Air intake: under the hood or behind the grill?

[kikkegek]

I have been having some discussion lately and I was wondering what you guys think?

What would be the best place for air intake:
- under the hood (see my first picture)
or
- an intake behind the grill connected by a hose? (see second picture)





both pictures are from my car. The second is how I bought it, the first is after I had it fit with an LPG system. It now runs on liquid natural gas. which costs less than half the price of regular fuel. and we took 80% of the eco-stuf of the engine. No use for it in th Netherlands.

I think the intake like it was should be better:
1. because air from behind the grill is always cooler
2. less dirt/oil/etc from under the hood is sucked into the airfilter
3. works like a forced air intake on highway? => better performance? I think?

what do you think?

[87 V20 Scottsdale]

You're correct that the original way is the better method of air intake. I don't know anything about vehicles that run on LP gas, what is the hose overtop of the air filter for?

[78 Chevyrado]

The stock configuration gives you much cooler air so its like a tad of free power vs the open element under the hood. but the accordian shape of the inlet tube screws up air flow, but its still better as long as you dont have some fire-breather that need huge volumes of air.

[gchemist]

81-82 bumpers!

[78 Chevyrado]

I like that!

[Keith Seymore]

Cool air at the grill is always better than hot underhood air.

K

[kikkegek]

Originally Posted by gchemist

81-82 bumpers!

thank for all the replies! Thats what I thought.

@gchemist: very, very cool!

alright. Did you design this yourself? or did you build it by yourself?

I recognize some parts as being standard airduct material. But like the filterhouse? did you buy or build that?

[kikkegek]

Originally Posted by 87 V20 Scottsdale

You're correct that the original way is the better method of air intake. I don't know anything about vehicles that run on LP gas, what is the hose overtop of the air filter for?

the hose over top comes from the evaporator of the LPG system. I can change from LPG to gasoline whenever I want. gasoline is still handled by the carb, whereas the LPG is fed into the air intake by the hose on top of the air filter.

They sell this for my setup here in the netherlands:

[Adams74Chevy]

Do you get better fuel milage with the LPG system? Is the performance any better or worse than gasoline?

[kikkegek]

Originally Posted by Adams74Chevy

Do you get better fuel milage with the LPG system? Is the performance any better or worse than gasoline?

the energy produced by burning LPG is less then reglar fuel, so milage and perfomance are less. about 5-10%. But at less then half the price of fuel, with current fuel prices, I am laughing every time I fill her up at the fuel station!

[gchemist]

Originally Posted by kikkegek

thank for all the replies! Thats what I thought.

@gchemist: very, very cool!

alright. Did you design this yourself? or did you build it by yourself?

I recognize some parts as being standard airduct material. But like the filterhouse? did you buy or build that?

I came up with the idea one day while looking at a 81-82 bumper. My 91 grill does not have an access hole. The air filter housing is available from www.ramairbox.com. I bought it from some on this site. The other parts I bought locally. Go through the entire slide show. You'll get a good idea on how to build your own. I'm the only 88-91 grill guru running dual ram air intakes on these squarebodies. I have yet to see anything similar.

[kikkegek]

Originally Posted by gchemist

I came up with the idea one day while looking at a 81-82 bumper. My 91 grill does not have an access hole. The air filter housing is available from www.ramairbox.com. I bought it from some on this site. The other parts I bought locally. Go through the entire slide show. You'll get a good idea on how to build your own. I'm the only 88-91 grill guru running dual ram air intakes on these squarebodies. I have yet to see anything similar.

thanks for the info. did you notice a big difference in MPG or performance?

do you also have a Quadrajet 4bl? if yes? which model ram-air-box is yours?