i have recently found out how shitty the merge is in my Pacesetter y so i'm going to get rid of it and have a local shop make me a custom y.... i have pacesetter lt's and a full 3" system at the moment... my question is, is it a bad idea to go with a 2.5" y to a 3" merge? and what kind of difference should i expect going from a 3" y to a 2.5" y, more power down low but a loss in mid and upper power? oh and i'm going to go with the Flowmaster 2.5" to 3" merge collector

 

No, assuming you're not running FI or a stroker. It's okay if the 2 sides of the y-pipe are 2.5" by the same logic that 2.5" TD's are fine on cars pushing tons of power. If anything, I'd be willing to bet that the 2.5" sides of the y-pipe will increase exhaust velocity a tad, and combine that with a better merge and I'm sure you'll see a noticeable gain in midrange power.

Gains down low, in the midrange and up top with the 2.5" pipes and a good merge. As long as the single I-pipe is 3" and not 2.5", you'll be fine. Remember, dual 2.5" pipes flow similarly to a single 4" pipe, and I doubt your car needs 4" exhaust

 

thanks for the quick reply man, and that's what i wanted to hear... but yea from the merge to the muffler it will be 3".... it just sounds way to raspy right now and seems like i'm losing a ton of power in mid and upper rpm's.... i'm hoping the new y and the new merge is going to help with the rasp... but i'm running no cats so of course i know its not going to completely fix the problem! i was thinking about just welding in a high flow cat in the I-pipe too... what do u think?

 

Also, the guy at the shop recommended i use flex joints between the y pipe and the headers... should i do that or just have the y pipe welded straight to the headers?? i've not seen any pics on here of anybody using the flex joints... he said they would be like $60 a piece... prob a waste of money huh??

 

The merge will help a ton with the rasp. LS1's have such a bad reputation for rasp because up until recently, all the y-pipes out there have been absolute junk from the aftermarket. The stock y-pipe had a better merge than almost all of them Once you replace the merge, even without cats, you'll be surprised how much rasp went away, I guarantee it. It won't be perfect, but it'll be a lot better.

I have Magnaflow 59959 cats on my car, which are the highest flowing available. My merge in my y-pipe is pretty good, and I'm practically rasp-free and I always have my cutout open. The only time I get rasp is when I stab it stuck in 4th gear around 2,000 rpm's because I'm completely bottoming out my car

Another thing that'll get rid of a lot of rasp is tuning, which I have yet to do But trust me, the merge will get rid of tons of rasp.

 

My y-pipe is welded straight to the headers and I HATE that. I had no idea the guy at the shop was going to do that or I would have gone out and gotten band clamps for a lousy $10 a pop. I was really upset, but what's done is done. I would recommend you get band clamps, although, sadly, the only way to make sure you have no leaks is to get it welded Even with band clamps, people have leaks. They're not 100%, but if I could do it all over again, I would have gone out and bought the $10 stainless steel band clamps from Napa or any other parts store and risked a small exhaust leak. Just get the $10 band clamps, don't waste a ton of money on something crazy unless you want to have really nice flanges installed...and on Pacesetter headers, it's ridiculous to have flanges worth more than the headers IMO

 

you can use v band clamps and they wont leak but they are expensive. i used them on my y pipe and they are great. plus i can have the exhaust off the car in 3 minutes. 2 of that jacking it up. 2.5" wont hurt much if at all on a nearly stock car but if u plan to make power in the future stick with the 3".

 

Yup...with my band clamps i was getting some little leaks. Only I noticed, but they still bothered me. I made some "gaskets" under the band clamps out of aluminum foil and there's no more leaks. No idea if they'll last a while, or if they'll blow out on me, but they work for now and I'm happy with it. If I have to replace them every once in a while, that's no big deal. Just an idea for ya.

 

thanks for the info guys.... as far as adding more power in future all i really plan on doing is getting a dyno tune, i'll prob just leave it alone after that...

i'll prob go with the band clamps then and hope for no leaks.... but it's definately a bad idea to weld to weld the y pipe straight to the headers? cause i think the guy at the shop said he would just do that if i didnt use the flex joints he has.

 

I would not weld the y and the headers together. One day for some reason you will want to replace something and it will be a bitch. And the shop should do it the way YOU want it done, don't let them con you. It will be interesting to see if there are noticeable sotp gains, I'm going to be replacing the Pacesetter y on mine eventually as well.

 

i def wouldnt use a flex joint. it would prob make it hit the floor worse then these cars are prone to anyways. band clamps is def a cheaper/ easiere way to do it. i had them before these and never one leak. i just got these for ease of install/ removal and they look cool so it was win win

 

alright sounds good, band clamps it is.... thanks!

 

I have checked out my ARH's sittin in my livin room inside and out out I am positive there is no way my headers will leak. The welds are flawless, everything fits snug and it even comes with band clamps. If they fit like I have heard I am sure I will be happy.

 

Don't say that. There is always a way things can leak. It doesn't matter how good the welds are on the headers because they leak at the clamps. Some people get lucky, some people don't. If your collectors aren't perfectly smooth and the placement of the clamps aren't perfect, you might get a small leak. If the collectors and the placement of the clamps are perfect, it still may leak. They've leaked on every brand of headers because the brand of headers don't really matter.