Quick Spool Turbine Housing Flapper Valve - Need help!

[Alky V6]

Attention engineers!
I'm starting a community project. I have a T4 to T6 adapter plate installed before my T6 split turbine housing. The plan is to modify the adapter plate to include a flapper valve that will close off one section entrance to the split turbine housing. The idea is to force exhaust gases to use half the available area of the turbine housing to vent exhaust gases to the turbine wheel. This will increase exhaust flow velocity and hopefully lessen spool time. This is not a new idea, and it's pretty much, already been proven to work rather well.

The T4 to T6 adapter is not split, so the first mission will be to install a dividing wall to the adapter to match the dividing wall of the split turbine housing.

The next decision will be, what side of the split turbine housing to close off?
I'm thinking leaving open the side that will allow the longest contact of exhaust gases to the turbine wheel. Furthest away from the exit of the turbine housing.

Then material questions:
Material for the flapper valve? Thickness?
Material for the flapper valve shaft? Diameter?
Material for the flapper valve shaft bushings? Shaft to bushing clearance?

Other questions:
How to retain the flapper valve to the shaft?
Which direction to have the flapper valve close? The angle when closed?

Control mechanism? Method to close? Method to open?
I'm thinking CO2 cylinder to open and a simple return spring to close. Maybe control pressure could come from the wastegate system or simply be manifold pressure?

 

[Twistin6]

I am anengineer but have no idea what a t4 or t6 adapter looks like to offer material thickness recomendations. I would probably stay with stainless for a material though.

Just a thought but have you considered a DC stepper motor for flapper control instead of C02? That way no need for a recharge they can be bought pretty small with alot of tourqe and offer the speed as well. I'll post a link for example

1A-TTL Controller stepper gearmotor 35mm dia. 30:1 from Excitron Corporation

 

[charlief1]

I know your work well enough Donnie so I'll be keeping an eye on this one.

 

[Alky V6]

Here's a link to a picture of the T4 to T6 flange adapter and the split turbine housing.

http://www.turbobuick.com/forums/1939693-post115.html
http://www.turbobuick.com/forums/2016976-post243.html

I like the stepper motor idea better. It would have to be isolated from the heat somehow.

 

[Twistin6]

I am attaching a quick auto cad sketch as a pdf file for you to review. This is what I was thinking about with a stepper drive in the adapter plate. Just go to view and rotate clockwise for the drawn orientation. We could get much more in detail just wanted to show roughly what I was trying do describe.

 

[Alky V6]

I am attaching a quick auto cad sketch as a pdf file for you to review. This is what I was thinking about with a stepper drive in the adapter plate. Just go to view and rotate clockwise for the drawn orientation. We could get much more in detail just wanted to show roughly what I was trying do describe.

Unless you have a specific reason for the blade to shaft mounting, I think it would be better to have the shaft mounted through the middle of the moving plate, with the action being very similar to a typical throttle blade. Similar, also, to the old heat crossover system of the 60s and 70s. The mounting might be best with just a little off-center bias so that exhaust flow/back pressure will have the tendency to want to push the blade into the open position with a certain exhaust flow level.

What if the shaft could be sprung and weighted to act just like the old heat crossover valves? With the weight and spring being calibrated so that exhaust energy opened the valve at a set flow rate? It would make the control mechanism very simple. The bushing and shaft material would be critical to control shaft sticking/binding.

 

[Twistin6]

I was under the assumption you wanted one side blocked at initial spoolup vs splitting up the blocked off area on each side. If I understand what your trying to accomplish I believe it has to be as drawn. If the shaft intersects the flapper at anything past its edge it would hit the divided turbo housing in the pic.

If you are using the other housing which is open for the full width then what your saying would work as well and balance out turbulant airflow a little better. Either shaft mounting scenario could be spring balanced to simplify opening and closing like you mentioned. It would take alot of fine tuning for that though especialy on the opening rate.

As for shaft material. Precision ground drill rod along with a bearing bronze sleeve pressed in each half would outlast the turbo most likely. Along with being self lubricating the bushing material is meant for these extreme envirements. This is the easy part in my opinion. The spring rate for exhaust pressure opening percentage is the tricky one. The only draw back to this is springs dont like heat they loose their memory to put it simply. I see them fail everyday due to heat in the 400 degree range. They will retain thier physical properties about 5 days before degrading in the envirement I am reffering too. Just like a torch on a car spring to lower ride height. Dont know for how long you plan on running or how long the spring would be exposed to really high heat. Just something to keep in mind as critical as the spring tuning would be in this application.

