That Guy 1987

What's going on everyone? So I came across a cheap NFR hood for 100 and wanted to get some opinions and factual evidence that cutting your hood works to cool the bay. Someone has once posted that when driving the heat wants to escape but can't because of the cool air pushing it down as you drive. Then I watched a vortex video and you could clearly see the wind going through the vortex hood.

I live in FL and want to take some measures to cool my bay. Was hoping to coat the manifold but that looks like a summer job considering I'll have to pay IRS this year. Also not to fond of the look of a vented hood and would rock it only in the summer months to help vent some of the heat. That's the reason why I wouldn't cut my current hood.

JJAUTOWERKS

Well you know my thoughts on this. My hood is elevated in the rear, not that it helps much. However, as i said before you know your driving conditions, just take those cooling off periods on long trips and raise the hood.

That Guy 1987

Bernard I guess I'm thinking of doing it because it can only help with the temp as I wait to coat the mainfold.

That Guy 1987

Anyone any input as to how drastic of a difference in temperature it made using an OEM vented hood vs an uncut hood?

spdracerut

Start here:
https://www.s2ki.com/s2000/topic/103...ted+hood+cheap

And why not to do the common ‘hood venting’ mod of cutting holes out:
https://www.s2ki.com/s2000/topic/877...#entry20812917

“I have hood vents, but they are ONLY for looks, and actually increased my engine ccolant temps at the track. I have only 3 vents cut on the passenger side, and my coolant temps went up to 225F at a track day last year. Another S2000 owner at the same track event hit 250F with his hood vented with the 4 smaller vents near the windshield.”

That Guy 1987

Read both but I would expect if in stop and go traffic that the hood vents would let air escape resulting in cooler underhood temps. Wonder why the temps would go up?

spdracerut

Sure, when you're sitting still, the holes in the hood allow air to escape. However, when you're moving such as on the race track, it's letting air into the engine bay creating a higher pressure behind the radiator. The new higher pressure area behind the radiator is reducing the airflow through the radiator causing the coolant temps to go up.

s2000Junky

Logic would tell me that if you’re sitting in stop and go traffic with a vented hood, hot air will escape, there is no factors of air pressure being produced to mess with the venting IF that is a factor at all, I don’t know. Sitting in traffic is when the car gets the most heat soaked so that’s when you would most need the venting anyway. When car is moving, air flow/circulation is produced. At the track and being FI, yeah you need all the help you can get in venting hot air at speed, so more creativity may need to be employed.

If the air vents don’t work at speed because of the pressure zone over the hood, then it doesn’t work, but I fail to see how it would make it worse. I’ve heard and seen people using a raise portion/louver in front of the vent opening to disrupt the pressure zone and allow air to escape at speed. Look at any aftermarket hood with venting and you will find that, probably what its for.

That Guy 1987

I messaged the Gernby to get more info from him. I've also read that it really doesn't release hot air as we would belive when driving. The hot air is trying to raise but the air coming over the hood is holding it down.

Junky I agree sitting still is going to allow the air to escape. The question lies which is more important when sitting still or moving and would argue when moving. Plan to make a three hour drive to kings dyno meet and the hood isn't going to any good but hurt my temps. In all honesty how often are we at a light versus driving around town? Interested to see what Gernby says and also want to ask him why he would still run that hood if it interfers with is coolant temps.

rrounds

If you used something like this, it will pull the air out of the engine bay at speed(just don't get the vents close to the base of the windshield, that is where the air pressure is very high at speed))
http://www.subaruforester.org/vbulle...d-vents-76826/
Just look at all the super cars that have those type of hood vents

ROD