Snorkel for Range Rover P38
Chris Crompton's Design On Coil-Converted P38
Installation When Retaining Air Suspension
A snorkel (in
the context of off-road vehicles rather than submarines) is a device
that raises the engine air intake to the top of the vehicle. Many
off-roaders erroneously assume the main purpose of snorkels is to
facilitate deep water fording. A snorkel is indeed helpful for this,
although many other measures need to be applied to the engine,
especially if it is a petrol/gasoline unit with spark ignition rather
than a diesel. However the main reason for adding a snorkel is to get
the air intake up out of the dust and sand that fills the air at lower
levels on off road expeditions (particularly in convoys). In World War
II, the British Eighth Army in North Africa quickly discovered that the
conventional engine air intake systems on their tanks and other
vehicles ingested so much sand and dust that engine life could be
measured in hundreds rather than thousands of miles. Reducing the
amount of grit that gets into the cylinder bores is a vital step in
prolonging the life of real off-road vehicles.
writing (June 2004) no commercial snorkel exists for the Range Rover
P38, so Chris Crompton
of Abu Dhabi made his own, after getting his air intake box filled with
sand (see photo at left). As
show, it looks pretty professional! Chris reports: "So far it seems to
be working pretty well. I bought the top “Ram Air”
section of a Safari Snorkel for a Nissan Patrol, and made the rest out
plastic drainpipe!! The hardest part was shaping the
drainpipe, but with a lot of heating, bending, tacking, riveting and
it’s not looking too bad. I removed the EAS “box” from under
the bonnet and ran a pipe straight into the existing airbox. I
about removing the airbox, but for version 1 of the snorkel I thought
leave it in and see how it performs. I had to relocate the throttle
assembly slightly as the pipe was in the way of this and by this time I
enough of bending plastic pipes!!"
and photos on this page, kindly supplied by Chris, illustrate in detail
the procedure he followed.
Chris Crompton's Snorkel Fabrication Project on Coil Converted P38
Chris reports: "I bought the top Ram Air section of a Safari snorkel direct from Australia, this was one designed for the Nissan Patrol. I figured that this one would be designed for a high airflow engine, so in theory should be OK for the air requirements of a Rover V8. The remainder of the snorkel pipe was made out of two different hard plastic water drainpipes, a larger diameter for the outer pipe and smaller for the pipe in the engine bay.
The first stage
was to remove the
EAS “box” from under the hood. On my coil-converted vehicle the EAS is
redundant anyway, so the
compressor etc is being kept until I remount it on the other side of
bay for my onboard air supply. With this box out of the way,
there is a nice
straight run from the existing airbox to the bulkhead, where the pipe
towards the inner fender.
Chris's engine bay
EAS box removed
Absence of EAS makes intake tube
I had to move the throttle assembly slightly towards the center of the engine bay, but otherwise, there was no major work required under the hood at all.
The pipe inside the engine bay was made with a single length of plastic drainpipe, cut, and heated to form the required bend, with the end of it positioned at one of the existing holes already in the inner fender, this saved me having to cut another hole in the inner fender, a fiddly job at the best of times, all I did was to make a few small cuts around the edge of the hole so I could bend the metal down around the edge of the hole fixing the pipe in place.
I used the
location of this hole
as my guide for where to cut the hole in the outer fender, I figured I
the outer pipe according to where it was best to put the holes in the
rather than cutting holes according to my pipe design.
Position of hole for snorkel in
Looking through outer panel to
The outer pipe
was also made out
of a single piece of plastic drainpipe, but this one was a bit harder
because I wanted a really nice finish. It took me several hours
of cutting and
heating until I had formed the right shape around the bodywork.
hood is very awkward as I had to make sure the pipe didn’t catch on
as it opens and closes. Once I had the pipe in the right shape, I
steel plate and rivets to form brackets to hold the pipe in the shape I
wanted (see photos below). I then heated the pipe and using pre-cut
pieces of the
same pipe, (to
keep the curved radius the same), “melted” these into place. Some
sanding and some filler and the finish on the pipe was very
smooth. This was
then sprayed black to match everything else (photo below right).
