Factory Five Racing Forum banner
1 - 16 of 16 Posts

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #1 ·
If I install a air pump and run hoses to the side pipes(after the O2 sensors) isn't this the same as running it behind the heads?

It should reduce emmisions and pass the normal Mass Dyno inspection method...

I currently pass mass inspection with the two speed test, but am limited to 2000 miles.

John
 

·
It's a car!
Joined
·
173 Posts
Tough call. The exhaust has to be hot enough for the unburned combustables to ignite when the air is introduced. Relative to the combustion chamber, the exhaust cools quickly in the pipes.

Is your major problem HCs? If not, the air pump could be a lot of work that doesn't accomplish anything. Have you tried retarding timing and running hotter plugs for inspections?

I asume you're running 4X headers. Otherwise cats are much more likely to solve your problem. The air pumps on the donors are only there to ignite unburned fuel due to another malfunction, like a fouled plug or bad valve, which would destroy those expensive cats. Basically they do nothing on a properly maintained car.

In the pre-cat old days, it was the timing retardation, lean mixture & low compression that met emissions. The pumps then were more to compensate for misfires by points & condensers. Remember, electronic ignitions were introduced more to save cats than any other reason.

Hope you find a solution and keep us informed.
 

·
Senior Member
Joined
·
4,494 Posts
If you are running Cats, which I believe is required in MASS???, I am fairly sure that you need that air output into the headers to get burned, and pass through the CATS, just like it was originally designed.
 

·
Junior Charter Member
Joined
·
94 Posts
Without a catalyst, the air injection probably will only dilute the exhaust gases. By the time you get that far downstream the temperatures are too low to promote any further reactions. You need the exhaust temperature to be around 600°C (1100°F) before significant oxidation can occur.

Hotter spark plugs will not have any impact on HC unless you have a plug fouling problem at light loads.

Spark retard is effective in reducing HC emissions by increasing exhaust temperatures. This could be a temporary fix for inspection.

Kind of a interesting thought: build side pipes with integral cats and inboard ego sensor bosses. This way one can keep the authentic 4x header look and have functional emission controls.
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #5 ·
OK how retarted should I go and be safe with a S/C. At low RPM (below about 4000)it make 0 boost anyway so I don't think it has an effect.
THat's for HC.

Dyno_CCW, so what your saying is installing the air line in the sidepipes won't do anything. THe air lines in the heads get the exhaust temps up and lets the Cat clean the exhaust?

What about CO? I think its CO? If wrong please correct me....

So the ideal set up is air lines in the heads providing I assume oxygen to heat the exhaust and busn up the HC. THen into the Cats to filter out even more....

Am I on the right track?

John
 

·
It's a car!
Joined
·
173 Posts
I know it's not in the spirt of the inspection process, but have you considered getting a second speedometer?

I'm not suggesting permanent changes, just ways to help pass inspection. On the timing, 6-8 degrees retarded should make a difference in HC. You'll hate how it runs.

With carbs, I always had to lean up to get CO in spec. Since you're running big injectors you could be on the rich side. I suggested the hotter plugs as a compensating alternative. If you pull a couple plugs & they're black & sooty, it might help. If they're greyish it won't.

Cats burn anything that will. Problem is, they'll self-destruct if raw fuel gets dumped into them. Without an air pump, any fuel exiting with the exhaust can't ignite because there's no oxygen, even though it's hot enough to burn. By law, manufacturers have to replace cats up to 50,000 miles, so an air pump is their safety net for lack of maintenance.

But, there is no raw fuel there in a properly running engine. Check out some newer cars. My '99 & '04 both run cats but no air pumps. Between improved valve materials & distributorless ignitions, they don't need them.

Just my 2c from simpler days. So where are all the S/C guys who've done this before?
 

·
FFCobra Fanatic
Joined
·
12,975 Posts
As for adjustments to pass. Think of HC as ignition. CO as mixture. HC will go up as timeing is increased. down as timeing becomes retarded.
CO will become less with a leaner mixture. opposite when becomeing richer. Be aware one effects the other. make a timing adjustment to retard and lowwer HC. The co will creep up some.
Go too lean to lowwer CO's. The HC's will creep up as result of a lean miss fire. Very small tweaks produce large effects of the readings. Tough to guess at without actually watching the meters.
What readings are you not being able to pass? What are they as tested and what do you need them to be?
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #9 ·
I don't know what the readings are at this point.
I passed last years two sped test but I wanted to pass with the normal test not to be limited to 2000 miles....

So I want to work on not needing the Mass Waiver.

Keep the info coming.
If their a meter I could buy to test emmisions as I work on the car?

John
 

·
FFCobra Fanatic
Joined
·
2,510 Posts
John If mine can pass with rings blowing a quart every 5-600 miles Your's should pass without a problem. If you need the cats again let me know. They really work well for the emissions I hate the sound and am looking forward to going back to my 4X4's.
Backing off the timing works great and is very safe with the blower.
Methanol addition to the fuel can helpbut will make it run even worse.
I run the air pump with the cats which I assume helps.
 

·
FFCobra Fanatic
Joined
·
12,975 Posts
John your running cats correct? Without them no chance of passing regular emmissions. Cats cover soo much.
Many repair shops have hc/co testers they use when doing emmision related repairs. A 5 gas would be better but not a must.
Maybe check with a local shop and explain what your trying to do as for making adjustment and seeing there results. Might cost you an hours worth of labor but gain a lot of knowledge and reference as to what and how much each adjustment will effect emmisions.
Too bad your not closer. Have 2 in my shop.
Not aware of any inexpensive testers avalable.
Got mine during a shop closure.
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #12 ·
I have no cats and air pump.......

GOing to lookinto installing them for next year.....

Thanks for all the info.
Going to start looking for a air pump and the tubes for the back of the heads.

John
 

·
FFCobra Fanatic
Joined
·
2,510 Posts
The Mass specs are:
HC grams per mile 0.80
CO grams per mile 15.00
NOx grams per mile 2.00
 

·
Senior Member
Joined
·
2,860 Posts
Going to start looking for a air pump and the tubes for the back of the heads.
Cobra 302... I just removed the Thermactor System from my Mark III (donor 1989 Mustang LX). The only thing that was broken, was the aluminum bracket eye that held the Alternator. Your welocme to it for the price of shipping. Do you still have the wiring hooked up?

PM me with e-mail; if interested.
 
1 - 16 of 16 Posts
Top