An exercise in overthinking - Junits15's street build

[Duece McCracken]

The noise would send me over the edge lol

Quite a sensitive young lad.

Quiet mode starts keep the neighbors from getting the torches/pitchforks out.

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[junits15]

All I’ve seen were supercharged.

Makes me think even more that this is a defect

 

[junits15]

Quite a sensitive young lad.

Quiet mode starts keep the neighbors from getting the torches/pitchforks out.

My ears cannot handle the raw coyote roar from catless longtubes, an x-pipe, and wide open active exhaust.

 

[engineermike]

@junits15 if you wanted to play with it, you can log lambda for both banks and rear o2 voltage for both banks. Usually within the first few miles when you hit steady state driving it will perform a cat test. It alternates lambda rich/lean for both banks in inverse and looks for rear o2 switching. If it toggles high low quickly then that’s why it’s showing bad. If it toggles once or maybe twice then the cats are good. At least you can see what the pcm is seeing and confirm.

 

[Duece McCracken]

My ears cannot handle the raw coyote roar from catless longtubes, an x-pipe, and wide open active exhaust.

Sucks you didnt smoke them sooner, sold my oem headers a few months back.

 

[junits15]

@junits15 if you wanted to play with it, you can log lambda for both banks and rear o2 voltage for both banks. Usually within the first few miles when you hit steady state driving it will perform a cat test. It alternates lambda rich/lean for both banks in inverse and looks for rear o2 switching. If it toggles high low quickly then that’s why it’s showing bad. If it toggles once or maybe twice then the cats are good. At least you can see what the pcm is seeing and confirm.

Blue - B1 Lambda
Red - B1 downstream
Orange - B2 Lambda
Green - B2 downstream


I can see that B2 downstream starts oscillating pretty much instantly, while B1 takes a while to start showing any signs. If it were a failed sensor there would be no correlation to lambda. The rest of this log is filled with similar dropouts while driving.

Dropouts:

red line is stable, green line drops out randomly, makes me think it could be a crack, sometimes its good sometimes it isn't.

See here:

This is when i let off the throttle the red line (good cat) takes longer to react than the green one. Indicating that it still has storage capacity.

Its cooked.

 

[engineermike]

Actually I think both are cooked, sad to say.

 

[junits15]

Actually I think both are cooked, sad to say.

ahhhh fuck, I was worried that would be the case, is it supposed to make it all the way through the test?
Must be from the meth injection, that's all I can think :(

I guess the question is answered, at least partially. No meth injection on stock cats

 

[Duece McCracken]

ahhhh fuck, I was worried that would be the case, is it supposed to make it all the way through the test?
Must be from the meth injection, that's all I can think :(

I guess the question is answered, at least partially. No meth injection on stock cats

Would be a shame if all the honeycomb happened to fall out...

Real shame.

 

[engineermike]

Here's an example of one bad and one good cat during a test. Guess which is which:

 

[engineermike]

Two new cats:

 

[engineermike]

BTW I don't think the Methanol killed them. Meth and Eth are very similar in properties and there are lots of catted E85 and Flex setups out there that work fine. In fact, the EGT is 100-200 deg cooler with alcohol so it's actually easier on the cats than gasoline.

 

[junits15]

Two new cats:

Oh yeah mines really Eff'd lol you're right the passenger side is also really weak. Damn thats awful I feel like such a dumbass.

BTW I don't think the Methanol killed them. Meth and Eth are very similar in properties and there are lots of catted E85 and Flex setups out there that work fine. In fact, the EGT is 100-200 deg cooler with alcohol so it's actually easier on the cats than gasoline.

That's a really good point. It was probably the misfires then, that's the only logical explanation i can come up with. I thought aborting the pull when I felt the misses was enough, but maybe it was just too many too often. I'll setup Justin's Shade Tree Failure Analysis Lab when I get them out and cut the old cats open to see what happened.

An expensive lesson, but Deuce knows, not my most expensive lesson to date! That was ebay transmission parts lol

 

[junits15]

Ordered these: Kooks Headers

1 7/8" tubing, GESi G-Sport "Greencats", stock exhaust connection pipes.

Should be in in a week, just need to get them installed at that point, the more research I do the worst this job looks. Passenger side is the problem child from what I read online. I'll likely remove the X-pipe and go back to the stock resonator to quiet it back down. I expect headers and an x-pipe will be too loud.

It can be done on jacks, but it doesn't sound easy. A guy online had a video about the install, he says he's done a lot of headers and it takes him 6h start to finish. I expect this will take me 2 days.

 

[mejohn50]

Ordered these: Kooks Headers

1 7/8" tubing, GESi G-Sport "Greencats", stock exhaust connection pipes.

Should be in in a week, just need to get them installed at that point, the more research I do the worst this job looks. Passenger side is the problem child from what I read online. I'll likely remove the X-pipe and go back to the stock resonator to quiet it back down. I expect headers and an x-pipe will be too loud.

It can be done on jacks, but it doesn't sound easy. A guy online had a video about the install, he says he's done a lot of headers and it takes him 6h start to finish. I expect this will take me 2 days.

I did my TSP headers on jack stands. Took me about 12 hours spread over three days. Could do it in half the time now.

Day 1 was driver side start to finish and remove passenger side. Day 2 was test fit passenger side (multiple times) to see exactly how many studs and bolts I needed to use. Day 3 was passenger side install and finishing up.

I got all brand new studs and nuts for both sides. Ended up using three bolts on the top of the passenger side. When I disassembled the passenger side I loosened the nuts then just unscrewed the stud with the nut still on it. Made it pretty easy to disassemble.

Reassembling passenger side I put as many studs in as I could while still being able to put the header in place and then hung the header loosely with nuts. Then I installed the rest of the studs I was able to use along with the three bolts and cinched it all down.

Not a fun job, but you’ll probably get it done in two days.

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