CIS air filter removal

[Aurel]

Just got an idea, maybe a stupid one, but I was wondering if I was the first to think about that...

Here goes: what if I removed the large air filter element on the CIS air box, and replaced it with a small air filter at the entry of the air intake plastic cover? Would that make the motor breathe better or worse? Flamesuit on .

[dlagerstrom]

Firemen don't try to put out a fire with a 3/4" garden hose. Same principle here.

Given the same air-flow style filter, you will get more flow with a larger surface area.

Now, the question is, would it really matter? Not sure.

It would get dirty faster though. Same amount of dirt going through a smaller filter will gum up the filter faster.

Why would you want to?

[sc_rufctr]

I built this prototype about 2 years ago...

I saw a kit in a magazine... The kit supplies a cone filter and adaptor hose that fits onto the air intake on the plastic cover and thought why not go one step further...

As you can see the cone filter is massive. It's an S&B filter similar to a K&N. The base is aluminium and filter mount is a thin walled copper pipe from a plumbing store. I sealed it with epoxy based fibre glass. The idea was to build this prototype and if it was any good then make a mould and build one entirely from fibre glass. The internal dimensions of the pipe are much bigger than the stock opening on the plastic cover. I measured the surface area of the cone filter and it's about 30% bigger than the stock rectangular filter.

Driving impressions: It was on my car for about 6 weeks. I did a lot of daily driving and some longer country trips. The first thing I noticed is that the idle was too high after starting the car for the first time. I adjusted the idle and the mixture using my portable O2 meter.

It is not on my car now. It was much louder. You could hear the induction roar from the cabin but the torque and power felt slightly down. So I removed it and went to a rectangular K&N filter and the stock plastic cover. (available from our sponsor)

I'm very happy with my current set up but I enjoyed doing the the experiment. But because of this I view any similar product with suspicion. However I didn't do back to back dynos so I don't have any evidence to prove my observations.

The only thing I can say is that I've had my car for a long time and it felt different... SLOWER... Also the revs dropped much faster with this set up and that's another reason I went back to the stock set up. I also think it looks ugly but that wasn't the point of the exercise.

[sc_rufctr]

Originally Posted by Aurel

Just got an idea, maybe a stupid one, but I was wondering if I was the first to think about that...

Here goes: what if I removed the large air filter element on the CIS air box, and replaced it with a small air filter at the entry of the air intake plastic cover? Would that make the motor breathe better or worse? Flamesuit on .

Are you looking at a kit or something you're putting together yourself?

[Zeke]

Not to hijack, but wow sc_, that engine compartment is stunning! You need something trick in there besides that dumb stock box cover you went back to. Keep working your ideas!!!

[Aurel]

Originally Posted by sc_rufctr

Are you looking at a kit or something you're putting together yourself?

I was thinking about putting and old sock on the plastic air intake. Nah, just kiddin .

[sc_rufctr]

Originally Posted by milt

Not to hijack, but wow sc_, that engine compartment is stunning! You need something trick in there besides that dumb stock box cover you went back to. Keep working your ideas!!!

Thanks Milt

I spent a lot of time cleaning and detailing my engine. I also replaced the main fuel lines with Dash6 line and fittings. (they were loose and leaky)

I have looked at "custom" air box covers but can't find something that looks better than the stock one. Any suggestions?

[sc_rufctr]

Originally Posted by Aurel

I was thinking about putting and old sock on the plastic air intake. Nah, just kiddin .

Why not try using a cone filter and adapter hose on the opening. the only thing is you'll need to create a seal between the cover and airbox as the stock filter has a silicone bead seal. I cut this seal off an old filter and glued it onto the alloy plate on my prototype.

[Aurel]

Originally Posted by sc_rufctr

Why not try using a cone filter and adapter hose on the opening. the only thing is you'll need to create a seal between the cover and airbox as the stock filter has a silicone bead seal. I cut this seal off an old filter and glued it onto the alloy plate on my prototype.

It would be similar to what you did, except really funky looking. Too bad your mod did not produce more power or torque, I really liked the idea, and the uncluttered engine compartment.

[sc_rufctr]

I still have the prototype. Maybe I should do back to back dynos to conform my results but the sudden rev drop was really undesirable.