4.3 exhaust modifications. . . .

[CDHenry6]

Ok so, here goes.

The truck is a 1992 4.3 V6 with a 5 speed manual. The exhaust that came with it when I bought it is as follows :

Stock manifolds
Stock Y pipe
Stock ancient catalytic converter ( semi plugged up, can tell after an hour of highway driving )

From the cat, it branches to another Y with glasspacks ( brand unknown , but look like 24' long, )
Pipe
12" long 3" outside diameter tips.

I am seriously considering a cat delete, with a straight pipe welded in its place. A shadetree mechanic friend of mine told me to just ram a pipe through the cat, but I know that an expansion chamber is NOT good for a V6, s I'm hesitant to go that route. Also, I'm pretty sure that I'll never get those bolts off and that cat will have to come off with a Sawzall, so I might as well do the pipe, anyhow.

My question is this : I'm pretty sure that the downpipe is a 3' pipe, do I want to make the cat delete pipe 3', or should I reduce it because of the 262 V6's sensitivity to backpressure ? I know that they're more tempermental than a 350 V8 that way. . . .

What are the board's thoughts on this ?

Also, replacement cat is NOT an option; I am aware of the legal and environmental ramifications of a cat delete, etc.

 

[CDHenry6]

No one has any thoughts on this ? Nobody ?

My Google-fu must be weak, because I have been fervently researching this to no avail. I'm just trying to figure out if I need a reducer or not. I also may be mistaken on the pipe diameters .

 

[bluex]

Just replace the cat with a section of pipe the same diameter as what's there. It will be perfectly fine....

 

[19trax95]

I agree that welding a pipe in the cats place is the best. But pounding a pipe through is the same thing having a pipe in its place. It won't make a expansion chamber.

 

[volunteerff21]

Mines just a welded in piece of 3" pipe. No issues.

 

[CDHenry6]

Thanks for the replies, folks. MANY many years ago in my teens I had a Buick with a V6 and dinked around with the exhaust, and I wound up making it gutless as all hell. I was trying to NOT replicate that event.

So just to clarify, the pipe I am replacing the cat with should be the same diameter as the existing factory Y-pipe, correct ?

 

[19trax95]

As long as whatever you change the diameter to it stats the same the rest of the way you should be fine.

 

[CDHenry6]

Well , three hours on my back laying on cardboard above the snow with a (very dull) hacksaw and I made the first cut at the Y pipe. It looks like it's 2.5" diameter so I ran to Fleet Farm for a pipe and clamp until I get it welded. I took the clamps of after the cat to discover that . . . . . apparently they welded AND clamped the joint there . I guess, there's nothing wrong with being thorough, unless you're the guy un-doing all of the work.