GMC Truck Forum banner

1 - 20 of 22 Posts

·
I'm back!
Joined
·
794 Posts
Discussion Starter #1
I am thinking about swapping my 350 TBI out, what would be a good 6 cylinder to put in? Someone was telling me to put a straight 6 in because they develop more torque. Someone please help me.
 

·
GMFS slowest truck :read:
Joined
·
5,501 Posts
Why are u wantin to put a 6 in instead of the v8??? gas mileage won't be that much better...the engine has to work harder to move these heavy trucks, and sucks up more gas. But yeah, an I6 should put out a good bit of torque...
 

·
Registered
Joined
·
1,816 Posts
I duno, but a 6 wont help a whole lot. First of all, putting an I6 would probably take as much work and wiring as doing an LS1 swap, with few of the rewards. Why are you getting 11-12 mpg? Hell, my trucki s a 4x4 with all kidns of crap on it and it gets your gas mileage. I think somethings broken. Or you could get a new F150 and get 14 :rolleyes:
 

·
I'm back!
Joined
·
794 Posts
Discussion Starter #11
The exhaust comes from both sides of the manifolds to a glasspack on each side to the back and thats it. It roars pretty good, but id rather have better mpg than loud exhaust.
 

·
Registered
Joined
·
1,816 Posts
yeah you need an o2. your TBI computer is saying something to the effect of...


WTF??!?!?!?!



It depends on the o2 sensor to adjust a whole bunch of stuff.
 

·
GMFS slowest truck :read:
Joined
·
5,501 Posts
lol...yeah, O2s will make the SES light come on...they are kinda important. I think the only one you can get away with is the one after the cat. It won't effect performance...but will still throw a code...
 

·
I'm back!
Joined
·
794 Posts
Discussion Starter #15
The guy who owned my truck before me was a dumbass. He did all kinds of shit that had to be fixed, the exhaust will be on my list once I figure out how much it costs to get a new setup.
 

·
Registered
Joined
·
1,895 Posts
TBI motors only have 1 O2 sensor, and it's before the cat. The O2 is a primary sensor on TBI motors, and without it the ECM will throw a fit. You can have a shop weld in a bung for the sensor for about $20. The body lift would lower your mileage a little, but not that much. I can get 13mpg in the city, if I keep my foot out of it. What size are your pipes? If you have a muffler or cat, then you have plenty of back pressure, even with 2.5" pipes.
 

·
I'm back!
Joined
·
794 Posts
Discussion Starter #19
91_bowtie said:
TBI motors only have 1 O2 sensor, and it's before the cat. The O2 is a primary sensor on TBI motors, and without it the ECM will throw a fit. You can have a shop weld in a bung for the sensor for about $20. The body lift would lower your mileage a little, but not that much. I can get 13mpg in the city, if I keep my foot out of it. What size are your pipes? If you have a muffler or cat, then you have plenty of back pressure, even with 2.5" pipes.
Right now I got no cats one pipe comes from the right side down, and another from the left side down and they run parallel to each other and there is a glasspack on each side and it goes on to the back before it corners out. So what do I need to have a shop add? 1 Cat or 2 Cats and how would the O2 sensor go on if there is 2 seperate pipes?
 

·
Registered
Joined
·
1,895 Posts
Stu Meat said:
Right now I got no cats one pipe comes from the right side down, and another from the left side down and they run parallel to each other and there is a glasspack on each side and it goes on to the back before it corners out. So what do I need to have a shop add? 1 Cat or 2 Cats and how would the O2 sensor go on if there is 2 seperate pipes?

Unless you're running a fuel cell, the pipe on the driver's side crosses over to the passenger side to avoid hitting the fuel tank. You only need a single O2 sensor. Take it to a shop and have them cut your pipe, and weld in an O2 bung about 12" away from the collector, on the driver's side (if you're still running the stock manifolds or shortie headers). It should be easy to access from the wheel well, and get hot enough to give an accurate reading. You can pick one up for about $5. Look around your tranny on the driver's side for a single wire with a connector at the end. Hook up the lead from the O2 to that connector. Disconnect the positive side of the battery for a second to reset the ECM, and you're all set.

What size are your pipes? I wouldn't worry about rerunning the exhaust, but if you want the best mileage, run a single 3" pipe all the way out.
 
1 - 20 of 22 Posts
Top