If you can figure out my pictures... Here is the OEM N10 collector Y. 4 pictures of the inside of the pipe. You can clearly see how the outer (passenger side) pipe goes into the collector too far. I ordered an extended length die grinder, and I'm going to cut back the inside pipe, so it matches the contour of the collector. When people talk about this setup losing 10 HP. This is the only reason, besides the crushed outer pipe.

 

The cats themselves will take a 2.5" pipe in and out, do that with a better Y section and they'll be pretty darn good

 

Was the connection that bad on all of them? Or is this one worse than others?

 

It's a shame you still can't buy this Flowmaster N10 after cat Y-merge pipe.




But you can still buy this and have your exhaust shop replicate a custom Y-merge pipe for you to fit your factory N10 exhaust system.

Flowmaster Scavenger Y-Collector - Y250300


The exhaust shop will make something that looks like this.

 

I should have been more clear. That is only 1 N10. I took pictures of various angles. Too many pictures I guess. But it was hard to get lighting in there. The driver's side is not restricted at all; it flows straight into the collector. The passenger side where it comes too far into the collector definitely needs a trimming. Also, the passenger side pipe is concave along the fender. It the passenger side pipe can be cleaned up, and replaced with a not crushed pipe, I bet it would flow as good as a magnaflow.

N10 is mass production, Mass production is just that, produced for the masses. GM set tolerances, and 100's of them got welded up.

 

I just checked mine, all original, and it’s the same way.

 

I'll say it again: N10 is mass production, Mass production is just that, produced for the masses. GM set tolerances, and 100's of them got welded up.

Aftermarket will tweak every little oz out of it, but mass production has it's limitations. It's a manufacturing process that is setup for 1000's of cars.

 

Yes, and mass production has variances. Hence my question a few posts up.

 

I don’t think there were any variances. I think they were all made like that with the outside pipe sticking out into the exhaust stream at the Y merger. Still, it provided a nice 10hp gain over the single cat cars.

 

All of them I have seen are like that. I haven't peeked up the 1991.5 to 1992 N10 Y-merge pipe though but I think all they changed was the connection to the intermediate pipe from the "Hog" clamp to a slip fit connection.