More evidence that good Y-Pipe matters
08-02-2003, 09:24 AM
#1
More evidence that good Y-Pipe matters I have had Grotts (the originals) for more than a year. They are a great header but like many of the currently available low priced headers, they came with a poorly designed Y-pipe that sufferred from 2 design flaws. First they merge the header flow by merging it at an angle rather than merging it using a parallel flow. Second, they merge two 3" pipes into a single 3" pipe with no additional volume to smooth the transition.
The solution for me was to have a custom Y-Pipe and intermediate pipe system built. The design uses 3" mandrel bent piping to connect the headers into a flowmaster collector. The flowmaster creates a nice smooth merge and exits to a 3.5" intermediate pipe that feeds a 3.5" cut-out. After the cutout, it narrows back down to 3" to mate with my catback.
The improvement in flow over my original Y-pipe is obvious and was even evident at idle, even with the cut-out closed. I needed to go out and adjust my idle tuning as I get some surge at idle after the switch. I was surprised that even at a low flow level of idle that the flow difference is enough to show up.
For you local peeps, Tyson at F-bodycentral did the work and a picture can be seen on FBC's site under exhaust.
www.fbodycentral.com/catalog/popup_image.php?pID=189
The solution for me was to have a custom Y-Pipe and intermediate pipe system built. The design uses 3" mandrel bent piping to connect the headers into a flowmaster collector. The flowmaster creates a nice smooth merge and exits to a 3.5" intermediate pipe that feeds a 3.5" cut-out. After the cutout, it narrows back down to 3" to mate with my catback.
The improvement in flow over my original Y-pipe is obvious and was even evident at idle, even with the cut-out closed. I needed to go out and adjust my idle tuning as I get some surge at idle after the switch. I was surprised that even at a low flow level of idle that the flow difference is enough to show up.
For you local peeps, Tyson at F-bodycentral did the work and a picture can be seen on FBC's site under exhaust.
www.fbodycentral.com/catalog/popup_image.php?pID=189
08-02-2003, 09:36 AM
#2
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Re: More evidence that good Y-Pipe matters I just did this with my mac's and i am very happy to say the least. We built a custom collector and cut my ball flanges off the headers.Nice work looks great gotta see if you gained any H.P. 
08-03-2003, 04:58 PM
#5
Re: More evidence that good Y-Pipe matters 2.5" header pipes into a 3" works pretty well for a bolt-on car. The smaller pipe diameter keeps low end gas velocity higher and therefore increases torque. Its top end is a bit restrictive on a heads & cam car that is spinning to 6600+ rpm so a 3" set-up is better if that is in your plans.
A good collector like the flowmaster will help even with a 3" to a 3" because it provides a smoother transistion.
A good collector like the flowmaster will help even with a 3" to a 3" because it provides a smoother transistion.