Radiator duct sizing question

[marshall_mosty]

I'm changing the front nose on my AI car from a LX to GT over this offseason. I'm going to take the time to duct the radiator the way I should have done a LONG time ago. Right now, my mocked up boxing comes out to 120 sq in of opening (30" x 4"). The radiator is approx 468 sq in of exposed core (26" x 18"). This equates to a 25% ratio between opening and core.

I didnt' have any cooling issues with the old LX nose, but did have a large section cut away in the front from an overheating issue from years past.

I've read that you should have 40-60% ratio opening to core, but I can't see the OEM GT's having this. The only part of the GT nose I won't use is the lower "bottom feeder" portion, as my splitter will cover that up.

I'm opening the GT nose a little on the front to get the full 4" tall for the ducting.

Any ideas?

http://www.mustangmods.com/ims/u/1280/10234/217438.jpg
http://www.mustangmods.com/ims/u/1280/10234/217439.jpg
http://www.mustangmods.com/ims/u/1280/10234/217441.jpg

[AI#97]

I would throw out all the "ratios" you find on the net because you have that nice piece of aluminum down there just a few inches off the ground causing other problems. When I ducted in my radiator along the sides ONLY...I started having concerns the car would not heat up enough. Only goes over 185 if it's sitting still.

Yours looks good in mock up...

I will be playing with covering up the upper radiator entry on my car soon with a few other updates under the nose as well. :wink:

[marshall_mosty]

Matt,
I have changed the design to give 50% more opening (6" tall versus 4" in the pics). I'm hogging out basically the entire OEM GT bumper cover below the bumper line to make this work.

I don't think cooling will be an issue, just wanted to get peoples opinions.

I do now have to figure out what to do for mounting lights. The angled duct has completely taken the area away from the turn signal (inner) lights... hmmm. Maybe I need to find a set of headlight covers and glass them in place.

[Al Fernandez]

I think Matt is right. Between your splitter, the fact that you're going at high freeway speeds or better all the time, and the fact that you're WOT almost all the time all amounts to OEM standards being not applicable.

I've seen lots of healthy race cars with a lot less air intake capability than yours, so I wouldnt be overly concerned there.

However...have you thought about getting air out from behind the radiator? That is probably why real race cars get away with very little air intakes...they get the air out!

[AI#97]

However...have you thought about getting air out from behind the radiator? That is probably why real race cars get away with very little air intakes...they get the air out!

I started working on that last year and found I needed another 4" of clearance to get the duct out of the hood. Even with moving my radiator 2" further forward and 2" down, even with a ton of accessory clearance there was just not enough room unless I start removing power steering and go to an electric water pump. Maybe some day down the road... :wink: