Strange.. I suppose under regular driving conditions, there is more than enough airflow for cooling duties - but on a track, you would probably want to remove them.

 

Some of you are making way too big of a deal out of this. Just think about it in simple terms, Mitsu wouldn't have made the rain guards (proper term, they are not restrictors) removable if there wasn't a reason for it. Remove them if you want to, and no, there's no harm to your engine by leaving them off and having rain/snow get in there.

 

Your new avatar scares me, otter. lol

 

What, you think maybe they should have somehow stamped that aluminum hood with built in rain guards? I don't think you appreciate the challenges of working with aluminum... though I do agree with you that there's not as much potential harm from rain as some people here seem to think. I'm less sure about snow -- in a heavy storm the engine compartment could end up completely packed with blown-in snow, and that would be very bad.

By the way, if you want to really improve your car's performance, then take off the roof and doors, mount a flat, thin titanium plate to seal in the passenger cabin, and install some sort of periscope camera so you can drive without windows (heck, drive the car remotely to cut down on weight). Throw a spoiler at the back of the monstrosity and you'll see almost no lift effects at all, and a big increase in top speed. After all, Mitsubishi wouldn't have made the windows, doors and roof removable if there wasn't a reason to get rid of them.

 

it is one reason i took them off, when i do low speed. Then the removal defenietly help to cool the engine bay. Specially with very low speed. So when i'm cruising back to service or standing still , the heat can escape much easier. When your engine is real hot you can even see it
Just like the old Evo's hood you can see the glaze.

 

But the important question remains: has anyone roasted some marshmellows from the vents?

 

This question was annoyingly beat to death with the CT9A hood. Otter is spot on. Its fine, no issues, user preference.

Only time my rain guard goes back on is the winter. Otherwise, its open, rain or shine.

 

thats right. I mean the water goes in from the front anyway, so i dont know what is a big fuss about it. Even back then with the older evos
The Evos opening on the front are huge .

 

I pulled them before a track day

Drive there - No Issues
Session #1 - CEL p0068 p0500. MAF/throttle correlation. VSS no signal. Cleared
Session#2 - ASC service warning (no limp mode). Some weird C38e0 code EVOscan V2.9
Session #2.5 - Same codes
Put the covers back in
Session #3 - No issues car remained cool. track temp was 80 degrees.

I don't really see any reason to remove them on anything that isn't a full fledged track car. For me it seemed to cause issues with differing airflow than what it is tuned at.