I recently purchased hooker competition shorty headers for my 84 trans Am. I am also looking to buy the Borla 3in stainless steel exhaust with a 3in catco converter. I as wondering that if I change they Y pipe with a headman Y pipe of a lesser diam how much will this effect the exhaust flow? Will I loose H.P.? Will it null the fact that I have 3in pipes behind it? Also if I do purchace the Y Pipe will I have to purchace reducers for the headers or do the the 3 bolt flanges come together. Any help would be appretiated.

 

The Hedman y-pipe has 3" collector flanges on it.
But, as far as i am aware, noone has yet posted about having tried the Hedman y-pipe on any other brand of headers, so the big question is, will it even bolt up?
As for losing any HP with a smaller y-pipe, that will depend on your current HP level. A stock 150 horse 305 may work better with the smaller pipe, while a built 350 or bigger will become choked by it.

Pete

 

I would be worried about hp loss with that Y pipe. It goes from a already mildley restrictive 2.25 inch dual pipes into a definenty rstrictive 2.5 inch singel pipe. And the collector where they meat leaves no room for the exhaust to transition. It's like hitting a brick wall.

 

Then what do you guys recomend I do. I just found out that the headman Y-Pipe is designed to fit thier own specific headers. So that is out of the question. I also found out that SLP sells a 2&1/2 inch. mandrel bent stock replacement. Is this my only option? Do you guys know anyone that makes a 3in pipe? Or should I take it to a muffler shop and see if they can make me a pipe? But my friend told me that most shops won't do 3in mandrell bends. Any help would be much appretiated.

 

JCWhitney carries mandrel bent pipes all the way up to 3 inch size in both 90 deg and 45 deg. Summit does also but takes a lot longer to get them to ya. I have also heard of people gettting mandrel bends from truck parts houses. To them 3 inches is small. I have also seen mandrel bends sold on ebay for pretty cheap.

I would find an exhaust shop willing to work with you and tell them you will provide the bends. From most of the y-pipes I've seen to shortie headers they should be able to work with 90 deg and 45 deg bends.

Just find a good picture on this site of a y-pipe and use it as an example. The Edelbrock y-pipe looks real nice to me cause it only requires one mandrel 3 inch bend and it's a 45. The rest of the bends are on the 2.5 inch pipes. And the transition to the 3 inch collector looks better going into a straight pipe. I do believe there are a few good pics in the stickeys above with good y-pipes.

EDIT: OK so most of the stickies are duals. Look at this picture, http://home.earthlink.net/~chris255/thirdgen1.jpg , it would be very similar but you would use a 3 inch 2 into 1 collector after the 90 degree turn by the passenger side front tire.

And by the way that is very similiar to what my set up looks like rigth now and I used a hedman Y-pipe and cut it off right before the 2.5 inch collector and used JCWhitney bends to make the rest.

 

1) The hedman headers have strange location for the collector dumps, which makes the y-pipe very proprietary.

2) The y-pipe blows. I cut mine up into many peices, re-welded it back together, and replaced the 2.5" sections with 3".

3) I investigated making a y-pipe for the competition headers. Prolly the same amount of work as fixing the hedman y-pipe. Get the mandrel bends, and rent a pipe expander..

-- Joe