E350 Cold air intake modification

Only had our 1991 in sig (it's an EFI) for a month, and no serious driving time yet, but my idea on that sort of thing is that if it has been like that since 1991 and it is still going----who am I to go changing things like that?

Do you mean for the radiator or for the air into the engine via the air filter?

If you have had some sort of issue with power or whatever, there could be lots of other reasons why besides air intake. ???

Are you subject to annual emissions testing? Any modifications could cause problems.

dont know what they offer but the big aftermarket booster sells CAI for several vehicles. Was just recently covered in a magazine about CAI for new v10 in ford motorhomes and their increased benefit. look at Banks for more info.

Don't forget about the MAF sensor. You will need to mount that in your new setup somewhere or the ECU will not properly adjust your fuel mixture.

You can do a FREE mod to the intake air inlet tube.
There is a double restriction in the inlet tube where it goes from the air box to the throttle body.
The restriction looks like a funnel, restricts down to 2".
Just cut those funnels off. Be sure not to cut the tube too far back to where the hose clamps won't hold.

I likely have same engine/year - never read an RV thread where someone has suggested that a modification is needed. Anecdotal evidence that it's not an issue.

X2 on diy

Pull the restricters and add some metal drier duct to pull air from below the radiator. Made a big difference pulling grades in the summer when I did my '94. Mine also had half the air filter covered in a plastics panel, so I trimmed that away too with a hack saw

No emissions testing in Indiana. Thanks for the input. I am learning more about this engine. Apparently part of what comes off the air filter box is a vacuum line that goes to a smog pump. Not sure if I can bypass this or attach it somewhere else in a modified air intake system.

I have heard of removing the inlet "trumpets" as pictured above, but my engine does not have them in the same configuration as the above picture. I believe the above picture is the configuration of the F350 truck, not the E350 van chassis. My "trumpets" are in the molded plastic that is all one piece and comes just before the air filter housing. Not sure how I would remove them in this location.

mmcclaid wrote:
No emissions testing in Indiana. Thanks for the input. I am learning more about this engine. Apparently part of what comes off the air filter box is a vacuum line that goes to a smog pump. Not sure if I can bypass this or attach it somewhere else in a modified air intake system.

If the connection is before the throttle valve (which I suspect it would be in this case), it's just the source for the air that's injected into the exhaust so the catalytic converter can properly convert. It should be fine to attach it anywhere between the air filter and the throttle body or carburetor. The purpose of having it attached to the intake system at all, of course, is for it to have clean air to pump in rather than potentially dirty air.

I suppose you could give it a little air filter of its own, perhaps such as might be used for the air intake of an air compressor (which often look on the outside something like a round lawn mower engine muffler).