Project Turbo Miata: We Broke It (Again)

Update by Tom Suddard to the Mazda Miata project car
Oct 10, 2017

After repairing a busted differential (thank you for the last-minute parts, Treasure Coast Miata), we headed down to “The Sebring 14,” a race hosted by the ChumpCar World Series Presented by RVA Graphics & Wraps, with a simple goal: Finish the race, have fun, and don’t blow up the car.

One out of three is acceptable, right? A few laps into the race, the car came back into the pits, steam billowing out of the radiator. Why? Despite our best attempts and two test days, we hadn’t managed to keep the rest of the car in one piece long enough to really test the drivetrain. Clearly, we’d done something wrong when reinstalling our rebuilt Treasure Coast Miata engine.

After letting everything cool down, we pulled the radiator for an inspection, and confirmed our fears: After pouring in a hail-mary of headgasket repair liquid during our last race (, a few chunks had clearly stayed in the car’s radiator, then worked themselves loose as soon as we went back out on track. The result? A partially-clogged radiator that couldn’t keep our turbocharged engine cool.

Why hadn’t we noticed the problem sooner? As it turns out, 1.8-liter Miatas don’t have a real temperature gauge, but rather a dummy gauge that always shows normal unless the engine is cold or properly overheated. Rather than indicate the car was running warm, our dummy gauge was insisting that everything was fine.

So, our radiator was clogged, our gauge was useless, and we still had 13 hours of racing left to complete. What next? Easy: Go back out on track. We installed a real temperature gauge, then flushed the radiator as best as we could and went back out. These fixes helped, but didn’t solve the problem. Rather than overheat, we now found ourselves driving to the coolant gauge’s demands, backing off the throttle as soon as it started climbing. That meant slow laps and little fun, but at least we were getting some track time. Why not install a spare radiator? We didn’t have one, and didn’t have any luck finding one locally. Oops.

After a few hours of near-overheating, the car came back to the pits with new problems: A misfiring cylinder and a huge exhaust leak. Fortunately the misfire was just a loose plug wire, but the exhaust leak was more serious, requiring removal of the turbo. Even better was a large oil leak, which we noticed while diagnosing the leaking exhaust.

At this point, we figured we’d pushed our luck enough with a brand new engine under the hood, so we put the car on the trailer. We’d failed at Sebring, but at least there were lessons to learn. Don’t bring an untested car to a 14-hour-long endurance race. Don’t trust a factory Miata gauge. Bring a spare radiator. And don’t trust headgasket-fix-in-a-can.

Time to spend some more time in the garage.

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View comments on the GRM forums
noddaz SuperDork
10/10/17 1:42 p.m.

Besides what you guys might think, (and I don't mean this in a bad way) it is good to hear that not everything works properly on race day for you.  You read some other magazines and everything seems to work perfectly all the time...

Miles Wilson
Miles Wilson Marketing Assistant
10/11/17 9:51 a.m.

@noddaz You would probably not be surprised to find out many of our readers feel similarly. It's good fun being part of a team that jumps into replacing a differential at 10:00pm the night before our race, improvises quickly enough to keep the car running after it quits on us, and lives to share these real experiences with other racers.

Win or loose, we come to have fun and keep it real!

alfadriver GRM+ Memberand MegaDork
10/11/17 11:09 a.m.

May be a dumb question, but have you guys thought about going to just a basic 1.8l engine?  Just to finish races and all?

May end up being too easy of a solution, though.

Tom Suddard
Tom Suddard GRM+ Memberand Digital Experience Director
10/11/17 11:30 a.m.

Nah, where's the fun in that? We've thought about it extensively, but keep having that vision of a winning turbo car instead.


sergio Reader
10/12/17 1:09 p.m.

That's the way it goes. You can race a few times not have any problems and  finish. Then out of the blue something breaks an hour or two into the race and your done. But when it all goes good it's lots of fun. 

NickD SuperDork
10/12/17 2:06 p.m.

Ya'll need to pit this thing up against the Roadkill Rotsun in a race to see which has a catastrophic failure first


GUNDY Reader
11/4/17 12:29 a.m.

Quote "And don’t trust headgasket-fix-in-a-can. " I seem to remember at Daytona while pouring it in, Tim saying this is from one of our advertisers that I am meeting with this week, we'll see if it works. I guess the answer is yes and no, it did plug up holes just the wrong ones.

jabos7 New Reader
12/30/17 12:46 p.m.

Tom-- I was reading up in the print about your 'braided stainless steel turbo oil feed line' and it reminded me (unfortunately) of a similar failure with brake lines.  Got 'em new off Flea-bay  for my '90 Civic hatch.  After 2 autocross meets I realized I was losing brake fluid from the master.  But, no drips, no puddles, no stains.  Topped it up and lost more --made me crazy until I pulled the front wheels off and noticed the brake lines were dis-colored.  -The fluid was leaking internally and starting to inflate the clear covering over the s.steel braiding!

I decided to go back to new OEM lines until I could trust a local hydraulic hose outfit to make up replacements, but found that the "feel" was so much better with fresh hoses I left them on.  -Cheaper to replace and keep fresh as needed.

Roll on!

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