mcm95403

As I had said in a previous post, when I get home I always open the hood to avoid having the engine bake any more than I have to. Often when I get to work I will pop the hood and just leave it an inch or so open at the back to help let the heat escape. All the plastic under the hood is already brittle as can be. I'm trying to prolong the life of all those plastic parts as much as possible.

I'm looking for info on hood venting for a real-world, daily driver. I drive the car in the rain, so I can't have water pouring all over the engine and hot exhaust (don't need anything cracking on me), so I'm thinking that a low cowl that's open to the back would be good. Problem is, I want to make sure that I'm not going to feed hot air from the engine into the HVAC system and just pump all that heat into the passenger compartment. Anyone with a rear-cowl hood who can speak to that, please chime in.

If I go with the more traditional vents, what can I do to keep water from pouring all over the engine in the rain?

As a side question - I've located an original HD cooling fan - the one that goes between the radiator and condenser - and I'd like to set it up with a timer that would run it for 5 minutes after shut down. Has anyone done that and/or any good ideas on a circuit to wire it up for that?

When I do my LT-1 manifold swap I'm also going to heat-wrap the y-pipe and cats, and when I have the trans out for a refresh, I'm going to put reflective heat insulation inside the tunnel to kill off the heat on my leg.

Thanks in advance for your helpful comments

ffvetteman

Not sure how it would look, but my 86 Trans am has 4 vents on the hood that are factory installed. What about something like that?

mcm95403

I dont' think they're big enough to vent the volume of heat we deal with, but good thought.

ffvetteman

Yea not sure how functional they are. I think they are mostly aesthetic on the T/A. Besides vents like that, I'm not sure what else could be done.

nathanours

You say you open the hood to prolong the life of the components under it, but did you ever think that allowing them to cool down more slowly may actually put less stress on them than a more rapid temperature change? As things cool down they contract, and I can only imagine that speeding up that contraction would cause more stress.

For example, many times if you spray cold water on a hot windshield it will crack because the glass contracts faster than the windshield can withstand in one piece. It would obviously be fine if the windshield was cooled slowly. Maybe the components under your hood would actually suffer more from sharper temperature declines than slow ones?

I'm not sure, just throwing ideas out there.

anciano

It's hard to believe that the fiberglass hood gets hotter from engine heat coming from underneath than from sunlight hitting it from above. I know I can put my hand on the hood after driving and parking in the shade, but would get a very painful result from touching the polo green surface after it's parked out in the intense CA sun for a while.

Don't know what good another fan would do either, unless it's placed to blow the hot air directly down and out from under the car. Putting it behind the radiator would just blow air over the exhaust manifold and create a nice convection oven in there, moving heat even faster from the manifold to the rest of the engine compartment. Wrapping the manifold and headers should help, though.

oldalaskaman

the fan you mention , goes in front of the condensor and you should already have the mounting holes there for it. It doesnt cool your engine as much as it cools your condensor and makes your a/c colder. The better hood louvers/vents have drip trays that channel the water to the wheel wells and out to the ground(some fab. required). I put them on my poor mans track car and they work excellent. also reduce the heat whle you're driving and instead of the engine taking 4 hours to cool down , only about 1 hour required . There are several threads on here with excellent info about either buying louvers/vents with the drip trays already installed or making your own.
hope this helps

wilcar

When I went to a carb system on my 84 Z51 I was having some fuel percolation problems after the car sat for more than 10 minutes and then was restarted. There is just so much heat that stays trapped in the engine compartment. I chose to mount a short cowl induction hood scoop and cut a 8X8 inch hole in the hood. It is also open in the front so I have plenty of air coming into the engine compartment. I needed the extra room also so I could mount a taller air cleaner on my carb. You might try wrapping your factory tube headers if you have them as some have done. I do not believe you can or should try to wrap your cat(s) as they may melt or start a fire. Have not heard of anyone wrapping their cats.

2rgeir

Yep, they are none-functional, have them on my -85 as well

oldalaskaman

the ones I use are extreemly functional or I wouldnt use them. the ones sold by the venders that include drip trays are functional also. it mostly depends on the person doing the install and the version used. hope this helps.

96GS#007

'90 and up didn't have a HD cooling fan between the radiator and condenser, standard or as an option. '90 and up uses the twin fans behind the radiator. If you install it....assuming it even fits since it's designed for the vertical orientation of the pre-'90 cars...you'll need to pay attention to the electrical system. If you have three fans turn on at once using the same circuit, you'll likely pop the fuse.

Functional hood vents....

Mr. Magoo...


Ricekilla has these:


Legal-Eagle....

oldalaskaman

http://forums.corvetteforum.com/c4-g...od-for-c4.html
the original thread

96GS#007

No way....there's a search function on this forum?

oldalaskaman

go figure

ch@0s

I think you are being paranoid.

RollaMo-LT4

383vett

I put these vents on my 84 after I carbed it because of the same perculation problems you had.

2rgeir

I was not arguing the functionality of your hood vents, just stating that the factory ones on the 3rd gen T/A from -85 and -86 are not
I'm sure the vents pictured here are real good mods, that actually do what they look like they would do

mcm95403

Thanks for the replies everyone. BTW, I did search, but wanted to ask specific questions, hence the new thread.

Looks like the Magoo style vents would do what I want - one more project to add to the list

TTA579

I agree with your reasoning behind this. I just replaced a brake booster that had cracked due to heat.

Cowl induction hoods have been around for a long time, this is because the windshield creates a high pressure zone where it meets the hood. This will force more air into the engine compartment at speed, though will still vent air at rest.

Your engine is exposed to water any time it rains, it will not split like a log just because it gets wet. Take a look at the WRX for example, it mounts an intercooler with no water runoff provisions on top of the engine, and a scoop to feed it. Water running off the hood is going to go straight onto the engine.

Lots of ways to do this, depends on how fancy you want to get. An even better solution would incorporate an electric water pump and a deep cycle battery.

Biggest problem with heat wrap is that it will also hold moisture to your exhaust manifold so you need to make sure you have a stainless exhaust. Ceramic/Thermal coating and/or head shields are better alternatives, though also more expensive.

These are marginally functional at best, as the front vent have virtually no opening, and the rear vents have openings too small to be of any real significance. I've considered opening up the back side of the vents however. My V6 turbo makes a lot of heat.

The thermal differential provided by venting the engine bay to ambient air is not on the same scale as pouring cold water onto a hot surface.