Headers & A.I.R.

[LannyL81]

Has anyone put headers on their '81 that lives in an emissions controlled area? I found that Headman Hedders makes a set with the A.I.R. tubes for like twice the price. Do the emissions people know that their are supposed to be tubes in the exhaust manifolds or can I get some type of waiver for this?

And I supposed that with headers you just do without the heat control valve?

Thanks,
LannyL81

 

[GerryLP]

Lanny,

When I bought my Hedman Hedders I thought I saw in their catalog a P/N for A.I.R. compatible hedders, but If I am not mistaken, I remember that it included only up to 1979. I always wondered why they did not offered one for the 1980 - 1982, but we're talking a couple of years ago. Maybe now they do.

The only one thing I dislike about Hedman is that they tend to be hedders that hug the block. I wish that they would post diagrams of pictures showing their installed position. This translates into pain and suffering if I do transmission torque converter maintenance, and I am limited to using the GM short oil filter. Also, I need to use modified collector adapters to keep the exhaust gases away from the tranny if want to race the car at the track with open hedders. When I dropped the engine oil pan, I had to remove the hedders (which includes starter removal).

 

[glaso81]

Trust me they do know what the car is supposed to have and no you can't get a waiver unless you want a one time non renewable waiver that you have to disclose to any future owner (I found this out the hard way on a jeep here in the Grand canyon state) who buys the car, so use your one time waiver and the next may feel it is a risk to buy it.

 

[sixty9vette]

Here's a pic of Hedman Hedders on my former '81, which also has a ZZ4 and passed emissions w/o problems. The ZZ4 has no exhaust crossovers in the heads for the EGR, but the EGR was left attached for the visual inspection (They don't test it to see if it's working - just has to be there). Anyway, there's also the heat riser issue. Thorley has some available, and I think Holley has them as well, but you won't find any that you can directly adapt to 3" header flanges without reducers. I think the largest riser I could find was 2.5". Decided just to forgo the heat riser. They never noticed (or looked). They will, however look for the the more obvious, and that's the EGR, the A.I.R. pump, diverter valve, exhaust manifold air tubes, cat., etc. The Hedmans fit perfectly. No having to 'ding for clearance'. They ran very close to the tranny, and I wrapped the two cooling lines with reflective heat wrap tape. I had the front Y made up at a muffler shop to retain the 2-1-2 stock style exhaust system. Oh, and how's about that performance improvement over the stock shorty headers? Not much that I could tell. Probably more worthwhile in the upper rpm range. I bought mine from Jet-Hot. They were right at $500 with the coating. They did a great job though.

Just wanted to add that if you go with ceramic coated headers, the heat will be so reduced that you may have problems with your 02 sensor. I had Jet-hot weld an 02 bung on the driver's side collector before they coated them. I ended up having to replace the 02 sensor with a 3-wire heated version.

 

[LannyL81]

Thanks for the pictures....nice. But have a question about your statement saying that with ceramic coated headers the heat is reduced to the O2 sensor. Why would that be? The heat in the engine compartment should be reduced as the coating keeps the heat in the pipe, so the O2 sensor should actually see a higher temp.

Or am I missing something?

Lanny

 

[sixty9vette]

The problem I had was running rich at idle. The original sensor is very near the heads on the '81. After relocating it to the collector, the problem started. Going with a heated sensor seemed to resolve it. What you say makes sense, but it didn't work out that way for me, so until the computer went into closed loop, it ran rich until the motor completely warmed up.

Thanks for the pictures....nice. But have a question about your statement saying that with ceramic coated headers the heat is reduced to the O2 sensor. Why would that be? The heat in the engine compartment should be reduced as the coating keeps the heat in the pipe, so the O2 sensor should actually see a higher temp.

Or am I missing something?

Lanny

 

[LannyL81]

Chris,

Okay n

 

[LannyL81]

Chris,

Okay now I understand...would have before had I actually "read" that you had moved the O2 sensor down to the collectors. Yep, that is not going to be as hot as the original location.

From what I have read from others, the headers just do not add much, so doubt that I will go to the trouble and expense of putting them on; just stay with the stock exhaust manifolds.

Thanks to all who replied.

Lanny