Highest Octane

[Smoking Cobra]

Will running the highest octane gas you can find help to pass the emission's test if your close to the limit's?

joeg

[Bob In Ct]

No! Go on a day when the barometric pressure is high. If you don't have a PCV valve, add one. It will lean out the mixture a little.

Bob

[vettestr]

No higher octane fuel will not help and maybe a bit worse depending on what they are testing. Have you tweeked it to get closer? Is it an idle only test or the loaded testing?
On a carb engine adjust idle ratio to lean miss and increase a tiny bit above miss, increase initial timing about 7 degrees if not already in the 15+ range for static timing.
Get engine up to operating range and mist a water fog into carb to remove any carbon build up = hold running engine at 2000 RPM and squirt a mist of water into carb throat, do this for about 5 to 8 pumps of the water bottle and then allow to return to idle. ( the water bottle is type a fog or fine mist comes out of the spray nozzle= like your mother used to iron clothes with) if you are older than them new fangled steam irons anyway ..... The cold water mist enters the combustion chamber and breakes loose the carbon build up. Be safe during all this and maybe get a helper to assist.

[RedBarchetta]

Originally Posted by vettestr

The cold water mist enters the combustion chamber and breakes loose the carbon build up.

Said anoher way...some of the water droplets will turn to steam under the heat of combustion. You're essentially steam cleaning the chamber. But don't overdo it. Also, make absolutely sure when the car is tested that you have it as hot as it will get without overheating. A hot engine burns fuel more effiiciently.

All good advice here so far...good luck!

-Dean

[vettestr]

Hey Dean,
The don't get carried away warning makes me laugh remembering an old story. As a teenager I worked in my Dads commercial garage. In the winter we would crank up the chokes on the old grandma cars that refused to let em warm up so the engine would not die on them to and from the corner store. Of course they never ran them long/far enough to clean them out so we would mist a little water in their old hot rods to keep them running until warmer months.
We never charged anything for misting the carb with a little water but one old gal hated to wait -wait long enough to make sure the engine was warm enough for the misting to help. We told her it was just a little water mist we used so she told he friend to do it for her. Do you know a pitcher of water will kick the rods out the side??? She does

[wtm442]

Do not laugh, but there is a product called "Guaranteed to Pass"... try it, it works!

[Smoking Cobra]

Thanks for all the reply's. I plan on taking it to Brain at Vintage first to set everything just right. I will look for the Guaranteed to Pass. Hopefully by July the DMV will have it all figured out.

joe g

[jams]

Don't know if it is true but I was always told to change my oil. I guess old oil may have impurities from blow by etc. that would burn during combustion causing you to fail emissions.

It doesn't hurt but not sure if it makes a difference.

[Bob In Ct]

There is no magic bullet here. The richer you run the more CO you end up with, the more overlap you have in your cam the more HCs you end up with. I would be very amazed to find that changing my oil or adding an additive to my gas would change any of that.

There is a reason the auto manufactures had to add Cats, air pumps, FI and computers.


Bob

[Cashburn]

We have a customer in CA that passed smog with a new Roush 342R. He is SB100 exempt but took it through the sniff test anyway. It had room to spare. I'm waiting on his fax to see the levels.

Perhaps another reason we love that 342R setup so much?