Emissions cam help UK
Emissions cam help UK Hi
I own a 2004 Vauxhall Monaro which has an M6 LS1, in the UK, basically an 04 GTO.
I am planning on doing a cam swap next year along with a set of heads.
The heads im planning on used are some used callaway C4B heads off a HSV GTS-R, basically a set of ported 241's i plan on skimming them by approx 20-25 thou to bump the compression up to around 10.5-10.7 range. They flow around 270 cfm of air peak and around 260 from .400 onwards.
I have been searching for cali smog cams but was wondering if the UK rules are more relaxed which would allow a slightly larger cam to pass.
I am also thinking of installing stock cast headers and cats purely for the emissions test and then remove them and go back to longtubes.
The UK smog test is similar to cali as in a probe is stuck up the exhaust and the car is run, but in the UK that cars are run in neutral and the test is done at natural and fast idle, by the operator adjusting the throttle.
Below are the limits for a LS1 monaro in the UK
Natural idle test
Speed = 450 to 1500 rpm
CO = 0.3 % Volume
Fast Idle Test
Speed = 2500 to 3000 rpm
CO = 0.2 % Volume
HC = 200 ppm
Lambda = 0.97 to 1.03
I will be tuning the car myself with the assistance of a few others using EFI Live
At the moment in the UK the consensus is that a 224 cam should pass, but thats with longtubes and high flow cats, and i plan on running stock headers and cats just for this test.
Could any cali smog experts provide any advice on a cam
thank you
I own a 2004 Vauxhall Monaro which has an M6 LS1, in the UK, basically an 04 GTO.
I am planning on doing a cam swap next year along with a set of heads.
The heads im planning on used are some used callaway C4B heads off a HSV GTS-R, basically a set of ported 241's i plan on skimming them by approx 20-25 thou to bump the compression up to around 10.5-10.7 range. They flow around 270 cfm of air peak and around 260 from .400 onwards.
I have been searching for cali smog cams but was wondering if the UK rules are more relaxed which would allow a slightly larger cam to pass.
I am also thinking of installing stock cast headers and cats purely for the emissions test and then remove them and go back to longtubes.
The UK smog test is similar to cali as in a probe is stuck up the exhaust and the car is run, but in the UK that cars are run in neutral and the test is done at natural and fast idle, by the operator adjusting the throttle.
Below are the limits for a LS1 monaro in the UK
Natural idle test
Speed = 450 to 1500 rpm
CO = 0.3 % Volume
Fast Idle Test
Speed = 2500 to 3000 rpm
CO = 0.2 % Volume
HC = 200 ppm
Lambda = 0.97 to 1.03
I will be tuning the car myself with the assistance of a few others using EFI Live
At the moment in the UK the consensus is that a 224 cam should pass, but thats with longtubes and high flow cats, and i plan on running stock headers and cats just for this test.
Could any cali smog experts provide any advice on a cam
thank you
TECH Fanatic
Joined: Jul 2010
Posts: 1,756
Likes: 4
From: Maryland
I wouldn't waste time on those heads, you can get better stock castings (243, etc) CNC machined to provide at least 30 CFM more relatively cheap. If you are running stock manifolds and exhaust I would go with a Thunder Racing CheaTR V3, Cam specs are 219/230 .607/.604 117 LSA (-9.5* of overlap).
(Courtesy of Pat G.)
The general rule of thumb is -7 degrees of overlap at .050" will pass smog every time. -4 degrees might pass, but the cats need to be really good and the tune needs to be razor sharp. 0 degrees of overlap at .050" almost NEVER passes.
TR 230 on a 111LSA = 5 degrees (dirty, no way pass)
TR 224 on a 114LSA = -4 degrees (maybe pass)
TR 220 on a 114LSA = -8 degrees (definitely pass)
215/230 on a117LSA CheaTR = -11 degrees (definitely pass)
If it comes to it, a cam is not too hard to change in an LS1...spend a couple hours a year to swap and you're golden. Or, you could send Pat G. $25 to custom spec a cam for you, but I think it would be pretty close to the off the shelf one I suggested.
(Courtesy of Pat G.)
The general rule of thumb is -7 degrees of overlap at .050" will pass smog every time. -4 degrees might pass, but the cats need to be really good and the tune needs to be razor sharp. 0 degrees of overlap at .050" almost NEVER passes.
TR 230 on a 111LSA = 5 degrees (dirty, no way pass)
TR 224 on a 114LSA = -4 degrees (maybe pass)
TR 220 on a 114LSA = -8 degrees (definitely pass)
215/230 on a117LSA CheaTR = -11 degrees (definitely pass)
If it comes to it, a cam is not too hard to change in an LS1...spend a couple hours a year to swap and you're golden. Or, you could send Pat G. $25 to custom spec a cam for you, but I think it would be pretty close to the off the shelf one I suggested.
I wouldn't waste time on those heads, you can get better stock castings (243, etc) CNC machined to provide at least 30 CFM more relatively cheap. If you are running stock manifolds and exhaust I would go with a Thunder Racing CheaTR V3, Cam specs are 219/230 .607/.604 117 LSA (-9.5* of overlap).
(Courtesy of Pat G.)
The general rule of thumb is -7 degrees of overlap at .050" will pass smog every time. -4 degrees might pass, but the cats need to be really good and the tune needs to be razor sharp. 0 degrees of overlap at .050" almost NEVER passes.
TR 230 on a 111LSA = 5 degrees (dirty, no way pass)
TR 224 on a 114LSA = -4 degrees (maybe pass)
TR 220 on a 114LSA = -8 degrees (definitely pass)
215/230 on a117LSA CheaTR = -11 degrees (definitely pass)
If it comes to it, a cam is not too hard to change in an LS1...spend a couple hours a year to swap and you're golden. Or, you could send Pat G. $25 to custom spec a cam for you, but I think it would be pretty close to the off the shelf one I suggested.
(Courtesy of Pat G.)
The general rule of thumb is -7 degrees of overlap at .050" will pass smog every time. -4 degrees might pass, but the cats need to be really good and the tune needs to be razor sharp. 0 degrees of overlap at .050" almost NEVER passes.
TR 230 on a 111LSA = 5 degrees (dirty, no way pass)
TR 224 on a 114LSA = -4 degrees (maybe pass)
TR 220 on a 114LSA = -8 degrees (definitely pass)
215/230 on a117LSA CheaTR = -11 degrees (definitely pass)
If it comes to it, a cam is not too hard to change in an LS1...spend a couple hours a year to swap and you're golden. Or, you could send Pat G. $25 to custom spec a cam for you, but I think it would be pretty close to the off the shelf one I suggested.
I can get hold of an eps 224/230 which i think is a 115 lsa off my friend cheap as he decided not to use the cam, so i was thinking of maybe using that and seeing how far out it was and then go from there. I dont think anyone in the UK has properly tried to find out how far you can go, but going by the above in theory it will fail, but still might be worth the swap just to see what happens.
The heads i can get for £400, stock 243's go for £450 if you can find them and by the time i have imported a cheap set of heads over it will cost around £1200-1300 minimum due to tax and shipping cost.
I will eventually swap the heads and cam again but thats if i do eventually go FI at some point
