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Building a TwinScroll Header

MadDog_945

Våga Vägra 8V
Joined
Apr 25, 2006
Location
Lower Saxony
I'm gettin ready for a hella busy weekend with the ipd car show......but ill pm you later about this. I know others will have great ideas for you.....compile them all and get your Tig'on! If you end up using the same material I do, I'm sure I could make a paper template of my cut jig for the collector and mail it flat to you. The collector is almost the hardest part....besides piping your primarys to tight so you can't get in there and weld it out! Sometimes I have to cut a primary out....bench weld and reinstall. Twin scrolls are fun.
 
Not trying to take away from this forum but Honda-tech.com has a very good fabrication forum if you want to get ideas and help. I learned how to make manifolds from that forum and some of the fabricators that post are second to none.

http://www.honda-tech.com/forumdisplay.php?f=53

1.5" 304 schedule 10 should be all you need and its way cheaper to buy 90's and cut them. To get the full effect two gates are needed.

Heres a divided manifold I made for my friends k20 powered bug,

IMG_1101.jpg
 
Was reading an turbo article in Hot Rod(or Car Craft/Popular Hot Rodding forget which) and it was said it helps to pair up the firing order sequence cylinders in pairs. Better spool time was the claim. The OEM Volvo n/a cast iron mani even does this.
 
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Not trying to take away from this forum but Honda-tech.com has a very good fabrication forum if you want to get ideas and help. I learned how to make manifolds from that forum and some of the fabricators that post are second to none.

http://www.honda-tech.com/forumdisplay.php?f=53

1.5" 304 schedule 10 should be all you need and its way cheaper to buy 90's and cut them. To get the full effect two gates are needed.

Heres a divided manifold I made for my friends k20 powered bug,

IMG_1101.jpg

:omg:

Whoa.. sexy :)

Do you dump the wastegate to atmosphere or do i miss the ju`nction behind the downpipe?
 
Hi.. since i have enough cash to buy a TigWelder with integrated Plasmacutter :oogle:, im now in the position to buy some mandrelbends..

What do i need to have? How many Elbows 45? , 90? how many metres? :D

Only buy 90 degree weld els. 45 degree weld els are about the same price as 90 degree ones (in other words, they're twice as expensive. Just cut a 90 degree el in half).

What diameter, wallthickness? Is there a masterplan of guiding the runners for a special turbo position?


1.5" schedule 10 stainless is pretty much the standard. It's 0.109" thick. No real master plan, other than that on a twin scroll you'll want to pair 1-4 and 2-3 together.

Twin scroll collectors are quite easy, because you only have to fit 2 runners together.

Trying to run a single wastegate on a twin scroll manifold gets ugly, fast. You need to keep the plumbing divided right up to the gate, otherwise you lose a lot of the advantage of going to a divided setup.

I would run twin 38mm Tial MVS gates, they're fairly cheap, and quite small and easy to package.

Couple examples of divided manifolds i've made over the years:

Sched 10 stainless, being set up for twin gates:

P4060565.jpg


16ga 1.625" set up for single gate (not reccomended):
P1020012.jpg
 
Ok,

I have found a new dealer for stainless fittings.. but they only have 33,7mm 40mm or 42,4mm all with 2mm wall

is 2mm too thin? 2,54mm is 0.100" and what diameter would be best?
 
Only buy 90 degree weld els. 45 degree weld els are about the same price as 90 degree ones (in other words, they're twice as expensive. Just cut a 90 degree el in half).




1.5" schedule 10 stainless is pretty much the standard. It's 0.109" thick. No real master plan, other than that on a twin scroll you'll want to pair 1-4 and 2-3 together.

Twin scroll collectors are quite easy, because you only have to fit 2 runners together.

Trying to run a single wastegate on a twin scroll manifold gets ugly, fast. You need to keep the plumbing divided right up to the gate, otherwise you lose a lot of the advantage of going to a divided setup.

I would run twin 38mm Tial MVS gates, they're fairly cheap, and quite small and easy to package.

Couple examples of divided manifolds i've made over the years:

Sched 10 stainless, being set up for twin gates:

P4060565.jpg

that guy looks familiar.
 
Ok,

I have found a new dealer for stainless fittings.. but they only have 33,7mm 40mm or 42,4mm all with 2mm wall

is 2mm too thin? 2,54mm is 0.100" and what diameter would be best?

2mm wall would be ok. You would want the 40mm or 42,4mm diameter.

If you're going to the effort of building a twin scroll manifold, I would use 2 wastegates if you have the space. The single with a divider is ok, but 2 wastegates is the ideal.
 
Thx :)


As flange material? 8 oder 10mm ?


/edit

yeah and for sure i will go the dualWG way.. when do, do it right ;)

So im looking for a good but affordable one... the TIALs are way too expensive.. thy are 320dollars here in germany each... thats the price i pay for a car :D

38mm woulkd be enough right ? hard to find in good china quality with V-Band
 
I like my MVS they are nice and tight, easy to get on and off. Keep an eye open on the used market, I bought my second that way and saved close to 50% off the original price. I've seen a bunch of external gate act funky, I wanted something reliable for those 25+ psi run where you don't have a second to watch the boost gauge.
 
Hey guys.. here are my first tries to fab a TwinScroll.. pretty newbish ;) But you'll first have to figure out how to merge oval to round.. this is really stealing my nerves :grrr:

DSC_0212.jpg


DSC_0213.jpg


DSC_0214.jpg


DSC_0215.jpg


DSC_0216.jpg


DSC_0217.jpg


DSC_0218.jpg


DSC_0219.jpg


DSC_0220.jpg


DSC_0221.jpg


DSC_0222.jpg


DSC_0223.jpg
 
So.. long time no progress in here...

Right now im trying to figure out how to cut the collector pipes.. which machine, what angle and so on.. bandsaw doesnt work for this job.. im turning a spacerdisc for my miter saw to fit a 10" Grinderdisc in it.. looks like this:
8.jpg



How would you weld the doubles to the scrollisolator?
 
Some tips on the welding: less heat. If your not back purging with argon you will want to keep the heat down so it won't "sugar" on the backside. Welds should be shinny.

Also, before welding on the header, practice on some spare tubing. Cut a straight section into multiple rings (maybe 20mm long) and weld it back into a tube.

For cutting tubes I just use an angle grinder with a 5in cut-off wheel.
 
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