Aftermarket Cowl Induction Hood

[Steve2003]

Split topic-HJ

Cool, What Style Did You Get?

The first generation one, like HJ's.

What can I expect to pay to have the hood painted and installed, any guesstaments? What about the insulation that goes underneath the hood?


Steve

[HenryJ]

What can I expect to pay to have the hood painted and installed, any guesstaments? What about the insulation that goes underneath the hood?

You will be very happy with the new hood. It really is one of those "feel good" mods. It may indeed help with ventilating the tight engine compartment.

I was told by a local bodyshop here that $200 per panel is pretty predictable. That is $200 for the top, and another $200 for the underside. Expect a little bodywork to straighten out the rough spot near the washer nozzle hole on the rear of the cowl. I think that mine ran close to $450, IIRC.

For the insulation I used Reflectix and new insulation fasteners.

[gocntry]

For the insulation I used Reflectix and new insulation fasteners.

Is The Insulation Required Or A Good Thing To Do?? I Am Running Mine Without Anything Underneath It. Think The Heat Will Mess Up The Paint Underneath Or On Top?

[HenryJ]

Is The Insulation Required Or A Good Thing To Do?? I Am Running Mine Without Anything Underneath It. Think The Heat Will Mess Up The Paint Underneath Or On Top?

The insulation is not required.
I ran mine for quite a while without.
When I switched to the K&N FIPK I wanted to seal the heat shield shroud to the hood. This requires the insulation.

The cowl section through the middle is open, so it is two separate pieces-



I used hood insulation retainers to attach them. Auveco part number 11130



The insulation that I used is a foil wrapped bubble sheet and is primarily a radiant heat barrier. It does deaden the sound some, but does not adhere to the metal to reduce the transfer of sound. It is available at hardware or building centers. I know HomeDepot and Lowe's carry it. It may come under different trade names. I have purchased Reflectix locally.

[killian96ss]

Be very careful with hood insulation that reflects heat. The reason I say this is because I have seen several guys attempt to use heat reflective insulation on the under side of their hoods (stock and aftermarket) with terrible results. Heat reflective insulation will reflect heat back onto the engine and melt some of the plastic pieces under the hood, while at the same time raise the under hood temperatures because the insulation is holding the heat in. This is exactly why all OEM hood pads are made of a sound deadener material and not reflective insulation. The only time you will see heat reflective insulation from the factory would be in small areas subjected to high temperatures like exhaust manifolds or turbos. Be careful with your choice of hood insulation!

Steve

[HenryJ]

...Heat reflective insulation will reflect heat back onto the engine and melt some of the plastic pieces under the hood...

You're kidding right?

If you aren't...sorry

I'm not in the least bit worried about it. I have done half a dozen street rods and at least as many daily driven cars with this stuff.
If you have enough heat to be able to reflect it and be hot enough to melt plastic you probably have a problem at the source that needs to be insulated.

I would offer that if you have engine compartment heats that hot ...the paint on your hood is not going to survive for long.

I have applied the same material to my heat shield, and AC box. They are the closest to the exhaust manifolds and do have plastic wire loom passing between the two. This has not caused any problems.

I understand the "theory" behind this, but don't see a concern in this application.
As you know this material, and a jute backed version are used on the engine compartments of turboed trucks. While the primary function is noise reduction. It also does well to reduce the heat transfer.

[killian96ss]

...Heat reflective insulation will reflect heat back onto the engine and melt some of the plastic pieces under the hood...

You're kidding right?

If you aren't...sorry

Not kidding! I can't say that I have seen this problem on any S10's, but I have seen melted under hood components on Camaros, Impalas, Firebirds, Blazers (full size), and various imports that tried using heat reflective material under the hood. I was not implying that the material you are using on your hood is bad because I have never seen anyone use that stuff before. You are right about needing something between the engine and hood to prevent possible paint damage from the heat. The overall climate where you live can also cause problems with this type of mod. For example, I definitely would not use this stuff under my hood if I lived in Texas or Arizona due to the number of days each year that the temps rise above 100*. If you do a lot of stop and go driving in traffic when it's hot out, adding reflective hood insulation is only going to make your problems worse. Let's also say for example you decide to cover everything under your hood with this stuff to protect all the components from the heat. Your components will now be safe, but you have also created an insulated oven for your engine to cook in.

