Got Mikunis. Pass emission test?

[srgunz]

Has any body passed emissions with your tripple mikunis or webers? 72 240.

Just got a notice to be tested before plate renewal.

I have had the car for 28 years and this is the first time I have been required to have test.

What they do is run a tail pipe test while the rear wheels are on a chassis dyno. They simulate city driving to include acceleration and deceleration. I do not think I have to add that there is no longer any smog equipment on the car. Went in dumpster 20 years ago. Sold the SU's also.

I do have some leaner mikuni jets if that will help. Am I screwed?

[SHO-Z]

I have a 2 stage catalytic converter and a Chevy electric air pump that I am planning on installing to pass the test. I have not tried it yet but for less than $70 on ebay in parts it was way cheaper than having someone try to tune my side drafts. It has flanged connections so I can put it in as needed.

[CruxGNZ]

Steve, what county do you live in? What plates do you have on the Z?

 

!M!

[srgunz]

I am in Sheboygan county. Plates are standard.

[CruxGNZ]

Damn, you live in Sheboygan. You have a PM.

 

!M!

[mario_82_ZXT]

Just found out my roommate-to-be for college is from there. What are the odds?

 

Good luck, hope you pass.

Mario

[Guest crawford]

Has any body passed emissions with your tripple mikunis or webers? 72 240.

 

First I'd give DMV a call and ask em how come the old dog has to meet emissions all of a sudden - maybe it is just a mistake.

 

I passed (2nd time around mind you) in new york city way back before the roller tests began so all it was was the exhaust gas sniffer at idle. I was grossly over the first time. Car had a cam (mild crane), ignition (jacobs at the time), motorsport auto header, thier 2.5" exhaust, 44mm mikunis, and a 150k engine.

 

To pass I re-installed smog pump and injected air into the EGR fitting on the #6 runner of my motorsport auto header, made sure carbs were synched, and used one of them clear sparkplug things gunson used to sell to make sure idle mix was a nice blue on every cylinder. After this I was running at around 1/3 of the max allowed and still had no converter. The ol pollution dilution method works quite well.....

 

Since you'll be on the rollers you might want to find a sympathetic garage that'll let you change air and main jets a few times to get past the highway speed section. Another thing to watch for is to make sure carb linkage is opening all the carbs the same amount at any given position. The mikuni setup I had sucked at this. Each carb would be opened a different amount at part throttle cause of all the slack in the bushings on the throttle lever shaft, cause throttle levers were indexed to different positions on the shaft, and play in the ball socket arrangement used in the linkage. Having the carbs at different throttle positions during the highway speed phase might play havoc with the emissions......

 

Finally I think sho-z's air injected cat solution should let you pass with ease if it comes to it. And it'd be relatively easy to install/remove as needed.

 

Good luck

[Pop N Wood]

Sounds like Mat is going to give you the correct information for your state, but I can tell you in CA you would fail the visual test because the carbs do not have a California Air Resource Board (CARB) certification. Doesn't matter what the tail pipe says, if it wasn't CARB approved then it won't pass. Also without the smog pump, snorkle and evap can if you had it you will fail.

 

And crawford is right. Tune the engine for best performance and you will get the best smog results. Trying to lean out the engine will cause the NO emissions to fail. It tried that the first time I took the stock SU equiped car in for a test and failed. Setting the carb to run right made it pass. A new smog pump also works wonders for lowering the levels of everything.

 

The dyno test is a good bit more challanging than the old idle sniff test. But with these old cars the emissions levels are actually quite high, so if you can get by the visual and your car is in reasonable shape with a near stock cam, then you might do alright.