ndisgii

I have an idea thats been in my mind for a while now, and I want to hear peoples opinion on it. Would there be any feasability in doing a sequential type setup with one big turbo that is using a divided turbine housing like the Garrett turbos or similar. Here is a crappy pic I threw together to demonstrate what I am talking about:



a Divided twin-scroll housing is essentially two exhaust inlets at half the area for each port. By sending exhaust gases into one port oniy, it is creating the spool gains similar to reducing your turbine housing in half. When the wastegate opens under a predetermined boost level, it now opens up the other side of the turbine housing inlet restoring full A/R of the housing.

Would this work and would it provide any benefits in the spool department. Also, would this design choke the turbo in any way due to its design? Thanks for any comments/suggestions/opinions you can share!

SPOOLINmatt

no, its useless.

ndisgii

Can you be a little more specific as to why please? One of the top Supra tuning companys out there, Sound-Performance, says that it does work, but they dont have an available kit yet. I just wanted to hear other peoples opinions about it. After seeing what Sound Performance has already created with the 1st and only aftermarket twin turbo sequential setup for the Supra, I trust they may know what might work. I am looking for anyone that may have already tried it and had problems with it. Or even hard facts as to why it may not work.


Modified by ndisgii at 10:21 AM 3/3/2008

Danza

lets think about energy.

youre using the kinetic energy of the exhaust gasses to create kinetic energy in the turbocharger.

Over some amount of time, say a second, you get the same amount of kinetic energy being transferred.

shouldnt make any difference

ndisgii

So you dont think that having all the exhaust energy traveling into effectively half the A/R as usual, will spool the turbo faster? I think also that the fact that initially, at least until the wastegate opens, it will be forcing more exhaust energy into a smaller area. This should also create more velocity and heat, which should also help spool the turbo sooner. Is any of that correct?

blinx9900

as long as you can route ALL the exhaust into one side, then be able to switch it to both sides it should work, not sure how effective it would be though...

ndisgii

blinx9900:
Yes, that would be the gameplan for sure. Whether or not it can be accomplished succesfully or not is another story...lol

wakedoe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Danza &raquo;</TD></TR><TR><TD CLASS="quote">lets think about energy.

youre using the kinetic energy of the exhaust gasses to create kinetic energy in the turbocharger.

Over some amount of time, say a second, you get the same amount of kinetic energy being transferred.

shouldnt make any difference</TD></TR></TABLE>
Energy is probably a poor way of thinking about that, because two turbos can have the same moment of inertia, but one will spool much faster than the other. Two identical turbos with different turbine housings will have different thresholds. A better way of thinking about is liquid flow. Even though water is incompressible, think about this. When you squish the end of a garden hose does water start spraying faster?

Danza

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wakedoe &raquo;</TD></TR><TR><TD CLASS="quote">
Energy is probably a poor way of thinking about that, because two turbos can have the same moment of inertia, but one will spool much faster than the other. Two identical turbos with different turbine housings will have different thresholds. A better way of thinking about is liquid flow. Even though water is incompressible, think about this. When you squish the end of a garden hose does water start spraying faster?</TD></TR></TABLE>

won't spray faster if you half the volumetric flow rate at the same time you half the cross sectional area, which is what we're talking about.

and we're talking about the same turbo, one with a traditional setup, one with this concoction

wakedoe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Danza &raquo;</TD></TR><TR><TD CLASS="quote">

won't spray faster if you half the volumetric flow rate at the same time you half the cross sectional area, which is what we're talking about.

and we're talking about the same turbo, one with a traditional setup, one with this concoction</TD></TR></TABLE>

You won't half the volumetric flow rate, unless you half the engine's intake, the exhaust gas has to go somewhere, thus increasing the velocity. And it's not same turbo, essentially it's two different turbos, with two different turbines. Now someone who's had experience with it has to chime in and say whether there's an appreciable difference.

Danza

ok I think what I think he's talking about might not be what he's actually talking about.

I thought he was trying to do two separate collectors, each for half of the cylinders.

MADMAX_zero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Danza &raquo;</TD></TR><TR><TD CLASS="quote">ok I think what I think he's talking about might not be what he's actually talking about.

I thought he was trying to do two separate collectors, each for half of the cylinders. </TD></TR></TABLE>


Go ahead and think about that one for a split second...and realize how completely retarded that sounds.

tokesGTR

You mean something like this?

wakedoe

Are you gonna have any additional wastegates with that or what? Is that a Holset?

Danza

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MADMAX_zero &raquo;</TD></TR><TR><TD CLASS="quote">


Go ahead and think about that one for a split second...and realize how completely retarded that sounds.


</TD></TR></TABLE>

i know this sounds retarded, which would be why i responded like it was a retarded idea

streetracer6rpt

Bullsye power S400 is all u need.............. the hell with twins

ndisgii

TokesGTR:
Yes, I think that may be similar. I am a little confused on where the two long tubes that come into a Y are actually coming from, but I think this is the idea. Have you tested this? Does it work?

Danza:
WTF are you talking about?

streetracer6rpt:
"the hell with twins"....Are you referring to twin turbos? Can you read? Who said anything about twin turbos?

White Smoke

I read about doing something like this on another forum. There was a plate/spacer with a flapper built in for one side of the turbo. There was some really good comments and ideas, lemme see if I can find the link.

HiProfile

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Danza &raquo;</TD></TR><TR><TD CLASS="quote">lets think about energy.

youre using the kinetic energy of the exhaust gasses to create kinetic energy in the turbocharger.

Over some amount of time, say a second, you get the same amount of kinetic energy being transferred.

shouldnt make any difference</TD></TR></TABLE>

So then... why do they offer different A/R housings? Why will a .48 be good for a D16 when it will "run out of breath" on a GSR? I guess certain parts of a turbo are above your level of understanding.


As White Smoke mentioned, there was some forum thread where a couple people posted stuff like this. One guy had datalogs from his 4.xL explorer V8 - spooled to 6-8psi just before redline with a huge Holset, then blocked one scroll/vane and instead got 10psi 2500 rpm SOONER. Earlier in it someone posted his homemade flapper idea, which is like the OP's idea, except it was just a butterfly blocking one vane.

I like the idea of a vertical flapper on a divided manifold. To help spool the turbo, the flapper diverts all gases to one vane, effectively HALVING the A/R. Once its about spooled, a normal WG actuator moves the flapper (to completely vertical) to divide the turbine inlets, turning it into a normal dual scroll manifold/turbo setup.

This is a shitty idea to people who live at redline or drag race with anti-lag, but to people who enjoy power AND fast spooling - or just want to have a huge powerband - this idea is ****.

ndisgii

Someone posted in my thread over at Supraforums with this pic:




I think this is an even sweeter idea and might be what HiProfile is describing. I wonder how hard that would be to fabricate.

streetracer6rpt

lol, i must be.....

ndisgii

Anyone else have any opinions or experience with a setup like this?

Danza

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ndisgii &raquo;</TD></TR><TR><TD CLASS="quote">Danza:
WTF are you talking about?
</TD></TR></TABLE>

I'm stil trying to figure out if what you described in your initial post, is what I responded to in mine, OR what other people are saying will work.

I'm lost in your description.

EDIT: nm, reread it. My initial response was to something different from what you described, my fault.

ndisgii

No problem...I am just trying to get as much feedback as possible from anyone that understands what I am aiming for. Peace!

93supercoupe

wouldnt u need another wastegate venting to atmosphere so u would stay at target boost?Otherwise the thing would max right out, and i doubt what ever its going on cant take that much boost.