External Wastegate Questions

Cummins Driver

Cummins Driver

THE Cummins Driver
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May 16, 2007
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Alright, I think i would really like to set my truck up to be a strong runner in work stock when i pull as some of you know.

What i am thinking, is running a 38mm external wastegate with an HX35.

The turbo would be a rebuilt HX35 with a 60mm compressor side, and an 18.5cm exhaust housing. I would rather not mount the gate on my manifold.

I was wondering if anyone would see a problem with cutting out the divider at the mouth of the exhaust housing, and drilling a hole and welding the pipe and flange that goes up to the gate directly to the exhaust housing. Would this still work well?

Im also curious if you guys think a 38mm gate would make up for the exhaust flow i would lose by going back to the 3 inch outlet instead of the 4 inch like what is on my HX40.

Also, what all boost lines have to be ran to the external gate? And what is a good price on a 38mm gate, and what are some good brands? I know tial is a good one, but there are many others, including knock off's.

Im not sure i would want to do this yet, but i would sure consider it. Id appreicate some information on the matter. thanks

Eric
 
zstroken said:
If your running an external gate, why not try the 12cm housing? Or a 14?
JGSturbo makes a good gate.

http://jgsturbo.com/50bmg.html
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I had thought about running the 12cm housing that came off of the stock turbo or a non gated 12. I have a non gated 16cm housing also. Just hate to cut it up since it was $160.

Do you think there would be any problem with running the gate pipe right out of the inlet of the exhaust housing? I dont think I want to put it in my manifold yet, because i could always do it later anyways. Of course i guess i wouldnt ruin my exhaust housing if i just did it in my manifold in the first place.

Would there be much to be gained running an external gate over just running the 12cm exhaust housing with a drilled out divider and larger wastegate opening? I hear that keeping boost down with that setup is no problem. But im not sure how drive pressure is, or if an external gate would have any real advantages.

Thanks for the help.

Eric
 
You can put a larger gate in the 12cm housing. If you have a decent machine shop it wouldn't be that hard. You can use an exhaust valve to replace it.
 
You can machine a pocket directly into the exhaust housing to install the gate. That way you can vent both sides of the scroll a bit better.
 
RonA said:
You can machine a pocket directly into the exhaust housing to install the gate. That way you can vent both sides of the scroll a bit better.
Click to expand...

Ron do you have a pic of how that would be done? Thanks
 
blkram said:
Ron do you have a pic of how that would be done? Thanks
Click to expand...

I don't have any pictures from the hx35 I did. It might still be on Bob Wagner's truck(the smarty guy). I'm getting ready to do another one on a different turbo. I made a really simple wastegate that uses either a standard actuator, or the spring type, and will fit on the ex housing just below the t4 flange.
 
What do you mean by machining a pocket? Just cutting out a small spot in the middle of the scroll?

How do you go about setting up an external wastegate? Do they have different springs, or can it all be controlled with boost?

Eric
 
I just machine a center hole that goes down about 1/2" or so(depending on the housing). Then a flat area with four drilled and tapped holes to hold the gate onto the exhaust housing. Depends on what the gate looks like. Sometimes i just bore a hole and machine a 1 3/8" hole through the wall and down into the divider, then thread mill a fine pitch tapered thread and make a matching threaded pipe to fit. Or you can just bore a hole in it with a hole saw and weld an old rusty piece of pipe into the hole. It all accomplishes the same end.
 

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RonA said:
I just machine a center hole that goes down about 1/2" or so(depending on the housing). Then a flat area with four drilled and tapped holes to hold the gate onto the exhaust housing. Depends on what the gate looks like. Sometimes i just bore a hole and machine a 1 3/8" hole through the wall and down into the divider, then thread mill a fine pitch tapered thread and make a matching threaded pipe to fit. Or you can just bore a hole in it with a hole saw and weld an old rusty piece of pipe into the hole. It all accomplishes the same end.
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What would a machine shop charge to do that?

Just an estimate is fine.

Where is that billet piece from?
 
bsmith said:
What would a machine shop charge to do that?

Just an estimate is fine.

Where is that billet piece from?
Click to expand...

It could take any where from an hour to 3 hours depending on what needed to be done.
My new charger will be here this week, and if it will clear the hood, I will take pictures of the gate install and machining involved.
I made that gate housing a few years back to install on a non-gated hx35 secondary charger. It is a 1.25" gate. It should flow about 1.5x as much as the gate in my 16cmss housing. It is also very simple. Just like an internal gate.
 
Keep us posted Ron.
I'm interested to see how it comes out.
I am always amazed at the stuff you machine.
 
RonA said:
It could take any where from an hour to 3 hours depending on what needed to be done.
My new charger will be here this week, and if it will clear the hood, I will take pictures of the gate install and machining involved.
I made that gate housing a few years back to install on a non-gated hx35 secondary charger. It is a 1.25" gate. It should flow about 1.5x as much as the gate in my 16cmss housing. It is also very simple. Just like an internal gate.
Click to expand...




Can you tell us about the new charger?
 
bsmith said:
Can you tell us about the new charger?
Click to expand...
Garrett GT4094R. I've been really happy with my 4718, so I decided to try a Garrett on top. Not much info available. Some say they work, some say they don't.
 
If i were to run a 12cm exhaust housing, and wastegate it at say 36psi, and it didnt have any problem staying there with the divider drilled, would I still benefit from an external gate, or would that mean that the stock gate is flowing plenty enough and that drive pressure and exhaust flow shouldnt be a problem? Thanks

Eric
 
RonA said:
Or you can just bore a hole in it with a hole saw and weld an old rusty piece of pipe into the hole. It all accomplishes the same end.
Click to expand...

All I can find is some new pipe, how can I get it rusty quickly?????!!!!!
 
Cummins Driver said:
If i were to run a 12cm exhaust housing, and wastegate it at say 36psi, and it didnt have any problem staying there with the divider drilled, would I still benefit from an external gate, or would that mean that the stock gate is flowing plenty enough and that drive pressure and exhaust flow shouldnt be a problem? Thanks

Eric
Click to expand...

i had my 12cm wastegated housing on and got the boost down to 34psi. seemed to run good. i put on the 18.5 i had and it picked up a lot! better bottom end and way more top end. i think the 12cm housing is too small for a single but thats just me.

Garrett
 
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