3.4l 5vz-fe headers - Page 2 - Toyota 4Runner Forum

Bad Luck · 09-16-2022, 03:20 PM

Quote:

Originally Posted by GunslingerT4R

I’ll be installing mini cats most likely.

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What are you going to do about the upstream oxygen sensor since it will no longer be reading both exhaust banks?

RandyBobandy · 09-16-2022, 06:26 PM

Quote:

Originally Posted by Bad Luck

What are you going to do about the upstream oxygen sensor since it will no longer be reading both exhaust banks?

This is the part I’m interested in, I’d imagine you would need some sort of X pipe to put the sensor in since I don’t think you could make two sensors work

diverscale · 09-16-2022, 09:00 PM

as far as I know, he will be ok by reading only 1 bank of the two no problem. You read 3 cylinders and assume the other 3 are at the same ratio. Some people have been running like this forever.

GunslingerT4R · 09-17-2022, 09:12 AM

Quote:

Originally Posted by RandyBobandy

This is the part I’m interested in, I’d imagine you would need some sort of X pipe to put the sensor in since I don’t think you could make two sensors work

I’m going to do an H pipe to allow for more even flow of exhaust. Oh and btw they fit like a glove. Haven’t bolted them in yet, just mocked them up.

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Ed_C · 09-17-2022, 04:42 PM

Quote:

Originally Posted by GunslingerT4R

I’m going to do an H pipe to allow for more even flow of exhaust. Oh and btw they fit like a glove.

Cool they fit! Have you test-fitted the included Y-pipe?

I wonder if using an equal-length Y would give it a nice, smoother tone like the newer Tacos with an equal-length Y.

GunslingerT4R · 09-18-2022, 10:32 AM

Quote:

Originally Posted by Ed_C

Cool they fit! Have you test-fitted the included Y-pipe?

I wonder if using an equal-length Y would give it a nice, smoother tone like the newer Tacos with an equal-length Y.

No I’m not using the Y pipe. Going to cut the ends of the headers and weld V bands on and connect them with a fabricated H pipe and run true dual exhaust. Installing an o2 sensor on the h pipe and a mini cat on one of the exhausts

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Bad Luck · 09-18-2022, 10:27 PM

You’ll need the first oxygen sensor to be upstream of the catalytic converter

Ed_C · 09-19-2022, 06:49 PM

BTW did you rebuild the engine or just "refresh" the heads?

GunslingerT4R · 09-25-2022, 09:43 AM

Quote:

Originally Posted by Bad Luck

You’ll need the first oxygen sensor to be upstream of the catalytic converter

Yep. It will be. Waiting on a side job to get the rest of the parts. Got the header flanges cut off and the first V bands welded on. Stainless steel exhaust pipe is kinda pricey lol

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GunslingerT4R · 09-25-2022, 09:44 AM

Quote:

Originally Posted by Ed_C

BTW did you rebuild the engine or just "refresh" the heads?

I had a head gasket failure, so I hade the heads resurfaced and checked the block for cracks and clearances.

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GunslingerT4R · 10-01-2022, 05:31 PM

Got them installed the other day. Just waiting for some more funds to become available to buy the rest. Does anyone know about valve clearances? I thought you always checked with the lobes facing up but what I’m seeing on videos is different.

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jbtvt · 10-01-2022, 09:30 PM

Correct, up or sideways, as long as the lobe isn't touching the shim. The book has you do it in 2 (if I recall) passes, rather than moving many times to get every lobe straight up, but you can do it either way

Devbot · 10-02-2022, 10:52 AM

Quote:

Originally Posted by GunslingerT4R

Attachment 400139
Attachment 400140
Got them installed the other day. Just waiting for some more funds to become available to buy the rest. Does anyone know about valve clearances? I thought you always checked with the lobes facing up but what I’m seeing on videos is different.

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What I wouldn't give for a lift and tube bender in my shop, or else I'd be right behind you

19963.4lsr5 · 10-02-2022, 10:54 AM

There is a tool set to remove the shims. It takes practice using it…..

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gamefreakgc · 10-02-2022, 07:57 PM

I see some daylight between the pipe and the steering shaft! I think you got it.

Yes lobe pointing up or at least higher than the 9 o'clock or 3 o'clock positions. If it's facing any lower than that the cam lobe starts to taper and you'll get a bad measurement.

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