It's stinky, but HOW stinky?
04-06-05, 08:48 PM
#1
Refined Valley Dude
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It's stinky, but HOW stinky?
Some of us love to blather on about what bad polluters rotary engines are. We have a perverse sense of pride about it. 
But have you ever wondered what the actual numbers are? I have.
So today I went and found out...
Here are the results of an e-test done to a S4 NA running premix at a hair over 100:1, with NO EMISSIONS EQUIPMENT INSTALLED. She does have an S-AFC, installed and tuned. More on that later.
ASM2525 TEST (he 'drives' the car on the dyno @ 40km/h for 2-3 minutes)
.................Limit.....Reading....Result
HC.ppm.....108.........373........FAIL
CO%..........0.61.......0.38......PASS
NO.ppm......1232......379.......PASS
RPM.........2857.....VALID
Dilution.....13.4.....VALID
CURB IDLE TEST
.................Limit.....Reading....Result
HC.ppm......300........2193.......FAIL
CO%..........1.50.......7.94........FAIL
NO.ppm......N/A.........N/A........N/A
RPM........855....VALID
Dilution...16.7...VALID
Now about the S-AFC. It's programmed to lean out the mixture when the engine's between about 2500 and 3000rpm. The stock ratio is 14.7:1. The S-AFC changes that to roughly 12:1. Look at the ASM2525 test - it was done at 2857rpm. Right in the sweet spot. How much of a difference does that make? I don't know.
She may have passed two of the three criteria for the 40 km/h test, but standing there in the bay while he did it - it got pretty harsh after the first minute and a half. And that was with both the front and rear bay doors open.
She'll be going in next week for her 'serious' test. And she *will* pass.
But have you ever wondered what the actual numbers are? I have.
So today I went and found out...
Here are the results of an e-test done to a S4 NA running premix at a hair over 100:1, with NO EMISSIONS EQUIPMENT INSTALLED. She does have an S-AFC, installed and tuned. More on that later.
ASM2525 TEST (he 'drives' the car on the dyno @ 40km/h for 2-3 minutes)
.................Limit.....Reading....Result
HC.ppm.....108.........373........FAIL
CO%..........0.61.......0.38......PASS
NO.ppm......1232......379.......PASS
RPM.........2857.....VALID
Dilution.....13.4.....VALID
CURB IDLE TEST
.................Limit.....Reading....Result
HC.ppm......300........2193.......FAIL
CO%..........1.50.......7.94........FAIL
NO.ppm......N/A.........N/A........N/A
RPM........855....VALID
Dilution...16.7...VALID
Now about the S-AFC. It's programmed to lean out the mixture when the engine's between about 2500 and 3000rpm. The stock ratio is 14.7:1. The S-AFC changes that to roughly 12:1. Look at the ASM2525 test - it was done at 2857rpm. Right in the sweet spot. How much of a difference does that make? I don't know.
She may have passed two of the three criteria for the 40 km/h test, but standing there in the bay while he did it - it got pretty harsh after the first minute and a half. And that was with both the front and rear bay doors open.
She'll be going in next week for her 'serious' test. And she *will* pass.
Last edited by Amur_; 04-06-05 at 08:51 PM.
04-06-05, 09:07 PM
#2
What a surprise, it failed both HC aspects of the test. That was always the problem when everyone was trying to get the rotary to pass emissions back in the 1970s.
Due to the large combustion area, the flamefront is extinguished when it moves to a cool area. It's then swept out by the rotor as unburned fuel.
Due to the large combustion area, the flamefront is extinguished when it moves to a cool area. It's then swept out by the rotor as unburned fuel.
04-06-05, 11:26 PM
#5
Refined Valley Dude
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[correction]I knew something didn't look right!
https://www.rx7club.com/showpost.php...0&postcount=50
The ratio was bumped up to about 15:1 for the 'cruising' range. Not down.
https://www.rx7club.com/showpost.php...0&postcount=50
The ratio was bumped up to about 15:1 for the 'cruising' range. Not down.
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