Tony D Posted March 1, 2011 Share Posted March 1, 2011 (edited) "Great discussion - simple questions often don't have simple answers." THANK YOU! As to Nigel's experience, consider that OEM's run their engines at Peak Torque for 200 hours on an engine dyno. The catalyst needs to be able to handle that. Your test is but a 'fart in the wind' compared to that kind of testing. You likely will go hundreds of thousands of miles if your mixture control remains proper. I believe that was the key to what people were saying: "don't just slap it on, make sure your MIXTURE CONTROL IS ACCURATE" If you have it, it will most likely work, or be passable. I'd like to see some actual dyno emissions test quantifications for all the people that have put them on. For all the 'theoretical' discussions on the 'be careful side' there is absolutely nothing but empirical about the 'I did it' crowd---not a single before and after tailpipe quantification of the 'improvement' of the 'fume reduction'... I have had people swear a car runs stronger and faster when I put a CAI on it too. Even though real results say 'nothing improved'... Psychology plays a big part in this kind of stuff. It helps if you provide actual impartial testing results. It's not 12:1 that will cause an issue go back and look what you will have to 'scrub' during these excursions at that AFR (re: rays previously posted chart). Most STOCK OEM systems will do 12:1 during WOT--this is not a radical number. Many of the early cars with 'burn down problems' were DOMESTIC and had CARBURETTORS. And in those cases, 'mixture control' could vary quite a bit. They also had first generation catalysts. I guarantee you put a catalyst on a car with 10:1 AFR under WOT conditions for 200 hours, and it will die. 12:1 it will likely live. That's what it's supposed to do. You just don't slap a cat on something thinking that is all there is to it. If you have poor mixture control there will be issues. The OEM test is designed to simulate 100K miles of road driving (in the early days the cats only had to last 50K miles, now it's 100K---they're built better now than before!) Sure you can ride around a considerable distance in 7 years of driving, but you're not at 200K miles (where generally an OEM catalyst is still functioning just fine.) For the talk of 'never having a heat problem' how many times have any of you had the "FLOOR TEMPERATURE SWITCH" activate? I had it happen during a sustained interstate drive---the tools in my kit over the muffler literally melted into the tar on the back of the parcel area. The tar strip was like hot butter and giving off fumes from the heat coming off the damn thing! 80MPH for tankful after tankfull towing a small trailer, I believe I was on my third tank of the day so that was after 6 + hours of driving at 3200rpms with a (what, 50HP?) load on it. I have had the floor in my GM Dually get hot enough to have the kid sitting in the back seat say "Hey dude, your floor is smoking!" and when he lifted the floor mat, found the carpet black, melted, and on the verge of igniting! It's not when the car is PROPERLY RUNNING that the catalyst will get hot. In the case of the dually the 7 pin HEI was on the verge of failing and went full retard (best I can guess) and dumped a lot of fuel into the exhaust. THIS is what OEM's have to design around: severe failure mode. They size their catalysts to survive this kind of abuse, so you can do all sorts of general driving and NEVER get near the taxing point of the catalyst. But that doesnt make a catalyst a slap it on and drive merrily away kind of modification. It takes some forethought, and it takes some effort at proper mixture control. Skip those two things, and you're screwed. Or on the way to being screwed. So you're running one. Cool. Post some before / after emissions certificates and quantify the changes. Do some posts with and without the cat. In SoCal this kind of testing would cost me maybe $120 for a very accurate five gas analysis (if I could get a Smog Guy to do it...RAY) After spending well over $2000 on dyno testing to quantify cooling systems modifications, going to slap a cat on my 260Z just to quantify the emissions reduction is probably not in the cards. Hell I got guys questioning the results of the cooling system testing, I'd surely get 'i'm stacking the deck' responses if I tested a slapdash cat installation and came out with less than phenomenal cleanup results. So I leave that ball in you 'I put a cat on and it runs clean as a baby fart' group to quantify the improvement and post it here, instead of subjective 'ooga-booga' testimonial. As easily as an argument against a 'theoretical' reason for not installing one (which I don't think is what anybody said---they just said MAKE SURE YOUR MIXTURE IS PROPERLY CONTROLLED), subjective 'less fumes' testimonials can be dismissed. The FIVE GAS ANALYSIS DOES NOT LIE. You guys put them on, go get it sniffed and tell us what the before and after numbers are, and what they are after 7 years. You may even be surprised when you do a cat on / cat off test at the 7 year point. With all the dyno time a track car has I would think you already have pre-cat five gas