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Old 08-23-2011, 11:29 AM   #342 (permalink)
hackish
Calibration Engineer
 
Join Date: Jan 2010
Location: Canada
Posts: 86

Subie - '00 Subaru Impreza STi JDM
90 day: 22.49 mpg (US)
Thanks: 1
Thanked 18 Times in 14 Posts
A 5 second interval is fairly typical for a 5 gas analyzer. I don't think it's adjustable either. When I have the time to play with it I've been thinking of opening the unit up so I can datalog the values directly. Thus far I've been doing it with a video camera then pulling the data from that

For the age of the vehicle, yes it's older but the VX was Honda's high efficiency engine and it does have some features like an onboard wideband and EGR.

More modern engines / management systems do have features to help cat lightoff - noteably the layout. Most transverse engines now have the intake on the front and exhaust on the rear which allows a cat to be placed closer to the engine. GDI engines have special startup modes that pull timing and add extra fuel to help the cat light quicker.

An interesting addition to this study would be to add an EGT probe to the cat so the cooldown time and lightoff could be measured. For sure extra insulation does help. I have many clients who can't pass the Ontario DriveClean because they put a header on their honda. Putting exhaust heat wrap on the header lowers their e-test results significantly. Emissions are very highly related to cat temp. Buying a $59.00 whitebox special cat doesn't help either
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