Gating around the VGT.

White_monster · Sep 4, 2013

First off this is in regards to any turbo setup capable of gating to between stages, ie high powers, max powers, etc.
Second I'm not calling anyone out, I'm really just interested to know why.

So here it goes. Why do we only gate off of one side? I understand its supposed to equalize pressure once into the housing of the VGT but ebp still is way up there and were not getting the atmo turbo to really do some work. Wouldn't merging a branch off each up pipe into a gate and around the VGT into the atmo get the atmo doing more work while keeping the VGT in its happy place?

Thoughts boys and girls, lets keep this civil and on track cause we all want the same goal of more power.

Stroked777 · Sep 4, 2013

I believe they don't gate the HP Becuase of the fact it's a VGT and the vanes could open up all that way and kinda bypass the hp turbo. I hope i understood the question correctly

forcefed6.4ford · Sep 4, 2013

I now we have chatted about this lately Shane.

My thoughts are that to blend the flow prior to the gate is likely the best. It balances the flow from the heads, allows more volume to stabilizing gate opening and keeping an even and balanced flow into the turbo. I know people have said that the exhaust will equalize at the turbine but I don't see how that is possible when the gate is opened on one bank. There would have to be backwards flow to the gated side to make up the difference causing inlet turbulence.

Just my thoughts

White_monster · Sep 4, 2013

Stroked777 said:
I believe they don't gate the HP Becuase of the fact it's a VGT and the vanes could open up all that way and kinda bypass the hp turbo. I hope i understood the question correctly

They gate around the VGT, it's built that way. What I want to know is why not gate off both up pipes around the VGT and if anyone has done this what kind of results.

Stroked777 · Sep 4, 2013

White_monster said:
They gate around the VGT, it's built that way. What I want to know is why not gate off both up pipes around the VGT and if anyone has done this what kind of results.

I see what your saying, do this to maximize flow/ drive pressure going to the atmo to get more power.

Stroked777 · Sep 4, 2013

I don't think I'm reading anything at all right lol

6.4psd916 · Sep 4, 2013

For the life of me I can remember his user name, but the lifted white truck that threw the 98mm or something similar in front of industrial's tow powers I believe, built his own up pipes with a h-pipe design to move as much exhaust to the big charger to drive it. It seems to me that elite has their turbos sized pretty well so gating to the atmo isn't necessary. Now if something really large was thrown in front of the vgt, I could see gating that way.

White_monster · Sep 4, 2013

Thing is I can't for the life of me get my 82mm in my max powers to do enough work. My VGT has seen as high as 45psi on its own. I'd like to see 40psi out if my 82mm and maybe 30-35 out if my VGT. Looking at a compressor map of a billet Garrett 80mm turbo shows its good to about 45psi or so and I know this isn't exactly perfect but that map gets me close to its happy range.

Is this completely wrong?

BFT · Sep 4, 2013

I'd bet it would be TONS of fun trying to get up-pipes off and on having them together to run one WG.

White_monster · Sep 4, 2013

BFT said:
I'd bet it would be TONS of fun trying to get up-pipes off and on having them together to run one WG.

That's likely. But 99% of ppl pull the cab so that's not really a concern. Plus bellows allow for minor fit issues.
This brings up one if my thoughts. Do we use only one up pipe to make it easier?

6.4psd916 · Sep 4, 2013

Its easier to do one, and one is probably all That's needed for the average person. And its easy and much cheaper to do because of the stock egr pipe.

BFT · Sep 4, 2013

White_monster said:
That's likely. But 99% of ppl pull the cab so that's not really a concern. Plus bellows allow for minor fit issues.
This brings up one if my thoughts. Do we use only one up pipe to make it easier?

Yeah, but I wouldn't want to pull the cab because one bellow blew. Now I either buy a whole new set up or get a similar bellow, find a lift, find a good welder to weld it...etc

White_monster · Sep 4, 2013

I can already see where this is headed. I'm out.

jimdawg185 · Sep 4, 2013

Tuning any gate is a tough and frustrating task for some and others get it by pure chance on the first try. I agree that balance would be a good thing, but will it drive your atmo harder, who knows until you try it and change nothing else. Which would be tough, because the gate will obviously have to change. Then you won't know what really made the difference.

6.4psd916 · Sep 4, 2013

If a v-band was put in the h-pipe, you could pull either pipe out.

jimdawg185 · Sep 4, 2013

Then log the changes? Not a bad idea.

NathannialD · Sep 4, 2013

the reason we only do one pipe is because after both banks enter the vgt there is an opening just after the flanges in the turbine housing to equalize the pressure if there was an issue.

Getting the atmo to do more work does take a little effort, we have done some vgt tuning to essentially make the turbine housing smaller on the vgt to allow more flow to be forced into the atmo. IIRC Tadd's truck with max power x turbos (88mm atmo) made 45 ish psi out of the 88mm while keeping bp around 80psi. total was in the high 60's low 70's.

jdgleason · Sep 4, 2013

I would be interested to see someone put some pressure sensors in each up pipe half way up or so, and watch what happens (if anything) when the gate opens...

That should tell the whole story I would think.

Jonnydime · Sep 4, 2013

delong_1 said:
the reason we only do one pipe is because after both banks enter the vgt there is an opening just after the flanges in the turbine housing to equalize the pressure if there was an issue.

So in theory only one bank is being relieved of back pressure unless the exhaust flows backwards through the VGT flange from the other bank?

SSpeeDEMONSS · Sep 4, 2013

jdgleason said:
I would be interested to see someone put some pressure sensors in each up pipe half way up or so, and watch what happens (if anything) when the gate opens...

That should tell the whole story I would think.

What about in the manifolds themselves? That should show more what is happening when the gate opens.

Garrett

probably getting paid at work to post this from my POS phone