I have a 2000 Z28 with bolt ons. The headers are Speed Enginering with 1 7/8” primary’s. Last time at the track I ran with a 4” open pipe welded right at the y, so it’s not necked down. Full weight and plus 1050da it ran 11.76@113.49. Would I be better off removing the y pipe and just running 20” collector extensions off the headers?

 

As long as there is no restriction, the Y-pipe might help scavenge better than without.

 

If you dont want to fab or weld, Get the speed engineering duals and call it a day.

 

I have the y cut to fit a 4” pipe so there definitely isn’t a restriction at the y like how they come.

On the street I run a 4” diesel turbine muffler off the y and that goes into a SLP loud mouth set up out the back, it sounds good, no resonance and not noisy.
I can fab/weld no problem just don’t want to do a bunch of work for nothing. Most cars at my track run collector extensions so that’s what got me thinking.