[Tom Vaught]

That is a nice looking set of parts. Plastic and will not transmit engine heat to the intake
air charge. With blocked heat riser heads you would have a inexpensive system that should work well.

Tom V.

[Jay S]

Be fun to see testing between the cowl set ups, a drop base to run a ram air pan, and the dual snorkel hose set up to the front valence. I think my money would be on which ever had the least air filter restriction. Not sure that will be a drop base. I sure like the looks of the drop base connected to the factory RA pan though!

Here is Jim Hands, claimed his was 1 mph and a tenth every time no matter the temp.

[Kenth]

Here is the nicest 1967 RamAir kit available:

https://secure.amesperf.com/qilan/De...7&web_access=Y

[NeighborsComplaint]

Originally Posted by Tom Vaught

That is a nice looking set of parts. Plastic and will not transmit engine heat to the intake
air charge. With blocked heat riser heads you would have a inexpensive system that should work well.

Tom V.

Yeah. I was surprised at how inexpensive that kit was too. I get the aftermarket stuff for the race car look if that's one's thing. For me, the clean OEM look is the best. I am still Jonesing for the pro ram air kit for my '71 but some rust flowers grew on my rear quarters and door bottoms and are getting $ome love this year.

[leeklm]

If a person is after max performance from a cold air intake, I once read an article suggesting the factory openings on the 66/67 gto hood were too small and poorly located (low position on hood??) to offer much benefit. I presume they are plenty good for normal street driving & cruising.

As mentioned below, would be interesting to do ET testing with the various air inlet systems. I sold my 66 a few years back so cannot volunteer.

Sent from my SM-G965U using Tapatalk

[Scott Stoneburg]

I tested my car at the track, back to back with the 5" cowl hood sealed to the air pan, a cold air box fed by 2- 5" ducts with the pick up located in the valance under the front bumper, and with just an open carb. ( 1050 Dominator ) both the air box and air pan sealed to the hood were good for almost .2 faster than with an open carb top. I stayed with the air pan because it was a cleaner look than having the 5" ducts running around the radiator.

[Keith Seymore]

Originally Posted by leeklm

I once read an article suggesting the factory openings on the 66/67 gto hood were too small and poorly located (low position on hood??) to offer much benefit. I presume they are plenty good for normal street driving & cruising.

This is true.

That's why when we ran our car we didn't run a nose piece that had been opened up; we ran no nose piece (just the wide open hole in the hood).

The hood bracing in that area had already been cut away and the battery relocated to the trunk when we picked the car up from Royal.

K

[Formulajones]

Originally Posted by leeklm

If a person is after max performance from a cold air intake, I once read an article suggesting the factory openings on the 66/67 gto hood were too small and poorly located (low position on hood??) to offer much benefit. I presume they are plenty good for normal street driving & cruising.

As mentioned below, would be interesting to do ET testing with the various air inlet systems. I sold my 66 a few years back so cannot volunteer.

Sent from my SM-G965U using Tapatalk

If that were true then the 69 GTO should be even worse. However I've found them to work exceptionally well. In fact that's one of the cars with a Sniper Stealth where I can monitor the air intake temps. Even after heat soaking with the engine shut off, it'll bring the air intake temps down to ambient temps as soon as you're cruising down the road for about a mile, so those 2 small scoops in the center of the hood are actually working pretty well.
He races the car with this configuration too, and I have that hood sealed to the pan with an L88 air box setup, so there is no room to experiment with a different setup on this car, but it seems to be feeding the 571ci engine just fine.

I've raced everything here for many years and they all have different fresh air intake setups on them. While each car is different and it would take a book to explain all the experimentation, to put it in short, whether it's forward facing scoops or rear cowl plenum setups, they all have responded positively to the fresh air, and slow down noticeably if blocked off and just subjected to under hood hot air.

It's most likely why NHRA refactored these cars for stock and super stock racing more than 50 years ago, when they realized it, and why that was worth mentioning earlier in this thread.

[padgett]

Don't forget these cars were designed to meet the emissions standards and even earlier GM decided the intake air temperature at the carb should be 100F, why the TherMacs and the 195 thermostats.

Repeat: this was for ease of tuning/emissions and not performance.

Also at speed the hood air inlets are in the boundary layer so air is cool but not getting any boost. The Formula Firebird was probably the best. The shaker kinda sorta points at the high pressure area at the base of the windshield but is to short to reach it.

Never tested but would not be surprised if an open shaker had a slight negative pressure..

[NeighborsComplaint]

The cold air is the key. My gut says the "ram air" claim is negligible, certainly not a supercharging effect.

[leeklm]

Speaking of designing for emissions, Pontiac pulled the plug on a working cold air box for the 73 GTO using the NACA ducts on the hood due to not passing CA noise emissions. How lame is that? A few of those systems were provided as a dealer add-on.

Sent from my SM-G965U using Tapatalk

[Tom Vaught]

Originally Posted by Formulajones

If that were true then the 69 GTO should be even worse. However I've found them to work exceptionally well. In fact that's one of the cars with a Sniper Stealth where I can monitor the air intake temps. Even after heat soaking with the engine shut off, it'll bring the air intake temps down to ambient temps as soon as you're cruising down the road for about a mile, so those 2 small scoops in the center of the hood are actually working pretty well.

