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Discussion Starter #1
so I've had my car for a long time now close to 12 years put almost 100k miles on it and recently my air fuels have changed at idle. Normally they would fluctuate around 14.7 like normal now they are up in the 15.s but when cruising its around 14.7 like it should. Is there anything I should look for or replace that would cause this??
 

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how old is the sensor on your wideband? it could be time for a new one (they do have a lifespan).
it could also possibly be an exhaust leak.
 

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Discussion Starter #3
Its pretty old now honestly probably 6 or 7 years maybe older. I was thinking exhaust leak i tbought I heard a slight leak at the down pipe ill have to pull it apart and check it out
 

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My a/f at idle is almost 16 but I have custom wiseco pistons, 9 compression
 

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Discussion Starter #5
Mines been 14.7 for probably 9 to 10 years only recently changed to 15.7 at idle but normal driving its 14.7 leads me to believe I have an exhaust leak at the o2 housing im gonna pull my downpipe and reseal it. And replace the flex in my pipe as well and hope that fixes it. I may throw a 3 inch o2 housing in there while I have it pulled apart.
 

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You may be right on where the exhaust leak is causing the leaned out a/f. More air is Getting to the sensor And gives you a false reading. Though the A/f is high I bet you could drive around like that forever and not have any issue. all though something IS wrong and can be fixed, to get your a/f to normal again.
My aem uego o2 sensor is still going strong 15 years old.
 

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Discussion Starter #7
Thats good to know bout the sensor mines not quite that old yet my whole downpipe is custom made so its not like I can go buy a new one and bolt it right up to my current exhaust lol. I think my flex may the culprit so worse case i order a 3 inch flex and weld a new one in.
 

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Modern performance has a nice 3” o2 housing. I don’t know of anywhere else that even sells one. It’s a pain to change out to. Without taking the turbo off.
 

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My a/f at idle is almost 16 but I have custom wiseco pistons, 9 compression
The compression ratio should have no effect on the idle a/f ratio. The car should still be tuned to be as close as possibly to 14.7.
By your logic, my car (with 7.2:1 wiseco pistons) should have what... like a 12.0 a/f at idle? haha

Mines been 14.7 for probably 9 to 10 years only recently changed to 15.7 at idle but normal driving its 14.7 leads me to believe I have an exhaust leak at the o2 housing im gonna pull my downpipe and reseal it. And replace the flex in my pipe as well and hope that fixes it. I may throw a 3 inch o2 housing in there while I have it pulled apart.
I think you're on the right track.

You may be right on where the exhaust leak is causing the leaned out a/f. More air is Getting to the sensor And gives you a false reading. Though the A/f is high I bet you could drive around like that forever and not have any issue. all though something IS wrong and can be fixed, to get your a/f to normal again.
My aem uego o2 sensor is still going strong 15 years old.
As i mentioned, the sensors are a wear part and do have a lifespan.

Info found online.
In addition to the effects of atmospheric pressure variations, O2 sensors wear out over time and become less accurate. According to Bosch’s published test data, its wideband O2 sensors are accurate to .15 of a point when new, but that margin for error increases to .29 after 500 hours of use, and increases even more to .59 after 2,000 hours. In other words, after 2,000 hours of operation, when an O2 sensor reports an 11.76:1 air/fuel ratio, the actual air/fuel ratio in the engine can be as lean as 12.35:1 or as rich as 11.17:1.


Thats good to know bout the sensor mines not quite that old yet my whole downpipe is custom made so its not like I can go buy a new one and bolt it right up to my current exhaust lol. I think my flex may the culprit so worse case i order a 3 inch flex and weld a new one in.
see my quote above.
 

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The compression ratio should have no effect on the idle a/f ratio. The car should still be tuned to be as close as possibly to 14.7.
By your logic, my car (with 7.2:1 wiseco pistons) should have what... like a 12.0 a/f at idle? haha
well after I rebuilt my engine the a/f are 16 at idle so assumed it is because the engine is a Brick shit house. Something the machine shop did to cause it. To tell you the truth I’m little concerned with it car runs just fine with a lil high idle. Something very well maybe wrong With the engine and could be “fixed” To make the idle 15 again. That info about o2 sensors is very interesting
 

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Discussion Starter #11
I retuned my car recently it did get better im gonna order a 3 inch flex joint and weld it in my down pipe. And I have no problem removing the turbo to install a 3 inch o2 id love to go big turbo but honestly im concerned my motor will probably detonate lol. 11 years and 100k miles of constant abuse idk if it will handle a big turbo. But local junk yard has turbo pt cruisers complete motors for 260 bucks so im gonna grab 2 lol
 

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What r your mods You have now? I put on a big turbo on at 90000 miles and the stock motor held up just fine. if your concerned with motor durability just run real rich always and you’ll never explode anything. if you just dump in fuel it should be safe
 

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Discussion Starter #13
I'm at 130k miles I put 100k on it myself. Full 3 inch exhaust stage 2 injectors wally 255 exhaust depot super beast intercooler ultimate racing hard pipes and hks ported intake and intake spacers aem short ram intake tuned by myself on 18psi billet wheel in the stock rebuilt turbo. Only reason id be worried is because i beat the ever living shit out of it lol i only recently starting taking care of it since I'm 30 now i calmed down a bit but she has had a hard life.
 

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If you do go big turbo just make sure you Have the fuel because it’s when you run out of fuel is when things start to break. I had to learn that the hard way. 130k miles is not that much imo but others may differ with my opinion and say it is high mileage and you should not risk throwing A rod putting a huge turbo on your car. I personally think it’s worth a try and it will only compliment your mods.
 

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Discussion Starter #15
I really want to go with a precision 6262 but there are so many options im not sure what i wanna do. My friend had a agp 50 trim I think .62 ar not 100% sure but my car from a dig would always beat it but his jist had so much more top end.
 

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I personally would install the turbo you want. Yah big turbos spool much later than the stock turbo and that is something you have to get used to when you switch over to a big turbo. I love my turbo though and I would only replace it with a little bit bigger turbo if at all.
 

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Discussion Starter #17
My goals for the car since its not really my daily driver anymore is to make around 500whp i could live with 450 but would love to hit the 500 mark ill probably build the motor myself tho in my garage. Ive built a 500hp small block for my 70 impala on the street in front of my house lol. But id like be around that number I know I probably wont find a quick spooling big turbo that would feel like a stocker as far as boost goes.
 

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Nice that the car is not your daily anymore I still drive mine daily. Even though I’ve only driven like 5 times in the past couple of months. This lock downs got me bored with nothing to do. I say get the 6262 like you want that’s a big turbo and would require you to upgrade your injectors to problay like1000cc would be needed for that turbo.
 
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