2.5" or 3" Y-pipe? Opnions wanted.
04-11-2003, 07:21 AM
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TECH Junkie
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2.5" or 3" Y-pipe? Opnions wanted. We're soon going to be installing my old MAC headers on my next door neighbor's relatively stock '98 Z28. He has a few of the basic mods done to the car so far (FTRA, Whisper lid, K&N, Ultra-Flow muffler), and a Vigilante 3200 converter. The car runs in the 12.7 range most of the time...
Anyway, my old MAC headers were loooong ago modified by cutting off the ball flanges and welding on a traditional 3" triangular flange. The MAC Y-pipe was long ago ditched as well, so we're going to have to fab our own to join the headers to the stock intermediate pipe.
Seeing as how his car still has stock heads/cam, we're having some trouble determining whether to step down to 2.5" for the Y-pipe, or keep it 3" from the headers back to the intermediate pipe. We're planning on using a Flowmaster Y collector to make the transition from the Y-pipe to the intermediate pipe.
So, in a nutshell, should we go 2.5" or 3"????? <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Anyway, my old MAC headers were loooong ago modified by cutting off the ball flanges and welding on a traditional 3" triangular flange. The MAC Y-pipe was long ago ditched as well, so we're going to have to fab our own to join the headers to the stock intermediate pipe.
Seeing as how his car still has stock heads/cam, we're having some trouble determining whether to step down to 2.5" for the Y-pipe, or keep it 3" from the headers back to the intermediate pipe. We're planning on using a Flowmaster Y collector to make the transition from the Y-pipe to the intermediate pipe.
So, in a nutshell, should we go 2.5" or 3"????? <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
04-11-2003, 08:27 AM
#2
Re: 2.5" or 3" Y-pipe? Opnions wanted. George, I would go with 3". That way once he does more mods, which most do, the exhaust will support them. I just had my Macs modified the same way. The ball flanges were cut off, and a flowmaster collector was used. Eric at Kent Island Speed did it and used 3" oval tubing on the drivers side, giving me awsome ground clearance. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Running through my Borla muffler, 95% of the infamous Mac rasp is gone. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Bruce
Bruce
04-11-2003, 09:01 AM
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Re: 2.5" or 3" Y-pipe? Opnions wanted. That's exactly what I was thinking... The 3" shouldn't hurt whatsoever, even if it's slightly overkill for the time being.
That way nothing needs to be changed out later down the road.
That way nothing needs to be changed out later down the road.
04-11-2003, 09:03 PM
#4
The Bull
Re: 2.5" or 3" Y-pipe? Opnions wanted. George, I built a custom 3" to 3-1/2" collector that tapers back down to 3". So far it works great. I'll be able to get some pictures of it when I get back home in a week or so.
04-12-2003, 07:57 AM
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Re: 2.5" or 3" Y-pipe? Opnions wanted. Looks like we'll do a 3" Y-pipe, then... Thanks, guys! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
