Finally dyno tested! 1992 Greddy w/ intercooler & more - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-06-2008, 06:39 PM   #1
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Default Finally dyno tested! 1992 Greddy w/ intercooler & more

Hello All,

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.








Full modification list here


-Tom
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Old 06-06-2008, 06:42 PM   #2
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that is kind of rich. From what i hear, the sweet spot is closer to mid 11's.
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Old 06-06-2008, 10:34 PM   #3
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Weird that you made more torque than horsepower.. What was the correction factor?
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Old 06-06-2008, 10:39 PM   #4
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Yeah that is pretty strange. Looks like the air cooled classics shop is pretty nice. You go there much?
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Old 06-06-2008, 10:48 PM   #5
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Looks like the boost spiked strong and then bled off steadily. That would explain the hp/tq spread anyway.
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Old 06-07-2008, 12:25 AM   #6
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Sleeper!!!!

That must be a torque monster
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Old 06-07-2008, 12:47 AM   #7
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how anyone gets any traction from 185, I'll never know. if the road's not perfectly dry and clean, my 225's will break loose around 4500rpm. and thats with a poorly tuned 5psi.
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Old 06-07-2008, 12:52 AM   #8
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All of the high-ish boosted greddy's I've seen have more torque then horse power.
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Old 06-07-2008, 12:56 AM   #9
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Damn, I need 10psi.

monday im ordering a boost solenoid.
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Old 06-07-2008, 11:47 AM   #10
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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.

Thanks again guys!

-Tom
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Old 06-07-2008, 12:03 PM   #11
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Quote:
Originally Posted by chokeasphyxia View Post
All of the high-ish boosted greddy's I've seen have more torque then horse power.
The numbers in my sig seem to be pretty typical of high-boost Greddys that I've seen... ?
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Old 06-07-2008, 01:45 PM   #12
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geez, you made that power on the stock greedy dp? color me surprised..
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Old 06-07-2008, 02:53 PM   #13
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no torque.jpg
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Old 06-07-2008, 04:37 PM   #14
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Quote:
Originally Posted by hustler View Post
no torque.jpg
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.

-Tom
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Old 06-07-2008, 06:05 PM   #15
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250ft/lbs @ 10PSI? Seems REALLY high considering what others have made at 15psi. I think the correction was somewhat optimistic, either that or the RPM hookup skewed the results.
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Old 06-07-2008, 06:10 PM   #16
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Quote:
Originally Posted by jayc72 View Post
I think the correction was somewhat optimistic
this.
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Old 06-07-2008, 06:58 PM   #17
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yeah.... um my ~14psi run with MS and full 2.5" exhaust, nice ic, and brainack at the computer i only put down 197 and like 184....... hmmm
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Old 06-07-2008, 08:48 PM   #18
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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.

-Tom
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Old 06-07-2008, 09:44 PM   #19
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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.
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Old 06-07-2008, 09:57 PM   #20
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Quote:
Originally Posted by kotomile View Post
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.

-Tom
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