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Discussion Starter #1 (Edited)
If one needs to use a carb hat (ev 4150 pro) in a n/a application (I have A LOT of room behind the carb, not none in the front, so a traditional 14x3 wouldn't begin to fit), would it be better to:

- stick on the appropriate sized filter right onto the end of the carb hat and accept some heat soak from the engine

- run ducting to a cold air source, but said ducting would require 1 u-bend, about 1.5-2ft of piping, and then a 90* bend (roughly - I'm just thinking it out in my head so there may be another bend or not, but assume at least 2-3bends).

Obviously neither is the most optimal - one has a bit of heat soak (although I suppose you could build an aluminum box around the filter, then cover it with heat reflective material) and the other has multiple bend (I believe 1 90* bend is the same as having 3meters of straight hose), but which is the best of the worst?
 

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Discussion Starter #2
btw, this is why I can't filter it a traditional way/doing a cai effect would require several ducting bends, because I know somebody's going to tell me to stick a 14 or 16x3 ontop of it....

(no rear roll bars in place, which would make routing even more onerous)


 

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Discussion Starter #4
close - 80s group C replica.




Another idea I'm thinking of trying out is to use a rectangular filter - k&n 17x11. That will flow 1200cfm. Then building a box with a flange and stickign that on the carb. Then cover the box with heat reflective foil (to reflect heat away from it) and insert the air filter onto the top of the box

I like the carb hat, but I have concerns about it on a high hp n/a application (502cid small block) since it is designed to force air into it. However, if I build my own box the concern is I know nothing about air flow and might do something I don't want to do, lol.
 

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i would bet that a ev pro hat with a 4 inch inlet has enough cross section to support it. if you wanted more area you could build your own hat. i think an ev pro would work fine

i know everyone says that you need to have at least 5 inchs above the top of the carb to give the carb enough air but i really dont buy it. i know that on an engine dyno you will see a horsepower drop when you lower a plate above the top of the carb, i have seen that but i dont see it on the track. i did a back to back test on a chassis dyno with my own car. i have 1/2 inch clearance from the top of my airhorns to the hood. made a pull with the hood closed, 422hp. let engine cool, got the intake manifold back to the same temp 105F and opened the hood. made 424.

take a look at a super stock hemi barracuda and look at the clearance between the carb and the top of the scoop. IMO i would rather have the intake be of the proper design and have less area above the carb then lower the carb and have a shorter intake, in a serious effort application.
 

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i was thinking a Sprint Car style air box, you could drop the base a bit along with a mclaren esk scoop up the back of the roof
 

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Discussion Starter #7
i would bet that a ev pro hat with a 4 inch inlet has enough cross section to support it. if you wanted more area you could build your own hat. i think an ev pro would work fine
But since a hat is designed for air to be forced into it, will it still be fine if it's just "sitting there" i.e., if I put an ev pro hat on facing backwards, then clamp on a 4''x12'' connical filter. There's no way to get a ram air type effect without having a gigantic u-bend in it, so air wouldn't be forced into it; it would rather just be circulating around/into the filter and then into the hat? :smt102
 

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I was thinking about taking air from the windshield wiper gutter(92 Firebird) and piping it through a carb hat-wouldn't draw any hot underhood air. I've heard 3" minimum clearance from hood to top of carb, also heard carbs like to draw air from the sides...............
 

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Discussion Starter #9
I was thinking about taking air from the windshield wiper gutter(92 Firebird) and piping it through a carb hat-wouldn't draw any hot underhood air. I've heard 3" minimum clearance from hood to top of carb, also heard carbs like to draw air from the sides...............
From what I know, the more room the better, I think minimum is like 1'' above the vent tubes? Also, you're right about carbs preferring air from the sides, but sometimes you gotta do waht you gotta do....
 

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If you measure a few times after the window or bars are in place you can then have a look at the Spectre modular CAI kits. Here are a few ideas for you...

http://www.spectreperformance.com/#HOME




also Rambox's range.....


Don't forget to call the dealer for exact dimensions as it looks very tight against you window. Nice car by the way....Reminds me of Can-Am racers and Moslers......
 

