1990 Blazer, putting on headers as the stock manifolds are broken, do I still need to make provisions for the o2 sensors or can I run without them? I know modern computers auto adjust fuel but I don’t think that obd1 does that
CK5
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Exhaust help
- Thread starter Corypheaus
- Start date
I’m assuming still stock TBI? Yes you need the 02….
All of the new systems still use O2 sensors
Some of the aftermarket systems will allow you to shut off the learn and you can run without. But they make no adjustments
Typically used at the racetrack, where you can pull the sensor and run leaded fuel
But if it’s off the tune, it doesn’t change. Definitely not something to do on the street
Still need 02 sensors, weld in a bung near the collector. You may need to swap to a heated sensor to work best.
Consider new manifolds. They are cheap, they seal well and have the O2 bung already in them. Cheap headers never seal well and long tube headers don't fit well most of the time. I used to do collector gaskets every year on my last square with headers and gaskets at the head needed changed often as well.. Expensive headers seal better, but on a stock 350 TBI they won't make any more power than the cast manifolds. Exhaust leaks on a fuel injected truck are a nightmare, the O2 sensor needs a proper seal all the time or it wont run right and throw codes. I have 4 squares with cast manifolds right now and have no complaints.
headers = more under hood heat and noise and most dont fit right on our 4wd unless you do your homework .
daily driver no mods just go stock manifolds
and our tbi fuel system uses a 1 wire o2 sensor . if you move the sensor down to collector best is to do a 3 wire swap . been talked a bout on hear over the years with good write up info . same goes for good fitting headers with part#s if you still wish to go this route .
daily driver no mods just go stock manifolds
and our tbi fuel system uses a 1 wire o2 sensor . if you move the sensor down to collector best is to do a 3 wire swap . been talked a bout on hear over the years with good write up info . same goes for good fitting headers with part#s if you still wish to go this route .
It's not really true, though. Not all manifolds are equal and not all headers are equal, but moving from log-style old manifolds to real headers pretty much always makes more horsepower. How much is questionable, but certainly something that could be measured. Whether or not it's worth it is a totally valid discussion.
yes but tbi engines flow like crap anyway after around 4k rpm . you have a tbi unit thats like 400-425 cfm . and the heads suck up top . there a low to mid rpm motor .
Measurable, probably. 5hp? Not even sure. I have never had a 350 where there was a noticeable difference putting headers on. With all the gasket troubles I quit looking for power there and went for reliability. I am a vote for not really worth it on TBI.
I didn't read the whole thing. But appears headers and tuning: 34HP, I believe this is an LO5. https://www.gearhead-efi.com/Fuel-I...350-with-Headers&p=52217&viewfull=1#post52217
