Writeup: Installing 5.7 TBI headers on 5.7 Vortec

[flyboy1294]

I swear without going out right now and looking that the first set of sensors are WAY down the line, like where the exhaust turns back and runs parallel with the truck, right before the cats. Isn't that where they were stock?

You were probably thinking of the post cat sensors.

 

[TruckinAin4Sissies]

You were probably thinking of the post cat sensors.

Just to be clear:
Pre-Catalytic converter o2's

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Post-Catalytic converter o2's

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[flyboy1294]

Well, I have about 650-700 miles on this setup now. No real problems.

The only think I would tell someone doing this is DO NOT mount your O2 sensor on the driver's in the TBI location... go ahead and plug that hole and mount it on the collectors. Your PCM is much happier that way.

Also, as expected, the paint burns off these things pretty badly. Mine are already not looking as hott as they did originally, and I never go off road or dirt. I plan to have them ceramic coated this summer when I do my cam install.

But yeah, best mod for your buck you can do to these trucks, imo. Still recommend it!

 

[big_mike]

^^Yea, in the collector for a OBDII truck is the best placement, thats where the primaries merge all the exhaust gas from that bank. Thats where you wanna get your reading from & most front O2 sensors have heating elements as well, being placed in the collector is a perfect spot to get them heated quickly & properly.

 

[Talisman]

Quick question... for my 97 I would have to keep all my emissions crap right? Or can it be tuned out on this year too? Someone told me the 96 and 97's couldn't take a tune such as efi live.

 

[big_mike]

Nope, you need to do the 411 PCM swap which puts a LS style PCM in the truck, then you can use HPtuner or EFilive.

 

[Talisman]

Thats what I had assumed, just clarifying thanks!

 

[flyboy1294]

Nope, you need to do the 411 PCM swap which puts a LS style PCM in the truck, then you can use HPtuner or EFilive.

My truck does not have the 411 PCM. I do not know if EFI live works on this PCM or not, but I can tell you that his 97 can have all the emissions stuff tuned out the same as my 98 can, because they are identical platforms.

Black Bear Performance tuned out my AIr injection, EGR, and rear O2 sensors along with giving me the performance 89 octane tune. My local exhaust shop which happens to have a snap on scan tool told me he could also tune out the EGR, AIR, and rear 02s by setting the values equal to '0'. He said he would charge $35.

Maybe I'm misunderstanding something about your posts. But to my knowledge, 96,97,and 98 are all the same electronics platform.

 

[flyboy1294]

^^Yea, in the collector for a OBDII truck is the best placement, thats where the primaries merge all the exhaust gas from that bank. Thats where you wanna get your reading from & most front O2 sensors have heating elements as well, being placed in the collector is a perfect spot to get them heated quickly & properly.

I kept getting faulty codes from the O2 sensor when it was in the stock TBI location. When I changed it to the collector, those codes all went away. I'd have to agree with you, the collector is really the best place to put the sensor.

 

[bjones]

I found this thread in perfect time! I'll move the O2 bung on my Hookers to the collectors on both sides before I install them. Thanks for your help OP and everyone else! I'm looking forward to doing my exhaust next week