Targa Miata
May 6, 2007 - The subframe brace here is from a 2003 model.
Not only does it stiffen up the rear suspension, but it also protects the differential. It doesn't protect against rocks as well as a legit skid plate would, but I'm more concerned about bottoming out the car on pavement and it should help out there. It also wouldn't be difficult to add a plate or two to this solid frame.
The little skid plate on the red PPF is visible here as well, and the brace does make it rather obsolete when I look at it now. Oh well.
It's also possible to see in this picture that the exhaust system is in place. The main power line running from the battery to the engine bay has been cut and modified so it goes through the cut-off switch, then the wiring was properly secured. The driveshaft is on - and all of a sudden, I have a complete drivetrain!
entry 162 - tags: exhaust, wiring, drivetrain, interchange
May 6, 2007 - Because the header I'm using is from a 1999 model (simply because that's what I was able to scrounge up), I have to use a 1999-05 exhaust system.
The hangers are in slightly different places. No problem for most of the exhaust as I cunningly used a 2003 subframe in the rear (no, really, I did consider this!) but one of the rear mounts just isn't going to work. No worries, I have a welder...
This muffler is actually a stock unit from a 2005 Mazdaspeed. I'll probably replace it with something else later, but it was handy so it got bolted on. The midpipe is an old Flyin' Miata unit with a bad catalytic converter.
entry 164 - tags: interchange, exhaust
June 8, 2007 - Naturally, as soon as the paint was dry enough I had to put some panels on the car.
They're not bolted in place yet, but it's a start!
You can see the 2005 Mazdaspeed MX-5 turbo exhaust protruding beyond the bumper. Those cars have a deeper rear bumper. I'll cut the pipe down a bit, it's goofy looking.
I never thought I'd get so excited about seeing a white Miata.
entry 193 - tags: paint, exhaust, interchange
June 17, 2007 - The car also had an exhaust leak on the short test drive.
The two-piece midpipe didn't have a clamp on the slip joint, so I figured I'd put that on. And I discovered that I'd left the entire exhaust system put together with bolts that were just finger tight. Well, it's not difficult to solve that particular problem. It should be nice and quiet now.
I've also fixed the vacuum leaks and painted the headlight covers and fuel door. Now I have a complete white body. All I need to do is read the manual for the ECU cover to cover a couple of times so I can break everything in properly...
entry 216 - tags: exhaust, testing
August 9, 2007 - A lot of little jobs got done on the car tonight.
The most obvious underhood is the installation of the red valve cover - that's an instant 15 hp gain for sure, although I need to get a filter for that cam cover breather. I installed an interior rear view mirror, the plastic cowl at the base of the windshield, cleaned up a bit of wiring, changed the throttle cable bracket and generally did a few small things on the car.
The Mazdaspeed MX-5 turbo muffler sounded terrible, so it's been replaced by a Flyin' Miata part instead. That sounds a lot better and also drops a few pounds. I also determined that my recent addition of a no-slip patch was a total failure, as it started to creep around the footwell and announced itself to be a hazard. So it's gone now although the bits on the pedals remain.
The car's heading for the alignment shop tomorrow morning and then on to the dyno to get the engine into shape. It's part of the push for the track debut at the Flyin' Miata open house.
entry 281 - tags: ergonomics, exhaust, alignment, engine
August 12, 2007 - A number of little things were done today in order to prep the car for the track day on Friday.
This little filter is on the valve cover to feed the PCV system. That's a pretty misunderstood system, and in most cases a filter on the cover would be a bad idea. In my case, I have an engine management system that uses manifold vacuum to determine load, so there's no problem if some air comes through the valve cover first.
The car also got the first oil change and is now running full synthetic. The transmission and diff were drained and refilled with the correct fluids this time (whoops), and judging by the condition of the stuff coming out of the diff it's not a bad thing that I "flushed" it. I spent a bit of time working on exhaust system alignment, I'm afraid I'll have a bit of a rattle on hard cornering.
