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NA Randall cowl intake duct

Carbon Fiber Randall Cowl Intake Duct
NA Randall cowl intake duct
Cowl induction for your Miata! Inexpensive, effective - and made of carbon fibre! CARB legal.

Made in the USA

Exclusive to Flyin' Miata

Availability: In stock



CARB approved for use in California. EO D-601-1

This is a really cool product. Get it? "Cool". Ha!

Anyhow...the Randall intake replaces the snorkel from your stock airbox with a carbon fibre tube that gets cool air from the high pressure area in front of the windshield. Cold air is dense air, which means more power for you. Most intakes are dyno tested with the hood open, so they perform at their best. As soon as you close the hood, the intake temperature shoots up and all the power gains go away. Not the Randall - in our testing, we saw a solid 5 hp gain with the hood closed. You'll also get a bit more intake growl under load.

Installation involves cutting a hole in the flange at the top of your windshield, above the firewall. This may not be allowed in some race classes, so do your homework. 1.25" holesaw required, not included. Please note that these are a hand-laid product made in small quantities. There may be some small bubbles or imperfections in the epoxy, but nothing that will affect function.
Fits all NAs with left hand drive. Sorry, it doesn't fit with right hand drive.

Dyno proof! These runs were done on the same car back to back. The blue run is the bone stock car with the hood closed and the usual fan blowing in the nose.  Red is the exact same situation, only with the Randall installed. The green dyno was us goofing around, we held a fan near the base of the windshield to simulate a "ram air" effect. As you can see, even without the handheld fan it's a very worthwhile upgrade.

Additional Information

Additional Information

Part number 05-27000
Fits: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
Manufacturer No
Flyin' Miata exclusive Yes
Fits Exocet? No
Proposition 65 Warning: Cancer and reproductive harm
California emissions Emissions legal in California

Customer Reviews 6 item(s)

Be Careful in the rain
Easy to install, small power increase, not much louder, but my exhaust is pretty loud anyway. One issue is in a rain storm a car passing by on the left threw a wall of water across the hood/cowl and almost drowned out the engine. Could have used a snorkel - just be careful of puddles.

Note from FM: In order to drown the engine with this intake, the cowl would have to be underwater long enough for the bottom of the stock airbox to fill with water. It has a capacity of a couple of liters.
Review by Jim / (Posted on 4/2/2019)
Worth it? Depends on you and your Miata.
I'm on the fence between 3 & 4 stars. Installing this was a beast. I'd rather remove rusted exhaust fasteners than install another one on a Miata. It was extremely difficult to get the snorkel through the cowl, with lots of swearing, filing, and Dremel work. I still chipped the corner of the bell mouth. It also didn't align perfectly with the air box inlet--I think the template in the instructions could be improved.

Now, the good. While I didn't notice any appreciable gains, I no longer experience loss on the autocross circuit. I co-drive my Miata, which means lots of duty and lots of under-hood heat soak. Intake air temps on average dropped 20F-25F. Throttle response stays snappy and it pulls strongly even on that 6th or 7th autocross run. The engine feels very awake at all times. I feel much better about running my advanced spark timing now, that's for sure.

There's a slight bit of inductive noise when the conditions are right (low speed, 3k rpm and you whack the throttle) but if you have any sort of aftermarket exhaust, the exhaust will be louder 99% of the time.

Do I recommend it? If you're planning to go for big power adders in the near future, it won't be as useful as the tube matches the stock inlet size and will probably be a source of restriction. But if your Miata sees hard duty cycles at nearly stock power configurations, yes. This (or something like it) is how they should have plumbed the intake from the factory.

Note from FM: We suspect that Derek installed the intake with the bellmouth on the wrong side of the cowl. There's no need to feed the snorkel through the cowl, it simply presses up against it.
Review by Derek S. / (Posted on 9/2/2018)
Great sound and looks good!
Nice, clean upgrade that goes well with a full exhaust. It amplifies the engine sound under load and sounds very nice. On my '94 M, I haven't noticed a real increase in power, but I also have a stock exhaust system. The only improvement I would suggest to FM is to construct it a bit thicker. The mouth of the intake seems a little flimsy.
Review by RyGuy / (Posted on 11/29/2016)
Great product!
A very clean look. Had mine installed for 4 years now and still looks awesome.
Review by Michael / (Posted on 8/24/2016)
One of the best intakes you can get
The intake is pretty good quality but there were some bubbles in the resin/clearcoat on the bottom side and the flange had a tiny bit of fraying at the edges. I felt bad cutting up my firewall but the install was easy and took less than an hour. The engine sounds quite a bit louder with the intake installed and there is a small but noticeable increase in power. Overall I'd say it's a little pricey but definitely worth it!
Review by Carsten / (Posted on 3/6/2016)
An Excellent Start
Great product! Install is fairly easy, and while not too noticeable, there is a very slight gain in horsepower.
Review by Seabass / (Posted on 10/9/2015)
Instructions for this part are not currently available online.