Something electricaly RPM triggered to open at a givin rate per RPM I would think would be ideal.

 

[Alky V6]

I was under the assumption you wanted one side blocked at initial spoolup vs splitting up the blocked off area on each side. If I understand what your trying to accomplish I believe it has to be as drawn. If the shaft intersects the flapper at anything past its edge it would hit the divided turbo housing in the pic.

If you are using the other housing which is open for the full width then what your saying would work as well and balance out turbulant airflow a little better. Either shaft mounting scenario could be spring balanced to simplify opening and closing like you mentioned. It would take alot of fine tuning for that though especialy on the opening rate.

As for shaft material. Precision ground drill rod along with a bearing bronze sleeve pressed in each half would outlast the turbo most likely. Along with being self lubricating the bushing material is meant for these extreme envirements. This is the easy part in my opinion. The spring rate for exhaust pressure opening percentage is the tricky one. The only draw back to this is springs dont like heat they loose their memory to put it simply. I see them fail everyday due to heat in the 400 degree range. They will retain thier physical properties about 5 days before degrading in the envirement I am reffering too. Just like a torch on a car spring to lower ride height. Dont know for how long you plan on running or how long the spring would be exposed to really high heat. Just something to keep in mind as critical as the spring tuning would be in this application.

Something electricaly RPM triggered to open at a givin rate per RPM I would think would be ideal.

I agree on the spring and heat. Electrically controlled would be ideal.
Keep in mind that the valve would cover approximately one half of the opening in the adapter. The adapter will have a wall separating the present large opening into two smaller openings just like the split entrance openings in the exhaust turbine housing. That wall is not in the adapter yet, and will match the wall that is in the split turbine housing. The valve will be operating to block off only one of the split openings.

So we have the material for the shaft and bushings. Easy enough to source. All we need is the valve material.

 

[Twistin6]

I now fully understand what your blocking with the adapter and how big the flapper is. I cant see the forest for the trees sometimes..lol

Now on to the flapper material. I am thinking light weight will be a benifit no matter which way you choose to index it. Easier on bushings easier for exhaust gas to have input over it and quicker responce. You also need plate integrety or strength. You could go thin like .100 Stainless and still be lite enough because of overall size. Besides if you mount the shaft in the center weight becomes even less of an issue. Moving on to mounting it to the shaft. Since no unreal forces will be imposed on either shaft or plate I would slot the shaft and slide plate through then drill and tap for two flatheads loc-tited of coarse. .375 shaft with .100 slot leaving .1375" wall thickness is more than enough considering material used and centrifical force imposed. Even with spring inertia since from center of rotating assembly to edge of flapper will be so short no big fulcrum force should be present.

PS I would make the bushing with atleast .100 wall thickness or you can keep it nominal and go to .500" major OD with .375 ID

Not sure I helped any heck you probably had all this figured out already.

 

[Alky V6]

I now fully understand what your blocking with the adapter and how big the flapper is. I cant see the forest for the trees sometimes..lol

Now on to the flapper material. I am thinking light weight will be a benifit no matter which way you choose to index it. Easier on bushings easier for exhaust gas to have input over it and quicker responce. You also need plate integrety or strength. You could go thin like .100 Stainless and still be lite enough because of overall size. Besides if you mount the shaft in the center weight becomes even less of an issue. Moving on to mounting it to the shaft. Since no unreal forces will be imposed on either shaft or plate I would slot the shaft and slide plate through then drill and tap for two flatheads loc-tited of coarse. .375 shaft with .100 slot leaving .1375" wall thickness is more than enough considering material used and centrifical force imposed. Even with spring inertia since from center of rotating assembly to edge of flapper will be so short no big fulcrum force should be present.

PS I would make the bushing with atleast .100 wall thickness or you can keep it nominal and go to .500" major OD with .375 ID

Not sure I helped any heck you probably had all this figured out already.

Actually, I hadn't worked on dimensions yet. What you've presented looks very good.
I think the screws retaining the blade will need to be staked. I don't think loctite will hold up under the heat, since one of the methods for pulling a screw that's been loctited is to heat it to make the loctite less effective. At this point, I like everything else. Thank you for the help and I hope you stay tuned for any fine tuning of things.

