Can someone please explain this to me? I hear a lot of good stuff about it. Basically the restrictive stock y-pipe is removed completely so the exhaust can flow more freely? From what I understand, the headers are brought into a collector and then out to the cat, preferably a high-flow cat? Should any exhaust shop be able to do this and will I still pass inspection in terms of emissions?
350 TBI y-pipe mod
- Thread starter derekjl
- Start date
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SunlitComet
OBS Jedi-Do Good
just buy this. http://www.lmctruck.com/icatalog/CSD/full.aspx?page=102
Wow, never knew that existed! Thanks very much. Another thought, couldn't I just replace the section after the headers and save a bunch of money? I know Flowmaster makes a y-pipe WITH a cat for about $200 shipped on Amazon, but I'm assuming it is the same as stock?
SunlitComet
OBS Jedi-Do Good
link please to study.
SunlitComet
OBS Jedi-Do Good
there is a few performance mods for the tbi that include heads, cam, manifold and tb work. it is like a power package.
Toomanyhobbies
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I would never spend $600 for those headers. I got $79 stainless steel ebay headers for a tbi and then had an exhaust made around them and spent the money there. There are so many cheap headers for a 350 it's crazy. And mine are great nice purple color no corrosion so far and no leaks.
You can buy a cat back single stainless out of a catalog for about $500 and you can get an exhaust shop to build you pipes from the headers with hi flow cats to a 2 in 1 out muffler probably for 400. So $1000 in stainless and will pass emissions in most states. If you go duals it will be probably $300 more but that's a guess, and there are dual kits for the pickups and 4 doors I was doing a 2 door tahoe so no kit for duals all custom.
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You can buy a cat back single stainless out of a catalog for about $500 and you can get an exhaust shop to build you pipes from the headers with hi flow cats to a 2 in 1 out muffler probably for 400. So $1000 in stainless and will pass emissions in most states. If you go duals it will be probably $300 more but that's a guess, and there are dual kits for the pickups and 4 doors I was doing a 2 door tahoe so no kit for duals all custom.
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Derek, yes the biggest issues with the TBI was the restrictive exhaust and back pressure. You can absolutely replace the y-pipe and fix that. Something like this will work: https://www.amazon.com/Flowmaster-Y250300-Scavenger-Collector-Primary/dp/B001NRXA2O
If you haven're placed the cat already, Flowmaster also has a kit I believe that includes a new y pipe and cat.
If you do go this route you will need to take into consideration that eliminating back pressure will create some issues with the EGR and the single unheated O2 sensor the TBI's run. Upgrade the O2 sensor into a heated 3-wire one and make sure your EGR valve is working correctly and you will be fine.
If you haven're placed the cat already, Flowmaster also has a kit I believe that includes a new y pipe and cat.
If you do go this route you will need to take into consideration that eliminating back pressure will create some issues with the EGR and the single unheated O2 sensor the TBI's run. Upgrade the O2 sensor into a heated 3-wire one and make sure your EGR valve is working correctly and you will be fine.
