Is soem of this cam emission leagal?
#1
Racer
Thread Starter
Is soem of this cam emission leagal?
I have a stock Ls2 ttix on e85 is anyone of this cam going to pass emission?
227/231 | .625"/.605" | LSA114+4
228/235 .605/.609 116+5
227/231 | .625"/.605" | LSA114+4
228/235 .605/.609 116+5
Last edited by n_brio; 03-15-2017 at 02:31 PM.
#2
Race Director
Member Since: May 2004
Location: Raleigh, NC
Posts: 16,664
Received 1,194 Likes
on
1,053 Posts
St. Jude Donor '15
Define "pass emission". What tests are required in your area?
#7
Melting Slicks
Pro Mechanic
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,916
Received 736 Likes
on
546 Posts
I'm hardly a camshaft expert, but I am pretty familiar with passing a smog test.
Without the cats, either are likely to fail.
With properly functioning cats and a reasonable tune, the second one seems likely. My reading of the specs say wide LSA=low overlap=fairly clean on the HC.
It compares pretty closely to my 224/236 .649/.649 on 117+4. 2 local tuners said "why, that's smaller than my smog cam!" (California smog)
Without the cats, either are likely to fail.
With properly functioning cats and a reasonable tune, the second one seems likely. My reading of the specs say wide LSA=low overlap=fairly clean on the HC.
It compares pretty closely to my 224/236 .649/.649 on 117+4. 2 local tuners said "why, that's smaller than my smog cam!" (California smog)
#8
Melting Slicks
With cats fitted, both will be almost zero. So yes it would be very easy to pass on such vehicles with an appropriate cam.
Even with a very mild cam and no cats, that would be doable.
But go too far with the cam and even with cats that will be difficult.
That said...both of those cams are probably pushing things a bit, and would most certainly need cats to have any chance of passing.
Even with a very mild cam and no cats, that would be doable.
But go too far with the cam and even with cats that will be difficult.
That said...both of those cams are probably pushing things a bit, and would most certainly need cats to have any chance of passing.
#9
Melting Slicks
Pro Mechanic
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,916
Received 736 Likes
on
546 Posts
Takes a pretty fresh engine and careful map to idle below 1/2%CO and still be smooth enough to read below 100ppm HC, even with a factory stock cam. Raising the idle helps a bunch!
With good cats and not a bunch of overlap, should read pretty close to 0 on both, but doesn't take much 'misfire' to overpower the cats and spike the HC.
NOx is the tough one... but doesn't sound like it's tested there. Lucky bastard!
With good cats and not a bunch of overlap, should read pretty close to 0 on both, but doesn't take much 'misfire' to overpower the cats and spike the HC.
NOx is the tough one... but doesn't sound like it's tested there. Lucky bastard!
#12
Melting Slicks
Pro Mechanic
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,916
Received 736 Likes
on
546 Posts
Someone please correct me if I'm wrong with this.... but .5%CO is right at stoich?
Too much leaner than that will make the HC rise ("lean misfire"), so needing to be leaner than that to pass CO will elevate the HC... and 100ppm at idle without a cat is already pretty tough. It's going to be a pretty fine dance on the mapping!
I think I'd pass on that challenge.
Too much leaner than that will make the HC rise ("lean misfire"), so needing to be leaner than that to pass CO will elevate the HC... and 100ppm at idle without a cat is already pretty tough. It's going to be a pretty fine dance on the mapping!
I think I'd pass on that challenge.
#13
Melting Slicks
it's not quite as straightforward as that...but 0.1% CO on paper is around 14.7:1 AFR gasoline
0.5% would be around 14.3:1
But that would be with a proper gas analyser, a lambda sensor may not always match
Havent a clue about E85 though and how it performs
0.5% would be around 14.3:1
But that would be with a proper gas analyser, a lambda sensor may not always match
Havent a clue about E85 though and how it performs
#14
Melting Slicks
Pro Mechanic
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,916
Received 736 Likes
on
546 Posts
Working from memory, all the O2 sensor cars wanted to hover right around the .5% mark pre-cat. But it's been a long time since we needed to make those routine adjustments!
It would be a fun challenge to see just how clean you could make this one... but I don't think clean enough. Theoretically, E85 will help with the HC, but zero first hand experience.
It would be a fun challenge to see just how clean you could make this one... but I don't think clean enough. Theoretically, E85 will help with the HC, but zero first hand experience.