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NB Randall Cowl Intake V2

NB Randall Cowl Intake V2

Exclusive to Flyin' Miata!

Regular price $125.00 USD
Regular price Sale price $125.00 USD
Sale Sold out
More expected on Aug 19, 2024.
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There are lots of intakes out there, but most of them make more noise than power. If you have an open air filter under the hood, especially if you don't have a heat shield, it's going to suck in hot air. Even a heat shield won't help much if it isn't fully enclosed. Hot air is less dense - i.e., it has less oxygen - so it's going to make less power. That open air filter is great for making noise, which can make the car feel stronger, but if it's sucking in hot air it's probably making less power than the stock intake. But what if they have dyno results?! Was that dyno testing done with the hood closed? If not, it's not a valid test.

We solved this problem a long time ago with our Randall cowl intake. It reuses the stock intake and air box for simplicity and economy (the stock parts flow great for the power levels here), but it makes it so the air comes from the base of the windshield. The benefit is twofold. First, it sucks in truly cold air, from outside of the engine bay. Second, it's force-fed - the base of the windshield is a high-pressure area, so more speed = more air forced into the engine. This results in a dyno-proven - with the hood closed! - 5 hp, as measured at the wheels. It also adds a bit of intake growl, although it's more subtle than an open filter.

The Randall has been gone for a while - our original supplier retired - but we've brought it back better than ever. It's now silicone, which makes the install dramatically easier than the old rigid tube. It's also about half the price! It's more durable, and we now have a firewall plate to secure the end of the hose. The firewall plate also eases installation (it's ridiculously easy to locate the hole), visually cleans things up, secures your clutch line, and has a simple (and unintrusive, flow-wise) screen to keep the intake from sucking up leaves in the cowl.

Installation involves cutting a hole in the flange at the top of your firewall (the firewall plate is your template, so it's pretty easy). This may not be allowed in some race classes, so do your homework. 1 3/8" (35mm) hole saw required, not included.

CARB approved (D-601-5) so it's fully legal everywhere in the US. Since it's pre-airbox, it's likely legal everywhere, but check your local rules to be sure.

Fits all NBs with left-hand drive, with no issues with cruise control or shock tower braces, though the cruise control actuator will have to be relocated slightly. Sorry, it doesn't fit with right-hand drive.

Note that if you use this with a cowl washer bottle, like what we sell, the parts will physically fit, but the washer bottle will sit very close to the mouth of the intake. Check out the dyno chart - on our car installing the cowl washer bottle meant the car picked up about 3 hp instead of 5 - so still beneficial over the stock intake, but not as beneficial as the Randall with no obstructions. 

Photos shown are sample product. Final production items may vary slightly from what is shown.



Ships free in the US.

There are no shipping restrictions on this item.

What does it fit?

Fits: 1999, 2000, 2001, 2002, 2003, 2004, 2005


Not legal in California.


1 year



Customer Reviews

Based on 5 reviews
Lynn M.
True cold air intake

Really nicely designed product. I love that it draws air from the base of the cowl instead of under the hood. The instructions were pretty good, but the cruise control relocation didn't work out well. By using the existing hole per instructions the wiring was stretched to the limit. I ended up drilling a hole 1/2" closer to the front of the car to give it some slack. All in all it was a fairly easy install and I'm really happy with the job. Well worth the cost and effort.

James D.
Best bang for the buck

The installation on my 05 NBwa a little complicated because I had to relocate the cruise control. FM provided a link to excellent photos and instruction so the install went smoothly. I have been driving with it for several days both in city and highway and hot and cool weather. The increased performance was more than I expected. The engine feels noticeablely stronger and revs quicker. The noise is noticeable but not annoying. All in all the car is more driveable in lower revs and really comes on in the higher rev range. The engine seems happy and so am I.


A good friend/ mechanic/miata owner and racer replaced my original NB1 muffler with a Cobalt and I’m very pleased with the sound. To me it improves exhaust note 30-40% over original without being over the top in your face. He let me borrow his Shinsen with CAI for a few days; never experienced intake sound and got hooked.

I wanted to improve intake sound with real lower air temps and possible performance gains decided on the Randall cowl. I installed everything myself pretty simple less than 90 minutes. Like the Cobalt muffler, intake sound is 30-40% louder/improved and complements the exhaust perfectly. Throttle response feels awesome especially above 3k rpm. Best affordable performance made yet. My friend will drive it this weekend at Lemons in NJ can’t wait to get his feedback.

Sean S.
Love it!

Installed on an NB2 w/ cruise control

Install wasn’t difficult, but I did recently install a rollbar, so cutting sheet metal was easier this time around. I relocated the windshield washing hose to the left side; it’d probably look better on the right, but I couldn’t fit my drill bit on that side. FYI the 12mm or 15/32” isn’t a common bit so don’t assume you have it like I did.

Moving the cruise control actuator was a little hard with only one person, but in the end I got it on by threading the nut onto the bolt slightly and then sliding the actuator bracket in between (has an open side).

It sounds fantastic, especially under hard acceleration. Great throaty growl that had me wanting to hear it again and again. I can’t speak to HP results, but the car feels quicker.

Well designed product

Installation was very quick and straight forward. With the right tools even the cutting part can be done in a clean way. I really appreciate that the tubes are flexible. My intake box is slightly pushed off it's original position to prevent rubbing against my strut bar but silicone tubes being flexible just fitted anyway. I can't tell if I gained any extra HP but the engine feels happy. Now my next project is to relocate the washer bottle out of sight to the area under the left headlight - the air doesn't need to flow through there anymore. Maybe FM can do a kit for it in some day in the future?