cosmick

I've spent days searching, there are NO offerings that are fairly priced and good-flowing. The Flowtech one being a prime example. It merges dual 2.5s into a single 2.5, and that merge is something like a 60* angle, further worsening the problem.
Last time I did cheap shorty headers on a SBC third-gen, I had to fab my own dual 2.5s into a single 3, with a Flowmaster Y. That thing flows great, but it isn't fairly priced. Thanks, Flowmaster.
Anyway, I want a dual 2.5 into single 3, mandrel-bent, that fits the Summit G9005s.
I have a welder, I can use it, I've ordered some mandrel bends, pics someday.

RWB____s

is this what you had in mind?
http://www.flowmastermufflers.com/?p...sub2=Scavenger


http://www.jegs.com/webapp/wcs/store...chTerm=y250300

cosmick

That's what I used before, but I'm not paying $48 for one. I now have a family to provide for.
I'd order Flowtech's if they'd only have the long one step up to 3" about 1/4" before the second one merges in. Why they don't is beyond me, but since each bank needs 2.5", then 2.5" isn't enough for both banks. Anyone here can grasp that, why can't Flowtech?

jharrison5

My Flowtech Y was a huge pain to install and I regret buying it. It was supposed to be a bolt in install, but I had to cut it in three places and re-clock where it hooked to the cat because it was bent at the wrong angle. My summit headers on the other hand were super simple lol!

cosmick

I saw that in your build thread, which makes me begin to doubt the Summit G9005s being re-boxed Flowtechs.
I guess running with no flow beats non-running, and in theory a single 2.5" mandrel-bent exhaust should be good to 260 HP with no muffler, but if someone is going to settle for a single 2.5", then there's no need for anything better than LO3 / LG4 exhaust manifolds.
I've been down that road before. An LM1 350 with a Performer intake and cam kit, but a stock LG4 exhaust. It ran ok to 3500 RPM, and felt stronger than any LG4, but why build it twice when it's ultimately cheaper to just get it right the first time?
Mac Performance used to sell the desired Y-pipe, for the '87-'92 B2L exhaust manifolds, and I could live with that, ( Dorman still makes those manifolds,) but Mac is long gone. It would be easier to adapt the Mac Y to G9005s than to build from scratch.

midias

I made this one for a friend take a look

https://www.thirdgen.org/forums/exha...al-y-pipe.html

Parts list

1. 6 @ 2.5" 90 degree bends
2. 2 @ 2.5" 45 degree bends
3. 1 @ 3" 45 degree bends
4. 5 @ 2.5" to 2.5" couplers.
5. Flowmaster Y250300 Collector

jharrison5

Looks really nice! Too bad my SFC's won't allow me to do that lol!

RamIt

Nice job Midas. Looks really good.

Twin_Turbo

iTrader: (25)

here's a set of 3" to 2.75" . I had initially made it into a Y pipe like this but it's a complete split exhaust now.

cosmick

The best design for emissions is to merge them as quick as possible, plus it saves weight and gives more room for SFCs.

novaderrik

i didn't want to screw around with single exhaust and wanted to let it breathe, so i built an X pipe to go off my Hedman long tubes, under the trans crossmember, then back to a set of Flowmaster 40 series Deltaflows that i got cheap last fall.. the X is 3" in, 2.5" put, with perfectly straight pipes back to the mufflers. ground clearance isn't the best, but it's as good as the old crappy single Y pipe that i had in it for the last 4 summers.. and it sounds mean as hell, a modern kind of refined mean..

cosmick

A big single is lighter than conventional-size duals, the big single doesn't lose flow if you make it an oval for clearance, and the sounds on old V8s with true duals but no x, h, or crossover is horrific. I gotta admit there are no 3.5" or 4" cats, so dual 3s may be necessary for a few, but a single 3 beats the heck out of trying to fit true dual 2.25s for street use under 400 HP, where there are speed bumps in parking lots and apartment complexes.
GM did it that way not for structure, but to discourage true duals, since they hadn't yet decided to play with dual cats, mostly due to cost. And that's still valid, dual 2.25" cats cost more than a single 3" cat.
The way GM did the Y-pipe, the gases from the driver's side are beginning to cool down by the time the right bank merge in wiith fresh heat. Keeping it hot helps converter light-off, that's why GM made the Y-pipes double-wall, not for corrosion resistance.
Dual cats are still used only on the engines that need them, all others still get a larger single. OK, it's not single when there's one behind another, but that's not dual exhaust.