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But since a hat is designed for air to be forced into it, will it still be fine if it's just "sitting there" i.e., if I put an ev pro hat on facing backwards, then clamp on a 4''x12'' connical filter. There's no way to get a ram air type effect without having a gigantic u-bend in it, so air wouldn't be forced into it; it would rather just be circulating around/into the filter and then into the hat? :smt102
i dont have any testing to back this up, but i would bet that the temperature of the air coming in is more important then having a "ram effect". its just like cars with forward facing hood scoops and cowl hoods, 1 is having cool air forced in and the other is pulling cool air in. ive seen guys go from front facing to cowls and not pickup or loose anything.

i would make whatever u-bends or routing path you need to get the filter in some cold air and then run the biggest one you can. im really not too big a fan of running filters (when super stockers and prostock start running them, ill get one) but on a street car i understand.
 

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Discussion Starter #13 (Edited)
If you measure a few times after the window or bars are in place you can then have a look at the Spectre modular CAI kits. Here are a few ideas for you...

That low profile sheetmetal spectre piece is, realistically, the only thing that would fit under my hood, BUT I've been cautioned away from it by several people - too much air turbulence in it.

Plus since it allows very little room around the vent tubes you can run into performance issues.

Also, the low profile of a lot of the spectre pieces really seem to hurt them - they're rated around 1200cfm (the above piece) wit dual 4'' inlets. However the ev pro hat (when I asked Gordon) in a n/a application would flow ~1200-1400cfm because of the height advantage (single 4'' inlet, but 5'' tall)

i dont have any testing to back this up, but i would bet that the temperature of the air coming in is more important then having a "ram effect". its just like cars with forward facing hood scoops and cowl hoods, 1 is having cool air forced in and the other is pulling cool air in. ive seen guys go from front facing to cowls and not pickup or loose anything.

i would make whatever u-bends or routing path you need to get the filter in some cold air and then run the biggest one you can. im really not too big a fan of running filters (when super stockers and prostock start running them, ill get one) but on a street car i understand.
Gotta run filters on the street, haha =)

I guess a question could be then, at what point is getting cold air into it not worth it?

For example, what happens if it requires 4 90* bends to reach a cold air source? There has to be some point where there's simply too many bends/distance in order to justify it :smt102
 

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If you have the room for the EV it's better. I run one.....Can you have cold air ducts in a perspex rear window? Any room above the rear wheels? (With inner fenders) Can you duct cold air to the filters? Have a look at what some have done when space is tight yet performance is required....Granted it's not n/A but the ides is to get cold air where you can.

 

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Discussion Starter #15
If you have the room for the EV it's better. I run one.....Can you have cold air ducts in a perspex rear window? Any room above the rear wheels? (With inner fenders) Can you duct cold air to the filters? Have a look at what some have done when space is tight yet performance is required....Granted it's not n/A but the ides is to get cold air where you can.
I can get cold air infront of the rear wheels (placing the filter between an open side-scoop and the rear splash panel) BUT the question is, at what point is cold air not worth it? It would require anywhere from 2-4 bends depending on how i do it, which might very well negative any benefit from doing it that way......
 

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I think your thinking 2 much about the bends. If you look at any aftermarket intake for most cars it has 4 bends in it. Dont worry about the bends. Make the pipeing big and get cold air
 

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Discussion Starter #18
I think your thinking 2 much about the bends. If you look at any aftermarket intake for most cars it has 4 bends in it. Dont worry about the bends. Make the pipeing big and get cold air
True, but I have no idea how air requirements (in terms of how it is delivered) vary from fuel injected to carb. Perhaps a carb manifold is more sensitive about more bends in the air path? (I honestly don't know, just thinking out loud here :smt102 )

It's kind of like the spectre plenum - I mapped out how to make it work, then had dozens of people tell me to run like the plague from it for several reasons, but the primary one being how low profile it is and effecting the signal .... I just don't want to choose the wrong path and hamper my engine, so I'm trying to think of every angle, which is further hampered by the fact most people are not using a blow-through carb hat as their air source, so there isn't much data to go on.
 

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spectre also do a round carb hat with the twin 4" outlets. I have one in the workshop. I can get you a part # and pic if you wish.
 

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Discussion Starter #20
spectre also do a round carb hat with the twin 4" outlets. I have one in the workshop. I can get you a part # and pic if you wish.
I have that one in my basement from a previous build when I was playing around w/ different ideas ...... the low profile of it kills it flow and creates air turbulence.
 
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