STR MX-5, Part II

When we’d last left off,, the car was starting to take shape. With the suspension done, and the start of the power build, it was time to move on to the remainder of the updates.
This started with a Saturday of fun. First, removing the “noise tube”, which appears to exist only to add weight and make shock adjustment in the front a hassle. Took about ten minutes and $25 in parts. Easy.
Next, I moved on to the JDL auto design header. Very well-made, easy install (simply remove the passenger side motor mount, remove all the header nuts and the O2 sensor, and reinstall). Fitment was great, and looks pretty neat too.
The next bit, I feel less great about. The Goodwin Racing midpipe was pretty expensive for what it is, so I expected the same kind of quality I was getting from the HKS exhaust and the JDL header. I was wrong. The welds look like they were done by a drunk sweat shop worker, and the fitment is VERY poor. Lots of prying and moving stuff around to get it to fit without contacting the floorboard. If I had it to do over again, I’d pursue a different option. As it stands, its done, and there was quite the fun removing the old O2 sensor from the OEM midpipe.
Finally, I took care of the differential bushing inserts. Dropped the subframe a bit, disconnecting the diff mounting bolts from it first. Slipped in, reinstalled. Easy. Should be a little peace of mind not worrying about breaking one, along with an axle, as has happened to other STR competitors.
In and amongst all the other work, I got some 245/40/17 BFG Rival S 1.5s mounted on 949Racing 6ULs.
So, the car existed in this trim for about a week, until finally taking the car up to Karcepts for some fender rolling, tack welding the slip joint on the midpipe, and corner balancing the car.
I left there, headed to an alignment shop, where I basically just took Brian Karwan’s word for where I wanted to start, and got that done.
All that’s left is the tune, which I’ve got sitting in my inbox now, just awaiting some free time to get it onto the car, which is still being driven every day. All that’s left now is to get a mic setup working, flash the tune, and probably find a way to better attach the side skirts. Karcepts also makes a small endlink, used to replace the OEM headlight alignment rod in the rear of the car, which is neat, as it fixes headlight alignment with the lowered geometry.

And so the cat explodes. Thus time to revamp the entire system.

Well, the NB had been stalled for a pretty long time. After a good bit of DDing it, it started to get really down on power. It mostly happened when warm, and got much worse at higher RPM, so I assumed it was the pre-cat that had failed, given the already-present CEL for catalytic efficiency.

I don’t think I quite grasped the level of damage in my original estimate. Here’s what I saw when I unbolted the midpipe.

Awesome. Luckily, I’d already wanted to convert the car to Federal emissions. So swapped in a Federal 99-00 header, and started her back up. The problem still existed. After thinking for a bit about it, it became clear why. When this cat had failed, it had shot its dust and pieces everywhere behind it, clogging the secondary cat too.
Alright, at this point, I didn’t want to buy another stock exhaust. With the TT plans in mind, I knew a 2.5 exhaust was in my future, but also wanted something cheap. I went online, and discovered this $300 special. I had pretty low expectations, but after a few weeks, it arrived. The car drives great again, although, I have to imagine I’ll want a different rear section, solely for visuals…
Now that it’s a working car again, time to move on with some track prep, as the season is beginning shortly.