analysis results extant, you just need to make a run and stuff the sensor in the actual tailpipe. That would pretty much quantify it in a way that would satisfy me, for sure. I like numbers. I don't like anecdotes. Everybody wins when the numbers go up! <EDIT> The alternative is I have a BAR90 compliant Allen Emissions Testing Machine that I could do idle and 2500 testing. Problem is, it's in Dover DE and I need to get it to my house in SoCal. I could do it, but I owe the guy his car, and he owes me the Smog Machine for my home shop... Then all I need is a dyno and I'm on my own island! Edited March 1, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted March 1, 2011 Share Posted March 1, 2011 Well stated Tony, you left me nothing to fill in. lol You know if you wait until 2012 the state is going to upgrade everyones machines and you will have a good chance of getting one of the old ones on the way to the junk. Most likely they will continue to use the dyno so your on your own there. BTW how you going to get the BAR calibration gas for the 3 day calibration? If I had a test subject to do cat tests on I would. I have the stock exhaust piping and an array of known good cats to test with. Just no car. Im not willing to use my 240z either. The the engine and transmission have to be removed from the car to remove the header and I dont have extra flanges to go from the 2 flange collector setup into one anymore. If I run across any good running donors in the future Ill be sure to tune as close to BAR90 stds as I can and get a baseline then run a cat and see what I can come up with. I have a good idea though of that outcome, but I will do it anyway for the sake of curiousity. Ive done similar tests with other vehicles. Its actually part of std cat testing procedures that MUST be preformed before any cat in Ca can be condemned. Its an intrusive test preformed before and after the cat that BAR requires before any cat can be replaced. OH, and upside down isnt much of an issue(other than the heat shield). Some older cats though have a flow direction. Almost all the new cats are universal installation and flow direction is un-important. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 1, 2011 Share Posted March 1, 2011 If I had a test subject to do cat tests on I would. I have the stock exhaust piping and an array of known good cats to test with. Just no car. When I come for the 10mm socket and ratchet, I'll bring the blue turd, stockest of stock and with NOS SU's and only around 40K miles on them, no leaking shafts! Maybe I can get my kid to follow me in the non-catalyst 76 as well... we can spend a week testing and then hoarde the information smugly... Maybe we could trickle it out 'elsewhere' and be Riders of the Hi-Horse. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted March 2, 2011 Share Posted March 2, 2011 (edited) When I come for the 10mm socket and ratchet, I'll bring the blue turd, stockest of stock and with NOS SU's and only around 40K miles on them, no leaking shafts! Maybe I can get my kid to follow me in the non-catalyst 76 as well... we can spend a week testing and then hoarde the information smugly... Maybe we could trickle it out 'elsewhere' and be Riders of the Hi-Horse. Ill ask and see if its possible to put it up on there with the owner. Should be okay. I did it with mine. I just gotta run it in training mode so it doesnt dial out. 77 would be perfect. 76 and newer is in the system with current standards. The older cars are no longer stored in the system as far as standards go. I ran my 240z as a 76 280z standard. gotta put my hands on the 10mm and proto racket. Not sure where they ended up in the move. Edited March 2, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 6, 2011 Share Posted March 6, 2011 Mount the cat in the back of the car.. just like the WRC world rally cars do!!! They mount them in the rear for weight distribution and to prevent damage when the car slams through rocks and dips and jumps. When heated up you get a very cool tail pipe glow and blue flames. take a look around 24 seconds into the video to see what i mean. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted March 8, 2011 Share Posted March 8, 2011 Mount the cat in the back of the car.. just like the WRC world rally cars do!!! They mount them in the rear for weight distribution and to prevent damage when the car slams through rocks and dips and jumps. When heated up you get a very cool tail pipe glow and blue flames. hmmm Rally cars with cats... I like the windsheild mount better. Just guessing but its probably more likely that they mount it back there for sustainability and its probably a specialized cat.You will not get that cool blue on normal road cars even if you cut the exhaust off right behind a stock cat. You will get the glow. The current cats are good for about 1200*F typically before failure. Rear mounting is not really practical for road cars... yet. The new cold start low temp catalysts that the industry is working on may well work well at the end of the exhaust, when they are available to us. Thats kind of cool though. Quote Link to comment Share on other sites More sharing options...
