Heya I've been trying to get my single turbo FD through emissions on a roller type dyno IM240 test.... here are some results.

2 years ago I passed:
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XS Eng PFC Base map for T04S
stock main cat
corvette air pump rigged up to pump air into cat
no stock air pump
no ACV
no EGR
1 gallon denatured alcohol in 1/4 tank of 93 octane

Results (actual/limit):
HC 0.07/1.1 -- PASS
CO 1.3/20 -- PASS
NOx .07/2.3 -- PASS



This year... 4 attempts.. no passes (waiver time!)
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same exact setup as before except:
PFC tuned for -about- 13.5-14.5 AFR in area applicable to test
plugs were 9s/10s

Results (actual/limit):
HC 4.2/1 -- FAIL
CO 53/20 -- FAIL
NOx 0.28/2.2 -- PASS

So I went back and fiddled with my fuel maps some and tried again....
only I FORGOT TO TURN ON the corvette air pump! DOH!

Results (actual/limit):
HC 7.1/1 -- FAIL
CO 58/20 -- FAIL
NOx 0.40/2.2 -- PASS

If at first you don't succeed... I tuned it more towards 14.7:1 AFR and went back AGAIN.

Results (actual/limit):
HC 3.9/1 -- FAIL
CO 33/20 -- FAIL
NOx 0.59/2.2 -- PASS

By now I was mad... no more F'ing around! I retuned the PFC for 15.0-15.5 AFR and got another batch of gasoline and TWO gallons of denatured alcohol. This made about 2 gallons alcohol in a little less than half a tank. The car wouldn't run very well on this mix so I had to bump about 5% more gas in on the PFC maps to get the car to run without crapping out or bucking.

Results (actual/limit):
HC 1.7/1 -- FAIL
CO 18/20 -- PASSSSS!!!!!!!
NOx 0.77/2.2 -- PASS

I looked at the printout of the last run... the only times my car made much emissions was when the doofus driver guy had it in about 5th gear and was lugging the engine going "up a hill" on the simulated test. He got into about 2-3 PSI of boost and the HC emissions went WAY WAY up at that point, screwing my test results. Other than that, the HC-graph is pretty smooth and UNDER the limit. GRRRRR. A better driver and I think it would have passed.

Well I have to go back now and apply for a waiver... so I guess for the next two years I'm good to go... Just wanted to share this information with other people trying to pass.

I probably should have used stock 7/9 spark plugs, they might have run a little cleaner at low load than the 9/10 setup.

Brian

 

I hate this crap. I've pretty much resigned myself to having to drive illegally.

 

Move to Alabama haha

emmissions? whats that?

STEPHEN

 

waiver? where do you live .. never heard of a waiver. Whats the point in trying to pass if you can just get a waiver? how old is your CAT?

 

also, did they put a laser temp sensor on your CAT, I am willing to bet you swap it with a new one and you will pass.

 

Lower the **** out of it so it doesn't fit on the dyno. Then they only do the tail pipe sniffer test. I'll let you know how it works in about a week.

Brian where can I get denatured alcohol?

 

Yes hotter plugs do help for these tests.

Could totally disconnect the secondary throttle so boost builds slower and lower.

 

Love living in florida. No emissions checks.

 

Update:

I was bored so I worked on my maps more and concentrated on P10 and P11 and P12 rows (right where the failure report shows my HC and CO went way up under acceleration.

I passed easily on CO with around a 10 and I ALMOST passed on HC with a 1.2 (needed a 1.0 to pass). The guy was driving it WAY too hard (not abusing it, just giving it more gas than he should have). He was hitting 3 or 4 PSI of boost where I had not tuned for that. Because of that I was running about 12.0:1 AFR there! Other than that ONE spot where my emissions went off the scale, they were below the cutoff line the whole time!

So I have now retuned again... and I'm going to pass damnit. Hahah. I'm getting me some stock plugs too.

A new cat would probably help but that costs money. Another test is only 14 dollars + my time to tune and drive it over there.

I'm to the point now where I don't bother hiding what I'm doing... I just sit there with the laptop and wideband hooked up while the guy drives so that I can see what's up

Justin: You can buy denatured alcohol at a good hardware store like Home Depot... a paint supply store, and Sears used to carry it too, but I am not sure if they still do.

Brian

 

you cant just sneak the guy(tester man) a little bit of cash and call it a day ?

 

..... hard

 

I love it. I was wondering about this when I was going through this a few months ago. They give you any hassle about it? Oh, and do you let them see you turn on/off the air pump, or did you hook it up to the stock wire.

 

UPDATE:

I passed!

o Tuned for high 14s - low 15s AFRs in cells P1-P12 and N1-N10
o removed the check valve for the purge control/evaporative emissions and plugged the vac hose (keeps fuel vapor out of engine)
o Still running my 9/10 heat range plugs
o Still running my same tank of 1/2 tank gas + 2 gallons denatured alcohol

HC 0.13/1 -- PASS
CO 1.1/20 -- PASS
NOx don't remember/2.2 -- PASS