Engine insulation for hybrids to improve fuel economy

[ps2fixer]

Yea the paper shouldn't be a problem, but it's not bad to be on the safe side. Paper can ignite according to google at around 480F, google also says the exhaust manifold can get up to 1200F. Of course don't put the paper against the manifold and it should be fine, but the paper doesn't do much, not like there's studs under the engine bay to staple it to lol.

125C rated wire is 257F, so the paper ignites at a higher temp than what the wire is rated for, but I've worked with that wire before, even with 300c solder iron temps it doesn't melt while soldering.

[hayden55]

Yup you can remove the paper. Waste of time though. If you are worried about temps put a piece of electrical tape under the hood in different spots and measure with a temp gun. If it was hot enough to light paper it would destroy the paint as well.

[Phase]

How are you guys attaching the insulation or keeping it from moving around?

[hayden55]

Originally Posted by Phase

How are you guys attaching the insulation or keeping it from moving around?

the hood

[ps2fixer]

Originally Posted by Phase

How are you guys attaching the insulation or keeping it from moving around?

My plan was tie wire, haven't tried it yet though. In theory could attach it near the rear of the engine bay and have a hood of insulation under the hood.

[Phase]

Originally Posted by hayden55

the hood

what adhesive?

[hayden55]

i didn't use any adhesive. the car holds it in place. ran through a rain storm and it stayed dry as well.

[Talos Woten]

Originally Posted by Phase

Here’s what my hood looks like. It’s thin barely metal with some holes and open cavities. No insulation or anything. How should I go about this?

Hey Phase!

That indented area looks perfect to put a consistent layer of insulation in. You could lay down some rockwool, cap it with a stiff material, and use the already existing holes to fasten it down. I'd use coroplast and butterfly bolts, but that's more a function of because I have them lying around and not because they seem like optimal choices.

Alternatively, if you want a simpler solution, you could just get some adhesive insulation and stick it on. Someone listed some somewheres here.

By the way, filling in the hood with foam would also 100% definitely work and add more insulation. But it would also 100% change the acoustics, and most hood gaps are tuned to counter the engine frequencies. I don't know whether the added sound-proofing would be sufficient to compensate for the loss of the dispersion cavities. It would be interesting to try it out... though I actually think the incremental benefit that you would get using foam over simply trapping the air with your layer of insulation would be marginal.

Be wary of the kickstand if you have one. I didn't take mine into account when I did my hood and had to cut a hole in my beautiful seal.

Hope this helps!

[Talos Woten]

Originally Posted by hayden55

Talos you win bud. never in my life would i have ever thought to do this, but this is why i love the internet.

Not even lying I think this is like the most effective mod ive done personally. I may redo it and cover the whole hood area and leave a gap around the inverter.

Thanks hayden!

My only long term concern with the insulation is it fraying and bits getting caught where they shouldn't. I covered mine over with a Reflectix-like foil and aluminum tape to seal it in. I've been checking the air filter, engine bay, etc. every time I gas up (I have to check the oil anyhoo since it burns it). Thus far everything seems hunky dory. Woohoo!

[Isaac Zachary]

I want/need to wrap my engine in mineral wool. I can get in my car, drive to work, and barely break 100°F engine temps in the dead of winter. And I'm very sure it's not the thermostat.