Duke wrote: I always autocross with the headlights up. Not only does it - possibly - let more air under the hood, but it also lets me see the corners of the car better.
Yeah, that was also part of our theory. When people asked us why we run with headlamps up we just say it makes them look better in photos.
Keith Tanner wrote: I have measured intake temperatures with an intake right behind the headlight, and lights up was far better than lights down. That's why I went to a TSI on that particular car. I would not expect it to have any functional effect on an autox.
Were those temperature measurements on a turbo or NA car? Since I'm thinking of going turbo I've been starting to look for heat/intake temp/pressure measurements to figure out the best way to set things up properly with little skill and less money.
Oddly? I've been seeing the same numbers as Duke for the headlight intakes on the website since around the time I bought the lift kit. Honestly haven't been checking in on the site all that often because my focus has been on the house and the challenge car, but 2 and backorder is a strange combo that sticks out in memory.
I've heard that those turn signal intakes are really heavy...is that true?
In reply to Woody:
I have the Jass TSIs and there isn't much to them. They're pretty light.
RevRico wrote:Keith Tanner wrote: I have measured intake temperatures with an intake right behind the headlight, and lights up was far better than lights down. That's why I went to a TSI on that particular car. I would not expect it to have any functional effect on an autox.Were those temperature measurements on a turbo or NA car? Since I'm thinking of going turbo I've been starting to look for heat/intake temp/pressure measurements to figure out the best way to set things up properly with little skill and less money.
The temperature measurement was taken at the filter, so what happened to the air after that is irrelevant 
For those who care, it was a naturally aspirated car with an FM II intake filter and baffle.
There are a bunch of TSI options on the market. The ones I made were basically weightless. The moulded ones do have some heft to them, but I don't remember being shocked at it. I probably have a set somewhere, I used to run them on one car. Maybe they're still there.
So whats the consensus on TSI vs Naca duct? Which works better
Keith Tanner wrote: I've never tested the relative efficiency of these two. I ran both on the Targa Miata in V8 form.
In reply to Keith Tanner:
Mustve missed that. Oops
I have the racing beat intake that sits right behind the headlight. I did some testing of air temperature at the intake. I don't have the data in front of me, but both the NACA duct and and the TSI were very effective at lowering temperatures. Using both at the same time was a small improvement over using just one or the other. My car has both. Side note: I also think they both look good.
In reply to NickD:
The PO of my car put a Moss 2-light conversion on it, so it doesn't really have surrounds under the lid. With them up, there's actually a bit of open area around them.
I say you should go to a DIY TSI for now since you're on a tight budget. It's cheap and reversible. Later you can save up for the NACA duct.
If you don't care about being able to see very well at night, you could remove the pop-ups...<img src="
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I grafted a small NACA duct from Pegasus 
into the driver-side headlight cover 
and I'm quite happy with how it turned out. I believe that adding an airbox around the filter to separate from engine-heated air is important too.
-- Pete
I bought the TSI kit from Moss. It took 3 of them to get a turn signal that would work more than 90 days, the socket was poorly built, and would lose contact with the bulb. I don't know if they work, but I figured on 100 degree SC day, anything helps.
In reply to PeteD:
Your second pic doesnt appear to work...
I took a chance and ordered one of these:
I found a damaged headlight cover leftover from a previous Miata vs. Deer episode that I was able to hammer back into reasonable shape. I will do my best to join the two together.
FYI, NACA ducts are easy to make. The geometry is published. All you really need to do is cut out the outline, leaving it attached at the "nose". Then build a couple of walls and rivet them on. They'll provide the depth profile. The sharp edges on the walls are important for the formation of the vortices, a lot of moulded ones are often too soft there.
In reply to Keith Tanner:
How about bringing back that na widebody kit?
Woody wrote: Lean on the back of the headlight cover. Add a bigger rubber hood bumper. Done. This is actually illegal for SCCA Spec Miata, even though I don't really think that it accomplishes much.
My car has this gap and id like to fix it. But wait, are you saying people do this on purpose?
In reply to plance1:
You can fix that gap by grabbing the back of the headlight cover and pulling it back up.
Hey...^that's actually the damaged headlight cover that I'm going to use!
I may end up copying this idea for my AE92. I do have two whole spare headlight assemblies and a shortage of grille opening area...
I think both is the answer your looking for. But grafting in the duct is a lot cheaper like you have found.
I really like those laser cut metal hood vents that I see on Miata's as well. Though I think from looking at what is under the hood a extraction vent may work better.
In reply to wearymicrobe:
Dude, you TOTALLY need to do that thing up like Kaneda's bike from AKIRA.
Duke wrote: In reply to wearymicrobe: Dude, you TOTALLY need to do that thing up like Kaneda's bike from *AKIRA*.
Get out of my head.
FYI I love this stupid all red miata like no other car I have owned for some reason. Honeymoon period I guess.
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