Superformance Cold Air Intake Design

[Ace23]

Has anyone ever seen or head of someone successfully creating a cold air intake system for a cobra / Superformance? I'm located in the south and I pretty much just park the car now from June 1st through the end of September. I despise driving these cars in heat.....they feel like they lose 200HP. The 1st year I owned the car I drove it year around but after a few years it is just not fun when the idle is down, you have to constantly clear the carb out and how sluggish they feel in the heat and humidity. When its 50 degrees out the car feels like it has a 150 shot of nitrous on it.

Fuel injection is on the table as well but I don't think that solves the problem. The air intake delivery needs to be part of the overhaul.

If there is a readily available modification short of full blown custom fabrication I've yet to come across it.

Thanks

[Mongoose930]

I have a turkey pan and phenolic carb spacer which definitely helps. I mixed in some 110 CAM2 with my 93 octane gas and that also helped with warm weather driving.

[Jim Vander Wal]

Long time ago in a different lifetime I ran Superformance #1855 and #2584 with a 427w and carb. Did have some heat issues but probably wasn't as hot, easily as humid. Probably wasn't as bad as OP's experience.

ProSystems 750 DP, mechanical fuel pump, factory fuel lines. Premium 93 or 91 as available.

Added the phenolic spacer, about .5" thick.
Plumbed in an Aeromotive bypass regulator after the carb. Ran 5/16" return lines.
Wired the radiator fans with a manual override switch. I think I ran a 160 degree thermostat.
Also ran a Setrab 915 oil cooler with the Canton thermostat and AN-12 lines.

Usually if I could keep moving there were no problems. No issues with idle unless for an extended period. Never noticed a significant power reduction.

But, when idling in traffic, think Woodward Dream Cruise, lifting the hood on the latches helped along with turning on the fans before it got hot. This opened a gap of about 3/8" along the back of the hood, usually solving the problems allowing the heat to escape. Never had a problem with the rear of the hood up, other than the hood would shake a bit more. Many owners did same w/o issues.

Now I did have that one time I drove I-80 from Lincoln, NE on 104 degree August afternoon. If I would have had a turkey baster and sufficient supply of water, I would have been "done" and "juicy" when I got to Colorado. As it was, I was bright red and crispy. The car was perfectly content running at 95.

Jim

[msinc]

I own 2621 and it has an aluminum Robert Pond FE. It has the turkey pan and an insulating spacer under the carb. I also have the fan over ride switch. Gets pretty hot in southern Maryland, but I haven't had any trouble with power when running. No overheating in traffic or idle either as long as I watch the gauge and switch on the fans. The problem I have had is when, after a drive, if I stop and cut everything off and didn't run the fans prior to stopping the ethanol will boil out and flood the engine. I believe, based on what I have read and researched that fuel injection is the answer. I find that as long as I run the fans 5 or 10 minutes before I know I am going to stop and shut it down and also open the hood and let the fans run a few minutes, after shut down, to cool things off then it wont boil over. One thing I would caution you on....I definitely do not recommend a cooler thermostat. The cooler you run an engine the more cylinder wear it will suffer. Engines that run at 190 or above wear the cylinders very, very little, 180 isn't too bad, but 160 and lower will wear cylinders out surprisingly fast. I first read about this in a popular engine building book back in the 80's titled "How To Rebuild Your Small Block Ford" by {IIRC} Tom Moore. He had a little chart that cited wear in an hourly test at different temps. I didn't believe it until I put in 20 years as an automotive machinist where I saw first hand older engine blocks {160 was a popular thermostat back in the 60's} almost all needed bored over. Engines run with no t-stat any amount of time had wiped out bores and the newer engines that ran 195's and 200's {after they found a hotter engine produced less emissions} rarely even needed to have the cylinders bored. Don't get me wrong, no doubt running the engine cooler will help the problem, but it will cause one that is way worse. I have to admit I was surprised at how hot the carb gets in spite of the working hood scoop and turkey pan. I may not have the best or most effective insulator/spacer, but staying ahead of the curve with a fan over ride switch works pretty good for me.

Edit: obviously, non-ethanol gas will solve the problem too. But, that is a little expensive if you drive your car a lot and in many places a little hard to find. 100 octane no-lead av-gas if you can get it will work too. That stuff is even harder to find, you have to get it at an airport and then they have to agree to sell it to you.

[Jim Vander Wal]

The bypass regulator relives the pressure when the fuel boils sending it back to the tank. This eliminated the fuel blowing past the needles that I experienced prior to adding the bypass.

Fuel injection and 50psi fuel pressures will solve the boil over problem too but what fun is that?

