senicalj4579

iTrader: (41)

anyone know how much power i can make with my 2.5" y-pipe?

Josh

iTrader: (9)

As much as you could with a 3" with a 346.

Josh

senicalj4579

iTrader: (41)

so the 2.5 wouldnt hold me back from making more power?

senicalj4579

iTrader: (41)

please explain

ELMiN8oR

LS1 stock block is a 346. so it doesn't matter whether it's a 3" or a 2.5", they are all the same. thats what he meant

senicalj4579

iTrader: (41)

thanks man. I probly didnt ask the question with enough detail. I guess what i'm asking is when I get more mods on my car like cam,heads,intake will the 2.5" y-pipe be holding me back from making more power because its not big enough? Is there some chart that explains and shows how much certain pipe diameters are good for? meaning at what point is it time to change to a bigger size?

RevGTO

iTrader: (12)

Word on the street is that it's good to about 450rwhp - or is it 500? Pretty high, anyway.

senicalj4579

iTrader: (41)

this is the answer i was looking for. thanks bro!

lsx24

iTrader: (45)

Yes, this post here:
https://ls1tech.com/forums/showpost....5&postcount=14

ypipe is going to start holding you back pretty soon, not based on the size of the y, but based on what it necks down to.

In other words, if your ypipe is 2.5" x 2.5" --> 3" collector, then you are going to be limited to the collector size of 3", for total efficiency of 369 hp.

All the more reason to save your money for 2.5" true duals. They are good for over 500 hp. Plus you will get more tq from true duals than you would any ypipe. And the sound is fantastic.

ELMiN8oR

i would go with his idea cause heads and cam + true duals will give you amazing rwhp

senicalj4579

iTrader: (41)

perfect thanks man. the only thing that sucks is i just bought my exhause system back in march. and its not a cheap system. looks like i may be doing it all over again will td this time thanks though, this is big help

senicalj4579

iTrader: (41)

ok wait, so you mean its not the size of my y-pipe its the size of my I pipe? i have 3"collectors and either a 2.5 or 2.75 y-pipe going into a 3" I pipe for he catback. The system is starting to hold me back at the 3" 369 hp mark? I'm not doubting this but why are there so many guys making like 500hp on 3"? These figures must be when the size of the pipe starts to limit your gains?

senicalj4579

iTrader: (41)

also, lets say i'm making 500hp with my current system....how much power do you think i'm not being able to use as if i had 2.5" duels?

lsx24

iTrader: (45)

Correct it's the size of your ipipe. That is the limiting factor, with 3", equates out to 369 fwhp is the max taking into account 100% efficiency.

In other words, this is the point where the exhaust starts to become a restriction in the system. That doesn't mean you can't make more power with it, as there are many people who are, but they are leaving some power on the table.

lsx24

iTrader: (45)

You are running withing 100% efficiency of 2.5" true duals, with 500 hp, so they are not holding you back at all.

senicalj4579

iTrader: (41)

no, i meant if i was making 500hp with my current settup. 3"collectors,2.5 y-pipe into 3" I pipe catback. how much would you think i would be leaving on the table because i do not have 2.5" duels?

lsx24

iTrader: (45)

It's hard to say, there really is no researched data that has measured these kinds of numbers. Let's just say it wouldn't be 'efficient'.

caviness

iTrader: (14)

you can make all kinds of hp with 2.5 pipe,probable 500 or more!! only thing is if you go bigger on the exhaust latter single 4 or duel 3 you will pick up some free hp.

senicalj4579

iTrader: (41)

ok, so if its not the size of the y-pipe and its the size of the I pipe then what if I go to a 4" catback off of the 2.5" y-pipe? I read somewhere your supossed to stay a consistant size throughout the system but who knows?

lsx24

iTrader: (45)

If you go 4" ipipe, after the 2.5" ypipe, you'll have a pretty evenly matched setup.

Dual 2.5" flow almost the same as a single 4", right around 500 hp. 4" will flow a little more than dual 2.5", more like 650 hp, according to the above link.