You miss one of the most basic Aero concepts: Listen to Engineers like Seymore or myself.

Never compare vehicles with different body configurations.
A 1966/1967 GTO BODY OR HOOD DESIGN IS NO WHERE CLOSE TO THE SAME AS A 1969/1970 BODY SHELL.

That would be like comparing a 3rd gen Trans Am to a 1964 GTO.

The 3rd Gen Trans Am Bonneville car campaigned by Gale Banks and driven by Stringfellow was a very nice vehicle aero wise. Been there and raced with them at Bonneville. Banks is the PR Guy and Stringfellow just does his job.

Tom V.

https://www.youtube.com/watch?v=cwk4WEuBttk

Ps Just for credentials sake:

Have you ever been in a Vehicle Wind Tunnel?

Personally I was paid to be in a Wind Tunnel as a JOB for my company. Not once or twice to see how one works
but for several weeks at a time at the Lockheed Wind Tunnel in Georgia, for 5 years of my work history.
Mostly did Truck Aero stuff but occasionally tested special vehicles like the Ford GT Sports Car. We added a better chin spoiler on that vehicle after Danny Thompson flipped a vehicle over on its back at Bonneville due to front end lift.

The point is don't assume, let data tell you what works, be it ram air parts or aero changes.

[Tom Vaught]

Originally Posted by Tom Vaught

You miss one of the most basic Aero concepts: Listen to Engineers like Seymore or myself.

Never compare vehicles with different body configurations.
A 1966/1967 GTO BODY OR HOOD DESIGN IS NO WHERE CLOSE TO THE SAME AS A 1969/1970 BODY SHELL.

That would be like comparing a 3rd gen Trans Am to a 1964 GTO.

The 3rd Gen Trans Am Bonneville car campaigned by Gale Banks and driven by Stringfellow was a very nice vehicle aero wise. Been there and raced with them at Bonneville. Banks is the PR Guy and Stringfellow just does his job.

Tom V.

https://www.youtube.com/watch?v=cwk4WEuBttk

Ps Just for credentials sake:

Have you ever been in a Vehicle Wind Tunnel?

Personally I was paid to be in a Wind Tunnel as a JOB for my company. Not once or twice to see how one works
but for several weeks at a time at the Lockheed Wind Tunnel in Georgia, for 5 years of my work history.
Mostly did Truck Aero stuff but occasionally tested special vehicles like the Ford GT Sports Car. We added a better chin spoiler on that vehicle after Danny Thompson flipped a vehicle over on its back at Bonneville due to front end lift.

The point is don't assume, let data tell you what works, be it ram air parts or aero changes.

Like humans, vehicles are different, Twins can "Look" the same but be totally different. Don't ASSUME based on one piece of data (which you obviously have for YOUR vehicle with good instrumentation) and assume it applies to other vehicles.

TV

[Formulajones]

Originally Posted by Tom Vaught

You miss one of the most basic Aero concepts: Listen to Engineers like Seymore or myself.

Never compare vehicles with different body configurations.
A 1966/1967 GTO BODY OR HOOD DESIGN IS NO WHERE CLOSE TO THE SAME AS A 1969/1970 BODY SHELL.

That would be like comparing a 3rd gen Trans Am to a 1964 GTO.

The 3rd Gen Trans Am Bonneville car campaigned by Gale Banks and driven by Stringfellow was a very nice vehicle aero wise. Been there and raced with them at Bonneville. Banks is the PR Guy and Stringfellow just does his job.

Tom V.

https://www.youtube.com/watch?v=cwk4WEuBttk

Ps Just for credentials sake:

Have you ever been in a Vehicle Wind Tunnel?

Personally I was paid to be in a Wind Tunnel as a JOB for my company. Not once or twice to see how one works
but for several weeks at a time at the Lockheed Wind Tunnel in Georgia, for 5 years of my work history.
Mostly did Truck Aero stuff but occasionally tested special vehicles like the Ford GT Sports Car. We added a better chin spoiler on that vehicle after Danny Thompson flipped a vehicle over on its back at Bonneville due to front end lift.

The point is don't assume, let data tell you what works, be it ram air parts or aero changes.

I guess you either misunderstood the point I was going after or I wasn't clear enough.

The low pressure area is in the middle of the hood. Basically right where a 67 GTO puts a scoop, or a 65 GTO, or a 69 GTO etc....

For a forward facing scoop in the middle of the hood to work effectively it's been documented many times the scoop really needs to be at least 2-3 or even 4 inches off the hood. That's a fact.

So as we all know the GTO scoops in the middle of the hood never reached up in the air very high, which is why I thought I didn't have to explain that. So my point was the 69 scoop shouldn't be any more effective than a 65, or a 66, or a 67. Yet from what I've seen with air inlet temps and at the track, the 69 scoops do in fact grab some fresh cooler air despite what's been written about the design being somewhat ineffective.

[HWYSTR455]

You can use a carb hat, tubing, and a cone type filter if you wanted to. Have to be careful of the type of cone filter you use, because some don't flow worth a crap.

