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Discussion Starter #1
I figured I'd share a my manifold build with my d-series peeps. I'm open for suggestion or comments, good or bad. i'm a big boy. I can take it. Its just tacked together so if any changes are to be done they need to be now. This is my first attempt at building any kind of manifold and I already see some things I wish I would've done differently.

Harbor Freight $45 chop saw. I welded some angle iron to the side at the guestimated angle I wanted for the collector. I just clamped the pipe down with a C clamp and hacked away.


...and ended up with 4 of these.


...which became this (x2)


decent welds for a $80 Harbor freight flux core welder.


Here's a shot of the flange I made lined up with the Holset inlet. You can see how much material had to be removed for a smooth transition.




And finally one side of the collector welded to the flange.
 

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Discussion Starter #2 (Edited)
After the collector was welded up, I made a bracket to hold the turbo in its place which will also support the weight of the turbo. This should help relieve some of the stress off the runners themselves and help prevent cracking.... I hope.


Once it was mocked up on the car I ended up cutting the angle out and using some all-thread. This allowed me to be able to bend the mount to get the turbo in its final position. which was an MFer BTW. It is tight in there.


I bought a box of schedule 40 90's in mild steel and got some scrap pipe from work.


Then went to work. Started with runner #2.


and paired it with #3



Didnt get anymore pics until #3 and #4 were done.


 

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Discussion Starter #3 (Edited)




Then #4 sneaking in there at the end.


and off the car.





So far I'm very pleased with how this is turning out. I still have to add my wastegate flanges then i'll be ready to stick everything together permanently. Their are a couple fit-ups that arent perfect. I should be able to make them dead on when I break it apart for final welding. Then a healthy coat of VHT high temp ceramic paint and some heat wrap and I'm done. I've got right at $100 in it. Much better than $1000 and I can say I built it!
 

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i have a flux core like that please let me know how the welds hold i was scared they wouldnt be strong enough. but good work brah i wanna make my own downpipe
 

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D-series SoCal Division
93' dx hatchback
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Looks really good man, can't wait to see it all finished.
What are you gonna do with the heatshield tabs?
 

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1999 EJ8
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Nice work man!

Might I ask what HF welder you have? I have an $80 one in my garage, never tried using it on anything with sufficient wall thickness. Worked like a plasma cutter on thinner stuff lol.

It has pretty much lived in the box for three years, only seen the light of day once.

This makes me want to buy some pipe and make a downpipe!
 

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looks pretty sweet but don't you want all the runners to be the same length? you have them coupled correctly. From what I understand about turbo manifolds you want to utilize the exhaust pulses as efficiently as possible, especially with a twin scroll turbo. like #1 gas will spin the first wheel then #3 gas will spin the second then #4 gas will spin the first wheel again and finally #2 will spin the second. it's like setting timing on an engine you don't want detonation. just like you want the exhaust pulses to hit the turbines in unison to keep the turbo spooling continuously.
 

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97 honda coupe
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looks pretty sweet but don't you want all the runners to be the same length? you have them coupled correctly. From what I understand about turbo manifolds you want to utilize the exhaust pulses as efficiently as possible, especially with a twin scroll turbo. like #1 gas will spin the first wheel then #3 gas will spin the second then #4 gas will spin the first wheel again and finally #2 will spin the second. it's like setting timing on an engine you don't want detonation. just like you want the exhaust pulses to hit the turbines in unison to keep the turbo spooling continuously.
1-3-4-2

Really you want 1 of each companion cylinder on each side that way it pushes on each side every 90 degrees. if you were to take from cylinders 1 and 4 for example you would get 1 exhaust pulse, and then 180 degrees of nothing, and then another exhaust pulse.
 

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Either way, if the runners aren't all the same length won't this process be messed up?

I like the DIY.
 

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My car...
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Looks good.

You want the support to have play in it (design, think of a motor mount), so that the whole assembly can heat up and move/expand a little. Ideally you wan the collector to be a slip-fit like you see on some high-end headers as well. I don't know if it really matters, but I know Steinar looked into it last year (he had problems cracking everything).
 
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