Reducing Ambient Heat in Engine Bay

"E30Joe drives a Subaru" (325joe)
09/14/2014 at 15:46 • Filed to: None

I've been doing some research on the topic and I thought I would share here since it is an easy upgrade and keeping things that should be cool that way, and reducing ambient heat floating around in the engine bay is always good for performance. I'm going to keep this Subaru specific (EJ engines) but this should all apply to every other make and model since engines all work in much the same fashion.

Heat Wraps and Ceramic Coating

We will start with heat wraps and ceramic coating of exhaust components. This is relatively inexpensive and fairly easy if you can turn a wrench, I'd rate it on a scale from 1-10 (1 being plastidipping wheels, 10 being rebuilding a transmission) at about a 3. It's really that easy as long as you can remove exhaust parts.

Heat tapes are used to keep heat inside the exhaust components instead of just letting it soak out in to the engine bay.

Heat wrapping your up pipe and headers will allow for faster spool (keeping heat in the exhaust = more better for goin' fast) cooler temps in the engine bay, and it can protect your headers/up pipe from corrosion. It's a commonly held belief that doing this will cause a crack in your tubing, which is valid and it's very common that people prefer ceramic coating over the wrap. Ceramic coating works equally as well but generally will cost more than heat wrapping and you will need to send your pipes out to get coated.

Wrapping or coating your downpipe isn't much of performance thing in the same way that doing it to your headers or up pipe, but it will help keep heat AWAY from your intercooler which is very close to the downpipe. Often ceramic coating is used on this as well.

One of the best bang for buck ways to use heat wrap or ceramic coating is by coating or covering the hot side or turbine side of the turbo, it keeps heat away from the TMIC (also close to the turbo) and it keeps heat in the turbo which is nice for the spool.

Heat Reflective Tape

This is a very attractive (in my opinion at least!) looking upgrade and will help keep heat out of things that don't need any extra temperature increases. You can get pretty creative with this stuff and it looks sexy under the hood!

This will do a great job keeping heat out of your intercooler, and since it is the closest thing to the turbo.

Also works great for intake tubing!

And air boxes!

I have not done any studies personally but I have read up on the threads of others who have datalogged AIT before and after doing some thermal taping with this heat reflective tape and across the board heat reductions were the result which is great, it wasn't massive in numbers but 9-12 degrees during normal operation is a big difference when you think of how effective it will be under stress.

Heat Shields and Intakes

Now, most cold air intakes actually pull warmer air than stock intakes (sad but true) because most people install them without proper shielding. Combine some of the stuff from earlier in the post with a cold air intake or short ram intake and it will actually be of some use for you aside from sounding nice.

Grimmspeed is one of the many manufactures of after market Subaru turbo heat shields, this paired with a ceramic coated hot side will great decrease the heat soak on the intercooler (especially with heat tape on the intercooler!)

Cobb is one of the many manufactures making intakes as well, I like their intakes because they include this nice air box that can be covered with the tape.

Like I said, you can get as crazy with that stuff as you want with no negative side effects. Heat staying out of the intake is good!

Learning!

DISCUSSION (19)

KnowsAboutCars > E30Joe drives a Subaru
09/14/2014 at 15:54

One reason to prefer ceramic coating over heat wraps is that heat wraps can catch fire.

E30Joe drives a Subaru > KnowsAboutCars
09/14/2014 at 16:01

Yes I forgot to include that!!! They do have a chance of setting on fire under certain conditions. Like if any oil/gas gets on them that's no good.

nFamousCJ - Keeper of Stringbean, Gengars and a Deezul > E30Joe drives a Subaru
09/14/2014 at 16:13

so I couldn't find an airbox for my intake (stock one went away a long time ago). So after some research I learned you can actually hack up a small black bathroom trashcan and create your own heat barrier. So I did and using my Toque app with and without the "guard" the intake air temp was 30 degrees cooler with the guard.

E30Joe drives a Subaru > nFamousCJ - Keeper of Stringbean, Gengars and a Deezul
09/14/2014 at 16:32

People underestimate how important that is.

K-Roll-PorscheTamer > E30Joe drives a Subaru
09/14/2014 at 17:10

Now does this also apply to NA engines?

nFamousCJ - Keeper of Stringbean, Gengars and a Deezul > E30Joe drives a Subaru
09/14/2014 at 17:15

And that you can do so with a freaking trashcan

Renescent > E30Joe drives a Subaru
09/14/2014 at 18:01

Take all the shrouding and pretty engine covers off should be the first thing anyone should do if you're trying to reduce heat sink.

That being said, still not taking my AMG covers off :P

AMGtech - now with more recalls! > Renescent
09/14/2014 at 18:24

Most AMG cars have enough coolers and heat shielding that it wouldn't be worth it for you. And the air intakes draw directly from outside.

AMGtech - now with more recalls! > E30Joe drives a Subaru
09/14/2014 at 18:25

GOLD HEAT TAPE BECAUSE SPACESHIP!

over1g > E30Joe drives a Subaru
09/14/2014 at 21:47

Wrapping the intake won't help, the velocity of the air moving in the intake is too high to have a measurable impact on performance by the reduction of intake piping temperature. Wrapping/coating or otherwise decreasing the heat transmission from the exhaust/turbo would go a long way towards reducing overall engine compartment temperatures, which may translate into longer component life...

E30Joe drives a Subaru > over1g
09/15/2014 at 00:15

The reflective tape helps keep heat out of the intake, and with it's relatively low cost it's generally worth it, especially in Subarus where a lot of the intake piping is pretty close to the turbo.

E30Joe drives a Subaru > Renescent
09/15/2014 at 00:16

Haha I keep my little Subaru one on, even though no one sees it. Engine bling...

E30Joe drives a Subaru > K-Roll-PorscheTamer
09/15/2014 at 00:16

Pretty much applies to every internal combustion engine.

over1g > E30Joe drives a Subaru
09/15/2014 at 00:58

Reflective tape may help keep the plastic intake piping cooler, which won't do anything to your intake temperatures. Not only are the thermoplastics used in intake systems nowadays terrible conductors, but there’s simply not enough surface area for the temperature of the piping to make a difference in the intake air temperatures -because of the high velocity and relatively small volume of the intake system considering the quantities of air moved.

I don’t imagine you’re going to start thinking I’m credible out of the blue, so you can do an experiment for yourself. Grab an OBDII scanner and look at the intake temperatures, compare at full throttle/high rpm with reflective tape on or off.

E30Joe drives a Subaru > over1g
09/15/2014 at 01:04

It's for sure not going to make a very noticeable difference, but that engine bling!

over1g > E30Joe drives a Subaru
09/15/2014 at 01:28

Well, duh lol

Renescent > AMGtech - now with more recalls!
09/15/2014 at 18:33

Yeah, I was just being a little vain with the engine cover sexiness of the AMG. I had an 07 TL Type-S that was horrid for heat sink.

Philbert/Phartnagle > E30Joe drives a Subaru
09/18/2014 at 23:40

Raise the back of your hood and inch or so. It increases airflow through the engine bay and substantially reduces underhood temps.

E30Joe drives a Subaru > Philbert/Phartnagle
09/18/2014 at 23:43

I had not even thought of this, if someone got an extended splitter for their TMIC this would probably be the best way to decrease ambient temp.