The RAM AIR BOX is a twin snorkel, high capacity air cleaner housing
used to supply fresh air to an engine. It is based on the popular 14"
open element air cleaner. The RAM AIR BOX is a one-piece,
hand-laminated fiberglass unit, offered in many sizes. The benefits of
cooler air, teamed with forced induction, have long been understood.
We have applied this technology and manufactured an air box to help plumb
the air to the engine. The RAM AIR BOX is the key to the whole system.
Let us consider the original equipment manufacturers and how they deal
with fresh air systems for their vehicles. These are their priorities:
low speed drivability, fuel economy, low emissions and low engine
noise. Some of the new inlet systems are in fact mufflers.
Air Inlet Systems is dedicated to maximum performance, be it power or economy.
When you increase efficiency, both may improve. The 60's were full of
air-grabbing ideas. Everybody had something. Then the fuel crunch of
the early 70's ushered in the emissions era. Only the odd insurgence
had been noted until GM re-introduced the RAM AIR on the Trans-Am and
Z-28 in 1996. Today, all manufacturers use some sort of fresh air inlet
systems. Over the years, few choice performance-optioned vehicles have
been graced with twin snorkel or high capacity air cleaner housings.
Most of these are still more restrictive than our smallest models.
A typical scenario would have an individual looking to improve his
engine's breathing capability by installing an open element air filter
and removing his single-snorkel original equipment air filter. What he
has gained in air quantity, he lost in air quality. This, in effect,
may void the potential gains. With the RAM AIR BOX, he can truly
decrease air restriction in the inlet track and retain the fresh air
benefits. With the RAM AIR BOX, he truly feels the performance
improvements due to the modification.
Although the cooler air is mandatory, there is another great benefit to be had with the RAM AIR
BOX. The fact is that when we drive down the road, we are pushing air
with the front of our vehicle. That is a source of high pressure air.
The potential pressure head at the grill is approximately 2" of hg.
This is available for the taking. With smooth ducting, most of that can
be channelled into the air box. Our 1/4 mile acceleration tests have
yielded .2 to .4 of a second elapsed-time improvement.
Test vehicles have reported up to 3 miles per gallons improvements, over long
periods. We generally expect to see as much as a 10 % increase in power
when installing an air box over an open element air filter. Gains over
factory single-snorkel / non fresh systems may even be greater.
How to select a RAM AIR BOX: The simplest way to determine which air
box you need is by installing a 14" diameter open-element air filter
onto the vehicle. Generally, by fitting the tallest air filter
possible, it will tell us the maximum size RAM AIR BOX the chassis can
accept. Please keep in mind that cowl induction rear open-hood scoops
are not wide enough to allow the twin snorkel style RAM AIR BOX to tuck
under them. If that is the case, start thinking cowl box.
After the height is determined, the included angle of separation between the
snorkels must be chosen. For narrow confines, the 80 degree
models work best, where some high-mounted front accessories may be in the way, the 110 degree models must be used. The 110 degree models can also be used to route tube to the inner fenders in some cases. In the cases where a
drop-base air filter assembly is used, interference with peripheral
components may occur. On a small block chev with an HEI, there is no
room at all between the filter an the distributor, in those cases a relief must be cut
in the back of the air box. Ford small blocks may have concerns in front. A relief kit can be purchased to fill the
Determining air filter size requirements
The graph at is a good guideline of engine requirements. It is
graduated for the 14" filter only. For example, a 350 engine would need
a 14" filter 3" tall at 6000 rpm. Please keep in mind that this is a
guideline; requirements do vary. These are also minimum requirements,
installing a larger than minimum air box will only improve performance.
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"Hot Rod", "Car Craft", "Super Chevy", "Truckin", "Mopar Action", "Ford
Muscle", "Chevy High Performance", "Rod Action", "Sport Truck", "Mopar
Classic Guide", "Rod & Custom", "Canadian Classics", "Classic
Trucks", "Popular Hot Rodding", "Specialty Manufacturer", "Gear