I am going to try to adapt my existing twins to use an external wastegate, would it be better to build a spacer to mount the wastgate or weld it to the manifold, or tap the manifold so it can be screwed in, and doesn't it take 1 1/2'' pipe for the wastegate, how do I remove the webbing between the manifold outlet after I drill it

 

I'm guessing building a spacer would be best. I think drilling and tapping might remove too much material (especially if you machine out the web) and add stress risers to the iron causing a crack. Those twins do weigh a lot. I know welding to cast iron can be done but I thought in order to do it right, you had to heat it first - something like that.

 

The manifold it cast steel, not cast iron. You can weld to it.

If you put a pacer in-between the turbo and the manifold you will have to redo your exhaust pipe. You might have to redo your cold too, as it may interfere with the filter pipe/battery when you move it over.

My suggestions would be to put it in the manifold.

Rowland, can you post a picture of the external wastegate riser you welded on your manifold?

You do have a support on the big turbo correct?


Justin

Edit to fix spelling corrections

 

Justin, I dumped several of my "under construction" pictures. Couple more in my Gallery.

I just followed Banshee's instructions here... https://www.dieseltruckresource.com/...threadid=54981
RJ

 

Looks good.

If I stick some huge injectors in I may have to put an external in the manifold.

Who welded that for you?

Are you using a flex pipe to dump it into the exhaust?

What did you do to the divider?

I am think I would just take a hole saw without the center bit, score a hole deep enough to cut through the manifold and clean the rest up with a grinder. (Building twins gives you alot of grinder expierence)

At what PSI do you have it set to start dumping?

 

You can see the flex pipe here. Could only find corregated stainless flex in 1-1/2" so went with galvanized. So far no indication of excessive heat...it's just not open long enough to do damage, IMO.

I have no welding gear. Had a friend, who is a pro, do the welding.

Ground out the divider about 1/2 way in a "U"...but left a lip on both sides on which rests the riser... about 5/8" in. 1-1/2 steel pipe for riser with strong weld should renew manifold integrity...at least for a big single! For twins may want to leave divider untouched for more strength...and just cut hole in top of manifold...like Banshee.

Same pipe welded at about 30 degrees to downpipe for other end of flex pipe.

Still experimenting with boost but with the Mach 4's I get no additional smoke when limiting boost to around 45 psi. Need to get some dyno time to test different boost levels!

RJ

 

Rowland,
Did you just use standard u-bolts on the flex pipe? i'm concerned about the seal of the flex pipe to the 1.5" pipe stub. i know there's not much pressure, it's just blowing into the downpipe, but do you get any exhaust leaking into the engine compartment?

 

Used 1-1/2" Muffler clamps. Had to order them. 4 wheelers are the only thing I found using 1-1/2" exhausts. No leakage so far. Had to retightened a couple of times till they stayed snug. Wanted to be able to replace with stainless flexpipe if needed....don't think I will need to.
RJ

 

Is the pipe dumping under the truck or in the exhaust pipe?

I remember the being a link for the stainless flex pipe. Do you have it again?

Thanks,

Justin

 

About a 30 degree angle into exhaust downpipe....about 12" past the bend.
RJ

 

Nice pictures!!

Mine went in pretty much as rjohnson described only mine's on the other side of the manifold. Start the hole saw with a center bit, but as soon as the teeth make a path to follow remove the center bit and then continue drilling through. Once you get through the top "dome" of the manifold just beat it out with a punch & hammer, and then grind everything smooth. I "U"-ed my center rib out about 1/3 of the way down and tried to smooth everything around for the best flow. Also, I scalloped the steel pipe end that went into the manifold to smooth the edges that would stick down into the flow.

Welding wasn't too bad with the right prep. The manifold is cast iron (not steel), so definitely get it good and clean and preheat (oven or torch). The ATS manifolds are a little better quality than the stockers, so they should weld a little easier. My out pipe is solid, but it's a little tricky when putting everything together, so the flex is a good idea IMO. The hardest part was just mocking everything up to make sure it would all clear and mate up. I'll post a pic later on if you're intested....

John

 

Did you use an arc welder? TIG? MIG?

I would like to see some pictures.

 

Would love to see your set up. The more pics...the better!
Did you plumb yours into exhaust...or big turbo turbine?

RJ

 

I would hope your dumping it into the hotpipe feeding the big turbo. With the 35, wastegating at around 20-25psi seems to give good transition.

 

Justin,

It was MIG welded together after being torch heated. So far it's holding good!

Rowland,

The exhausted gas is routed back into the "hot pipe" that feeds the bottom turbo. The Tial opens first at around 19 pounds, and the internal opens in the low 50s. Cranking the Tial tighter via the regulator will raise the total boost as well as improve low end by working the top turbo harder. I didn't have any good closeups of the wastegate, so I ran out in the rain and took one I couldn't get a clear shot of the back pipe, but it's behind the wastegate. I'll try to get some more pictures soon.

wastegate closeup


full shot


John