I'm thinking about ditching these fuel rails so it'll be easier and I'll have room to mount an airbox with velocity stacks In It. I'm only using 2 injectors so I could just run them in the stock on housing location. With rails off I'd have about 5 inches of height to work with vs the 3 I have now. my other thought was to use a 90 bend and put the airbox behind the alternator. Even in cool weather I'm running 130-145 intake air temps.

 

Efi hardware

i had the same problem with intake air temps. got the box from efi hardware. 50mm tapered bore efi hardware tb with 4 injectors. Only using 2 725cc bosch ev14 primary right now. I had to get spacers to clear the fuel rail. It fit under the hood just had to adjust hood latch all the way up. Air filter housing i made myself from sheet metal witb a stubby k&n filter.

 

 

There was a dramatic difference in temps with a noticeable increase in power. Before intake air temps were above 150°f. Dont remember the exact temps. Now on a hot day 80° is the hottest ive seen. Plus its quite when you hit the gas because of less intake noise. Being quiet is a big deal on street driven car in cali for me. Exhaust is loud enough. I had to use the tallest spacers efi hardware had to clear the fuel rails. Hood barely rubs on one corner of the box. I slightly elongated the hood latch holes to clear it. But u cant tell when the hood is closed. Looks stock. The hose going to that box is 5inch so it was a pain in the *** to find a way to step down from 5 to 3inch for the filter. Found the hose at a airplane parts supply website pretty cheap. In the mazda factory race manual they put the filter in the air box itself. The air box is getting harder to get from efi hardware. Supposedly they cant keep them on the shelf. Not cheap either but worth it.

 

Weird that their in high demand now. I ordered mine right After your post.

 

Cool. Couple months ago friend tried to buy one and was told they are out of stock.

 

did u ever check temps after the carb . .... u can make a lil shield to keep the fuel off the sensor ...

 

I'll do a before and after post once I get mine. I should be able to get close to ambient.

 

let us kno..... goin to do the same in the summer

 

before i had the air temp sensor in between the 2 air horns. Temps were 150°+. Now i have sensor on the fiberglass air box in the same spot as before. Temps now the highest i have logged is 85°. That was on a hot day. I had a heat shield from racing beat that worked ok. I made one out of the stock manifold heat sheild that works really good.

 

good **** .... think venting the hood should be done also

 

I actually have a vented hood. I'd guess all I'm doing is creating a space for the hot *** header air to go, then be sucked into my engine.

Here's another qestion related to airboxes.
under the passenger headlight cover seems to be a popular place. Just at a glance it seems like a bad choice. It's sealed off from just about everything without a duct to it or a ducted headlight cover.

 

I'm not fancy enough to test the effect of doing that to a car so I dunno that I'd spend money on it. Just a passing thought

​​​​​​​Speaking of vented hoods. I had this notion of running the radiator at an angle like the FC . I have already been looking into an electric water pump. With a side mount alt and some hood mods I could probably duct all the air from the oil cooler and radiator out the hood.

 

seen someone do that good idea and venting the hood on the exhaust side .. never wanted to cut my hood since i hav a turbo2 scoop ... next build definiteiy goin to do it

 

I have my filter next to the radiator with a hole in the radiator support and a small scoop that draws air before the radiator. I also have a half of a front blinker to get some air in that way. Doubt it makes much of a difference tho. I dont like the look of the headlight cover scoop and dont see where the air can go maybe to cool the headlight. The hole in the hood is good if its sealed up for a intercooler or for the radiator in front of the motor. Other wise if not sealed a hole in the hood will just draw hot air up from the exhaust and engine. instead of out the back and underneath the car. Especially if when the cars not moving. U dont want exhaust heat coming up into the engine compartment.

 

Mazda, on the race cars, moved the radiator over to the left, and then you get a straight shot from the carb/throttle body to the front of the car.

its really common for the guys in Japan to run an FC radiator, and make brackets so its at an angle like the FC

 

Should be pretty easy to cut a hole in the side shroud on the radiator.
Mines been turboed so that spot is taken up by i/c pipes., but i have my aircleaner nestled in behind the r/h headlight, it gets some fresh air there through various oe holes and gaps in the inner guard, but i just jammed a ****-off 4" 90* silicone elbow in betwee the torsion arm and a slight cuttout in the undertray lol. It picks up air from under the car and blows it straight onto the aircleaner.
In a previous life i had it boxed in semi airtight and temps were always ambient as long as the car wasnt stationary.

 

Ive also been looking into the david craig water pump. Trying to find a radiator that fits that uses 16an fittings. Or i would have to get some fittings welded on.

 

Somewhat related, so I'll add my question here. I've got a side draft and I was wondering if I could delete the battery and plumb some piping up to the two round holes that the coils used to sit in. That's fresh air right? Added bonus, intake sounds when I open the vent in the dash.

 

you certainly could delete the battery, not sure the coil holes would flow enough, its not a very direct shot to anywhere, better to modify the panel on the side of the radiator

 

I'm still on the fence on doing a headlight scoop. I'm track only do there's nothing under the headlight cover. I also strongly considered an itg inline airbox and Spectre makes one also. A sealed and ducted airbox sounded really ideal.

Its awfully easy to overthink things like this.
I'll probably end up just cutting a 5" hole though the bulkhead between the engine bay and area under the headlight cover and slap a k&n on one end and a 5" duct to the airbox on the other. The goal is to get close to ambient air into the engine.

I'll probably spend 10% or less than my ideas above and make the same power.

 

Yah I wanted an fittings as well. If you find something share that info.

 

One of the cooler air box setups I saw was on Jesse Prather's EP RX7. He opened up the HVAC plenum and ducted an air box to use the high pressure air at the cowl like they do in NASCAR. He was able to use a round filter with a KN filter top. Other than his setup, everybody else in the EP world is pulling air through a NACA duct(s) mounted in the outer headlight door(s) on their cars. Some also use the turn signal holes like I do on my car.

Engine Masters did an interesting shoot out regarding air filters/air cleaners. What came out of it was that opening up space directly above the carb air horn is critical. So an air box that is tall as possible above the air horns/velocity stacks would be beneficial.

 

Was that the episode where the salad bowl produced the highest numbers?

 

Yes! Been looking for the right salad bowl ever since!