fresh air ducts

Flick

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Jan 15, 2012
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Central Pa
I need a suggestion as how best to duct some fresh air into my 79 Vette. I reworked the engine to max performance. 350 pushing 500 hp I removed all the extras including the AC now I need to duct some fresh air on to the floor as it is too hot to ride in. I am currently fabing up a new radiator support and installing electric fans. Where and how can I duct some air into the interior
 
First off, Welcome to the motley crew....

With NO a/c I can only imagine your problem in CANADA/NORTH....here in FLORIDA....best of freeking LUCK, you going to need it...

IMO, you need seal off the airflow ducts from the stock position and put that fan on super high speed, meaning swap for a C4 type blower with larger fan and more air speed/flow....and methinks to change it to recirculate from behind the 'firewall' and under the pass side, kick panel....OR, maybe put a ~4" hose up front to the suck side of the fan....just a concept....:nuts:
 
First thing, make sure your ducts are all connected together properly and have foam seals at the junctions. In bone stock form they're leaky as can be. Second, either install a hot water cutoff or make sure the stock one is in good shape and only comes on when you have it set to "heat" - it might have been disabled when you removed the A/C, or it might just leak - either way, you're going to have a hot heater core down there.

Beyond that, I cut apart the fan housing and added about 1.5" inches to the depth to allow the C4 fan upgrade to work as efficiently as possible, without the blade being shrouded at the bottom as happens with a spacer install. And make sure you line the footwells with good insulation.

Oh...I also lined the inside of the HVAC box with foil/bubble insulation. If you've permanently removed the A/C, get an air box from a non-A/C car to properly direct air into the system.
 
Reflectix from Home Depot, floors, trans tunnel and firewall. Pull the carpet, wait until dark and hang a work light or two in the engine bay. look for "leaks" under the dash.

Rob
 
Thanks for the suggestions. I will certainly try the C4 fan. My biggest challenge is finding a place to route the 4" flex hose to access a source for fresh air. I understand the advantage of the higher speed fan but what I'm really trying to do is duct air directly into the cabin much like the older cars with fresh air vents. ie my 53 Olds Rocket 88
 
Where are you trying to pull air from? The HVAC system has a cowl inlet on the passenger side, pulling air right off the windshield. I know earlier non-A/C cars had a driver's side cowl vent, too - not sure about the later models.
 
I had the same problem with my '79. The reflectix idea is a good and cost effective way to reduce cabin heat. I did a post on my install a while back, maybe you could do a search. I also found that my shifter was allowing a lot of heated air to enter the cockpit due to a P.O. cutting some sheet metal out of the tunnel, so I patched that. I installed a Ford heater control valve that shuts off both the supply and return sides of the heater hoses. I found an aluminum radiator at southwestspeed.com (best prices!) and installed it along with a high volume (Stewart) water pump. I wrapped the headers. In addition to all of these other items there is a "Horse Collar" foam rubber seal that goes between the bell housing and the trans. tunnel, it is supposed to block the hot air. I use black foam rubber pipe insulation from Home Depot or Lowe's for the Horse Collar.

As a last resort you can get some flame proof socks.
 
zero clearance is top notch stuff also, this was from 7-8 yrs ago and looks just the same today


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I had the same problem with my '79. The reflectix idea is a good and cost effective way to reduce cabin heat. I did a post on my install a while back, maybe you could do a search. I also found that my shifter was allowing a lot of heated air to enter the cockpit due to a P.O. cutting some sheet metal out of the tunnel, so I patched that. I installed a Ford heater control valve that shuts off both the supply and return sides of the heater hoses. I found an aluminum radiator at southwestspeed.com (best prices!) and installed it along with a high volume (Stewart) water pump. I wrapped the headers. In addition to all of these other items there is a "Horse Collar" foam rubber seal that goes between the bell housing and the trans. tunnel, it is supposed to block the hot air. I use black foam rubber pipe insulation from Home Depot or Lowe's for the Horse Collar.

As a last resort you can get some flame proof socks.

I like the pipe insulation option. Thanks. :thumbs:
 
Sorry, can't answer your question about how/where to duct cool air. However, like a lot of other people, I had the "hot foot" problem too. It's not so much that you need to get cool air in, but need to find out what's causing the hot air and address that. Otherwise, I don't think the outside air will really add enough cooling to make it comfortable.

1) As previously mentioned, you need to keep the heater core cool, as the fan runs even when off (unless you or a previous owner modified it not too -- if you want to do that, do a search and you should find a couple good threads). Make sure the hot water cutoff valve works, and you can even put a manual one in on the return. There's also a vendor who sells shielding for the firewall area.

2) Heat can also leak in, as previously mentioned through the trans tunnel, or the windshield cowl area. Make sure all the seals are there, both in the trans tunnel and the ones that seal the engine compartment. Also, make sure the "fresh air doors" (can't remember the technical term) work and seal properly. It's possible for debris to get in and block them open. Ditto on the comment about the ducting having leaks.

Addressing those two areas usually resolve hot feet.

Mike
 
I need a suggestion as how best to duct some fresh air into my 79 Vette. I reworked the engine to max performance. 350 pushing 500 hp I removed all the extras including the AC now I need to duct some fresh air on to the floor as it is too hot to ride in. I am currently fabing up a new radiator support and installing electric fans. Where and how can I duct some air into the interior

Take the T-tops off.
 
My 77 has a worked-over (though I'm not exactly sure of the specifics) 350, and with the modifications that I made to the HVAC system, the footwells stay cool - even with a pair of unshielded catalytic converters/pre mufflers close to the angled parts of the footwells.
 
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