Okay I have yet to see anyone do this. I got it ready to go together. My plan is 2.5'' check valves or anti blowback valves so as i do not push boost backwards at the turbo before it spools and wont push boost back at the supercharger when the turbo spools. My plan is 12 psi from the blower and 16 from the turbo. I have a vortech v1 s trim and am still deciding between the t76 or t88. It is going into a full cage 2000 firebird with a forged 6.0 from a 04 silverado. stock ported heads 9.5:1 compression. 126 pound per hour injectors planning on running alcohol on this setup. this piped through a 4000 stall eliminator converter and th400. the only thing left i gotta get is the rear end and turbo hot piping. I am shooting for 1000 wheel and still drive it to work. So I guess after all this ranting I am seeing what people think about the twin charge plan. If it does not work oh well I jsut figure what the hell why not try. I am trying to find the 2.5'' check valves currently. anyone have any better ideas? maybe boost sensative throttle bodies on each poweradder?

 

Wow...

-Will

 

I think u way over ur head on this one. I love the idea but there alot more needed

 

I know for a fact you can get either threaded or sweat(solder) check valves from a piping supply house. You would want to use a spring check, not swing.

 

There is no real benefit here...people do twin screws and turbos to add low end(twin screw), and top end power(turbo). By alcohol do you mean methanol? I am not sure 126 lb injectors will make 1000 rwhp through a stalled auto on methanol.

 

You could do one throttle upstream from the centri so you could yoke off its air supply when it wasn't needed anymore, and another in the normal spot to let in air from either in non-spooled operation. You might need a bypass bleed from the centri output back to the inlet to prevent overheating when its throttle was closed but the blower was still being spun.

Lastly you could look into an electric clutch for the centri, like they use on air conditioning compressors. Being able to de-clutch the centri would avoid a lot of problems and power waste (from spinning it but not getting any value or work from its output).

JIm

 

any reason you want to use a centri and a turbo? have you considered a Positive displacement and turbo setup for real low end grunt and good top end? you would have to run a side mounted blower and configure as follows...

Air Filter to Turbo. turbo to intercooler. Intercooler you 'Y' pipe. One suide of the 'Y' through a bypass valve to the intake maniofld. on the other side of the 'Y'pipe to the intake of the SC. then SC to an intercooler/chargecooler and then to the intake manifold.

With this setup you get all the benfits of the SC down low, but one the turbo is boosting the bypass valve openand allows the turbo to do ALL the work. This prevents the restriction/inefficenies normally seen with a conventional turbo/SC compund setup. Also once the turbo is spooling the SC will just be free-wheeling as the presure will be the same on both sides.

The only probelm is where to put the Throttle bodie. It would be ideal to run 2, one in front of the SC and one on the manifold.....

Alternatively hy not run a compound/sequentical turbo setup? I have been thinking about this for a while. You could run a Truck maniolfd turbo setup with a T70 turbo at the front. This should spool REALLY quick! then 2 60mm WGs feeding into a 3inch downpipe. run the 3iunch to the rear and then stick a 88 or even 91 mm turbo at the rear. this rear turbo would also need a WG. run the pipe work back to the fornt of the car and into the intake of the smaller turbo.

Now you have a choice, Compound turbo or sequentical turboing.....

For compound set the two front WGs to say 12psi of boost and take the feed from anywhere after the front turbo and the reference to the intake of the front turbo. then set the rear to whatever presure you want MISSUS the 12psi from the front turbo. so for 20psi set the front WG to 12psi and the rear to 8psi. The rear WG will need its reference just to the atmosphear.

If you want a sequntial setup you set the fornt gates to say 12psi and the rear gate to whatever presure you want (say 20psi). reference will all be to atmosphear and feeds will both need to be from the intake manifold. with this setup the front trubo will spool, then once upto presure the gates open and the rear turbo can take up the slack.

Just some food for throught.

