[Gmecm] Help me get my LT1 a new sticker

[Gary Evans]

95MY emissions standards cannot be met without a cat. Simple as that. Even assuming that the IM20 test allows some extra margin to account for wear and variation between test equipment, the standards your are trying to meet are well past the level where you it is possible pass without a catalytic converter.

Why not put a cat on there and leave it? The difference in RWHP with a good quality cat is a HP or two at most.


-Gary


On Sep 13, 2011, at 8:56 PM, Ron Gregory wrote:

> 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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