Gollum Posted April 1, 2011 Share Posted April 1, 2011 First off, wonderful work Ray and Tony. My hat is off and from what I've read you guys know what you're talking about, and what I personally know regarding the subject seems to line up nicely. I want to give a real world example though, just to play the role of devil's advocate here. I truly believe the key for the O.P. is to get the car running right, but that being said... My friend, who happens to be a smog technician who's worked for state refs with good report, had a CRX with a JDM B16A1, OBD0 engine. Ran the car with a test pipe, aftermarket intake, lightweight flywheel, good clutch, cold air intake, and maybe some other small items I can't think of. But the EFI was completely stock and untuned. This car had a slight smell when going through the drive-thru and it was just part of life. It was a budget 14 second street car that we drove the hell out of. A slight smell when in a confined space was the least of our worries. But after a handful of tickets, even after having cops have him lift the hood (had CARB stickers on the intake and such, which was enough to satisfy most cops), one finally sent him to the smog ref for an inspection (cop noticed the AFR gauge and knew that was illegal in most cases). Well, the answer only had one solution. Convert the car to USDM EFI from a del-sol. He got the necessary parts and started on converting it over (during breaks working for the very smog ref that would be doing his inspection). Before the EFI swap, it was obviously running a little rich and as such wasn't going to pass smog, it was surprisingly close though. But with the USDM efi it was ABLE TO PASS with NO cat installed!!! But due to visual reasons and genuinely wanting to make it legal, he installed a cat. What really surprised all of us, is that his two way cat actually reduced NOx by a decent amount. Not astounding, but enough to be certain. Never quite figured that out, but it wasn't a huge concern for us at the time. After that the car never stank as much waiting for our fast food, but we also felt a decent drop in power. The power difference was most likely due to the ECU difference, not the cat. The cat certainly affected the SOUND, which can change the perception of power, but even between the changes it was less than a 5hp difference. I'm positive if the CAT made a difference, it was less than 1hp either way. But the question remains, did the CAT affect the smell, or was it the USDM tune? I personally believe it was the ECU, while my brother is certain it was the CAT. The owner of the car though, thinks it was a bit of both, but doesn't have a strong opinion as he doesn't care much either way. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted April 1, 2011 Share Posted April 1, 2011 It's not 12:1 that will cause an issue go back and look what you will have to 'scrub' during these excursions at that AFR (re: rays previously posted chart). Most STOCK OEM systems will do 12:1 during WOT--this is not a radical number. Many of the early cars with 'burn down problems' were DOMESTIC and had CARBURETTORS. And in those cases, 'mixture control' could vary quite a bit. They also had first generation catalysts. I guarantee you put a catalyst on a car with 10:1 AFR under WOT conditions for 200 hours, and it will die. 12:1 it will likely live. That's what it's supposed to do. Okay, I see now. I thought you were implying earlier that anything other than 14.7 will kill the cat. Now you actually specify some values. