DIY_EFI Digest Sunday, August 1 1999 Volume 04 : Number 444 In this issue: wide range pressure regulators Re: DIY_EFI Digest V4 #442 Re: Nox challenges See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 31 Jul 1999 17:43:36 -0400 From: "C. Brooks" Subject: wide range pressure regulators I don't remember who was looking for a regulator for the turbo carb application but I looked through my parts catalogs and found a pressure regulator with adjustability over a wide range. It's made by Russell, p/n 4532. It's a 2 port regulator adjustable between 3psi and 25psi. Hope that helps, Charles Brooks ------------------------------ Date: Sat, 31 Jul 1999 22:37:55 -0400 From: "Gary Derian" Subject: Re: DIY_EFI Digest V4 #442 My guess is that headers cool the exhaust causing the catalyst to run cooler and less efficiently. Try insulating them, but then you will need stainless. Gary Derian > > I have a 1999 Infinity QX4 that I'm trying to get a set of headers > emission legal (Smog Exempt) in California. My first test failed > because of high Nox. This is determined by a formula they come up with > that extends the results out to at least 50K at which point my Nox > exceeded that limit. (It would pass a standard street smog test no > problem) After some investigation I found an Infinity Service Bulletin > that suggested adding a ground wire from the intake manifold to the > righthand cylinder head. Further diagnostics revealved a lazy or slow > O2 sensor at which time I replaced all four. After this I had the > vehicle sniffed to verify any changes. The Nox was down substantially. > At this time I set all the SRT's and drove approx. 50 miles to make sure > no DTC's popped up. Off to the test lab again and failed again with > high Nox. This vehilce has no mods done to it. Factory ECU. The only > thing I can think of might cause this high Nox would be the design or > flow of the tube off the header to the EGR on the engine. Any ideas???? > > JT > ------------------------------ Date: Sat, 31 Jul 1999 23:45:16 +0000 From: xxalexx@xxx.com Subject: Re: Nox challenges If this is a cold start test, a problem would be CAT light off. The headers are loosing to much heat. Use all methods to retain heat: ceramic coatings, wraps, paints etc. 90% of emmisions or in 1st 60 sec. of test. Check your cats for damaged honeycomb. Install some small precats at collectors. Use catalyst's with more loading. Get some electric CATS. Install a engine heat recovery system. Try to get a realtime exhaust gas trace to see were Nox is max. During ARB test ask for a cold start modal analysis for precon, this is usally less $ than a bag reading. If dilute Nox is over 30 ppm for more than 3 sec. the car will fail. When car warm it should be < 1 ppm at cruise. You can also get similiar data with any one who has a Nox analyzer, or go to Az. where they do a IM240 or ship it to east coast and I will see what I can do. Alex EPA-CARB recog. lab manager. > > I have a 1999 Infinity QX4 that I'm trying to get a set of headers > emission legal (Smog Exempt) in California. My first test failed > because of high Nox. This is determined by a formula they come up with > that extends the results out to at least 50K at which point my Nox > exceeded that limit. (It would pass a standard street smog test no > problem) After some investigation I found an Infinity Service Bulletin > that suggested adding a ground wire from the intake manifold to the > righthand cylinder head. Further diagnostics revealved a lazy or slow > O2 sensor at which time I replaced all four. After this I had the > vehicle sniffed to verify any changes. The Nox was down substantially. > At this time I set all the SRT's and drove approx. 50 miles to make sure > no DTC's popped up. Off to the test lab again and failed again with > high Nox. This vehilce has no mods done to it. Factory ECU. The only > thing I can think of might cause this high Nox would be the design or > flow of the tube off the header to the EGR on the engine. Any ideas???? > ------------------------------ End of DIY_EFI Digest V4 #444 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".