I decided to use the existing airbox and route the new air supply through this as this would avoid having to mess around with the airflow sensor and also finding a new filter. The original plan was to discard the whole airbox and use “elephant” tubing to re-route the air pipe with a straight through filter, this may happen in the future, but for now I decided to use as much of the existing air supply system as possible. The pipes were then fitted in place, first the internal pipe, into the airbox and bracketed in place and sealed with more silicone (picture below left).
Sealing the connection to the
air intake box
Blocking off the old air intake
The airbox was sealed using another piece of soft steel and riveted in place and I cut a hole in the bulkhead side of the airbox for the new air supply pipe. The sealed hole was surrounded by a liberal coating of silicone sealant (picture above right). How well this will hold up I don’t know, but I will test it and see!
The outer pipe
was fed into the
hole in the fender and I used a section of radiator hosing from a truck
the two. The radiator hosing was slightly conical in shape, and
extremely tough rubber and allowed for the change in pipe diameter
outer and inner pipes. I mounted this in the end of the outer
industrial adhesive and sealant, making sure that it wouldn’t affect
airflow too much. This was cut to shape and jammed, glued and
sealed into the
inner pipe as far as possible, with more silicone applied liberally
inner and outer fenders.
Checking fender depth
Sealed fender pipe.
The bracket for
the top of the
pipe was made out of a soft steel trim also taken from the truck body
(photos below). This was
bent into shape and screwed into the body frame on the outside of the
seal running down the edge of the door. The pipe was then secured
in this with
two small bolts and given a coat of black paint.
The top “Ram
section was then screwed into the top of the pipe (photo above right)
with a small amount
silicone used, (avoiding the drainage holes), to seal this in place.
I have used a small plastic plug at the lowest level of the outer pipe to provide drainage for any water or debris that will collect there, although I am not totally sure about this bit, so I may change this and just put some screws into the bottom of the pipe which can be removed to provide the required drainage."
Installation When Retaining Air Suspension
Chris offers the following advice on installing the snorkel on a 4.0 without removing the EAS compressor and control box:
would depend a lot on
whether you want to retain the original air filter box. My original
idea was to leave
the EAS box in place and re-route the air supply from the end of the
sensor using “elephant” tubing and a straight through K&N type
filter. This would then also allow me to have removed the airbox
and moved the
EAS box slightly towards the front of the car, allowing enough room
tubing to pass behind it.
would have been to
continue the pipe further down the outside of the fender, and cut the
directly through the fender into the existing airbox intake, or use a
diameter pipe in between the two fender sections to join the outer pipe
and the airbox,
but this would be seriously fiddly and I didn’t want to get into this.
"One more option
that did cross my
mind was to mount the snorkel on the RHS of the car instead of the
the Rover V8, the whole plenum section is reversible, the bolt pattern
exactly symmetrical, so I did think about turning the plenum around,
throttle assembly, and routing a pipe and snorkel out through the RH
there is lots of space in the engine bay (on LHD vehicles).
"If you didn’t want to go this far, then there is space to move the EAS box slightly towards the center of the engine bay without disturbing the air lines too much. This will then allow enough space for a “slightly flattened” pipe to be passed alongside the outer edge of the EAS box towards the bulkhead in a similar way that I did. This will allow you to keep the original airbox in place and just seal up the existing intake hole above the wheel arch.
"These are the four main ideas I considered before going ahead with the option I chose – of course I was heavily influenced in my decision by the fact that I didn’t need the EAS box in place anymore, so it made life a lot easier for me. One thing I never really looked at was how easy it would be to move the EAS box to a new location, ultimately all there is going into the airbox are 8 airlines, (I think it’s 8, but I need to check !!), and the two control and sensor cable bundles. These have quite a lot of slack on them anyway, so it may be possible to turn the EAS box clockwise by 90 degrees and move it right down next the airbox. This would provide quite a lot more space to play around with."