Finally dyno tested! 1992 Greddy w/ intercooler & more
Well I finally made it to the dyno! It was hot as heck (92 degrees inside the shop) but the car made 222.7hp and 247.0 ft-lbs corrected on 10psi and 93 octane gas. For whatever reason, the dyno operator couldn't get a great rpm connection, so the graph is pretty choppy. Also, the A/F meter probe wasn't far enough into the exhaust, so it was reading way lean. I had my wideband connected to a laptop and the 02s were around 10.5-11 the entire run.
Overall, I'm pretty darn pleased given how simple this setup is. I've been driving it every day and it idles and runs exactly like a stock Miata until you put your foot into it. The icing on the cake is the fuel economy. I've gotten no less than 33 mpg on my last four tanks of gas!
Thanks for reading and let me know what you think.
Thanks for the comments and support guys! I appreciate it.
The main thing I learned from this was exactly how restrictive the tiny greddy downpipe is. I knew that going in, but to see it on paper is another story. My first order of business is welding up a new full 2.5" version. I'm confident that will flatten out the torque curve at higher rpms and keep the HP curve moving in the right direction as well. That piece is really only designed for 5psi max.
As for the tires, yes these 185s are terrible. The car had some big ole 17s when I bought it, and one day I took one off and weighed it. All told, by switching to the stock wheel/tire I cut out almost 90lbs of unsprung weight.
Hee Hee! Indeed. I'm calling this my baseline graph, because it definitely points out that I need to open up that exhaust side and focus on getting my tune nailed down. I knew this tune was "safe" but I think it may be a little too safe.
I'll do that stuff sometime in the near future and then get some new numbers. Until then, I'm just really enjoying convertible weather in Tennessee.
Honestly guys, this is why I'm not a fan of using dyno numbers as a comparable performance metric from one car to the next. It always comes down to dyno brand, dyno operator, dyno correction factors, temperature/humidity in the dyno facility, etc, etc. I think most of you will agree that the only way it is comparable is if the cars being compared are run on that same dyno within minutes of one another.
If you'll check out my websites and other car projects, you won't see any dyno figures. What you will see are some pretty decent 1/8 and 1/4 mile ETs and MPHs which is what I've always known to be the most reliable measure of what a car can do.
By posting this info up I'm not trying to set any records, just sharing the experience I had of running my car on a dyno that's local to me. I'd never dyno'd a car before (always did my tuning via datalogger and the drag strip) and it seemed like a fun/inexpensive method of learning more about what my car is doing.
I don't think anyone's bashing you man, but we would like to know what correction factor was used. There are many variables, yes, but generally people understand the difference between different dyno brands' behavior and temperature, etc. We can account for that. But when a variable (CF) is unknown, there's no chance.
I don't think anyone's bashing you man, but we would like to know what correction factor was used.
I'm curious now too after reading the responses that some of y'all had. I'll give the shop a call next week to find out. I do know that they dyno tons of competition Porsches and stuff, so it would seem crazy that they have their settings fubar'd. Anything is possible though.