Hood blanket... literally? (engine compartment thermal insulation)

[theunchosen]

Please do Keep us posted about all thermal losses.

I'm interested specifically in temperatures when the engine is on compared to temperatures when it was on and not insulated.

[Christ]

I'm going to make a prediction about that right now.

It's not going to affect running/driving temperature.

I say this because, even with a grille block installed, and while driving, the air flowing under the car causes a pressure loss under the hood, and most of the heat lost from the engine while driving happens by way of this flow.

This, of course, is a theory, and may be proven wrong, but it's my guess as to what's going to happen in that aspect.

I also theorize that heat loss will take longer, although not significantly (i.e. less than 3% gain in timespan).

[FastPlastic]

Originally Posted by Christ

I'm going to make a prediction about that right now.

It's not going to affect running/driving temperature.

I say this because, even with a grille block installed, and while driving, the air flowing under the car causes a pressure loss under the hood, and most of the heat lost from the engine while driving happens by way of this flow.

This, of course, is a theory, and may be proven wrong, but it's my guess as to what's going to happen in that aspect.

I also theorize that heat loss will take longer, although not significantly (i.e. less than 3% gain in timespan).

I think your probably pretty close from what I've been seeing so far. I think it may affect temps sitting at stop lights with the engine running. But otherwise it gets enough airflow under the vehicle that it doesn't affect it when it's moving.

I've been looking at my options for insulating the hood and found this stuff at lowes.com Reflectix 16" x 25' Foil Insulation They have it in some places in up to a 4' wide roll. Sadly where I am the biggest I can get is 16" wide. The 16" wide roll is about $20.

[theunchosen]

I was banking that would sadly be the the truth. Fluid mechanics dictates that the engine is a high pressure area and would tend to force air out(towards the ground) and suck air in through the grill and the top(forced induction occurs along those surfaces).

[Christ]

Blow smoke into a bottle, then blow over the top of the bottle, from about 8 inches away... blow smoothly, not quickly. You can watch the smoke swirl in the bottle, and some will leave.

Kinda the same concept under a car in motion.

But wasn't the original cause for this action to keep it warmer while sitting, engine off?

I believe that was the reason for asking about the hood blanket and such, to insulate the bay a little more from the thermal losses WHILE SITTING, and without idling the engine to make it stay warmer, right?

For that purpose, there still may be some hope... but I'm pretty sure we'll find that the engine won't heat up anymore because you've further sealed the hood... Unless you have a full grille block, a mostly sealed belly pan, and a sealed hood.. then you may run into airflow issues, and the engine just might overheat with no place for the heat to go.

Fact is, no matter how much the average person blocks stuff off, there are still airgaps somewhere that are allowing airflow, and thus heat loss, somewhere on the car.

[FastPlastic]

Originally Posted by Christ

But wasn't the original cause for this action to keep it warmer while sitting, engine off?

That's true. In fact I would prefer if it didn't affect the warm-up time at all. You just start with a warmer engine in the first place. That way it wouldn't need to be a seasonal thing. Just leave it on year round.

But it never hurts to discuss all the effects of the mod.

[Christ]

Well, obviously, we want all the technical data you can muster, because some of that might help gauge the effects of other types of vehicles, those with/without different mods, etc.

The technical data that you get from your one vehicle might help to lay ground for equations that will gauge the performance of this mod for others without actually employing it.

And, we like lots of numbers. And graphs. And plots, piecharts, graphical layouts, etc.

[Frank Lee]

"In fact I would prefer if it didn't affect the warm-up time at all."

Are you mad???

[FastPlastic]

Originally Posted by Frank Lee

"In fact I would prefer if it didn't affect the warm-up time at all."

Are you mad???

I realize that faster warm-up would be good in the winter. But here in iowa the temps at times can go over 100F in the summer. With my brick the grill blocks are one of my big aero mods. So if it does speed up warm up, in the summer I either need to take it off or cut back on the grill blocking over the summer(Adding cost or reducing MPG's).

Does that make sense?

[Frank Lee]

I bet you cannot detect the effect of that "big" aeromod. BUT the benefits of fast warm-ups are easily detected.