Cheers

Chris.

 

I promise I am not in over my head lol. I like the electric clutch idea though but not sure how much they will hold when a supoercharger is spinning 50k rpm and that much rotation. I imagine I would run into slippage with that set up. the plumbing idea with the y and two throttle bodies is probably the way I will go. Curious why spring check valves. I figured the swing like the old mass air flow sensors that used a potentiometer to measure air flow are pretty close to the same thing. those seemed to work for ford. I was close to twin charge on my last ss cobalt but a trailer laying across the freeway prevented that from happening. So here i am. I do not see it being done anywhere else. If it works cool if not whatever. The car was a V6 turbo before this that made 377 wheel on 12 psi so I have done more worthless things with building cars than attempting this. I like the bypass valve idea because it allows you to gradually switch from sc to by just normal spring opening characteristics. If i went with the y pipe configuration on the centri and turbo what benefit would there be putting a throttle body infornt of the supercharger? would it be operated in reverse of the other? my only problem with that setup is i can see massive iat temps.

 

I think it's a fantastic idea. Do it. More check valves though. Can't have enough of those. Definitely don't want to push boost into the turbo.

 

jrocstar are you planning on compound boosting or sequentical? Im just not seeing how you are running the turbo and centri. Which will be first in the cold air stream?

Cheers

Chris.

 

air filter into turbo turbo pressure side into supercharger inlet, 2 bov's bypassing the supercharger (bypass valves whatever) into the throttle body, those springs set to 12 psi and the supercharger boost side into intake. i figure this way when i exceed 12 psi from the turbo it will flow past the centri and be the main power adder. If i do check valves it will be different though.

 

Since it's a Centri blower you should just leave the pressure side from the turbo feeding the centri and thats it..no bypassing no headaches and everything.

 

Don't forget that in compound boost applications boost is not a factor of addition but rather multiplication.

I understand that you are looking use a bypass to limit boost but a word of warning is that if your bypass valve(s) get stuck it could blow up a even a built motor fairly quick.

I agree with blowing a turbo into a positive displacement. Easy to do and a good power band.

 

I agree, but i have only ever seen people runing a Centri into a turbo, and never read anything on it!

i can see a centi into a turbo working. Small turbo gives GOOD low end power and then the SC can at power at the top.

Another solution might be to have a small centri feed a BIG turbo. obviously the SC would then become the restriction so you would need a one ways valve BEFORE the turbo (AFTER SC) that contacted to another air filter. Then as the turbo starts to consume more air than the SC can produce then vavle open and the turbo pulls ADDITIONAL air from the other filter.....

Chris.

 

so should the centri pressure into the turbo that way all boost is cooled or turbo feed the centri? I think either way I am going to find restrictions but I am most experienced with roots and screw blowers and heat issues. does tghe centri produce similar heat characteristics? if so I may just put the centri through the turbo. and if not I will pressure the turbo into the centri and centri into an intercooler.

 

and the pre turbo centri with a check valve is a good idea also. that is a really good idea

 

You are going to have a high(to me atleast) stall converter on your auto, a turbo is all you need. At the end you won't be making anymore useful power with both and it will cost you alot more.

 

What a dumb idea.


You want to use a really small supercharger, that makes no boost low down, to feed a big turbo, that also makes no boost low down ?

No valves or crap are needed though. Just blow one compressor into the other. Which way round probably wont matter, as the supercharger is simply the wrong choice.

If you're going to do it, at least use a proper PD style, where it WILL improve low rpm performance.

 

I'm with stevie on this. It's a bad idea, too complicated, lots of parts needed to work right, won't make any more power than a well-matched single turbo, plus some basic laws of thermodynamics are being ignored.

As long as you are spinning the centri, you aren't getting the "turbo advantage". Might as well just run a centri alone. Even with the discharge routed to atmosphere, it will be sapping up 50++ hp.

 

Sequential twins.

/End Thread