3in to 4in Y-pipe with Hawks LS Swap Headers
 

Just wanted to share my 3in into 4in y-pipe that i made for my 6.0L swap. When i bought my hawks LS swap headers i got them with the 2.5in collectors and made a 2.5in into 3in y pipe. Well i got bored and decided to cut the collector off where it necked down to the 2.5in and tig welded on a 3in collector. Then i ran two 3in pipes into a single 4in with a 4 inch cutout. After the cutout i necked it back down to 3in. to go over the axle.

First the old y-pipe:

Attachment 402457

Attachment 402458
I made my own cross member out of some 1/4 plate and angle iron.

Attachment 402459
Passenger side of the cross member (I cut off the piece that sticks up once i was done).

Attachment 402460
Driver side of the cross member.

Re: 3in into 4in Y-pipe with Hawks LS Swap Headers
 

The new y-pipe has a lot more ground clearance than my old one, mostly because i didn't tuck the old one up very well when i made it.

Now the new Y-pipe:

Attachment 402451
There is just a small difference in size :D

Attachment 402452
Attachment 402453
I took my time building the y-pipe and smoothed it off inside for the best flow.

Attachment 402454
I added a nice little mount right in front of the cutout. It makes it really easy to remove the y-pipe because it holds it up while i take the clamps off.
Attachment 402455
Y-pipe installed

Attachment 402456
4 inch cutout located under the rear passenger seat hump.


Ill have to post up a video of how it sounds once i get my fuel injection swap finished.

Re: 3in into 4in Y-pipe with Hawks LS Swap Headers
 

Nice! I need to redo mine but im using 3 1/2 where us using 4'

Re: 3in into 4in Y-pipe with Hawks LS Swap Headers
 

Yeah 3.5 should be plenty big, its was definitely worth redoing mine. The final product was way nicer than the first one i built.

The exhaust part of this thread is what convinced me to go 4 in.
http://www.ls1tech.com/forums/genera...heads-cam.html

IMO mine will even flow better than the one in this thread because the y-pipe doesnt neck down like his does and it has fewer bends.

Re: 3in into 4in Y-pipe with Hawks LS Swap Headers
 

Do you have any pictures of the car on the ground, I about to buy those same headers. I have a 700r4 that i am using as well in my swap and it's built for the 9's so should be good with the 700r4.

Re: 3in into 4in Y-pipe with Hawks LS Swap Headers
 

I dont have any pictures of it on the ground but i will take some this weekend when im home from school. With this y-pipe i have only drug it once, thats because i was driving on a country road and i tried to straddle a loose clump of asphalt.

Overall i am pretty impressed with the headers besides having to dent the floor in to clear the o2 sensors. Just make sure you build your own y-pipe because there are plenty of horror stories on here about the hawks y-pipe.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Ya I already have a guy that builds really nice exhaust systems, I was either going to notch the frame or notch the crossmember. Not to worried about notching it though. my frame is already a little tweaked anyways.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

I didnt have to dent or notch anything with my SW Headers. All Fit perfect. Since SW was 5 miles down the street I dropped off my car and had them make me up a Y pipe so I know it would fit right ! lol Also had them use a resonator after the Y to avoid drone since I dont have cats.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

i was referring to the y pipe for clearances, not the headers

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Well thats convenient.

My car has never had any droning unless the cutout is open:nod:

What are you running for a muffler? I have a flowmaster 3in catback system.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Yeah the only thing i did before i made the first y-pipe was make that double hump trans cross member. If you dont make a cross member you pipes will probably hang really low.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Here are some pics of the clearance of both the headers and the y-pipe. My car has 3/4 of a coil cut off the front springs and stock rear springs.

Attachment 402230

Shows the clearance at the header.

Attachment 402231
Shows the clearance of the y-pipe. The lowest point is by the can.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

I'm running a stock edelbrock exhaust that I installed back in 99. It was my first ever mod from bone stock. Its kinda rusty now but I want to see how far it takes me!

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Haha yeah nothing wrong with that.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

You should flip those clamps so the bolts are not the lowest point. My Vbands always scrap first at the collector.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Yeah i have been meaning to do that. The drivers side clamp cant turn much more up because the shifter linkage is right above that one.

Re: 3in to 4in Y-pipe with Hawks LS Swap Headers
 

Nice work :burnout: