TOPIC: Exhaust Analysis

I plan to groove my 1998 Buick Park Avenue 3.8 V6 so I had it put on a gas analyzer this morning. As I suspected, the cat was working well.

No load: 600rpm CO=0 HC=0
1500rpm CO=0 HC=3
2500rpm CO=0 HC=3

Loaded: 1650rpm CO=0.7 HC=11

What is the trick to get a useful reading since the cat cleans up the exhaust? I don't think most people want a hole drilled before the cat to take a reading. What is normally done to get useful readings?

I would say that Ron has knowledge about exhaust gas analysis, since he has a 5 gas analyser, I watched him use on a vehicle that went to Zero on both Hc and CO after the Groove, and put my face at the pipe tip-only hot moist air w/no smell!

One other thing that can be measured pre and post Groove is temps. Get a decent infrared thermometer I think even Harbor Freight has 'em now. you want one that can go to say at least 600 deg.F or higher since cat's get that hot. Once engine is warmed up after some driving take/record temps at: all cat's, exhaust manifolds, thermostat housing, anyplace that gets hot during operation where temp's could be affected by operating characteristics. Repeat After Grooving, PCV re-route, and computer re-learn procedure.

You could also get a white cloth and hold over exh. pipe tip for a measured legnth of time before/after watch for a change in soot. Might want to give some miles after Grooving to let things clean out.

Those are my ideas, sounds like yours runs well now and your cats are working well too. will you hit Zero Emissions...?

Good Luck Keep us Posted!

TracyG Gadgetman Reno

If your checking before and after groove youll see the difference in emission numbers.

If you want a real accurate check on how much it will cut check a carb engine without cat before and after and youll see big differences. Sure the cat eats alot but the groove causes the cat to work less.

Dan gadgetman mo.

Hi orrist hear from manitoba canada doing the groove on the 3.8 has a very thin TB you will have to bild up the out side first. You will brak thrue in 2 places. My 1994 buick went from 25 mpg to 39mpg it shure is grat to drive and not see the gas gage move for millllllles Hope this helpes

Since all we have ready access to are the tailpipe emissions, that is where we take our readings. After sitting for a short time, those numbers tend to climb rather dramatically on most vehicles. That is how I gathered the numbers on the others.

Some do not. That's okay, but it represents a cat that is (IMHO) too tight. If they're processing all at idle, it is certainly going to blocking more at higher speeds. I would explain that much to my customers.

You see, the Cat cannot open and close itself according to flow rates. The higher the flow, the greater resistance is applied to the exhaust exiting the engines.

BAD engineering... We should design a replacement, don't you think? Something with variable flow rates?

Hmmmm....