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 3, 2011 Share Posted April 3, 2011 To Gollums experiences---I thank him for posting and independently confirming what I've tried to tell people for years: an EFI car SHOULD PASS without a cat (at least the older cars with original compliance criterion.) This was an extreme example, and it shows the importance of making the EFI work like it's supposed to work! My original exposure to this was a Master ASE Tech who was involved with OEM calibrations, and mentioned that when testing Saab's it was very difficult to properly diagnose a bad cat---they simply ran so clean (this was BAR90 Days) that it was nearly impossible to tell when it 'went off'... To the B16, the ECU was the big change. Unfortunately he never drove it around long enough to determine the odor reduction before putting the catalyst on it. Does one SMELL NOx? In the early days, the compounds in fuel (sulphur) really made a bad name for Catalysts because the cars were horridly smelly on startup due to sulphur contamination of the catalyst bed being burnt off when you started the car (and you can still smell it these days going up a long hill behind catalyzed cars, you can tell who buys cheap high-sulfur fuel when behind them!!!) Again, a catalyst is not really a 'scrubber' it doesn't really work all the time, it's a transient mask. The biggest fume problem on S30's is from lack of proper Fuel Cut on decel... And guys that remove dashpots which 'never do much anyway' but in reality make HUGE reductions in drop-throttle HC emissions. I can drive with the windows down on the 260 running like a madman and be fine...drop throttle because of a slow mover in the fast lane and WOOOH! Yeah, there's HC! Really, it can come down to which fuel you are buying! Changing brands on my Corvair made a BIG difference with no change in Fuel Mix! With brand XX it would smell terrible at idle and make your eyes water. But Brand XXX was like a steam bath. No explanation, I'm not a fuels chemist. But something was passing through. Either brand passed smog back then--so it wasn't a pollutant that was tested for... and so might be the 'odors' many people complain about in the S30. As for this: "cop noticed the AFR gauge and knew that was illegal in most cases" What cases makes an AFR gauge illegal? Not in the Great State of California unless it is so mounted to obstruct the forward view of the driver from the vehicle... Quote Link to comment Share on other sites More sharing options...
Gollum Posted April 3, 2011 Share Posted April 3, 2011 Technically it's illegal in california, IF (and that's a big IF) it uses the factory O2 sensor. The reasoning is that even though the gauge is in parallel, not series, it can affect the O2 reading which is "smog controlling device" thus and AFR gauge is "tampering with a smog controlling device". It's complete rubbish, but it seems the smog bureau has mad it's stand on it and even if it's not something openly spoken about it's in the smog ref's reference materials. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted April 3, 2011 Share Posted April 3, 2011 Adding another passenger "tampers with a smog controlling device"... Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 3, 2011 Share Posted April 3, 2011 Do people actually believe the B.S. readings they get from a NB interpolation? My god man, if that is the kind of meter he had he DESERVES a ticket for stupidity! Quote Link to comment Share on other sites More sharing options...
Gollum Posted April 4, 2011 Share Posted April 4, 2011 He didn't buy it for tuning purposes, trust me. Actually I think the only reason he bought it was because he found a good deal on it and figured he'd be upgrading to a wideband eventually so why not do the work of mounting the same size gauge while he's got his car half apart? This friend of mine has made his fair share of "moments of stupidity" but he's the best I know when it comes to tuning. He's actually worked for a high profile subie tuning and has really shown that he knows his stuff when comparing his "uneducated" tunes versus tune files of the "pros". I'd go more into his history and how he's developed as a tuner now, but I think that'd just be getting us farther off topic. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted April 4, 2011 Share Posted April 4, 2011 Do people actually believe the B.S. readings they get from a NB interpolation? My god man, if that is the kind of meter he had he DESERVES a ticket for stupidity! What's not to believe? "Oh, I'm too rich--oh wait! Too lean! Wait, rich--no lean!" Quote Link to comment Share on other sites More sharing options...
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