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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

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Old 10-18-2010, 07:45 AM   #1
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Default 2 exhaust issues

First, where do you guys get you o2 sensore. i was just quoted 210 from mazda and there are only 6 left in the usa? Will the bosch from autozone work well? Will it hold up to the egt?

Second, is there some kind of trick to keeping the flanges tight. I now from the header flang to the tailpipe have fresh grade 8 hardware, new stainless exhaust piexes and coper gaskets. I am forced to tighten everything every 2 days cause it keeps loosenong and its getting annoying.

Please excuse my typos, my android phone isnt as rasy to type on as my old tp2.






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Old 10-18-2010, 09:00 AM   #2
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The Bosch will work just fine. Try using some lock nuts & see if that helps on the exhaust.
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Old 10-21-2010, 09:43 PM   #3
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The stock ECU runs pretty fat, I doubt that the EGT will hurt any sensor. I think all narrow band O2 sensors are the same anyway (with the exception of heating techniques).

The 'secret' to the exhaust flange tightening is to beat the car around for a while, pull it into the garage and immediately tighten the extremely hot bolts to a very snug level.

You should check your engine mounts, a bad engine mount will cause exhaust pipe loosening.

I doubt that your stock engine torques hard enough into good mounts to do much flexing of the exhaust.
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Old 10-21-2010, 10:16 PM   #4
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I think my trans mounts and engine mounts are pretty warn. What I have been doing is every few nights, really run the car the last 2 minutes of my commute and then toss it on the ramps and tighten the hell out of the extremely hot hardware. I do think you may be on to something with the motor/trans mounts, mine seem loose. I guess thats the next upgrade.
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Old 10-22-2010, 08:02 PM   #5
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Old 11-03-2010, 10:02 PM   #6
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Copper rtv on the nuts and bolts along with locking washers. That should pretty much eliminate any type of loosening your experienceing.

Zack.
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Old 11-03-2010, 10:30 PM   #7
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Quote:
Originally Posted by rxspeed7 View Post
Copper rtv on the nuts and bolts along with locking washers. That should pretty much eliminate any type of loosening your experienceing.
That's a real stupid thing to do.
Copper RTV is only good for like 700F intermittent - see package.
It turns to dust on a rotary exhaust, unless you're talking about fasteners back in the rear muffler.

Also, no locking washer on the market can handle high heat.
Locking exhaust nuts are the only solution.


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Old 11-04-2010, 01:14 AM   #8
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Nothing wrong with the Bosch O2 sensors.
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Old 11-04-2010, 07:23 AM   #9
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That's what I thought he meant. I know on the header it'd be useless but on anybof the flanges after the header I don't quite think they get that hot. Shoot I know of someone that's been building aviation and road race rotaries since before I was born that uses mearly tub and tile silicone for header gaskets and doesn't have a single issue with it. The heat may be there but on a n/a it's such a low pressure area that a leak isn't that likely. Iirc and exhaust leak will actually pull in outside area through the scavenging effect.
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Old 11-15-2010, 02:20 PM   #10
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The bosch sensors work fine. I know that was already stated but just incase you still doubted it there you go.

You can get them with the stock connector on them at Autozone for just a few more dollars then one without one. Buy the one with the connector. I am currently trying to get ahold of the factory sensor connectors at this time and they will be available seperately as soon as I get them. All will be converted to S5 spec connectors as they are really just a better piece anyways.
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