Air Care

[CP]

I suspect this question has been discussed a few times before, but here goes. My sons 510 failed air care on the idle portion of the test. The drive portion sailed through with excellent readings, but idling, it was off the map in the other direction. It is an LZ 2.2 with dual side draft Webers. The carbs were set-up professionally so the car would run properly. My questions is, how has this problem been dealt with by others. Is this something a gallon of methol-hydrate in the tank and cranking the idle speed way up will cure?

[rnorrish]

What is the idle set for?
Try and get it as high as they will let you get away with.
The max they say is 1250 isn't it? I don't know whether diconnecting the tach would be a help or not in this case... how loud is the car?

[tmpnet]

More info please. what were the readings? what are the maximums? Can`t tell a thing without knowing what reading caused the fail. What cam, plugs, timing valve settings, thermostat, igntion timing, etc used on the engine? May have to set things up alot differently to pass emissions than you do for best power/driving. Particularly to pass the idle test as this is where an otherwise strong performance motor is least efficient with our old "carbed and cammed" cars.

[CP]

I think the idle is at about 800 rpm, plugs are new NGK BPR5ES, thermostat is about 185. bit of a cam, the rest I don't know. It passed last year, but ran lousy so it went in to Specialty to be set up. Runs better but.... It failed on Hydrocarbons..allowable reading 1052,,actual 2000+ Trying to avoid going to have the car set-up for the test and then set-up again after.

[Byron510]

CP
The problem with all of our cars with cams is unburned fuel at idle. The problem is that the simply isn't enough velocity through the carb at idle to properly atomize the fuel in the mixture of air. This is compounded by the fact that you now have four 44mm throats instead of one 30mm one, as the stock configuration is. Consequently, there are just huge drops of fuel literally rolling down the manifold and into the cylinder, not at all mixed with air around it. When the fuel is ignited, it burns iradically, and doesn't even come close to completing the burning cycle - and emissions are through the roof. You don't see this at higher engine speeds because the velocity is now present to properly mix the air/fuel.
I’ve used methanol to help the situation, it effectively leans out the mixture for you, and it burns with far fewer HC’s – but don’t worry to much when the car starts running rough, I couldn’t believe my own car passes last time, it was barely running at all!
Anyways, there are a few other tricks you need to do.
Timing needs to be dropped back, I ran mine around 2-4 degrees, it was hard to tell as my timing light was jumping all over the place.
Next, run the car as hot as you can, a 190 or even 200 deg. Thermostat does help.
Idle as high as you can, my car was near 1500 rpm for my test, and no one questioned it.
Clean oil obviously helps to a certain extent.
The absolute best fuel is Mohawks 94, it’s already got methanol in it, but not much.
Methanol mix is up for debate. My last test was about 50-60% methanol, this was way too much! I think Keith and I agree that around 30% methanol in the tank is about right.

That’s about all I can pass on to you at the moment.
Have you ever considered dropping in on one of our local club meetings? This kind of info is what we like to pass around. It’s a pretty laid back group, feel free to drop in on us. Let us know here on the board what your out come was.
I’m sure there will be a few more additions to this post; tmpnet and 510rob will be able to expand on this. Tmpnet had extensive experience, and 510rob has the uncanny ability to remember damn near everything he reads, and can add some info on what’s happening in the fuel department I’m sure.
Good luck.
Byron

[CP]

Thanks for the info, make sense. We will be taking another try at it next week, can you tell me where to buy methanol?

[Byron510]

Any hardware store or Candian Tire sells it by the 4L jug. It's cheap, as long as some crystal meth lab in the area hasn't cleared out the stores stock!!....I know, thats a hard stab at out comunity, but fairly realistic lately.
Byron

[supersportsedan]

Methanol is also known as Methyl Alcohol, or Methyl Hydrate. It can also be marketed as Gas Line Antifreeze. Sometimes GLA is Isopropyl Alcohol, so check the "Ingredients" before you buy.

[CP]

Didn't know methyl alcoholand methyl hydrate were one in the same. Port Coquitlam businesses actually are participating in a voluntary program monitoring the sale of this stuff in excesive amouts. I guess if I get funny looks buying it, I'll know why.

[bertvorgon]

I buy it by the ton at Home Depot in the paint section, $7.+ for four litres. Lordco carries it also. I have lots of Fondues..that's what fondue fuel is also. Just in case they ask, your having a REALLY BIG fondue! LOL!

[///FiveOneOh]

What is the idle set for?
Try and get it as high as they will let you get away with.
The max they say is 1250 isn't it? I don't know whether diconnecting the tach would be a help or not in this case... how loud is the car?

careful with turning up the idle.. Air care just denied my Jetta because it was idling at 1300. they even gave me a hard time at 1000 because it sounded higher.

[CP]

A little late following this up from my post in October. Got my son's car through Air Care today using all of the points suggested earlier.

Mohawk 94 & Methal Hydrate mix at 40%
Thermostat changed to a 200 degree
Timing set back to as close to 0 as would allow
Idle at around 1000 rpm (not very steady)

The readings were actually very good, nothing even close to a fail. The car was coughing and sputtering so bad I thought we were going to have to push it out of the station.

Thanks for all of the help.

[rnorrish]

I just failed my AirCare test... woo hoo!!

anyways...
Driving Test: | Max. Allowable | Vehical Reading | Avg. Passing | Result
Hydrocarbons (HC) ppm | 409 | 224 | 111 | Pass
Carbon Monoxide (CO) % | 4.76 | 5.71 | 1.08 | FAIL
Oxides of Nitrogen (NOx) ppm | 4356 | 140 | 867 | Pass
Idle Test:
Hydrocarbons (HC) ppm | 1052 | 522 | 294 | Pass
Carbon Monoxide (CO) % | 5.54 | 2.64 | 3.44 | Pass

So what's the deal? What causes Carbon Monoxide to be high?

FYI:LZ22 w/ DGV w/ unknown jets, 445 cam, ~190° Test Temp., started with 2L Methyl Hydrate + ~8L 92 Chevron, some driving and an "unable to test", then added 6L 94 w/ Ethanol from Husky, idle of 1300 or so. Cleaned and gapped the plugs this morning, cleaned airfilter, set timing to <5°@800 rpm. oil was changed 3 weeks ago.

[Rehs]

CO is an excess of unburnt fuel I believe. Lean out your mixture, drop your main jetting down one size. Are you using the vacuum advance on your Dizzy? If so, unhook the vacuum line and plug it.

Just F.Y.I. For my car to pass aircare, I throw 95 Main jets in my DCOE45, retard it 7 degrees, turn the idle up to 1250RPM and lean out the idle mixture to just before it starts to miss. The first year I tried passing it I did not have smaller jets to run, so I loosened off my rockers and it seemed to work. Running Shadbolt 445 cam. I also have a buddy that works the Richmond Aircare station and he will also direct me to the bay that has the dirtyest line filter. That seems to help as well.

[510rob]

leaky throttle shaft?