Looking to do some performance mods

[cudabob496]

you can do ram air without cutting up car.
I think they have air scoops that mount just under the lower front valence.

[stinger]

I don't see any way of adding one of these ram air kits without punching some holes in the core support.

[cudabob496]

I don't see any way of adding one of these ram air kits without punching some holes in the core support.

well, just went into the garage to take a closer look. I have a front spoiler and splitter now, that comes
off the lower valance, and I have thin plywood covering the entire underneath of the car, to improve
aerodynamics, and a diffuser in back, so its hard to see all of the potential ways to route it.
But it looks like some creative sheetmetal work may be possible, and on each inner fender, about even with the front of the engine, is a 3 inch by 4 inch hole, put there by the factory,and going into the wheel well, where there is cold air. So, I agree, it would be a challenge, but I think it is doable.
Cold air to the carb is a cheap and big power booster!

And, a nicely cut 4 inch diameter circular hole, on each side of the radiator, is not that big of a deal to me, if
I can gain 30 hp! But I understand the reluctance of some, to make those cuts.

[stinger]

one of two ways is either cut up the core or route some 4" hard pipe up along the wheel well high on the inside of the fenders and drop it back down along the bumper brackets, then plumb into the engine bay through the access holes in the inner's and have the snorkels of the air box pointing towards the fire wall.

or get a glass hood,aar or six pack.

[cudabob496]

one of two ways is either cut up the core or route some 4" hard pipe up along the wheel well high on the inside of the fenders and drop it back down along the bumper brackets, then plumb into the engine bay through the access holes in the inner's and have the snorkels of the air box pointing towards the fire wall.

or get a glass hood,aar or six pack.

yep, I'm sure most of us could come up with something functional. Probably
the cheapest hp you can find. You drop carb inlet temp by 50 degrees on a 500
hp engine, and that is supposed to gain you 7.5% X 500 = 37.5 hp.  Or look at it another way,
if its a hot summer day, and you increase carb inlet temp by 50 degrees, you lose 37.5 hp.

lotta diff airbox models, too.  I like the one that goes back to the firewall. Nascar has those.
Some only need one air hose going to them.
http://www.ramairbox.com/models.html

[stinger]

I'm starting to warm up to the idea of running an aar or six pack hood. I do like the chally ta hoods the most though.

[Yellow Submarine]

I'm early in my build and am looking at aircleaner options as well as the possibility of a cold air intake. One is the ram air set ups you touched on is very similar to a 68' 442 I had a long time ago.
Dr.Olds just clamped 4" flex tubing onto both snorkels and ran them down the front corners of the engine compartment. They terminated into two plastic scoops with rectangular openings just under the front bumper. They were not very noticeable but were very functional.
In our cars the tubing would need to exit differently as Cudabob described maybe through the inspection holes.
Another thought I had would not likely give you much ram effect but would provide cool air. That is cover the center section of a Rallye hood with sheet metal. Then use a TA type air cleaner to seal to the "boxed in" section through a hole cut to match the air cleaner. Leave out the plastic plugs for the two openings to allow for air to be sucked in.
Another idea is use a stock dual snorkel air cleaner base but use a smaller diameter  top leaving the filter element open all around. Fit a seal around the perimeter of the base so it can seal to the hood opening. Ford used this arrangement on some of their cars to provide ram air.
John

[cudabob496]

notice in 3rd blue car, most of air pressure above hood is negative, and will not force air into engine compartment.
But, lot of pressure at base of front window, that NASCAR uses to feed air to carb.

http://www.gmecca.com/byorc/dtipsaerodynamics.html

[Yellow Submarine]

Nice article Cudabob. Good descriptions of several aero issues. I still wonder if opening up the Rallye scoop openings and sealing to air cleaner would help with intake temp.  68 and/or 69' roadrunners had a cold air intake through upward facing rectangular openings. No ram affect but cool air. 70' Runners had a different setup available.

John

[cudabob496]

Tough call, as there might be negative pressure in the area of the opened ralley scoops.

[dfrazz]

Nice article Cudabob. Good descriptions of several aero issues. I still wonder if opening up the Rallye scoop openings and sealing to air cleaner would help with intake temp.  68 and/or 69' roadrunners had a cold air intake through upward facing rectangular openings. No ram affect but cool air. 70' Runners had a different setup available.

John

The rallye scoops are too small of an opening on the hood to make a big difference on intake.  They would help cool off the engine when stopped, but not much else.

[Yellow Submarine]

Frazz
You are right about the limitation for air flow through the rallye hood scoops. I have been looking at the large holes left when the pot metal inverts are removed.

For fun I made some surface area measurements through a stock dual snorkel air cleaner, rallye hood with plugs removed and with the pot metal inserts removed. I came up with some surprising results. Keep in mind these are estimates only and meant for comparison only.

Stock rallye hood with scoop plugs removed: 9.9 sq in
Rallye hood with pot metal inverts removed: 36.75 sq in
Stock dual snorkel air cleaner: 6.9 sq in.

Amazingly the air cleaner has a smaller total opening than the scoops with plugs removed. So for me the snorkel air cleaner needs to go. I'll change the AC compressor to allow for one of the large oval air cleaners like those on multi carb engines(6pk, hemi etc).

John

[cudabob496]

ya, always thought snorkle air cleaners were too restrictive.