Solving V8 Conversion overheating, Exhausting out the HOOD is THE answer Options

[stewteral]

Hey V8 conversion 914ers,

I’ve been running my car for some 7 years now and chose to exhaust the radiator out the bottom of the car. It seemed to work fine, but in the 100 degree summer heat of Willow Springs, I was seeing water hitting 250 degrees with fans blazing.

We all know that from the 60’s, race cars have vented out to TOP of the hood and it worked well for a friend’s Corvair 327 Chevy we ran at Riverside (142 MPH on the short course back straight). However, I originally didn’t want the car to look too “radical.” When I got the car running it had 11” fender flairs, side scoops, roof scoop and a wing……Ya’ cops won’t notice my car!

With some time before my next event, I redid the whole radiator layout where I sealed the bottom of the trunk, HACKED a hole in the hood and fabricated radiator shrouding and an exhaust air dam. I upgraded my fans too.

This morning in 60 degree temps, I took the car for a drive AROUND town at low speeds to see if I could keep it from overheating in traffic, as it used to. What I found surprised me: I drove the whole run with NO fans and water temp at 140 degrees. When I was caught by a stop light, the temp went up to 160, but once moving again, it moved back down.

I jumped on the freeway and both oil and water dove down to 120 again. EUREKA, I have found my solution!

Conclusion:
-Of course 120 is lower than desired, in spite of the 180 degree T-stat, but I’m aiming at the right temp ON-Track in Summer. If I want to so some street driving, I can always tape off some of my intake opening.

-In the previous configuration, I would have had to run the radiator + oil cooler fans and worry about over heating, now with NO fans, the temps are on the low side.

-Before, the oil temp would exceed the water temp by some 30 degrees, now the oil matched the water temps, at least in street driving.

-The internal hood bracing defines the hole shape as a trapezoid, so I cut all the width I could get right to left. The back edge is defined by the rear wall of the trunk and from there I measured 12” forward, held my breath, and cut.

-If your V8 car is on the edge of overheating and big fans aren’t enough, give this a try. Mine is a pure “racer” design, but our friend byndbad914 came up with an attractive louvered approach that keeps his 500 HP small-block cool. In another design, AndyS created a very attractive molded “air dam” for his LS1 conversion.

Being pleased to see all the work was worth it, I wanted to pass it along.

Best,
Terry

[ChrisFoley]

I'm curious about how much the engine lid needs to be vented to help cool the engine and to keep from cooking wires and hoses near the exhaust.
If the air intake is connected to ramair ducts in the quarter panels the lid isn't needed for combustion air but can the lid be closed off to help keep heat out of the cabin? Would that cause excessive temps in the engine compartment?

[stewteral]

I'm curious about how much the engine lid needs to be vented to help cool the engine and to keep from cooking wires and hoses near the exhaust.
If the air intake is connected to ramair ducts in the quarter panels the lid isn't needed for combustion air but can the lid be closed off to help keep heat out of the cabin? Would that cause excessive temps in the engine compartment?

Hey Racer Chris:

All good questions. It is apparent that you also know that 30% of cooling of the Chevy is AIR FLOW over the block. I attached some photos to show what I've done:
-ENGINE COVER: I removed the entire stock cover, shined it up and put it in my living room as Porsche Art. Then I made my own "cover" from aluminum tube for the frame and ALL open screen. This also allowed me to raise it a bit for better aircleaner clearance. With 500 HP, I make a lot of heat, but have got it to work by running the ignition wires UNDER the headers, along with insulation tubing.
-All the water hoses are FORWARD to the high header heat and last for many years.
-With the cooling airflow for the V8 coming from under the car and flowing up & out the engine cover, I am a FIRM believer in OPENING up that airflow, rather than trying to close it off to reduce any heat getting into the passenger compartment. If that engine bay were closed off, it would be a HOT BOX!
-I'm resolved to the fact that inside the car is always WARM. Not only heat from the firewall, but I have the radiator water flowing in copper tubing in the shift tunnel! My solution that has worked great is the ROOF SCOOP I made with a sliding air control.
-Valve Cover View: Forget the Porsche Logo, that's just to confuse cops as most weren't BORN when the car was built. The photo is to show how the engine sits in the bay. The firewall is on the left and completely sealed.
-3rd Photo: This is to show the 180-degree exhaust system that I am running which required cutting out most of the trunk. I've taken advantage of the extra open area through the trunk by jacking the rear of the trunk lid by 1" (not even noticeable) to create a 56" wide exhaust vent.

In the 3rd photo, you can see the engine cross bar I built to hold the Chevy.
Since the photo, I've added a flexible air damn sticking down 3" to push more air up through the engine bay.

Also, at the bottom of the 3rd photo, you can see the stack of 2 oil coolers (each with a fan) next to the side scoops I made: Left side for oil coolers, Right side for fresh air to the air cleaner. I used to have a "ramair" tube & aircleaner set up, but
it didn't fit with the 180-degree headers. Now I have vanes channeling the air to the aircleaner and cannot tell any difference while the car has gotten faster.

I hope I've answered your questions, good luck with your car,
Terry