On the less mechanical side of things, I put some small rubber bumpers under the trunklid to ensure it doesn't rattle at all. Windshield wipers are in place (and functioning) and I added Grassroots Motorsports and SSR decals to the side of the car in front of the door. This is partly to acknowledge the support from GRM (go pick up a copy of the October 2007 Grassroots, you'll find my Seven in there) and to give SSR a bit of credit for originally supplying the wheels being used on the car. It's also partly a test of how to arrange sponsor decals on the car. Oh, and there's a big black FLYIN' MIATA on the nose of the car now to match the rear bumper. Pictures will come.
entry 289 - tags: drivetrain, exhaust, decals
October 30, 2007 - Time to get ready for a big test.
There's a track day in Pueblo on Friday. This will be the first time I've taken the car on a "big" track, instead of the tight kart track I've been using. It's going to be interesting to see how it does.
One of the jobs to be done before heading to the track 200 miles away is to swap out of the differential. Howard Booster is building a Westfield, and graciously allowed me to borrow his differential for the weekend so I could test with a Torsen and not have to disassemble the Seven. Thanks Howard!
While pulling the diff, I discovered the source of a banging noise under hard cornering. I'd figured it was the exhaust hitting the differential. Close,but not quite. It was the exhaust hitting the flange on the two-piece halfshafts! You can see the evidence in the picture. The two piece halfshaft was never used from the factory with the 1999-05 exhaust system I'm running. I'd used two piece units because it makes it a bit easier to pull the differential, but after dropping the open diff out of the car today I've realized that it doesn't really make all that much difference! Substituting one-piece halfshafts gave me the clearance I need.
So, almost ready to go. I'm going to tow the car over so Janel can come with me. I'll pile a bunch of swaybars in the back of the tow vehicle so I can play with handling, and I'm going to try a couple of different alignment setups. Oh yes, and I have to receive and install the new suspension! Little stuff, you know.
entry 330 - tags: exhaust, drivetrain, interchange
August 6, 2009 - I've noticed recently that I'm getting some vibration through the chassis of the car.
I'm not sure if it appeared after my last header r&r, but I got under the car to check it out. It turns out the catalytic converter was pressed up against a bump in the transmission tunnel.
The bump is one that I hammered in place to give myself a bit more room for the driver's seat. Also, the car runs a cat from a 1999 car because the whole exhaust system is from that generation. No problem, there's a heatshield on the outside of the cat so I figured I could bend that out of the way.
I pulled the cat off, reshaped the heatshield and went to put it back on when a chunk fell out. That's not right! The cat was breaking up internally. Since this particular cat came from discarded exhaust with "bad kitty!" written on it, this isn't exactly heartbreaking. I grabbed a long prybar and encouraged the core of the cat to break up completely. The hollow cat went back on the car. And of course, I was able to place it so there was loads of room between that bump and the cat.
I've had a bit of pinging at full throttle and high rpm recently. Could a failed cat have raised the backpressure in the exhaust system? Quite possibly. We'll find out tomorrow when I return to the track.
The car doesn't sound as good now, having picked up a nasty rasp at about 2600 rpm. The long-term solution will involve a resonator in place of the cat, but I didn't have time to do that today.
entry 689 - tags: exhaust
May 27, 2011 - In preparation for the first noise from the car, I've loosely installed the exhaust system.
I'll have to take it out again after the driveshaft arrives on Tuesday, but it was just too pretty to leave on the floor. Besides, this way I can plug in the O2 sensors.
entry 842 - tags: exhaust, conversion
June 1, 2011 - The installation of the V8 is going to require the reworking of a few things.
When I first built the car, I installed the rear subframe brace from a 2003. This not only stiffened up the rear of the car, it also provided protection. That wasn't just theoretical, inspection after the race showed how much abuse it had soaked up. Granted, I had some other problems that were causing this, but still.
