bushnut Posted April 15, 2014 Share Posted April 15, 2014 (edited) so the time has come, I'm tired of keeping my exhaust patched up with beer cans and muffler tape. It's 14yrs old and its gotta go. the questions are.... 1. bigger diameter pipe or stay stock? (exbrit posted some interesting info on flow rates vs power though I can't remember where.) 2.why are catalytic converters in the US are almost $300 less expensive than in Canada?(rockauto $170ish vs autopartsway $495) I am pretty sure my cats are plugged as I have poor mid range power and my fuel consumption is also poor. Or could that be caused by all the holes? 3. muffler recommendations? the goal Is power and performance not volume. in fact I'd prefer something quiet. thanks guys. Edited April 15, 2014 by bushnut Link to comment Share on other sites More sharing options...
Precise1 Posted April 15, 2014 Share Posted April 15, 2014 Hold off on replacing the cats until you have taken a look at them (How many miles on your Pathy?) Yes, enough exhaust leaks (and where) can definitely rob you of power, but so can a few other things. Increased diameter fron the cats back or at least where the two streams merge on back would be a good idea, but it seems to me that the R50 design has at least 150% flow area than the WD21 with only 10% more displacement. The cats shouldn't be a choke point unless they actually are clogged. I'm not sure what is available for cat back systems but Borla is a good brand... B Link to comment Share on other sites More sharing options...
kdj Posted April 15, 2014 Share Posted April 15, 2014 My last e test I was quoted over $900 for a new cat! I had to pay extra for a conditional pass. I have 140 acres of forested land that the MNR says absorbs the CO2 from over 50 cars and supplies oxygen for over 2000 people each year. You'd think I could get a break...I mean what has any one else done for the enviroment today? If they didn't charge me more per year in property tax than my father payed for it all when he bought it in 1955 maybe I could afford a converter. Sorry but that's my rant, maybe the converter lovers could tell what they have done to "save the planet" today. I pay for them everyday. Link to comment Share on other sites More sharing options...
CNAM Posted April 15, 2014 Share Posted April 15, 2014 California is a real PITA due to emissions regulations. The CA primary cats for my 01 R50 list at like 895$ US or something close to that. I needed all four and a muffler. I went with catco primary's and catco universals for the secondary's. Since they will not shop to CA I had mine shipped to Colorado. They were significantly cheaper about 350$ each and 120$ each for the secondary's. . I have a few tricks up my sleeve to get it to pass smog as I have already failed in the past I'm now locked into a smog check every other year. I'm still waiting to see my test results come Dec when it's due. As for the muffler I went with a Flowmaster dual in/out and custom high back tail pipes. 2.5" in/out. Link to comment Share on other sites More sharing options...
kdj Posted April 15, 2014 Share Posted April 15, 2014 Is California the strictest for emmisions in the US.? Ontario is in Canada. Link to comment Share on other sites More sharing options...
bushnut Posted April 15, 2014 Author Share Posted April 15, 2014 Hold off on replacing the cats until you have taken a look at them (How many miles on your Pathy?) Yes, enough exhaust leaks (and where) can definitely rob you of power, but so can a few other things. Increased diameter fron the cats back or at least where the two streams merge on back would be a good idea, but it seems to me that the R50 design has at least 150% flow area than the WD21 with only 10% more displacement. The cats shouldn't be a choke point unless they actually are clogged. I'm not sure what is available for cat back systems but Borla is a good brand... B 230???kms it always seems to "bog" at around 40km/h and seems sluggish. it feels like the engine is working way harder than it should for the speed I'm going. Link to comment Share on other sites More sharing options...
Adambyrd Posted April 16, 2014 Share Posted April 16, 2014 Just want through this probably had nothing to do with it (exhaust) probably the mass sir flow! Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
bushnut Posted April 16, 2014 Author Share Posted April 16, 2014 MAF is fine, cleaned as well as new filter and cleaned throttle body cleaned as well. It idles fine 800rpm. does have a O2 sensor code though, bank 2 sensor 2. planning on replacing that as soon as the weather is warm enough to crawl under. That code has been running since I bought it the year before last. take off is Ok, 0kph-35kph. between 40kph and 60kph it feels like its struggling and once I hit 70/80 kph it sounds just fine. 100kph tac is at around 2200 rpm. so I figure it has something to do with the back pressure in the exhaust system. though I'm probably wrong, I'm not an automotive mechanic. Link to comment Share on other sites More sharing options...
Adambyrd Posted April 16, 2014 Share Posted April 16, 2014 It may be a swirl control valve is it bucking on exceleration? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
bushnut Posted April 16, 2014 Author Share Posted April 16, 2014 (edited) "swirl control valve"? wtf? no bucking just seems like its working to hard. RPMs are in line with acceleration but I have to give it more right pedal than I used to. and it sounds awful. the tone changes at around 40ish and thats when it starts to lag. Edited April 16, 2014 by bushnut Link to comment Share on other sites More sharing options...
Slartibartfast Posted April 16, 2014 Share Posted April 16, 2014 The VG series engines didn't have swirl valves, Nissan started with those on the VQ series (2001.5+). My dad had the bucking problem with his '03 and it was not mistakable for an exhaust condition! Of course the SOB didn't code so we had no idea it was the swirl valve circuit that was plugged up... luckily the mechanic we took it to had seen the problem before. If it's leaking exhaust before the primary O2 sensors, the computer won't get the fuel mix right. I would imagine scavenging is also effected. When I got the exhaust on my WD fixed, it seemed to pick up a little power. It also made a lot less noise afterwards! Link to comment Share on other sites More sharing options...
Precise1 Posted April 16, 2014 Share Posted April 16, 2014 230???kms it always seems to "bog" at around 40km/h and seems sluggish. it feels like the engine is working way harder than it should for the speed I'm going. So 142k miles. Our 1999.0 has 176k miles (284k km) with the factory cats and runs fine. The two things I would look at first are the timing and the Throttle Position Sensor. Any OBD2 codes showing? MAF is fine, cleaned as well as new filter and cleaned throttle body cleaned as well. It idles fine 800rpm. does have a O2 sensor code though, bank 2 sensor 2. planning on replacing that as soon as the weather is warm enough to crawl under. That code has been running since I bought it the year before last. take off is Ok, 0kph-35kph. between 40kph and 60kph it feels like its struggling and once I hit 70/80 kph it sounds just fine. 100kph tac is at around 2200 rpm. so I figure it has something to do with the back pressure in the exhaust system. though I'm probably wrong, I'm not an automotive mechanic. This makes exhaust seem not to be the problem. The higher the RPM, the more exhaust flow, the more it would choke so watch that, not the speed. Again, it seems that it is engine timing or control related to me. B Link to comment Share on other sites More sharing options...
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