i just started to build my turbo headers for my new motor,
i hand cut the stainless flanges,and made my own press form to make my own collectors.

the ex ports on my heads are only 1"1/8 round[1.5 inch when ported},so im using 1"3/8's inside diam stainless steel tubing,with an outside diam of 1.5 inch.now the collectors i made ,are 3x1.5 tubes into a 3 inch collector.now im running twin turbos with t3 hotsides so the ideal pipe to the t3 flange is 2.5 inch since it can be formed perfectly into the shape of the flange.but unfortuneantly a 2.5 inch pipe cant be made to fit three 1.5 inch primarys.

so my ? is would it be better to get stainless cone reducers 3.-2.5 inch or just slice up the 3. inch collector to shrink it down.im quessing the second one would have a smoother transition.

the second thing is would getting the headers coated after there done be worth the extra cost?

and last but not least im gonna do dual 2.5 stainless downpipes,but how far away from the turbine ex should i go with the stainless,id go all the way out the muffler but it would cost way to much

thnx guys

what type of conical reducer are we talking about a perfect cone or a stepped cone?

they are steped, 1inch in from the end is 3" then the cone is about 1.5 inch long then it has 1inch long section of 2.5 inch tubing.

i could just roll my own stainless cone,but what would an ideal lenght be for the transition be ?? or am i just thinking to much and overly complicating this

well you would want to roll your own a step wouldnt be very effective... i would say you would want the taper to be either very slow or very fast dependin on how much room you have to work with i would say about 3.5-4in

you might like to try something like this

Use a 4-into-1 and use the 4th for the wastegate :-)

i am wondering your exhaust ports are 1.5 ported i am taking that yours are ported. if they are why would you go with a smaller tube then your exhaust ports. mine i had coated in nickel plating they looked great but i wrapped them to get rid of heat out of the hood. I would run 3inch down pipes i ran stainless all the way from the turbos to the mufflers. I had 2.5 into a 3inch y with 3inch all the way back. wasnt enough so i put the dual 3inch in then instead of making 13psi it spiked 30psi in first and second felt really cool until my brother lifted the head.my exhaust housings were to small and the wate gates couldnt keep up. so just a heads up it is alot easier to do it right the first time instead of chasing crap tryning to make it right the second or third time.

cause i cant fit anything larger then a 1.5 inch tube inbetween the bolts,if i try to use 1" 5/8's tubing the bolts wont fit.what i did was to have a 1.5 inch hole on the head side to match the port that tapers down to 1"3/8's,near the middle of the flange the header side is counter bored to 1.5 inch so the tube drops in nice and neat and can be welded solid. i ended up making my flanges from 1/2" thick stainless in order to do this

would that actually work ? if ya think about flow to the wastegate would be completely opposite the rest of the ex gasses.

Things flow to the path of least resistance, right? I would think that the gasses would rather go around the turbo then through the turbo, so I don't see why it wouldn't work.

hmm ill have to try it,though i spent the better part of one day machining the press form to make my 3 into one collectors.which worked really well i didnt have to heat the 3 inch stainless tubing to make the 3 -1 collectors.hopefully a 4 into 1 form will work just as well. im trying to do this with stuff i have at laying around the shop.

Well, imho, I wouldn't do out of my way to do it that way. 4-1 collectors are easy to find, 3-1 are basically impossible. I was just giving you an option incase you ended up buying collectors.

I thought Burns Stainless had 3 in 1 collectors that they sell?

http://www.burnsstainless.com/MergeC...into1base.html

yeah they do for 255 $'s i can make my own for about 30$'s lol

I think you would be better off making your own 3 into 1 collectors. I am going through kind of the same thing as you in terms of the pipes at the flange. I chose to use steel weld-els over stainless in the end. I thought about stainless alot but eventually picked mcmaster weld-els. I got the 1.66" ID, 1.90" OD, 90* bends. I had to cut the sides where the bolts thread into the head. I then cut out some 1/8" plate pieces and tacked them in place. It allows enough room for the bolts (V8 882 heads). I have one more pipe to make and then I could post a pic of the unit tacked together if it would help.

ive got my collectors made,ive changed my setup for the last time, im not gonna go with twins like i had originally planed,im sticking with a single turbo GT66.
what i have to do now is decide if i want to put 3.0-2.5 reducers on my collectors and a 2.5 y into the turbo.or leave the 3 inch collectors and build a 3 inch y to the turbo with a single reducer right before the turbo flange.

i also go tmy hands on more stainless tubing and v band clamps, so the y pipe
is now gonna be stainless,and from the turbo outlet to the cutout is also gonna be stainless,

my turbo outlet is 4 inch but i cant fit a 4 inch downpipe past the header/starter, so im going to reduce it to 3.5 inch or 3 inch right off the turbo,( need a mini starter for the v6 motor lol then i could fit a 4 inch dp).

anyways as soon as i unpack my camera ill get some pics of it up while its on the engine stand...

lol this is also the last time i build stainless headers,stainless is to much of a pain in the *** to work with

I'm interested to see how yours came out, Dave! I built my prototype set (headers and y-pipe) a little over a year ago. I'll probably rebuild them after I get the motor going...I'm sure I'll come up with some things I can change. Mine are steel...didn't really have any means of welding stainless.

ill geta pick of them soon, they are sorts like urs, except i relocated my ps pump to were the ac compressor used to be, my driver side header comes right out under the ps pump. and my passengers side comes out right under the alt.

i had to notch the motor mount bracket on the block to fit my downpipe in between the header and frame.


i really wanted to do twins,but i relized my only reason for doing them was for looks,which is the last thing im worried about right now,would have been cool to pop the hood and seen twin t4's, but the single turbo im using now will make just as much if not more power anyway.

i have a few othe rprojects u might be interested in (direct port mechanical ethanol injection ) direct port nitrous manifolds, and some custom intake manifolds for the gen2/gen 3 heads

Man, its scary how much we think alike! My headers come out under the alt on the pass side and right next to the PS pump on the driver's side. That was a tight squeeze but, I think it'll work. My DP is going to run over top of the header on the pass side then drop down by the firewall.

Yeah, I'm by no means a turbo expert but I had kind of wondered why you wanted to go with twins. I'm actually not even sure if my turbo that I have now will do what I want it to. It'll get me started, anyway.

I've got some other projects started too! One of mine is a manifold to fit the FWD heads, also. I've seen the pics of the one your working on (unless you've got another design going too) and I think we are taking different approaches on those. I just have to find some free time (or a time to stay late) at work to throw some material in one of the CNCs to finish cutting my flanges. Then decide if I should try to weld it or just cough up the money and have it welded by somebody who's good at welding alum!