Im certain it's the tray, you did open the thread on this so sounds like the tray takes care of high speeds issues however idling and part throttle seems to be giving you issues?

 

Had to do it. Started with a compressed board that i made a temp and used it as V2 of my initial design to test efficacy. My initial takeaway was AC got colder upon start up. This i realize now is because a lot of air bleeds between the bumper and the rad support. Next was the increase is radiating heat, the tray does not vent so vents should help but wont be the same as an open floor. 3rd possibly an instalation effect but i noticed a calming quietness, its possibly the panel has muffling.

Air temps rise quickly at idle but heat soak lowers quicker that it rises once I start driving.

I have not tested high speeds yet but so far at 60 no hood bounce.

 

Got some more data today. For those that are having heat exchanging issues this shield is what you may be missing.

AC continues to get colder with the shield than without it - Makes sense since the bumper mouth is now enclosed.

I'm doing tests with AC on and OFF to determine more things. AC on is one of the biggest variable being that the fan itself will increase the velocity in this area by pulling air at low speeds.

Quietness is still constant which was surprising but does not surprise, maybe if OEM undertrays looked better/stronger people would not ditch them.

Hood bounce is gone and butt dyno feels faster between 60-100mph which it could be due to not hard pressure lingering in the bay.

ECTs stay between 185(Tstat closes) to 200s while driving

Trans temp only got up to 150-160s for 30 mins of normal driving. Without it works the same up until 20 mins where the shield maintains a lower threshold.


Draw back is that lower speeds the engine bay will stay as hot if not hotter than without the shield.

What I want to work on now is venting of the shield. My Idea is two raised vents to form a venturi after the radiator and before the crank pulley, that spot would be the best for relieving.

 

Thanks for all the research. No the heat issues with this car are at speed, but I think I am done with track days with the beast for now.

 

Here's the final result of the version 2 shield. It survived it's first Florida monsoon yesterday. Flex seal is some ****. I believe even once I go to a metal shield it will still get coated with this stuff. Just like under liner but with a smooth glossy finish.


I wonder if I remove the L sections at by the oil pan if they'll affect it. Unsure if the gap that the lower oil pan and lid create by the sub frame will relieve pressure or if the outside pressure will sneak in through there.

 

Just keep in mind that the design of the sway bar may cause some interference issues with the skid pan, especially under full compression (and if your car is lowered). I've had mine hit and it's not the greatest noise (I have an aluminum shield).

 

I noticed that, I lucked out due to not being lowered but I know now why aluminum versions have that dip.

 

A little late to this thread but definitely subscribed.

Not sure how similar the hoods are from sedan to coupe, but I’m planning on cutting my OEM hood in a few areas between the frame, and will have some vents made from carbon fiber using a 3D printer to create test molds. Designing everything in autoCAD so I’m hoping the final result will turn out nice. I’m not a fan of the aftermarket hoods personally and would rather try this out.

The spots I’m planning on using are circled in yellow in the pic below and you can see where I put my paper templates in to show it a little easier. I’ll do this to the driver and passenger sides. There are a few other areas where there’s room to make cuts above the block (circled in red) but not sure if I want to add any in that area...maybe one towards the center/back of the hood. I’m using APR performance hood vents as my model since they seem to be one of the best in the business.

In my case, since I’m planning on running the front mount single turbo from SOHO Motorsports, I think the positioning will be perfect to help extract hot air from the turbo and piping.

 

Nice! I've thought about this. I was first exposed to this idea with the s2000. The way the under hood webbing is designed makes for a pretty cool vent design.
The G's webbing might take some modification for it to look good but I'm certain it has potential. Just need the right set of eyes.

 

When testing the theory of hood spacers I added some strings to the lip of the hood that meets the cowl and witnessed a really cool effect.
So that cowl area is a low point where the air actually goes in towards the cowl as physics would mandate. This is because most experiments are drawn without wipers.
When you add wipers to the mix this disrupts whatever tumbling effect/vortex takes effect.
Next time your driving in the highway in the rain you'll notice the raindrops change direction as soon as the wipers go up.

 

That is an idea I had as well, but when I talked to a few guys in my body shop they recommended against it since aluminum is very finicky to cut and shape. I will be curious to see how this goes. What are you using to cut and prep the metal?

 

I suspect he's using a Dremel tool, about 30 cutting wheels, and a pair of heavy brass *****.

 

 

Hahaha too great reading the replies. I was reading through any other forums with motorsports/track experience and came across some S2000 owners who went about it the same way with great results (they had framed aluminum hoods also). They used mesh instead of actual vents, and I’m avoiding mesh since it is awful for airflow (maybe not in this scenario? Still reading up). Here’s a link to the first thread I was reading through on the S2k forum. Be warned, it’s an old thread, but the information is still just as relevant today.

https://www.s2ki.com/forums/s2000-un...m-hood-324009/

I figured I have to get a vented hood either way for the turbo, so if this doesn’t work out and ends up awful I’ll just buy the Seibon/TS style hood and call it a day. Fun experiment regardless. I won’t be cutting anything in the center/rear of the hood anymore since to my knowledge the hood vents will be less effective and can mess up the pressure zones if they are placed too far back/too close to the windshield. Not sure what I’ll use to cut yet, I’ve heard people have success with a few different tools. We’ll see about our hood lol.

 

You can use these as well - from what I understand from the various groups I'm in, the hoods are very similar shapes and would likely fit. Since you're already cutting up the hood.

https://trackspecmotorsports.com/sho...le/nissan/370z