headers, where do i put the o2 bund
Thread Starter
Racer
Joined: Jan 2007
Posts: 252
Likes: 5
From: bethlehem PA
headers, where do i put the o2 bund
Hi i'm putting headers on my 85 vet.
I was going to put the o2 sensor at the collector,
is that too far down the header.
where is a good location for a good read
Also looking for reference on who can burn a custom chip for a 1985 corvette.
many mods. Cam, heads, tpis inj sys.
85 is a stand alone year, lots of chip co won't burn it
Thanks, nick
I was going to put the o2 sensor at the collector,
is that too far down the header.
where is a good location for a good read
Also looking for reference on who can burn a custom chip for a 1985 corvette.
many mods. Cam, heads, tpis inj sys.
85 is a stand alone year, lots of chip co won't burn it
Thanks, nick
Last edited by nickpe; May 3, 2013 at 11:33 PM.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
Ideally, you want the O2 bung at the first available point after the collector so the sensor gets a taste of all the cylinders...not just 1 or 2.
Its not always easy with many headers...limited tubing after the collector...then its the flange and pipe. Too far downstream and the sensor gets cooled exhaust gas and a worthless read. Some folks use the self-heated sensor that comes in late model cars to solve this problem.
Can;t help with the chip. Many folks swear by PCM for less...may give them a call. I'm not a real fan of mail-order tuning...but it beats a blank. From what they say the investment to burn your own (if you read and understand geek) is not horrible...$600 or so. Then you can burn as many as different as you want for pennies each.
Its not always easy with many headers...limited tubing after the collector...then its the flange and pipe. Too far downstream and the sensor gets cooled exhaust gas and a worthless read. Some folks use the self-heated sensor that comes in late model cars to solve this problem.
Can;t help with the chip. Many folks swear by PCM for less...may give them a call. I'm not a real fan of mail-order tuning...but it beats a blank. From what they say the investment to burn your own (if you read and understand geek) is not horrible...$600 or so. Then you can burn as many as different as you want for pennies each.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
For a street car, putting the O2 sensor down at the reducer works OK. For my '87 I picked up an O2 bung (18mm thread dia), cut a 1" hole in the reducer and welded the bung in place.
Another thing that some people will do is to use a heated O2 sensor. They are easy to wire up; one wire for ground, one wire for the sensor wire and another for a 12v power source when the ignition is ON.
Another thing that some people will do is to use a heated O2 sensor. They are easy to wire up; one wire for ground, one wire for the sensor wire and another for a 12v power source when the ignition is ON.
Racer
Joined: Sep 2010
Posts: 327
Likes: 2
From: se iowa
If you're doing longtubes and are putting the sensor by the collector I would recommend going the heated o2 sensor route. I did not at first on my '87 and it wouldn't stay closed loop while driving, it would swap back and forth a lot.
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Definitely locate the O2 in the collector. A heated sensor won't be needed. I have mine located there with no open/closed loop issues.
PCM4Less won't burn an 85 chip. I had Ed Wright from Fast Chip do my initial burn. Then I invested in the hardware and software to make my own changes. It gets to be a real pain sending the chip back for a change. No matter who does it, you will need to be able to data log to fine tune. I started with WinALDL but I found that Tuner Pro RT was better suited.
PCM4Less won't burn an 85 chip. I had Ed Wright from Fast Chip do my initial burn. Then I invested in the hardware and software to make my own changes. It gets to be a real pain sending the chip back for a change. No matter who does it, you will need to be able to data log to fine tune. I started with WinALDL but I found that Tuner Pro RT was better suited.
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
TunerCat has a bare-bones kit for the 85 for $200. But caution, the chip adapter needs to be soldered to the ECM board. Unless you are skilled at this I recommend you send the ECM to Moates and have them do it. I learned that lesson the hard way. Their soldering service is cheap. Also, I added a socket booster ($40), chip extender ($20), extension cable ($9) with Zif socket ($10) from Moates. That allows the chip to be quickly swapped without removing the ECM.
A better option is to swap the ECM for an 86. Programming capabilities are significantly improved and you'll have no problem finding a tuner to work on it. I've done the above and am now planning the ECM swap.
Race Director
Joined: Sep 2003
Posts: 16,837
Likes: 338
From: Database Error Indiana
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
I didn't realize outside air temperature had that much effect. It makes me wonder why there are Closed Loop Delay Timers in the .bin file. Since the O2 has to be hot to operate, I would think the delay is pointless. But then again, there are a lot of things in the bin file I don't understand.
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