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Does this cold air box need a lid or is the hood enough?

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Does this cold air box need a lid or is the hood enough?

 
Old 10-14-2018, 01:48 PM
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Default Does this cold air box need a lid or is the hood enough?

Had some issues with the car heat soaking at the last autocross I did. It was mid 90* temps and I was able to get about 10 (~50 second) runs in before it started to pull timing on my co-driver. I had the intake coming right off the turbo behind the radiator fan. I would spray down the intercooler and tires between runs 4-10 but it didn't seem to help the heat soak. This is 2nd gear rev limiter stuff so all the boost/rpm. Would closing in the top of this box help me more than just using the hood? I am sure there are a few gaps under the hood as I didn't take the hood off and attempt to build this thing upside down. I'll probably put a small vent or something in the headlamp cover, or a small NACA duct? It's a non-vented hood as well. I've got a build video in my build thread for those interested.



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Old 10-14-2018, 02:28 PM
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I'd do an experiment: simply remove the headlight cover, run another event, and compare logs. Unless this is an AutoX course the likes of which I've never seen, the minor aerodynamic disruption should cause no harm.
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Old 10-14-2018, 02:46 PM
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Originally Posted by Joe Perez View Post
I'd do an experiment: simply remove the headlight cover, run another event, and compare logs. Unless this is an AutoX course the likes of which I've never seen, the minor aerodynamic disruption should cause no harm.

That's a good idea. I was going to try it with the headlights up and remove the drive side light. I've not removed the skin of the light before so I am not exactly sure how difficult it will be.
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Old 10-14-2018, 03:28 PM
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Been a while since I owned an NA, but I've done it. My recollection is that it's fairly easy. Put the lights up, remove the black plastic trim piece, and then I think it's only two screws on each side holding the lid on.
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Old 10-14-2018, 05:39 PM
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Originally Posted by 90civichhb View Post
That's a good idea. I was going to try it with the headlights up and remove the drive side light. I've not removed the skin of the light before so I am not exactly sure how difficult it will be.
Its 4 screws and 4 8mm bolts or something. It is stupid easy and takes 3 minutes to do. You could even pull it between runs to compare if you wanted to.
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Old 10-15-2018, 11:57 AM
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Cool, I'll remove it and compare logs. Good to know it's that easy to take off. I may just print a NACA duct and rivet it under the skin.
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Old 10-15-2018, 12:19 PM
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Originally Posted by 90civichhb View Post
Cool, I'll remove it and compare logs. Good to know it's that easy to take off. I may just print a NACA duct and rivet it under the skin.
you misspelled epoxy.
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Old 10-15-2018, 12:36 PM
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Originally Posted by Braineack View Post
you misspelled epoxy.
Not against it. I just have rivets all over the car already.
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Old 10-15-2018, 04:50 PM
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On my NA build with a similar heat shield / air box, just putting the lights up dropped my intake temps 5-10F. It's not really sealed to the hood (couldn't with custom hood vent). I'm planning on cleaning and painting a RS Aiziwa lid to better direct air into shielded area on that premise.
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Old 10-15-2018, 04:54 PM
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Originally Posted by Midtenn View Post
On my NA build with a similar heat shield / air box, just putting the lights up dropped my intake temps 5-10F. It's not really sealed to the hood (couldn't with custom hood vent). I'm planning on cleaning and painting a RS Aiziwa lid to better direct air into shielded area on that premise.
Those seem pretty affordable. I just hate trying to match paint. This old 1990s red is just going to be impossible to match with anything in a spray can. lol
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Old 10-15-2018, 05:08 PM
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Originally Posted by 90civichhb View Post
Those seem pretty affordable. I just hate trying to match paint. This old 1990s red is just going to be impossible to match with anything in a spray can. lol
A less I learned long ago:

Don't try to match old finishes. Do something contrasting or complimentary.

Maybe you just leave the original red in place, try to screw up as little of it as possible during the process, and trace the outline of the cutout with a 1/2" wide stripe of semi-gloss black, for instance.

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Old 10-15-2018, 05:24 PM
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Originally Posted by Joe Perez View Post
Maybe you just leave the original red in place, try to screw up as little of it as possible during the process, and trace the outline of the cutout with a 1/2" wide stripe of semi-gloss black, for instance.
That's a great idea. Would really help keep the car a 10 footer.
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Old 10-17-2018, 12:44 AM
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This may be a dumb question but "Where is the Cold/Fresh Air entering this box?".
Only through the front via the slim channel on the engine-side of the headlight?

NB's duct cold/fresh air in on the front port-side of the engine bay but you've walled that off.
If NAs do the same, get rid of that wall and run the rear wall all the way to the side of the car.

Here's mine (an NB but you get the idea):

I also ducted air up from the front fog light into this box too.
Details here: Cold Air Box
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Old 10-17-2018, 07:38 AM
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Originally Posted by Lokiel View Post
This may be a dumb question but "Where is the Cold/Fresh Air entering this box?".
Only through the front via the slim channel on the engine-side of the headlight?
I run a single hood strut on the driver side (MERCA!) of the car. I don't have access to a large amount of tooling like a metal brake or Tig welder, so 90* corners were about the only option I was going to consider. Hand bent corners can look fine but setting up the steel bar and clamps multiple times until I get the correct angle is just not something I wanted to fool with. On the NA there are small plastic brackets that "box" the headlamp in, separating it from the hood (see image). I removed the plastic behind the lamp in hopes that the air would find its way in. I might be completely wrong and and the high pressure from the inside the bay may push itself out of the area instead. I plan on venting my hood next but am weighing my options on what I want.



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Old 10-26-2018, 05:09 PM
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So here is what i made for the first track day with a turbo. Car has done lots of events being NA, track and autox and always had good temps. Im running a coolant reroute and ducting for radiator and inter cooler and hood vents. The box for the intake itself seems to help a lot. Ambient was roughly 80 that day and i had intake temps of 100-105 all day. I have not experimented with a closed box or anything else yet. What really did help was the ducting while street driving especially.

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