Reducing Turbocharger Turbine/Internal Mass? 1

[BP5811]

My background is limited in regards to automotive. I've been around and delt with several vehicles that have been plagued by turbo lag. I've wondered if there was a effective way to increase the velocities of the exhuast gas to increase spooling properties. Like on some of your twin scrolls turbos etc.
Something I've been tossing around is if that increasing the velocity is hard to impliment what about reducing the mass of the internals/turbine of the turbocharger?
I've done the math and what materials could be used to do this. Although they are not very cost effective they would reduce the rotational mass by 62-64%.
Materials is what my background consists of so this would be something i'd be interested in to r&d, if there would be any gains to this.

My question(s) are if this would show any gain? Should I just throw this idea out? I haven't found if anyone has tried this before anywhere on the net yet. Maybe I have to dig a little farther.

 

[MikeHalloran]

Don't tell us here.

If you really could reduce the rotating mass by 2/3, without making the cost completely skyrocket, the people who make turbos would be _very_ interested in hearing what you have to say, and would probably be prepared to spend a lot of money to do so.

... Well, okay, but maybe you could talk them out of a modest salary.



Mike Halloran
Pembroke Pines, FL, USA

 

[BP5811]

The cost would be skyrocketing. But I wouldn't mind doing some r&d on this. I have access to basically any material and the machinery to make it happen. Although it would be an extreme cost to do this. I still haven't got all the cost number done yet but I maybe able to do some testing on this.

 

[Fabrico]

We had a large purchase of large vehicles with Brand X Diesels in them. The OEM turbo blades were ceramic, and very responsive. In this case the desired response was less puff, not more pull, but the requirement is the same. Two problems came with the improvement. One was very definite sensitivity to over-speeding. Even the slightest leaks in the plumbing or aftercooler would cause over-speeding and catastrophic failure. The second problem was rebuilding. All the rebuilts, including those from the same OEM, were back to metal early on. It was never revealed whether it was the first problem or an overly comprehensive manufacturing and assembly process, that caused the change back to conventional materials.

 

[turbomotor]

A good deal of money, time, engineering hours, etc. have been spent over the past twenty or so years to improve the response of the turbocharger. Ceramic turbine wheels, titanium aluminide intermetallics, variable turbine nozzles, and smaller than desired nozzles paired with exhaust bypass (wastegate) controls are but to name a few. If you have a turbine wheel material solution that has the promise of reduced rotating inertia but maintains current durability, reliability, and low cost, I assure you that the turbocharger industry is interested. Have you patented your solution?

 

[black2003cobra]

BP5811 - Perhaps you can consider using this material on the cold side, as well.

 

[tbuelna]

turbomotor,

Sounds like you're a bitter, jaded old turbomachinery designer.

Regards,
T

 

[BP5811]

As for all that have posted regarding this. We have calculated the costs at producing these. They will still have to be fully tested, but the prototypes will be completed in 3-4 weeks minus holidays. The mass reduction would make it a little more then a third of its original mass. Will it work? In testing we've had good results with the material. Costs would make it 20-40% higher to produce depending on quanity(large quanities)

 

[whitehendrix]

hm.. interesting concept on lighter internals.

of course, as you know, decreasing hotside A/R is the easiest way to spool faster. i would also surmise that the helix of the turbine fines would affect spooling characteristics.

that, and coming as close as you can to the exhaust ports..

yes, lighter rotation components would certainly affect spool time, BUT i would question the spool time between shift on a manual-tran application.. after all, the torque developed during spool up carries thru a little bit (dependant on boost pressure, of course) between shifts.. unless you're utilizing an auto or sequential trans, in which case boost is always present.

on a few bike forums i'm on (i build racebikes..) i've seen an "epoxy mod" that seems to be gaining popularity.. while this is actually done on N/A motors on the intake side, and seems to be quite effective (creating a venturi in the port itself.. which can individually be tuned per port..) i kinda wonder if it could possible affect port velocities on exiting gasses.

these guys have it to a science to where they'll set the left port for low-mid rpm effectiveness and the right port for high-rpm gains.. its pretty wild.

fabbing a smooth flowing collector and manifold pays dividends in low-end spooling, as does an effectively sized hot side. the internals, parasitic losses and drag also play a huge role as i'm sure you know.. thus the reason top builders utilize ball bearing or ceramic-bearing cartridges. the only thing i don't like about ceramic wheels is that if they shatter, you're going to have a long, expensive day. the aluminum alloy based comp wheels seem to take an ass whipping and withstand it..

 

[BP5811]

whitehendrix- That epoxy mod sounds interesting. I'll have to look at what they did. We are working with a few people to develope these lighter components and they "will not" shatter. Reducing the A/R will reduce your top end, depending if your turbo is at its efficeny range.
A few companies are utlizing the twin scroll turbos and making a plate or device that blocks one inlet and increasing the exhuast gases velocity making it spool up that much faster. Then once a certain pressure is obtained it will open the other inlet. If we could couple that idea with the lighter components, just think of the spool up. The guys are gaining on average 700-1000 rpms on your average gt4202.

 

[whitehendrix]

ya.. to get supercharge-type response would be amazing.

i'm building my ZX7-R for drag and LSR right now, and plan on utilizing a T3 with a 50 trim and .48 hot side.

my concern IS top end tho.. i could use TDO4-L which was my original intention and still may do so, but i wanted low boost, as i'm trying to eclipse 200mph at maxton and make 250+ on the dyno.. i'd like the power as low as possible..

variable vane is awesome stuff, and seeing about the twin scroll posrt blocking makes me wonder as well..

this could be operated with vacuum and switched by a controller depending on accumulated speed, rpm and gear..

...makes it VERY "tunable" that way.

heres the epoxy mod site.. one of my favs..

http://www.mototuneusa.com/

Hmm..

 

[izzmus]

Mazda did the twin scroll turbo/flapper valve thing in 1986 on the RX-7. I believe the flapper opened at 5psi boost with a 7psi wastegate.

And then, for the 1989 redesign/update, they went to a standard configuration.