Tuning the ’Roach

By Robert Goldman

The ’roach is getting angry. There are few visceral experiences in a street legal little British car that surpass those of the Flaming Cockroach, when aroused. The problem is, or has been for a while now, the delivery of sufficient fuel. Being a high energy creature, he needs lots of it.

I rarely name, or anthropomorphize physical objects. In fact, only twice have I ever done so. Once was a defensive maneuver. After helping clean my RX7, the new girlfriend informed me Red Eagle told her he was very happy. I responded in stride, “REX says he’s happy too. Who is Red Eagle?” Third generation RX7s have bloody, gnashing teeth, not a beak and feathers.

The other naming event came as an inspiration. Years ago, while attempting to deliver an insult, an English friend referred to my MG Midget as “that cockroach.” Being of somewhat twisted mind, I realized it was a perfect definition of the car—scurries about, tough to kill. The double-entendre “flaming” describes both the painted flames on the hood, and is British vernacular with a somewhat negative connotation. The ’roach was pleased. My friend Garry, not so much. Although Garry has since passed, it was his desire to fuel inject everything which lead me to my current situation.

Perhaps the greatest credit to be laid at the feet of SU carburetors is their ability to cover a multitude of sins. We’ve tried feeding superchargers from several different carburetors, and the one which produced the best combination of driveability features was the SU. Where it struggles is in acceleration fuel (something a supercharger desperately needs), and float bowl capacity. The float bowl could be made deeper, but that won’t help. It would have to be wider, and there’s little room for that.

The better solution, while avoiding the word easy, is fuel injection. Fuel injection comes with a steep learning curve, but it can be very effective. After installing what I might refer to as a nest of snakes under the hood, the Cockroach was delivered back into my care able to start. It could also run down the road on a lunch trip, but not a lot more.

From drive tests, one could tell the car was punch drunk. You would be too if your analog brain had just been replaced by a loosely programmed electronic version. And so, the learning begins. Sure, I’ve seen those pretty pictures of colorized 3D maps, along with headlines screaming how “it’s easy to program!” Hoot Gibson would tell you the Space Shuttle was easy to fly, but then look what NASA went through to get it that way.

The Moss R&D team would mention to me the concept of data logging, and then wax lyrical about how one can sit on the couch and study data for hours. I don’t work that way. I need to know what is happening now, as I floor the accelerator to pass that minivan full of wine country tourists. I have also needed to relearn virtually every single tuning lesson the R&D guys warned me about. To learn what they really meant, I had to make these same mistakes myself.

My approach has been a combination of: drive down the road, stop and reflash to fix a specific item which caught my attention right now. Then go home, try to visualize what’s going on with the car in my mind, make wholesale changes across multiple tables and graphs, all of which have an effect on other tables and graphs, and find out how bad I messed up next time the car gets driven.

I call it the “circling the field” technique. It’s working, albeit slowly. The ’roach is getting angrier every day, by which I mean one can hear and feel the blower working. It’s getting angry. Not in a mechanical failure way, but in a way which can only happen when there’s enough fuel. With Motorfest just around the corner, by the time you read this, the car should be in Virginia. Who knows if it will run in humidity, but I can fix that with some test driving. Mothers, keep your children inside. There’s a flaming Cockroach in your midst. He’s scurrying about, and angry.