When we bought Sleepy she only had straight pipe and two cherry bombs for an exhaust. Although this was great when you were out goofing around in the car there was no way I could drive her to work in the morning like that. I tried it a couple of times but instead of taking a nice relaxing drive and listening to some music in the morning it felt like I was at the drag strip. I'd definitely have to tame the exhaust down but I wanted to get her on the dyno before I did. I wanted to go to the same Dynojet dyno that we put Red Beast on but the shop had closed. Luckily the owner had sold the dyno to another local shop so we packed up the cars (we took three Miatas and a supercharged truck with us) and had a mini dyno day.
Strapped down and ready for some pulls:
Watch the video here (the fun starts around the 20 second mark):
I was pleased with the results. I had convinced myself that the car would only push around 310 HP at the wheels but the car was running 353 HP / 358 TQ. Not too bad when you see how lean it was - especially after 4800 RPM. I could easily add some fuel and get more power but there wasn't really any need to. The 353 HP was more than enough for the street. Since I didn't know if the car had a working fuel cut off at redline I opted to only take it to around 6,000 RPM. Luckily the power leveled off at that point so I got a good run. I stopped after one pull because there was no need going any further:
Two weeks after the pull I decided to get the car dyno tuned. They were able to remove the lean spot but there was no hidden horsepower found during tuning. I wasn't able to get a fuel pressure gauge on during the run but the ECU was reporting about a 90% duty cycle on the injectors. I'll have to keep that in mind if I ever want to do any upgrades to the engine (not likely - I have more than enough power to keep me happy). FWIW, if you turn off the Correction Factor the "after tuning" makes about 4 HP more than the "before tuning" but when you turn the correction on that HP disappears. I was puzzled by this but a quick check of the parameters showed that the first run was done at an altitude of 4500 ft and the second was done at 100 ft (which is probably right for Charleston, SC). In any event, I am still very impressed with the car: