There are no down sides of not having the hood liner. It's there for noise reduction, not heat insulation/protection.

supark · 11-23-2004, 01:21 AM

Actually - this may be for Saabs only but the hood liner on my old 900 had a clever safety function in that in the event of an engine fire, the hood liner would fall down onto the engine and dampen the fire. I don't know if this is true for Bimmers though.

93 325i · 11-23-2004, 07:56 AM

yea, but im thinking it does "insulate" somewhat tho because my hood was always cool to the touch. My old hondas never had a liner and the hood would be very hot. I'll try to reinstall on the new hood but if its a PITA- screw it. Just wanted to make sure it wasnt vital or anything to have

Autotechnica · 11-23-2004, 09:18 AM

Quote:

Originally posted by 93 325i@Nov 23 2004, 07:56 AM
yea, but im thinking it does "insulate" somewhat tho because my hood was always cool to the touch. My old hondas never had a liner and the hood would be very hot. I'll try to reinstall on the new hood but if its a PITA- screw it. Just wanted to make sure it wasnt vital or anything to have

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They should put this on myth busters. I've heard of people saying that without a hood liner the paint would baked off. Sounds like total BS to me. Half of all the import and domestic cars out there don't have hood liners, I don't see their paint baking off. I ran without a hood liner with my stock hood for 3 years on my 10 year old paint, no problems ever.

Plus it looks a lot cleaner without it.

93 325i · 11-23-2004, 09:29 AM

Quote:

Originally posted by Autotechnica@Nov 23 2004, 10:18 AM

They should put this on myth busters. I've heard of people saying that without a hood liner the paint would baked off. Sounds like total BS to me. Half of all the import and domestic cars out there don't have hood liners, I don't see their paint baking off. I ran without a hood liner with my stock hood for 3 years on my 10 year old paint, no problems ever.

Plus it looks a lot cleaner without it.

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I agree...honda paint doesnt compare to bmw quality paint and i never seen the paint "bake" off. Besides in the scorching sun in the summertime i bet that hood gets way hotter than what the engine could ever do. What people think is "baking off" is they were prolly lazy and never maintained the paint with wax and what not. Im not gonna stress- if it goes back on easily then great. If not oh well

bitcore · 11-23-2004, 02:34 PM

Autotechnica said it exactly.

There are actually a few people roaming around here without hood liners with a stock hood for years and havn't had problems.

RAiMA · 11-23-2004, 03:42 PM

Quote:

Originally posted by Autotechnica@Nov 24 2004, 02:18 AM
They should put this on myth busters. I've heard of people saying that without a hood liner the paint would baked off. Sounds like total BS to me. Half of all the import and domestic cars out there don't have hood liners, I don't see their paint baking off. I ran without a hood liner with my stock hood for 3 years on my 10 year old paint, no problems ever.

Plus it looks a lot cleaner without it.

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I heard it was more to stop baking contaminants into the paint work. It only weights 0.44lbs. For what it's worth, I'd keep it in.

B_w. · 11-23-2004, 06:18 PM

Quote:

I heard it was more to stop baking contaminants into the paint work. It only weights 0.44lbs. For what it's worth, I'd keep it in.

do you mean baking shit onto the inside of the hood or on the outside. if it is on the inside why would it matter. i just would not want stuff being baked onto the outside.

bitcore · 11-23-2004, 08:35 PM

Both sides, the whole hood gets hot (more in the center than anywhere else)

If your hardcore stripping the car down for race prep. Loose it.
If your looking for weight reduction, Keep it.
If you want a flashy nice engine noise incease, loose it.
If you are thinking about reselling the car to anyone other than a dude who knows what that liner is for and the cons of having it removed and driving around like that for years on end, keep it.

I say keep it unless you get a badass CF hood that kinda already colormatches your car like autotechnica's