RoadsterSport Miata Header 99-00

Our take on the classic 4 to 1 Miata header! The most bang for your buck, with all the features you need in an all stainless steel header.

Manufactured entirely from 304-stainless steel with thick flanges that will not warp like other stamped or cast flanges. Large 1.7" primaries collecting to a 2.375" OD tube via a smooth 4:1 merge.
Now UPDATED to include TWO O2 sensor bungs: one right after the merge, for your primary O2 sensor, and a second bung further down by the outlet flange which you can use to add an auxiliary wideband sensor, or use it when you go to the dyno for the sensor that's hooked up to the dyno, etc. All without having to weld in an extra bung later.

Manual transmission only. EGR compatible.

Gasket included for the connection to the cat pipe. You re-use your factory gasket for the engine to header connection as that is a metal sheet gasket and not a crush gasket, it is good for the lifetime of the car.

Comes with a plug loosely installed in the oxygen sensor bung. MAKE SURE to tighten these down where you are not installing an O2 sensor.

Now updated with a SECOND o2 bung down near the outlet flange, which you can use it to add an auxiliary wideband sensor, or use it when you go to the dyno for the o2 sensor that's hooked up to the dyno, etc. All without having to weld in an extra bung later.

Note that adding any header results in an increase in the exhaust sound level on your Miata.

Note there is an INTENTIONAL small dent in one of the primary tubes for clearance to the steering rod.

Manual Transmission Only.
SORRY, WE CANNOT SHIP TO CALIFORNIA CUSTOMERS! CARB NOTICE: Not CARB approved (and therefore legal in California for off road use only). Note that there are states in addition to California that now follow the California model and require CARB compliance, please check the rules of your state before ordering, in some states this setup is legal only for race cars and may never be used on public highway. Sorry, we will not ship these to residents of California.

This header is a direct replacement for the factory 1999-2000 header on all Federal Miatas that do not have a catalyitic converter in the factory header. For Miatas that were originally sold in California which DO have a catalytic converter in the header, this header will fit those cars but you will need to relocate the oxygen sensors downstream to the catalytic converter located in the midpipe, and you will need our "Race Header O2 Wiring Kit" to accomplish that.

Brian's Application Notes: Year after year our top choice was the Racing Beat and year after year they ran out of stock because the batches of CAST flanges would be too warped to use and then they would be out of stock for months trying to get a good batch. We got tired of that, customers were tired of that, so we did our own that avoids the use of the problematic cast flanges and otherwise is similar for pipe size and length and all stainless construction. We think it is the best header you can get for the money and as a result our warranty is lifetime, which you will not get on ANY other choice!

Not compatible with the old Jackson Racing supercharger kit that sits on the "hot side" of engine.

Installation note: With header in place and all bolts loose between the header and engine and also the header and midpipe, press upwards on the header from underneath the car (upstream of the flex pipe, but after the collector), and keep that upwards pressure on the header while tightening all of the bolts at the engine and midpipe (tighten the bolts at the engine first). This will ensure the header is not sagging on the engine studs, which can result in the header hanging too low. If you don't have a friend to help you with this, you can use a floor jack to press upwards on the header while you tighten the bolts (be careful you don't overdo it with the jack and dent/bend the header). Some other headers that do not have a flex pipe in them get forced into alignment when you tighten them up, because there is no flex in the system. Our header features a flex pipe which offers huge benefits in isolating vibrations and flex to avoid damaging the exhaust downstream, but with that extra flex you must be aware that during install when all the bolts are loose, if you just let it hang on its own weight the header will try to drop at the tail end due to gravity and it can sag more than a completely rigid header, so if you just tighten up all the bolts while it hangs there, the results can be the exhaust hanging too low and possible clearance issues with the subframe. The solution is to loosen everything back up and preload the tail of the header upwards while tightening everything up.