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Old 09-13-2010, 01:07 PM
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Default open headers?

i had a few questions as to my exhaust setup. I want to run the lightest and least amount of exhaust i can, but keep my 02's safe and reading accurately... or could i just do away with o2's run open loop and plug the bunge? The reason im asking is bc i have been running open loop for some time now plus it would save on money without having to buy new 02's. Im doing a cam swap so i will need a tune afterwards. I have been contemplating speed density tune, but dont have enough info or knowledge on the subject. Any replies, info or knowledge to help me out is much appreciated guys, thanks!
Old 09-13-2010, 01:10 PM
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i was wondering about just running 14" turndowns right off the headers as an option also, if i decided to keep my 02's.
Old 09-13-2010, 01:11 PM
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If you want to run 02's and open headers just add about 12" pipe to the end of the header that way you won't get unmetered air from the 02.

This way even if you do go SD you can use a wideband accurately as well and just plug whatever extra 02 bungs you have.
Old 09-13-2010, 01:16 PM
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At that point at least. have the rear O2's turned off, have a bumg welded for a Wide Band as well. A 12" Turndown would be ideal.
Old 09-13-2010, 01:16 PM
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Originally Posted by StreetSilverado
If you want to run 02's and open headers just add about 12" pipe to the end of the header that way you won't get unmetered air from the 02.

This way even if you do go SD you can use a wideband accurately as well and just plug whatever extra 02 bungs you have.
ok that was what i was wondering if the 14" turndown would be enough pipe. What about not running o2's and just running the turndowns in open loop? I dont understand exactly the benefits and or negatives on this.
Old 09-13-2010, 01:17 PM
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Originally Posted by BlackScreaminMachine
At that point at least. have the rear O2's turned off, have a bumg welded for a Wide Band as well. A 12" Turndown would be ideal.
I had the rear o2's disabled when i had the car tuned last year so thats one problem out of the way.
Old 09-13-2010, 02:13 PM
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Originally Posted by BennyB
ok that was what i was wondering if the 14" turndown would be enough pipe. What about not running o2's and just running the turndowns in open loop? I dont understand exactly the benefits and or negatives on this.
Really depending on what you're using the car for. I'm assuming it's track only? I used to run open headers, but recently went back with a Y pipe and single Magnaflow. I did this to slow the car down just enough to run 7.0 Index though.
Old 09-13-2010, 02:24 PM
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yeah pretty much track only getting her ready for next year
Old 09-13-2010, 02:47 PM
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Originally Posted by BennyB
ok that was what i was wondering if the 14" turndown would be enough pipe. What about not running o2's and just running the turndowns in open loop? I dont understand exactly the benefits and or negatives on this.
Open loop helps the car tune of the car. Really Emissions related. IF you have no requirement Speed Density Tune in Open loops is ideal and easier to do. I am not a Tuning guy but thats my understanding.

The length of tubing helps get the exhaust not to reverb on the body and behind the driver seat. Again IF not street use, then that is ideal.
Old 09-13-2010, 06:33 PM
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what does speed density and open loop have to do with running open headers if you're running open loop throw the o2s away. It doesn't matter if you're running MAF, SD, Alpha-N or whatever.
Old 09-14-2010, 01:32 AM
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Originally Posted by Wicked94Z
what does speed density and open loop have to do with running open headers if you're running open loop throw the o2s away. It doesn't matter if you're running MAF, SD, Alpha-N or whatever.
oh yeah i know that. Im just trying to look at my options here.... and if i ran open headers and bought new 02's without extensions on the collectors the 02's wouldnt read right, but what i think im going to end up doing is just run open loop and plug the bunges on the headers.
Old 09-14-2010, 05:50 AM
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good call I've been OLSD for over a year now, it's great. Finally I'm going back to closed loop with the DFI stuff... but I'll probably just tune it in closed loop with the wideband, then go back to open loop again
Old 09-14-2010, 09:18 AM
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I messed around with different length pipe with a turndown when I ran my car on motor. I had it open loop tuned so all the o2's were off.

I found, that there was no difference running 16, 12 and 8 inches of pipe that was consistant enough, compared to running just the turndown off the end of the header fwiw.

As long as the o2's are off, ditch everything. I ran the turndown, just so the bottom of the car didn't get as dirty... if not for that I wouldn't have even bothered with that to be totally honest.
Old 09-14-2010, 10:19 AM
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Originally Posted by JL ws-6
I messed around with different length pipe with a turndown when I ran my car on motor. I had it open loop tuned so all the o2's were off.

I found, that there was no difference running 16, 12 and 8 inches of pipe that was consistant enough, compared to running just the turndown off the end of the header fwiw.

As long as the o2's are off, ditch everything. I ran the turndown, just so the bottom of the car didn't get as dirty... if not for that I wouldn't have even bothered with that to be totally honest.
Ive been running open headers with no turndowns and i know exactly what your saying. The underside of my car is really dirty now and not only that, but i figured with the extra 14 inches of pipe and the turndown that the cabin noise and vibes might be a little less also.... im hoping anyway
Old 09-14-2010, 12:25 PM
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Honestly noise, unless you're running at a track with a regulation is the last thing I would worry about. Turndowns, will keep teh car alot cleaner, and that's about it. And, honestly are really about all you need. Open loop the car, get rid of the O2 sensor's completely, then you can crank the timing up and run race fuel to control the detonation, pick up some power at the same time.
Old 09-14-2010, 12:32 PM
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Originally Posted by JL ws-6
Honestly noise, unless you're running at a track with a regulation is the last thing I would worry about. Turndowns, will keep teh car alot cleaner, and that's about it. And, honestly are really about all you need. Open loop the car, get rid of the O2 sensor's completely, then you can crank the timing up and run race fuel to control the detonation, pick up some power at the same time.
theres no regulation on noise so that wont be a problem. where can i find some plugs for the 02 bunges?
Old 09-14-2010, 01:21 PM
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Originally Posted by BennyB
theres no regulation on noise so that wont be a problem. where can i find some plugs for the 02 bunges?
Usually exhaust shops will have them laying around. If not I'm sure Pacesetter, Kooks, etc. can sell them.
Old 09-14-2010, 06:46 PM
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ok cool. Thanks for all the help/ replies guys.
Old 09-16-2010, 12:47 AM
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Check autozone or whatever you have in your area for an Oil Drain Plug for a '83 toyota tercel. Dorman Part # 65220. Thats what I use and it works great!
Old 09-16-2010, 06:10 AM
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I've always just gotten an bolt the right thread from the local lowes/home depot bin and cut it short, so it wouldn't protrude into the pipe. Never had a problem capping an O2 bung that way. Or, leave a dead sensor in the hole, and just don't hook it up to anything.


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