OBX Header install on 1994 1.8L NA Miata

Engine work, Tranmissions, LSD's, Diff swaps, etc
Johnny 1
Stage 0
Posts: 44
Joined: Sat May 12, 2012 11:40 am
Car(s): 1994 Miata C package
Location: West San Jose California

OBX Header install on 1994 1.8L NA Miata

Postby Johnny 1 » Sat Feb 16, 2013 12:58 am

I bought this header for about 170 dollars on eBay with shipping. It looks nice, stainless steel, the welds look good. It has extra weld points relative to the more expensive Jackson Racing and Racing Beat headers because I don't think they use as many, if any, mandrel bends. Installation was NOT easy. The ERG connector on the header was not the same size as the ERG mating connector on the stock ERG tube. The tube had to be modified to fit, which was easier to do with the engine out. Had to weld the ERG connector to seal it properly. Could probably find a connector that is the right size for the OBX ERG connector and put it on the Miata stock ERG tube.

The next problem was once the header was in, it barely cleared the floorboard right where the tranny tunnel meets the driver side floorboard (near the gas peddle). The OBX header is designed with the two pipes feeding to the last single tube laying side by side, hence there is a mere 1/2 inch or less of clearance. The Jackson Racing header has an over under design so there is plenty of room. The OBX header will vibrate against the floorboard at this point, annoyingly so. You can dry fit it without connecting the ERG tube to see where it will rub and then remove the header and pound the area in about an inch to give it some room. I did not do that because the ERG tube was already modified when the engine and tranny went back in. It was too much of a pain to remove again so I left it. I had vibration in first and second gear only.

As for performance, it sounded nice and worked well with my Flowmaster DBX muffler. I am running a stock catback configuration between the header and muffler. Because it is stainless steel the engine compartment got really hot however, which is a problem without adequate venting. It had a drone to it, hard on the ears at speed on the highway. I did not notice much of a performance gain however.

I have since replaced it with a Jackson Racing carb legal header. Installed in minutes, after taking off the OBX header (which took about 30 minutes to remove). Much smoother, no drone, no vibration either. I can feel the power difference after 3500 rpms. Very nice chirp of my wheels from a standing start with WOT. Funny, my muffler is much louder with the Jackson Racing header, probably because of the better flow.

Do I recommend the OBX header? Not really, even for the price (I'm selling mine for $80 if you want it). I would save your money until you can afford a Jackson Racing header if you are concerned about CARB legal status or a Racing Beat header. However, if you are willing to go through the hassle to install it and save some money...it might be a good option.
94 Cpkg, Torsen LSD, 1999 engine swap, RB intake, Jackson Racing header, Cobalt SS catback, SS lines, slotted/drilled rotors, ST springs, Koni Strt, FM Swaybars, 949 links, Hella H4 headlights, louvred covers, refurbished interior, alarm with kill switch
Johnny 1
Stage 0
Posts: 44
Joined: Sat May 12, 2012 11:40 am
Car(s): 1994 Miata C package
Location: West San Jose California

Re: OBX Header install on 1994 1.8L NA Miata

Postby Johnny 1 » Thu Sep 26, 2013 9:09 pm

I sold it to a kid that was handy with a hammer and welder. Very happy with my Jackson Racing header, I highly recommend saving your money, being patient, and either buying a new one on sale or a good used one. It also fit fine on my 1999 1.8L engine swap.
94 Cpkg, Torsen LSD, 1999 engine swap, RB intake, Jackson Racing header, Cobalt SS catback, SS lines, slotted/drilled rotors, ST springs, Koni Strt, FM Swaybars, 949 links, Hella H4 headlights, louvred covers, refurbished interior, alarm with kill switch

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