VA emissions tuning

[rkreigh]

trying to get a VA shop with an exhaust gas analyzer who can work with Marc to do a mail order tune on the LSV

My idle is pig rich, and HC high at 130. need to get below 48

I talked to graham and he suggested going to a closed loop chip to provide finer control over the fueling.

just need an emissions chip to get the big 234 cams to pass!!

need to get this done soon as I expire at the end of July

any help or suggestions are much appreciated. I've been using the LSV as my daily driver now that the weather is nice and don't really want to park it.

life's too short, drive em.

[zr1don]

The following got me through CA emissions, don't know if this will apply to the big cams, but this will help emissions on most engines:

Reduce stock spark tables 2 to 6 degrees (mine worked best for NOX at -4 deg)

Use thermal wrap on both the headers and CATS to get CATS hot (they remove more gases when hot).

Make sure fueling is at or very near stoichetric. If your computer is adjusting away from where you want to go, you can do closed loop or (my preference) reduce max min block learn cells to 1, both max and min block learn the same cell #. That lets the computer adjust up and down within that cell only.

If the engine is carboned at all use a cleaner like Seafoam to get the deposits out

Be sure the cooling system is keeping temps 200 to 210 deg F. Cooler or hotter will push regulated gases higher, they will be min at above temps.

If not using stock cats, use the biggest after market cat you can find (example: late 90's to early 2000's chevy big block pickups)

If I remember any additional relavent things, will post up again.

[Pete]

Originally Posted by rkreigh

trying to get a VA shop with an exhaust gas analyzer who can work with Marc to do a mail order tune on the LSV

My idle is pig rich, and HC high at 130. need to get below 48

I talked to graham and he suggested going to a closed loop chip to provide finer control over the fueling.

just need an emissions chip to get the big 234 cams to pass!!

need to get this done soon as I expire at the end of July

any help or suggestions are much appreciated. I've been using the LSV as my daily driver now that the weather is nice and don't really want to park it.

life's too short, drive em.

Ron, .234 cams are tiny.
Do you have .234 on exhaust side? if so i think might be a bit big for exhaust cams.

No worries should be able to do it.

Besides all of the above info i would hook your AIR pump directly into the header air tubes,hot wire pump to stay running so it pumps fresh air into your exhaust.

Pete

[XfireZ51]

Pete,

I was wondering same thing since the intakes we put on my motor are 236. Especially if Ron's motor is a bigger cube motor.
My suggestion would be to bring the car here and leave it for tuning. Trying to do what Graham recommended won't get done in
one or two passes.

[Jagdpanzer]

Just got my 94 through VA emission inspection.
Last inspection in 2009 was a real struggle so to pass this time I temporarily rigged up a pair of Magnaflow #94119 3" two stage ceramic cats equipped with air tubes
http://www.magnaflow.com/02catalytic_converters/02product/displayuniversal.asp?universal=94119
Hooked up the EGR valve and AIR injection pump lines to avoid problems with passing the visual inspection.
Also swapped in the original stock 94 chip so the AIR injection pump and EGR valve were active.
Passed with plenty of margin on the first pull without the inspector having to play with it for 30 minutes like last time.








2011 Emission Inspection Results




2009 Emission Inspection Results



As the numbers show HCs were down by 1/2 from what they were in 2009 with Magnafrow metallic bullet cats and Haibeck chip installed.
Relieved to be good to go for another 2 years.
Now to proceed with swapping in the 402 CID stroker motor.

[zr1don]

I tried hot wiring the AIR inj pump on my 90. When first started the O2 sensors showed a way lean condition (air being pumped past sensors), NOX went down, then the computer dumped fuel in to correct the lean condition, HC's went up and continued to climb. I turned the AIR pump off after about 1 min. As a result of this experiment, the passenger side (brand new) cat was completely burned out, no internals.

[Jagdpanzer]

Originally Posted by Pete

Besides all of the above info i would hook your AIR pump directly into the header air tubes,hot wire pump to stay running so it pumps fresh air into your exhaust.Pete

I thought of doing the same thing but found out here in Virginia they also measure "Dilution" which threw this idea out.

[Aurora40]

Originally Posted by Pete

Besides all of the above info i would hook your AIR pump directly into the header air tubes,hot wire pump to stay running so it pumps fresh air into your exhaust.

Pete

I'm fairly certain they test for that, it's the "dilution" number.

The VA test is quite strict. My '90 was right on the limit for HC's with headers and cats on a basically stock 350.

I wonder if the best bet wouldn't be to toss stock manifolds and cats back on. Then you'll have lots of cat, and really good low-throttle O2 feedback to help it get as close as possible to stoichiometric. I have to think at low exhaust flow that the O2 in those huge header collectors really isn't getting a good read on things.

For what it is worth, my HC numbers from just adding headers/cats to a car with an already ported intake went from 13ppm HC's to 48ppm HC's. That's a 3-4x increase. You need to cut your numbers by 3/4 to get down where it's acceptable. I wonder if stock manifolds and cats won't be the best way to do it?

[mike100]

^^ interesting to know

NOx seems to be the biggest hurdle now in Cali since they lowered the standards unrealistically low. I had an idea to try to get the tech to run the entire test in the lower gears to reduce the load at 25 mph...either that or bring it to the test with 4:30 gears.

[rkreigh]

thanks for the advice everyone. going to get new cats, get em hot, run some seafoam through the car, fresh oil (plugs are pretty new) and maybe a fresh air filter and get a baseline.

if it won't pass, I'll need to retune but I'm sure the fresh cats are better than the worn random SS that are probably shot as far as emissions go.

I'll keep you all posted and thanks again for the help!