Cam lope and emissions compliance
02-13-2006, 12:09 PM
#1
Cam lope and emissions compliance This maybe a somewhat ignorant question, but is it possible to get an emissions compliance cam with a decent lope? I've seen that -7 degrees of overlap or less equates an emissions friendly cam, but I'm not sure how that translates into cam specs.
My current cam is moderate (see in sig) but fairly lopey which I love. Unfortunately, its not emissions compliant. I've heared that the TR224/224 114 lsa cam is boarderline emissions complaint, but my guess is that it doesn't lope very hard.
Is there any way to have your cake and eat it too?
Btw - will be adding Dynatech headers w/ cats for the test.
My current cam is moderate (see in sig) but fairly lopey which I love. Unfortunately, its not emissions compliant. I've heared that the TR224/224 114 lsa cam is boarderline emissions complaint, but my guess is that it doesn't lope very hard.
Is there any way to have your cake and eat it too?
Btw - will be adding Dynatech headers w/ cats for the test.
02-13-2006, 01:01 PM
#2
you will find that more overlap = the more lope = less friendly emmisions will be. i have a 228/232 on a 112 and i pass the OBDII cause all they do is plug it in and no codes then you pass i have no cats also. how are you not passing down there in austin? it should be the same. you are right about a 224/224 on a 114 is borderline. if you get a tune and no codes you should pass though. less lope and you will be emissions friendly. the reason the overlap kill emissions is because when you have more overlap that means that both the intake and exhaust valves are open longer at the same time and you get more and more unburned hydrocarbons going out the exhaust before it get burned.
02-13-2006, 06:39 PM
#3
The way to have your cake and eat it is through superior tuning work and a bit higher idle speed. I'd raise the idle to 1000 rpm for your test and make sure that you are not running too rich.
As mentioned above, if you are OBDII and not rollers, there are ways to deal with it.
As mentioned above, if you are OBDII and not rollers, there are ways to deal with it.
02-13-2006, 06:54 PM
#5
Originally Posted by Ragtop 99
The way to have your cake and eat it is through superior tuning work and a bit higher idle speed. I'd raise the idle to 1000 rpm for your test and make sure that you are not running too rich.
As mentioned above, if you are OBDII and not rollers, there are ways to deal with it.
As mentioned above, if you are OBDII and not rollers, there are ways to deal with it.
02-13-2006, 07:03 PM
#6
The key to passing the sniffer and having lope is by selecting a cam that has -7 degrees of overlap at .050", then having the idle fairly high (900rpm) when you need to go for inspection and 700 rpm for the lope you want. Even the stock cam will lope very hard with a 450 rpm idle. You can tailor your lope tastes by raising and lowering your idle speed, it's as simple as that.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
02-13-2006, 07:07 PM
#7
Originally Posted by SUTTERERMAN85
you will find that more overlap = the more lope = less friendly emmisions will be. i have a 228/232 on a 112 and i pass the OBDII cause all they do is plug it in and no codes then you pass i have no cats also. how are you not passing down there in austin? it should be the same. you are right about a 224/224 on a 114 is borderline. if you get a tune and no codes you should pass though. less lope and you will be emissions friendly. the reason the overlap kill emissions is because when you have more overlap that means that both the intake and exhaust valves are open longer at the same time and you get more and more unburned hydrocarbons going out the exhaust before it get burned.
See above for why I didn't pass... He also went to a visual and said I wouldn't have passed even if I showed no codes b/c I didn't have cats.
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02-13-2006, 07:07 PM
#8
Originally Posted by Patrick G
The key to passing the sniffer and having lope is by selecting a cam that has -7 degrees of overlap at .050", then having the idle fairly high (900rpm) when you need to go for inspection and 700 rpm for the lope you want. Even the stock cam will lope very hard with a 450 rpm idle. You can tailor your lope tastes by raising and lowering your idle speed, it's as simple as that.
