CO emissions vs gasoline brand? (1 Viewer)

[Fast Eddy]

I've been thinking about trying to figure out my smog issues so I can drive my 40.

Was reading something JimC sent me in an email about E85 to add some O2 to the fuel and lower the CO and I got to searching.

I came across this .pdf: http://www.cleanairchoice.org/fuels/E85C02Report2004.PDF

In Table 4 it compares the CO emissions of some 10% ethanol (E10) fuels from various stations. They vary by over 30% from the highest to the lowest.

I guess I'll try some Techron/E85 mix for the next test. I'm over on CO by about double the limit at 15mph and 25mph.

Last test attempt I swapped my 315s for a pair of 33x9.5s and it seemed a lot mellower on the dyno, but it didn't effect the test output much, if at all.

I just want to drive it.

 

[74bruiser]

Yours too young to get historic plates?

 

[Pin_Head]

There is little variation in CO in the different fuels in that paper, especially among those with the same composition. There is no indication that any of the differences are statistically significant either, which is a red flag. If you are 2-fold over the CO limit, you aren't going to fix it by changing fuel type. Either there is not enough air or too much fuel. What size main jets do you have?

 

[Fast Eddy]

Dunno. JimC rebuilt the carb knowing that I had to pass smog. Are they marked if I could get one out? I have another carb too, that I could check.

It's got a reasonably new K&N filter, so it's not that.

What if the heat riser door was closed when it ran the test before? That's something I didn't check and also something that I could easily control.

Yours too young to get historic plates?

Homey, er, Cali don't play dat. '76 and newer has to pass. They want people to give up and scrap them, or sell out of state. The limits are much higher than for newer cars.

 

[Pin_Head]

The jets are marked. You can remove them without removing the carb if you are careful. I think the stock CA jet is a 124 for the primary. Before I threw in the towel on my '76, I had a spare carb that I used to pass smog that had a 130 primary, but it didn't run as well as the carb I usually ran that had a 150.

 

[Fast Eddy]

If I had to change jets to reliably pass smog every couple years, I'd be ok with that. I'll pull the primary jet on my spare and see what size it is.

My '76 runs great. My '78 that likely passes does not run as well. Could be...

Thanks.

 

[65swb45]

Take out the K&N and put in a paper element.

 

[subzali]

The jets are stamped assuming nobody drilled them out to a different size. That happened to a guy in RS a couple years ago.

 

[1911]

All of the gasoline in a given area comes from the same refinery. The main differences between brands boils down to two things: the additive package that major brands add to theirs, and the cleanliness standards for underground storage tanks that different brands have for their retailers. The additives, although beneficial, are measured in parts per million. The underground tank standards mostly relate to what is an acceptable amount of water to be tolerated in the storage tank. The major oil company brands have tighter standards than the quikee marts.

 

[Fast Eddy]

Take out the K&N and put in a paper element.

Ok, but why? I thought I needed more oxygen to help burn off the CO?

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Regarding jets, I pulled the ones from the spare I rebuilt myself that didn't run great. On the left was a 120. On the right was one that was pretty dinged up, but looked like a 71 (171). Comparing the sizes visually, that seems about right.

Edit: These are the original jet sizes for a 12/75 Cali model, according to SOR.

Isn't the primary on the right? No wonder I get pros to do this for me.

How are you supposed to get them out without tipping the carb over? Screwdriver plus a thin wire or something?

 

[subzali]

The primary is closer to the engine block and should be the smaller one.

Split blade screwdrivers can grab the jet and hold it while you remove. That's one option.

 

[Fast Eddy]

The primary is closer to the engine block and should be the smaller one.

Split blade screwdrivers can grab the jet and hold it while you remove. That's one option.

Ok. That's how it was in the spare carby. I'll pull the primary out of the installed carb over the weekend and see what's in there.

My engine was installed in Reno, as I understand it. It is an '85 or '86 2f with all the bolt-ons from the original early '76. I'm sure emissions wasn't their #1 concern. Maybe they took the original primary jet from the '80s carb and put it in the earlier carb? That would have been a 1.47.

I've seen a post where JimC likes this size for this carb. I surely like how it runs, and the smog test agrees that it's richer than CA wants it to be for emissions purposes.

 

[Fast Eddy]

Ok @Pin_Head and @65swb45. I found jets in the carb matching '75-'76 federal, 1.44 and 2.30. I swapped the primary with the 1.20 that I have.

Of course I had to take off the top once the jet got lost in the bowl. Not sure how you'd ever do that in the field without pulling the top.

Now it runs like sh*t. Actually, it idles great, 20 in hg. Just off idle, when needing a little power, it stutters hard. Then with 1/2 pedal or so it runs well again after a little tire chirp. I re-adjusted the idle mixture. It might have gotten a little better, but it still sucks. I've been through the timing enough to know that it's right.

I want fuel injection. I really have to concentrate to not hate on CA sometimes.

 

[Pin_Head]

Maybe it will pass smog now with the 120. Make sure you don't have a manifold vacuum leak. If it is too lean it will misfire and you will be over on HC.

 

[Romer]

If you're marginal, some folks here have been successful using a full tank of premium fuel and adding two bottles of HEET, then drive it for 20 minutes before getting to the inspection station

Fuel Injection is nice

 

[Canarias]

All my cruisers are diesel, but heres how i get my CO down with non injected gasoline engines in general

listed in order of effect on CO
1) Use up/drain all the old fuel. Octane goes down while your fuel sits in the tank.
2) Put in high octane fuel for your test
3) Turn your idle up on your carb
4) Set your mixture as lean as poss on your carb

 

[Fast Eddy]

heres how i get my CO down with non injected gasoline engines in general

3) Turn your idle up on your carb
4) Set your mixture as lean as poss on your carb

That implies they are testing at idle. Most areas (?) in CA test on a dyno at 15mph and 25mph. Idle mixture doesn't matter. That's why I'm having to mess with the jets.

 

[Canarias]

That implies they are testing at idle. Most areas (?) in CA test on a dyno at 15mph and 25mph. Idle mixture doesn't matter. That's why I'm having to mess with the jets.

you turn the idle up so u can tune the mixture lean without it stalling

 

[65swb45]

Ok @Pin_Head and @65swb45. I found jets in the carb matching '75-'76 federal, 1.44 and 2.30. I swapped the primary with the 1.20 that I have.

Of course I had to take off the top once the jet got lost in the bowl. Not sure how you'd ever do that in the field without pulling the top.

Now it runs like sh*t. Actually, it idles great, 20 in hg. Just off idle, when needing a little power, it stutters hard. Then with 1/2 pedal or so it runs well again after a little tire chirp. I re-adjusted the idle mixture. It might have gotten a little better, but it still sucks. .

That's kind of a hint. That's a BIG drop in jet size. You should aim for something more in the 1.36 range. I don't have any to offer, but I could send you a small jet you can drill out to that size. More than happy to do it...as long as you call the shop to remind me. D'oh

 

[Fast Eddy]

Are other parts of the Fed vs Cali carb different besides the jets? If so, I should just complete what I started with the spare carb, that had the cal-spec jets in it. It's likely an original cali carb. I rebuilt it and it didn't run well. I'd have to put it back on to remind myself why not.