Author Topic: Welding onto exhaust manifold question (Read 7721 times)

rallydiesel · « **on:** January 07, 2009, 01:56:35 pm »

I'm planning on building a compound turbo. I will be using a k14 for the small turbo and a hy35 for the large one. I want to use an external wastegate to bypass the k14 at high flow because the kkk turbos have such small wastegate passages. I will enlarge the exhaust ports on the head extensively. This is all to keep the EMP as low as possible so the head doesn't warp.

Since the k14 will be first after the manifold, i'm thinking the easiest approach would be to use the 1.6TD manifold to match the trapezoidal flange and cut/weld an additional flange for the external wastegate.

The question is, how easy will it be to weld a flange onto the cast manifold or would it be better to find a VW manifold with an external WG flange already of on and cut off the turbo flange and weld on a trapezoidal one?

rallydiesel · « **Reply #1 on:** January 07, 2009, 02:11:24 pm »

Here's a manifold I'm thinking about. It looks pretty monstrous though. I don't know if it will even fit without hitting the firewall. Plus the turbo flange would be difficult to weld because there is so little room.

That manifold has a rectangular turbo flange though.

cyrus #1 · « **Reply #2 on:** January 07, 2009, 06:00:50 pm »

Welding cast iron is a pretty involved process. It involves pre-heating, and a very slow cool down combined with lots of hammering to relieve stress. Because of this, many shops prefer not to do it.

I personally think that you would be better off starting with something that has an external wastegate flange. Here are a couple of manifolds that have provisions for external wastegates.

http://www.kineticmotorsport.com/products/KINETIC_MOTORSPORT_VW_2L_8V_TURBO_MANIFOLD-467-93.html

http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ATP-VVW-004&Category_Code=VVWM

I have one of the Kinetic manifolds in my possession. It is going to flow infinitely better than the stock manifold. The wastegate flange has nearly the same area as the stock manifolds flange. :shock: I think that would really aid in keeping the emp down.

zukgod1 · « **Reply #3 on:** January 08, 2009, 07:04:33 am »

I know you want to use the trapezoid flange but if you get a manifold off a Audi 5cyl turbo car you can cut the front exhaust flange and they already have the flange for the wastegate. They bolt right on our heads but have the extra flange due to the 5cyl

thus cutting it off.
A friend of mine JUST gave one away damnit!

The Audi manifold have the flange for the k26 turbo which would be easy to adapt to any flange type.

53 willys · « **Reply #4 on:** January 09, 2009, 07:54:38 am »

Quote from: "zukgod1"

I know you want to use the trapezoid flange but if you get a manifold off a Audi 5cyl turbo car you can cut the front exhaust flange and they already have the flange for the wastegate. They bolt right on our heads but have the extra flange due to the 5cyl thus cutting it off.
A friend of mine JUST gave one away damnit!

The Audi manifold have the flange for the k26 turbo which would be easy to adapt to any flange type.

Dan do you have any pics of a audi manifold that has been cut??

rallydiesel · « **Reply #5 on:** January 09, 2009, 11:38:10 am »

Lucky me, I found a spare k24 exhaust housing in my parts pile. Time to break out the grinder and cut that trapezoidal flange out!

I like this manifold:

zukgod1 · « **Reply #6 on:** January 09, 2009, 12:35:08 pm »

Quote from: "53 willys"

Quote from: "zukgod1"
I know you want to use the trapezoid flange but if you get a manifold off a Audi 5cyl turbo car you can cut the front exhaust flange and they already have the flange for the wastegate. They bolt right on our heads but have the extra flange due to the 5cyl thus cutting it off.
A friend of mine JUST gave one away damnit!

The Audi manifold have the flange for the k26 turbo which would be easy to adapt to any flange type.

Dan do you have any pics of a audi manifold that has been cut??

No but I can take you to the guys house that hase it so you can see it with your own eyes.

EcoMod · « **Reply #7 on:** January 13, 2009, 08:23:40 am »

I use to change flanges and add a wastegate flange to a nissan sr20de manifolds. Just use a stainless or nickel rod. For a diesel you should never have an issue. The Nissan manifold with ghetto fab flanges, use to glow cherry and not crack.

The right way to do it is out there...but, sometimes over-engineering isn't worth the cake it costs. :wink:

Smokey Eddy · « **Reply #8 on:** January 13, 2009, 01:11:04 pm »

Quote from: "EcoMod"

The right way to do it is out there...but, sometimes over-engineering isn't worth the cake it costs. :wink:

Haha, i like that

foxracer1 · « **Reply #9 on:** January 15, 2009, 07:06:28 am »

I welded on my turbo and manifolds much like libbybapa has on his. No issues to this date.

blkboostedtruck · « **Reply #10 on:** January 15, 2009, 07:56:43 am »

here's my 2 cents about welding cast! i have welded it a lot my process i use a DC stick welder! mainly because for the use of nickel rod witch allows it to be machinable! where i can drill, tap,mill, if need be? you can weld with a wire MIG machine and stick weld with 7018 rod are the same welds! doing it this way makes the weld a lot harder because of the high carbon content in the cast ! if your not gonna do any machine work to it after what ever you welded to it then it's fine to weld with wire and or stick weld with 7018 rod!
but if you need to do some machining after it's been welded then you gotta use nickel rod and a DC stick welder then the only other critical thing that has to be done before welding is pre-heat evenly above 250^ and let cool
on it's own! don't quench in water!!
so that basically it! just knowing what rod to use if machine work is needed
after it has been welded! and pre-heat! pretty simple!
Duane