[Gmecm] Help me get my LT1 a new sticker

Ron Gregory ron
Wed Sep 14 03:56:24 UTC 2011


My son has a '95 Firebird that needs to pass the Texas IM240 dyno testing. 
The vehicle is run on a dyno at 15 mph and 25 mph while sniffing the 
tailpipe.  The car has long-tube headers, no EGR, no air pump, 160-degree 
thermostat, and an empty cat-con.

Last August, I played with the tune a bit, but couldn't get the car to pass 
without installing a new cat-con *and* a special tune. This year, I'd like 
to try [with your help] to pass with an empty cat-con.

The TunerCAT .bin and .txt dump files of the tune that finally worked last 
year are here:

    http://oldpizza.net/formula/2010_08_25_austin_firebird_emissions_5.bin
    http://oldpizza.net/formula/2010_08_25_austin_firebird_emissions_5.txt

I had to mess with the timing, injector constant, and finally the shift 
tables, so it would stay in 1st gear for the 15 mph reading and 2nd for the 
25 mph reading.

The shop is really cool about it. They will actually let us install another 
PCM before we put it on the dyno, so we won't have to actually drive highway 
speeds with this tune.

Any ideas on how to cut emissions down enough to pass "the test"?
Do I have a snowball's chance in August of passing without a cat-con?

I know where I can get some E85.  Would that help?

Ron




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