Jim

[Dominik]

I drove my car with a 427 FE (iron heads, ally intake, 600 Holley, mech pump) in 110F stop go here in south africa. No carb spacer, no turkey pan. Hood closed, small scoop, under car exhaust with headers, small air filter.

16" pusher fan came on at 95°C, kept the engine under 100°C. I built it without inner fenders. And I left the gap between radiator top and body open, but shrouded the rest of the radiator.

It has no relevance in stop-go, but I had no oil cooler either. Timing was properly set for idle, mid range and WOT (obviously)

Did you check under hood temperature?

The turkey pans, while good at speed, tend to become a terrible hear sink at low air flow.

[Blas]

Ok, I’ll chime in here on this, you can also run a cooler thermostat and change out the fan temperature switch on the radiator. As they say in the medical don’t chase pain, stay ahead of it…. Same for heat in the engine compartment, try as best to stay ahead of it. Phenolic spacer under carb, be sure fans are both pulling air into engine area thru radiator, manual fan switch. If you have the normal bug screen in front of your radiator, ditch the house screen material on it and replace it with a piece of hardware cloth screen with bigger openings. Insulate fuel line along the frame rail on drivers side. Add Water-wetter to standard antifreeze or try Evans coolant? And keep electric fuel pump cooler with the addition of a relay on its power supply.
Latter is covered on SPF wiring diagram.
Blas

[Ace23]

I think my complaint turned into a problem solving discussion that I might not have. I think my situation is more related to the actual heat and humidity that our area has through the summer. My car doesn't overheat or anything of that nature I was just thinking if there was a way to draw fresh air into the air cleaner instead of pulling directly from under the hood it will be a huge improvement. Seems as if this would be a full custom request.

In the past when I had motorcycles it was the same way. When it was hot and humid it was if you could watch the tachometer just waiting for it to rev out. Go ride in 50 degree weather and it was night and day.

[Jim Vander Wal]

Ace23

I included this in my response, but it was probably missed.

Try lifting the hood on the latch arms. Open hood, turn latches to the locked position and setting the hood down. This provides a 3/8" or so gap to vent air.

If this works, then you'll have an idea if venting solves or at least helps with the problems. It's a no harm, no cost test. But you'll still need to be proactive with a manual fan switch.

As I mentioned previously it worked during summer cruises in stop & go traffic, often on 90+ days.

Hope you find a solution; I can appreciate the frustration.

Jim

[eschaider]

When you experience a significant tick up or down in humidity, air temp and possibly also barometer, carbs will show a significant change in engine performance because they have a more difficult time correcting the fuel delivery in these situations. A MAF (mass air flow) based EFI system will do a much better job of correcting fuel delivery. The sluggishness you feel is caused by a decrease in air density and an increase in humidity both of which displace oxygen in the air making the engine run rich.

A MAF-based EFI system will measure the actual air mass injested by the engine and correct the fuel delivery to exactly match what the engine needs. You will immediately feel the difference in throttle response and the vehicle acceleration your seat of the pants dyno reports. Your Cobra will be able to accommodate these climatic changes as easily as your daily driver does.

[Ace23]

Originally Posted by eschaider

When you experience a significant tick up or down in humidity, air temp and possibly also barometer, carbs will show a significant change in engine performance because they have a more difficult time correcting the fuel delivery in these situations. A MAF (mass air flow) based EFI system will do a much better job of correcting fuel delivery. The sluggishness you feel is caused by a decrease in air density and an increase in humidity both of which displace oxygen in the air making the engine run rich.

A MAF-based EFI system will measure the actual air mass injested by the engine and correct the fuel delivery to exactly match what the engine needs. You will immediately feel the difference in throttle response and the vehicle acceleration your seat of the pants dyno reports. Your Cobra will be able to accommodate these climatic changes as easily as your daily driver does.

I agree. Using an in-tank fuel pump and a nice multi-port injection system would likely be a world of difference.

[eschaider]

Originally Posted by Ace23

I agree. Using an in-tank fuel pump and a nice multi-port injection system would likely be a world of difference.

Not just a multi-port EFI but a Mass Air Flow (MAF) based multi-port EFI. A Speed Density EFI system will be a significant improvement over carbs, from a tunability perspective; however, significant changes in air temp, barometer, humidity etc., are extremely difficult to accommodate with a Speed Density fueling model. As a result, without a new tune, you still experience the power reduction we all so dislike.

The MAF-based EFI fueling model measures the mass of air entering the engine, making AFR determinations and fueling adjustments in real-time, no matter the atmospheric conditions. Remember, AFR is lbs of air per pound of fuel.

This doesn't sound like a big deal until you spend your dollars on your favorite multi-port Speed Density EFI system and discover not much has changed from your carburetted experiences, except the amount of money that is now in your pocket.