Been spending some quality time under car this week. One thing on my list to finish is modifying and reinstalling the plastic under engi cnne tray. I trimmed here and there, bit by bit until it is close to being able to go back on. Now that I'm looking at it in place, I'm not so sure I want to install it. There already isn't alot of room for hot engine bay air to escape and the tray minimizes that even further.
So far I've been lucky to not have any overheating issues. Also I don't have hood vents and would like to stay that way.
So any opinions on the undertray? Should it stay or go?

 

I've worried and wondered about the same thing. I never put it on and so far so good. No overheat issues (I have the Ford Contour dual fan setup behind the radiator though).

 

Ditto. No undertray, though I've kept it all these years just in case. Mine's been on the road 6 years but never raced. Only got warm once in bumper to bumper traffic in 100 degree temps with ac on, and even that was questionable because I was going by the suddenly low oil pressure which turned out to be a loose ground. At that time I had the kit pusher fans plus about a 15 or 16 inch puller. Just finished a hilly curvy 500 mile trip last week, (3 sisters in South TX), temps in upper 80's, ac on, no problems at all. First real trip with the Contour fans, (no pushers anymore) operated by the CCRM controller. Mine is an SN95 setup all the way. No hood louvers. We'll see how it does this summer in TX. There is a lot of heat soak; one of these days I might build louvers into my spare hood but I prefer the "sleeper" look, and I'm guessing that the louvers would also draft the hot air from the engine compartment right over the top of the windshield, over me, then circle back in to warm the back of my neck. As it is, my wife tells me it's a good ankle warmer when she's standing by the car and the fans are on. BTW, those Contour fans are a LOT quieter than the kit fans.

TM

 

The purpose of the under tray is to improve aerodynamics. Important for a sports car with a tiny engine. Especially if you want good gas mileage. Unless you're racing and need all the advantages, I wouldn't worry about it.

 

bob is correct, its an aero piece. the under tray creates a low pressure zone right behind the radiator aiding in flow through the radiator and keeps the air moving through the engine compartment (down the trans tunnel and out the back of the car). if you take it off, the air will curl up into the engine compartment and become turbulent, this increases under hood temps and decreases the pressure differential from front to back of the radiator decreasing its efficiency.