Since I did a LS-type throttle body on my last project, I went this route, but like I said, you can do the same with a carb hat.

Granted, you may not actually get a psi increase with a cone filter/carb hat setup, but you can still pull colder air than what's coming thru the radiator.

My cone filter is inside the engine bay, in front of the passenger inner fender, and surprisingly, pulls cooler air than from the top/behind the radiator. I've confirmed it with IAT sensor.


.

[Tom Vaught]

Originally Posted by Formulajones

I guess you either misunderstood the point I was going after or I wasn't clear enough.

The low pressure area is in the middle of the hood. Basically right where a 67 GTO puts a scoop, or a 65 GTO, or a 69 GTO etc....

For a forward facing scoop in the middle of the hood to work effectively it's been documented many times the scoop really needs to be at least 2-3 or even 4 inches off the hood. That's a fact.

So as we all know the GTO scoops in the middle of the hood never reached up in the air very high, which is why I thought I didn't have to explain that. So my point was the 69 scoop shouldn't be any more effective than a 65, or a 66, or a 67. Yet from what I've seen with air inlet temps and at the track, the 69 scoops do in fact grab some fresh cooler air despite what's been written about the design being somewhat ineffective.

The testing that we did in college on the 64 Hood showed that the snorkel inlet worked at 5 inches about the 64 hood. Maybe 4" off the hood would have worked, the Hood Box/snorkel scoop was a 5" part. I only post what I have data for.

Cool air coming in 1969 GTO scoops should make the air cleaner inlet temps
cooler vs under hood temps. Can't disagree with that either.

And the topic is about cool air, not a working Ram Air system.
Thanks for the clarification on your post.

Even the little shorty NACA scoops used on the side of the vehicles will duct some cool air to the rear brakes, but those scoops are not optimized scoops.
The 73 NACA scoops were closer to the real think on the Herb Adams NASCAR 73 GTO but they were not allowed to run the car. Maybe the NACA scoops wood have worked well at NASCAR vehicle speeds. Obviously not at highway speeds.

Again Thanks for the Clarification.

Tom V.

At street speeds the air hits the grill/ front nose and angles upward basically missing the hood.
At highway speeds the on-coming air deflects the air from the grill/bumper lower and more is closer to the hood line and trying to pass thru the grill area. At Race speeds on the track, the air tries to go around the sides of the vehicle vs fight the straight air pointing at the hood line/grill area/windshield.

[Kenth]

Atmospheric pressure, about 14.7 psi, will regardless of vehicle speed fill the vacuum in intake below the throttle plates in various grade depending on throttle blade position thus regulate power output of the engine.

To gain Ram Air effect, more than 14.7 psi, how fast do you need to drive?

I´ve came to the conclusion the RamAir system is to induce cold denser air into the carb/intake to burn more fuel, instead of overcoming the atmospheric pressure.

But, i could be wrong.

[Formulajones]

Originally Posted by Tom Vaught

And the topic is about cool air, not a working Ram Air system.


Tom V.

Yes, and since the OP is talking about a 67 GTO, it only seems logical, as many others have already suggested, to just use what has already been engineered for that vehicle and make the existing scoop/hood functional. It's clean, it's aesthetically appealing, all the parts are readily available, and it does work to at least bring in cooler air.

Pontiac chooses to call it a working Ram Air system but how effective it is at ramming air can be debated.

[ZeGermanHam]

Originally Posted by Formulajones

Yes, and since the OP is talking about a 67 GTO, it only seems logical, as many others have already suggested, to just use what has already been engineered for that vehicle and make the existing scoop/hood functional. It's clean, it's aesthetically appealing, all the parts are readily available, and it does work to at least bring in cooler air.

Pontiac chooses to call it a working Ram Air system but how effective it is at ramming air can be debated.

Exactly. I feel that this thread has been dancing around the topic of ram air effect a little too much given the OP is only asking about cold air induction. As has been pointed out, they are two separate functions.

Since OP is only asking about lowering the air inlet temps on his '67 GTO, opening up the stock hood and using factory-degined "ram air" parts should be sufficient, easy to accomplish, and aesthetically pleasing as you say. No need to go off the deep end if all you're concerned with is pulling in cooler air from outside the engine bay.

[Keith Seymore]

Originally Posted by NeighborsComplaint

The cold air is the key. My gut says the "ram air" claim is negligible, certainly not a supercharging effect.

Originally Posted by Kenth

I´ve came to the conclusion the RamAir system is to induce cold denser air into the carb/intake to burn more fuel, instead of overcoming the atmospheric pressure.

This is correct. The introduction of cooler air trumps any increase in restriction or ram effect.

Originally Posted by Tom Vaught

The point is don't assume, let data tell you what works, be it ram air parts or aero changes.

This, this, THIS!

We decided to make an inlet duct out of a parking light lens. Our road data did not show any improvement.

When we put it in the wind tunnel the smoke showed the air going into the inlet opening at the outboard edge, and then coming right back out the same opening at the inboard edge.

I never would have guessed that.

My take away: "...you never know 'til you smoke it".

K