In order to make room for the V8 exhaust, I had to go to the less beefy version of the brace used from 1999-02. The two forward cross braces are gone because the exhaust pipes hang too low - and that means they're going to be susceptible to damage. I've got some ideas, but it's one of the things I'll have to address.
entry 850 - tags: exhaust, conversion
August 10, 2011 - One of the biggest concerns with the car is ground clearance.
I'm running a higher ride height and stiffer springs than before (the race setup last time was 375/300, this year is 550/400) which will help, but the V8 exhaust system does hang down more than the four-cylinder setup did. One of my solutions is to delete the resonators. It's a bit of a shame as I really don't want to make this car any louder inside, but they're the lowest point of the car and this gives me a significant improvement in clearance. As you can see, I've already damaged one!
The catalytic converters have a similar problem, but they're required by the regulations. The good thing is that they're a metallic core, so they won't shatter on impact like a typical ceramic setup. Still, I'm doing what I can to tuck them up a bit and protect them.
Between front and rear suspension work as well as this exhaust modification, there were bits and pieces all over the shop today!
entry 904 - tags: exhaust, ground clearance
July 20, 2012 - I've had enough with hot transmission tunnels.
The exhaust heat was actually enough to melt the heat shielding on the tunnel. So I decided to delete the catalytic converters. They're the source of most of the concentrated heat right beside our legs.
Now, it says in the Open Class regulations that the car has to run cats if it came with cats. In the OE location, too. Obviously, the latter isn't really possible due to the engine swap. But I overheard that at least one of the other Open Class cars was in Open because they had removed theirs. Racing gossip, of course. But I decided to ask.
The answer was "run them if you can, but we know you build legal cars so we'll understand if it can't be done for heat and packaging reasons". I've always been very careful about sticking to the regulations, and I'm glad to see it's been noticed. Then again, I'm probably the only person who's ever required about the minimum required length of the tow rope...

Anyhow, I cut the cats out of the car and replaced them with pieces of straight pipe. I discovered while doing this that one of my cats had actually been damaged at some point. Quite a while ago from the looks of the battered core that came out of it. Interesting.
With the cats gone, the car is noticeably louder. It has more ground clearance, too. It's too early to tell if it's going to be cooler, but taking that broken cat out of the exhaust can only be a good thing.
entry 1048 - tags: exhaust, cats
July 20, 2012 - Here's what the core of the cat looked like once I got it out.
That's a piece of broken ceramic core cat on the left. The round one is a metallic core cat, which is probably why it simply bent and banged up instead of shattering. It's a pretty compressed little unit, though - it's about 1.5" smaller in diameter than it was originally! It's just about small enough now to slip into the 2.5" pipe. I'm thinking it just kept on getting banged around inside the housing and eventually got smaller. Good failure mode I suppose, it didn't clog anything the way a ceramic one can.
The housing had an impact mark on the bottom. Not that bad compared to some of the other stuff under there and it probably pre-dated the skid plates, but the cat had taken a hit.
entry 1049 - tags: exhaust, cats
August 22, 2013 - It's been a long time between updates.
Mostly because it's been a long, long wait for parts. The replacement axles took forever. I took the opportunity to upgrade from the standard axles to the G2 version, which have stronger CV joints and come with the new, beefier hubs. Good thing, too - you'll see why soon.
Elsewhere on the car, I replaced the bent-up muffler, fixed an alignment problem up front and went over a few other things. One bent wheel and one questionable wheel were replaced as well. Since the muffler had burned the rear bumper cover during a dyno run, and then it got all scarred up in the crash, I decided to cut it out further than before. I liked the look better before, but not all the damage.
The car is now back on the ground and self-propelled for the first time in forever.
entry 1089 - tags: repair, crash, axles, exhaust
November 11, 2013 - This should take care of the heat problems I've been experiencing.
The headers and the first part of the exhaust system have been given a Swain "White Lightning" ceramic coating. It's a big step up from the locally applied "ceramic" I had done years ago. That particular coat lasted about as well as my high-temp paint job did. This is much thicker and stronger.
entry 1109 - tags: engine, 6.2, ceramic, exhaust