undertray mod solution for overheating problems
 

anybody who has owned an FC know they overheat very easily.. I had upgraded to koyo radiator, and i still had overheating problems when I pushed it hard when in the mountains or on track days.. it would always get hot after about 10 mins of WOT driving on a track, even in cool weather.

the solution is all in the ducting.. I looked at the factory undertray, a lot of air is lost to under the radiator and through that space between the top of the radiator and the radiator support. I used aluminum tape to seal off the upper gap and it helped a great deal. The next thing I did was modify the undertray by cutting off the back half, right where it meets the bottom of the radiator. I zip-tied the tray to the bottom of the radiator, and then used aluminum tape to seal it off. This forces all air through the radiator

before the mods, the temps would get up to about 1/4th of the gauge at interstate speeds with a/c on, and I had to up my e-fan setting to 205F to prevent it from constantly running. after the ducting mods, the temps never get above 1/8th of the gauge when at speed. I recently took it to the mountains and ran around several hours with a/c full blast in 90+ degree weather and it stayed at 1/8th of the gauge.

Please tell me your next mod is a proper temp gauge.

i can get some actual numbers with the haltech and post some pics next week

On the stock radiator there is (or was) a foam piece on the bottom of it that sealed the air from going under the radiator. On my Koyo I bought insulation that goes around a window air conditioner (Wal-Mart) and expoxied it to the bottom of the radiator. Do that and get a new thermostat and you'll be fine.

I took my car to Talladega (Alabama) in July and ragged it for 30 minutes at a time and it barely budged over 1/4.

Yeah even the first gens have/had that foam piece between the oil cooler and
the radiator (on the SAs) so that air would be forced thru the cooler and
radiator. Plus the underpan missing on a 1stgen is a prescription for overheating.

Good work on dealing with it Jamin. Hope to see you around. B3R for sure!

I think because these cars all tend to have the openings under the bumper,
the trays and how things seal around the radiators are key. Otherwise the
air takes the easy way out and dumps out under the engine. The trays also
help create a vacuum under/behind the radiator to help pull the air thru, at
least to my untrained eye that seems to be the case for why the trays
often extend back all the way to the engine.

I'm not a 2G owner but I see a lot of similiarities all the same.

That would be much better then 1/8th...1/4

^Roger that, I did almost the same thing on my Koyo. Instead of gluing the foam strip to the Koyo with epoxy, I used a only the hook side of an industrial-grade adhesive backed velcro strip that I stuck to the bottom of the Koyo. The foam strip attaches to the velcro very securely, but you can remove it when needed for servicing. Figured that to work on the oil cooler lines, or draining coolant, it would be nice to be able to get the foam strip out of the way so it doesn't soak up any fluids.