 

[charlief1]

Actually, I hadn't worked on dimensions yet. What you've presented looks very good.
I think the screws retaining the blade will need to be staked. I don't think loctite will hold up under the heat, since one of the methods for pulling a screw that's been loctited is to heat it to make the loctite less effective. At this point, I like everything else. Thank you for the help and I hope you stay tuned for any fine tuning of things.

This may sound a little different Donnie but once you get the screw in it instead of staking then you could weld a tack on them for security. It's not like you're planning to remove them anytime soon. If you do need to remove them you'll have to shave the staked section anyway, right?

 

[GNVYUS 1]

Hey Don, Sound Performance in IL already has a T4 and T6 Quick Spool Flange like what you're looking for ( probably not the adapter version you're doing ).
Their flange is 3/4" thick with stainless parts and many Import racers love it, a member on here has one but I'll hide his identity so he can keep his edge.

I know you're looking forward to pulling this off, but last resort could be to see if they'll offer the adapter you need.

 

[Alky V6]

This may sound a little different Donnie but once you get the screw in it instead of staking then you could weld a tack on them for security. It's not like you're planning to remove them anytime soon. If you do need to remove them you'll have to shave the staked section anyway, right?

Good point.

 

[Alky V6]

Hey Don, Sound Performance in IL already has a T4 and T6 Quick Spool Flange like what you're looking for ( probably not the adapter version you're doing ).
Their flange is 3/4" thick with stainless parts and many Import racers love it, a member on here has one but I'll hide his identity so he can keep his edge.

I know you're looking forward to pulling this off, but last resort could be to see if they'll offer the adapter you need.

Thanks. I'll keep the option open.

Unfortunately, my adapter is wedge shaped for clearance reasons. It's either modify mine, or modify theirs.

 

[ijames]

Rather than tacking the screws with a spot of tig, why not just tack the plate to the shaft? Hit it with a dremel cutoff wheel if you ever need to take it apart and no holes to tap or screws to worry about.

 

[Adam Connell]

my guess would be that most of your information you will need is here: LS1TECH

there is also a lot of info in that thread about testing and results.

Hey Don have you thought about just welding a t6 flange to your headers and using a prefabbed valve? Sounds like you may be making this more complicated than it needs to be... something I am guilty of constantly haha!

The valves I have seen just use a waste gate actuator to open them.

Honestly Im just tired as hell, and knew where that post was and that it had good info so I figured I would throw it in here before I hit the hay. I'll re read this all tomorrow and hopefully have some more helpful info.

 

[charlief1]

Good link Adam, my gears are turning on a posible mod on what I'm doing right now. This may just be what I need to shake some guys confidence.

 

[Alky V6]

my guess would be that most of your information you will need is here: LS1TECH

there is also a lot of info in that thread about testing and results.

Hey Don have you thought about just welding a t6 flange to your headers and using a prefabbed valve? Sounds like you may be making this more complicated than it needs to be... something I am guilty of constantly haha!

The valves I have seen just use a waste gate actuator to open them.

Honestly Im just tired as hell, and knew where that post was and that it had good info so I figured I would throw it in here before I hit the hay. I'll re read this all tomorrow and hopefully have some more helpful info.

For me, it will be a lot easier to mod the adapter than to change the flange on the headers. More fun too.

 

[turbofabricator]

Donnie,
Use a wastegate actuator to control the flapper. Use inconel for the flapper, as SS won't take the heat you are going to run through it. (even with methanol) Weld the flapper parts together, as any threaded fastener will fail over time. (you can always build a new adaptor) Use inconel bushings for the shaft, too. Look into the flapper valve issues with the old ATR Terry H. copy down pipe. The flapper shaft would freeze up due to SS material being used. Bronze won't take 1800+* either. Simple is best. (Do as I say, not as I do )

 

[Alky V6]

Donnie,
Use a wastegate actuator to control the flapper. Use inconel for the flapper, as SS won't take the heat you are going to run through it. (even with methanol) Weld the flapper parts together, as any threaded fastener will fail over time. (you can always build a new adaptor) Use inconel bushings for the shaft, too. Look into the flapper valve issues with the old ATR Terry H. copy down pipe. The flapper shaft would freeze up due to SS material being used. Bronze won't take 1800+* either. Simple is best. (Do as I say, not as I do )

I'm going to assume inconel for the shaft too? What about shaft to bushing clearance and lubrication issues? .001" clearance and run it dry?