Reducing Intake Air Temps

Ok, the Scangauge II has made one thing abundantly clear, intake air temp is a problem I need to tend to, to improve the performance of my car (even
though I've only noticed the problem in stop and go driving in 90+ degree weather, I'm seeing that intake air temps are 20~50 degrees above ambient air now, with weather in the 70's which results in 90 ~130 degrees! I can't imagine what a power killer that is in the summer when, to make it even worse, I'm likely to be running the AC also!
I know that there 100's of thousands of words written about this topic on Miata.net (trust me, I've read ALLOT of them) however, this group has many intelligent people and I would like their (YOUR!) input on a few questions that remain;
1) Is 10~20 degrees above ambient, a reasonable 'goal' (while at speed)?
2) I have a header (no heat shield), does the muffler tape (thermal wrap) do much to alleviate under hood temps?
3) Assuming it does, is there a down side?
4) Assuming there is not, how far should the wrap extend, to the lower 'floor' of the engine bay?
5) I believe my best bet is a 'Randal Cowl' type of set up pulling air from behind the firewall however, I'm trying to minimize my cost for this improvement and think this might entail buying allot of stuff.
6) I believe my next best bet is to shield the intake (I have a Monsterflow, cone type that breathes from behind the drivers side headlight), and try to direct cool air from the front of the car, into this area.
7) While I've been researching this, I've also seen some people installing thermal protection on the brake and clutch master cylinders, Is this overkill or 'track day' necessary kind of stuff or might this be a good idea for everyday use too?
Any / all input appreciated including if you know of a thread on a particularly good set up (for an NB w/ Monsterflow please).
Thanks, Chris 99BBB
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If it's stock, put the heat shield back on. If not, make one. The forum is full of stories of tape wraps eventually causing header rot.

Yes, the Randall is the best solution. Plenty of owners have made DIY versions cheaply, and while they're probably not as efficient as the FM product, they have to be better than any scheme involving a cone filter. Hope you still have your OEM airbox. Search miataforum for examples.
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Lanny Chambers
St. Louis, MO
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Lanny Chambers wrote:

Based on your experience with the Randall unit, do you think it could be made to help the under-hood temperature with a turbo.
My idea was to have it draw air to a point right above the air filter.
Obviously this would not as good as a direct connection to the OEM airbox, but maybe better than just drawing in the hot air from under the hood?
Assuming I keep the car, I also plan to add a turn signal intake, maybe on both sides. When the car is running hot, I can take the driver-side turn signal out and it knocks the temperature down a few degrees according to one infrared thermometer I have used to measure the difference.
Pat
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Probably not. The Randall is rigid carbon fiber, made to connect to the OEM snorkel hole in the airbox. Every Miata turbo I've seen is smack in the way.
For a CAI system to work, it must be sealed from the underhood environment, so the intake receives only outside air, preferably under positive pressure. As an engine bay air inlet, I'm not sure how well a hole in the firewall would work. It might become an outlet.
For that matter, I've read claims that Miata TSIs actually act as air outlets. Dunno if that's true, but airflow is complex, and may not behave the way you'd think.
Hood louvers might work OK...unless they'd bleed off air needed to cool the transmission or something. I suspect that nothing on the Miata was done by accident, and everything is there for a good reason.
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St. Louis, MO
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Lanny Chambers wrote:

Thank you, sir. That makes sense to me.
The previous owner claims to have modified the temperature gauge to be more accurate.
Not sure how that was done, but it always shows a little higher than the stock gauge does on other Miatas, and in the summer during the hottest part of the day it climbs to an uncomfortably high point.
The infrared thermometer verified that the temperature was still within normal operating range. It only takes a few degrees to move the needle a good amount.
Removing the turn signal caused the needle to drop back down almost to where it sits during the colder times of the year.
I am guessing that having no driver-side turn signal, or a turn signal intake will increase the air flow going in to the engine compartment and that this is a good thing on this car. I am not, however, positive on anything even related to most simple matters, certainly not on complex subjects like air flow. :-)
Thanks again!
Pat
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pws wrote:

Bad wording there, the temp gauge/sensor was modified to be more sensitive to fluctuations.
Any idea how this would be done? The accuracy is actually off because it shows a little hot when it is at normal operating temperatures, but small temperature changes that would not register at all on my previous stock temperature gauge will cause the needle to move on this one.
Pat
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put the heat shield back on. If not, make one. The forum

Previous owner installed the monsterflow and didn't pass along the OEM part. Maybe I can find someone interested in trading.
Header is J.R.so, no bolt up points. I'll have to get creative here.
Chris 99BBB
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Chris D'Agnolo wrote:

I will keep an eye out for a 1999 OEM intake for you.
Will an intake from any 1999-2005 Miata work? (excluding the MSM turbo Miata, of course).
Pat
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I think so. I know there were some variations but I don't think they would be functionally different, would they?
Chris 99BBB
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Chris D'Agnolo wrote:

My NB knowledge is quite limited, especially compared to the NA.
Can someone who is more familiar with the 1999-2005 model Miatas offer some advice on this?
Thanks,
Pat
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