Turbocharger compounding question

[RZ350]

I have read quite a bit about running two turbochargers in series to increase the pressure ratio, but I have no hands on experience with this concept, I'm hoping someone might be able to help me.

I'm building an EX500 Kawasaki landspeed bike, methanol fueled, I hope to make about 200 HP on the wheel. This is a two cylinder, four valve motor, 498cc displacement. (upgraded of course to handle the power level.)

I need quite a bit of boost pressure to achieve these power levels, and I can't easily find a turbocharger small enough that has a high enough pressure ratio to achieve what I'm trying to do...

Does anyone have any knowledge regarding compounding turbos, or can anyone recommend a turbocharger that will support a pressure ratio of about 4.0-4.2, and flow about 400 CFM?

[jl222]

I have read quite a bit about running two turbochargers in series to increase the pressure ratio, but I have no hands on experience with this concept, I'm hoping someone might be able to help me.

I'm building an EX500 Kawasaki landspeed bike, methanol fueled, I hope to make about 200 HP on the wheel. This is a two cylinder, four valve motor, 498cc displacement. (upgraded of course to handle the power level.)

I need quite a bit of boost pressure to achieve these power levels, and I can't easily find a turbocharger small enough that has a high enough pressure ratio to achieve what I'm trying to do...

Does anyone have any knowledge regarding compounding turbos, or can anyone recommend a turbocharger that will support a pressure ratio of about 4.0-4.2, and flow about 400 CFM?

[jl222]

    RZ350
  I have a book by Hugh Macinnes called TURBOCHARGERS by HPBooks. It explains every thing you ask,basically the cfm of the engine times the pressure ratio taking in considerations of voumetric efficiency and turbo temp.
This would be the 2nd stage The 1st stage should match pressure ratio of 2nd stage. Multiply 2nd stage cfm times Ist stage pressure ratio =cfm. More complicated than this but as you can see the 1st turbo is bigger than the 2nt.
    This is called staging, tractor pullers have been doing it for years,up to 250lbs with 3 stages no room for intercoolers, injecting 3 gallons of water or more per min.
   Turbo conpounding is when a turbine is geared back to the crank.
        Good luck hope you can find this book.
               
                    JL222


 

[ddahlgren]

The short answer is you need 20 lbs perminute of air to make 200 hp in round numbers.. You may have another problem though. Will you have to change classes at the 2 when you go from fuel to diesel?? This is a way cool trick for 5 or 6 seconds 2 minutes is a bit different..
Dave

[maguromic]

As Dave mentioned running one turbo into the other is a bad idea for long runs. The tractor pull guys don't run long so they can get away with it.  One of the big problems you will have is as you push heated air into one turbo, that will heat it more coming out the second turbo and then your manifold temperature will go too high (unless you have a monster inter cooler I wouldn't do it).  Then you will have other big problems.  Give Cliff at Turbo Power a call www.turbo-power.com 530-677-2233  he did some of the turbo work on the BUB liner and should be able to help you.

[maj]

Would a bit of chemical supercharging help ?? and 1 bigger turbo..
kkk turbo's will usually run to higher pr than say garrett , but finding one to suit 200hp at ~40 psi boost may not be easy.

[racin jason]

give IHI usa a call and they can build you what you need. they just sent me a 220hp 600cc turbo.

[jl222]

     Most world war2 aero engines used 2 stage supercharging some intercooled between stages some not, the merlins were not.Thanks to the merlin we speak english in this country.Some merlins were modified to run up to 35lbs of boost to chase down V2 rockets.
     In the book 'Thompsen Trophy Racers" about air racing 1929-49, the ultimate merlin was a -9 with the right fuel  and properly calibrated water injection was good for 2800-3000 hp at 3400rpm at 120ins."about 45 lbs boost". Pg.148.
     Cummins has been 2 staging their diesels since the early 80s, ever wonder why the newer big rigs haul ass?
      I'm old enough to remenber trucks creeping up the grapevine. "long steep grade in Calif".
      I have been wanting to post pictures and info about ww2 aero engines for a while now but my computer is not capable, have to get bvillrcr to do it.They were doing things with supercharging that we have yet to do.

                     JL222