1988 GMC TBI dual exhaust

[01mudslinger]

i have a 350 TBI and want to put headers and dual exhaust but am alittle confused as to how to go about the o2 sensors, my plan is to do away with the cats and go headers and 40 series flowmasters with 2 1/2 inch pipes. would dummy o2 sensors do the trick to make everything work right?

 

[sweetk30]

from what i have been told you can run a heated o2 on the collector. and then it will work over the longer distance.

but my self i hate the heat and noise of tin tube headers.

i my self would run a set of manifolds in to a good ypipe with 2.5-3" collector and then 1 single inlet and 2 outlet 40 flowmaster.

i have had both single like listed and 2 muffler style exausts and i like the sound better with the single. i think it has more bite.

now if it was a built to the hill motor then 2 mufflers on dual sytem for sure. but stock tbi motor is just fine with single. i have seen ypipes in 2.5 and 3 inch outlets. so check yours.

and if you go duals make sure thay stay away from your tbi fuel filter on pass rail by tcase.

 

[DukeBoy88]

I had a heated O2 sensor at my emission heddar collector and It worked ok. 2 1/2 true duals with no cat as well. I liked it, and I believe there was a small gain of power, however my cat could of been clogged too. Don't know yet what I'll be putting back on the truck but it will be simular. I believe the dummy O2 sensors you are refering to are intended for vehicles that run sensors after the cat, not your primary sensor.

 

[Thunder]

Dummy 02 sensor will not work. You must run a working 02 sensor with TBI. Engine wont run right without one. It is the main sensor that the computer uses to maintain the proper fuel ratio. With no 02 the computer goes into closed loop limp home mode.
You will either need to buy headers that already have a threaded hole for the 02 sensor. Or drill a hole in the collector and weld in a threaded bung for the 02.
IMO single 3" exhaust is best for TBI

 

[cabledawg]

I installed dual 2.25" in both of my Burbs. Wifes has turbo mufflers, mine has glasspacks. Hers got replaced cuz the cat was plugged and I was too cheap to get a quality single setup. I actually lost hp in mine but gained a little low end torque. It takes longer to get up to speed, but I can pull 6k lbs like it was nothing. Never had anything bigger than my wifes Burb on the back; I'm sure it could haul more. If you want hp gains, go with a large diameter single. There are hi-flow cats on the market, so you'd stay legal without sacrificing flow. As for headers, Gibson makes some that are supposed to be direct replacements for manifolds. Should bolt right up to the stock crossover. Prices vary by retailer, anywhere from $250 to $350 for the pair.

 

[01mudslinger]

another "true dualer" thinking he's gonna get an adittional 100 HP by adding another exhaust pipe??

simple, less weight and material to go bad or get damaged,,,just run a slightly larger single, into the high flow cat, single into a duak in muffler, then run 2.5" duals out back.

get the same exterior look and probably a better controlled sound as well.

Well first off, im not planning on replacing the whole exhaust again when i do get around to building a motor for this thing so i figure why not do it right the first time and have it ready for when the new motor gets put in. And by the way everybody knows that you get a 100HP from adding a cold air intake not adding another exhaust line...

 

[Leper]

Well first off, im not planning on replacing the whole exhaust again when i do get around to building a motor for this thing so i figure why not do it right the first time and have it ready for when the new motor gets put in. And by the way everybody knows that you get a 100HP from adding a cold air intake not adding another exhaust line...

Werd!