I had a whiskey influenced idea... Kind of a twin charge, thing.
06-13-2007, 08:12 AM
#11
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
Originally Posted by HiProfile
Are you suggesting that you essentially block off one 'scroll' of the turbo until it reaches full boost? If so, its essentially like sequential turbos, except with just the turbine. It may help, but the problem is that you still have X amount of energy pushing into the turbine, just under more pressure. Its also only working on half of the inducer's height. Since you're running half of the exhaust through it, it will have to be something like a sodium-filled valve most likely, and would contribute to blocking flow.
The reason a twin-scroll works is that the pulse is kept in a small volume till it acts upon the turbine, and by due to turbine wheel speed and pressure in the other scroll/side, it doesn't revert to that 2nd scroll, and goes out the DP. I'd think the valve in the way and the crossover tube would contribute to enough blockage to negate any gains, or at least do nothing besides spool a completely oversized turbo up a couple dozen rpm faster w/o hurting topend.
The reason a twin-scroll works is that the pulse is kept in a small volume till it acts upon the turbine, and by due to turbine wheel speed and pressure in the other scroll/side, it doesn't revert to that 2nd scroll, and goes out the DP. I'd think the valve in the way and the crossover tube would contribute to enough blockage to negate any gains, or at least do nothing besides spool a completely oversized turbo up a couple dozen rpm faster w/o hurting topend.
I dont think I will wait until full boost, maybe just a couple psi. Open up the second gate once the turbo has begun spinning.
I will try it and see.
06-14-2007, 08:47 AM
#12
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
i know many of my customers have reported blocking (permanently) one of the 2 holes of a twin scroll turbine to accelerate spool up and that definitely works. Yes, it impedes flow of course, but in the current project, the second hole will open before it becomes an issue.
06-17-2007, 12:57 AM
#13
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
Since they permanently block one of the holes, that tells me they don't have the exhaust pulses split, rather they're using a regular manifold with a divided turbine. Of course that will help spool (essentially like halving AR), but so will proper pairing of the exhaust pulses. An ideal setup would split the cylinders between the holes, and have 2 valves (1 open while the other is closed) - covering a hole while diverting to the other via crossover tube, then opening the hole while closing the cross-over tube.
Although that may help spool, when you have the right manifold for a divided housing, its doing the same thin. Its like splitting the exhaust between 2 small manifolds/housings, while using 1 turbine wheel. When you do that, the majority of the gas will not revert into the other side, as it still has a higher pressure then the downpipe.
By all means, try it. I'd like to see back-to-back tests of a properly divided manifold vs this single turbo, sequential turbine setup deal. Preferably with a D16 on a GT30 with the divided T3 .78AR housing.
Although that may help spool, when you have the right manifold for a divided housing, its doing the same thin. Its like splitting the exhaust between 2 small manifolds/housings, while using 1 turbine wheel. When you do that, the majority of the gas will not revert into the other side, as it still has a higher pressure then the downpipe.
By all means, try it. I'd like to see back-to-back tests of a properly divided manifold vs this single turbo, sequential turbine setup deal. Preferably with a D16 on a GT30 with the divided T3 .78AR housing.
06-23-2007, 08:32 PM
#16
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
True sequential (2 turbos) works, but thats because you are moving 1 turbine wheel at low engine speeds, then split the exhaust between that turbo and a 2nd at higher rpm's. This idea, if I'm seeing it correctly, uses 1 turbine wheel regardless of opperation. Its just restricting flow in one mode, and adding extra flow capacity (if you use a large AR housing) in the other mode.
06-24-2007, 11:27 AM
#17
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
it'S being done only on the new acura RDX AFAIAAO.
except that the honda turbo they use to do this has the two scrolls on top of each other (concentric) as opposed to side by side.
I wish i had more spare time in order to give a try to this first!!!
i have many customers who purchase twin scroll turbos and plugged one scroll to accelerate spool up with great results so it will work for sure.
except that the honda turbo they use to do this has the two scrolls on top of each other (concentric) as opposed to side by side.
I wish i had more spare time in order to give a try to this first!!!
i have many customers who purchase twin scroll turbos and plugged one scroll to accelerate spool up with great results so it will work for sure.
06-24-2007, 01:03 PM
#18
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
I'm not saying it won't work, I'm saying its completely different from twin sequential turbos.
As for the people ordering divided housings and permanently plugging one hole... :1 Maybe its just because they wanted to make a merge collector half the size of a normal one? I can see it helping, but not like selecting the proper AR housing and stage wheel. If you want to argue flow on that one, think about where it necks down on a undivided housing, then where it has to for the plugged divided housing. Unless you have the exhaust slam into the flat blockoff plate, you're going to have a couple extra inches of very small runner volume. To make an analogy, its like having a 4" exhaust with a restrictive baffled muffler vs a 4" DP w/2" exhaust and that baffled muffler.
As for the people ordering divided housings and permanently plugging one hole... :1 Maybe its just because they wanted to make a merge collector half the size of a normal one? I can see it helping, but not like selecting the proper AR housing and stage wheel. If you want to argue flow on that one, think about where it necks down on a undivided housing, then where it has to for the plugged divided housing. Unless you have the exhaust slam into the flat blockoff plate, you're going to have a couple extra inches of very small runner volume. To make an analogy, its like having a 4" exhaust with a restrictive baffled muffler vs a 4" DP w/2" exhaust and that baffled muffler.
06-25-2007, 06:41 AM
#19
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
Originally Posted by HiProfile
I'm not saying it won't work, I'm saying its completely different from twin sequential turbos.
As for the people ordering divided housings and permanently plugging one hole...
As for the people ordering divided housings and permanently plugging one hole...
we are interested in what works and is cheap.
seems to me what Blaast is saying is what we're interested in. Blocking a divided housing works. If you've got the money to order a custom turbo, go for it, but remember this is homemadeturbo...
06-25-2007, 11:51 PM
#20
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Re: I had a whiskey influenced idea... Kind of a twin charge, thing.
I know its totaly different from sequential twin turbos. You're missing one for starters. I just mentioned sequential in the title just because it seemed to bescribe the idea while I was drunk.
Anyway, I'm just waiting on the gate. I already have some spare mandrel tubing, I'll have to make some plates. But otherwise, it should come together soon. Just figuring out how I'll fit this extra gate. I have next to no room under the turbo. But I'll get it.
I'll take lots of pictures.
Anyway, I'm just waiting on the gate. I already have some spare mandrel tubing, I'll have to make some plates. But otherwise, it should come together soon. Just figuring out how I'll fit this extra gate. I have next to no room under the turbo. But I'll get it.
I'll take lots of pictures.