Steve

[HenryJ]

I would counter that having a cowl hood eliminates all the concern here as it has an opening to vent any trapped heat.
I have put mine through worst case heat. 120 degree plus temperatures. This high mountain desert sees the extremes.
I would suggest that this material would actually benefit a vehicle in the hotter climates. It reduces interior temperatures dramatically. This is why I added it under my headliner.

I don't know what happened with the material that was used that caused problems, but there are many foil faced products that are marketed as engine compartment, and hood liner material.

The addition of this material does not serve to create more heat in the engine compartment, actually it is quite the reverse. It prevents the protected component from absorbing heat. The engine is designed to transfer heat to the coolant and the coolant transfers it to the air. It is the air movement that keeps things cool. Basically if you confine the heat to the engine , It is designed to deal with it.
Insulating the biggest heater in the engine compartment would be a great idea. The exhaust is where most of the heat lies. Gasses travel faster over a hot surface. The hotter you can keep the exhaust pipes , the better they perform. Insulating them would both benefit the engine compartment temperatures and the performance.
If you block the airflow in the engine compartment you increase the heat.
I do not see the stock hood as a valuable place to dissipate heat. No amount of insulation would have a significant affect on the engine compartment components temperatures. The steel of the hood acts as a barrier to some extent. Now the addition of the cowl hood does certainly improve the cooling abilities.

The whole thing sounds like an urban legend to me. While some of the rational does offer a hint of truth, I would really have to see it to believe it.

Bear in mind that I do drive a car that will develop more heat than is believable. It sports a big heat pump right on top and regularly sees 220 degrees on the street. I uses a eight gallon cooling system, engine oil cooler and remotely mounted transmission cooler. If anything would melt things due to reflected heat it would be the polished aluminum firewall that surrounds the rear half of this mid engined car.

Sorry for my scepticism, but I have had some experience, and a really hard head

[killian96ss]

I agree the cowl hood is the way to go, and I wish I had one also. My Crew can barely handle a 100* day in stop and go traffic here in CA. My stock clutch fan will stay on constantly and the temps will still creep up to unacceptable levels (220*+). Your tip about using the material under the headliner is an excellent idea. My truck is black and believe me I know what you mean about a hot interior. The brands I know of that caused some of these melting problems in these various vehicles are Thermo-Tec, DEI, and Dynomat. I know there are others, but I'm drawing a blank right now. I agree with everything your saying about protecting components from heat, but not all engines can effectively remove heat at any temperature with just coolant and a fan. If you radiate heat right back at the engine and create an insulated oven then it really doesn't matter how good your cooling system is because your engine simply won't be able to overcome all the added heat. I also agree with you that exhaust gases flow better over a hot surface. If I could afford to have my entire exhaust system ceramic coated then I would because the coating makes a dramatic increase in performance and would definitely lower under hood temps. You mention that insulating the exhaust system would both benefit the engine compartment temperatures and the performance. This is true if you directly insulate the exhaust away from engine components with an insulating wrap or thermal coating. When you insulate the components and not the heat source, you are only lowering the temperature of the protected component while increasing the under hood temps by radiating heat back into the engine compartment. This is exactly why OEM heat insulation is only placed where it needs to be and not all over everything. For example, if you took 2 identical running engines and placed one in a steel box, and the other in an insulated steel box, both with identical airflow and cooling, which one do you think will get hotter? If you trap heat by insulating in a closed environment then you will certainly be making more heat than without the insulation. The melting of under hood components due to added engine compartment insulation is no way an urban legend, but I do understand what you are saying about seeing is believing, as I am also skeptical and very hard headed.

Steve

[Steve2003]

When I used the word insulation for the stuff under the hood that probably wasn't the right word, I just didn't know what to call it. I have always been under the impression that the stuff under the hood was more for noise reduction, but then again what do I know.


Steve

[HenryJ]

When I used the word insulation for the stuff under the hood that probably wasn't the right word...

It was the right word. Sound and heat insulation is what it does