Twins with a B-1

[Diesel Freak]

Basic Fluid Dynamics

if a fluid under steady flow conditions travels from a pipe of 1"in diameter to a pipe of 2" in diameter..... its velocity drops to 1/4 it's original. and vice versa.





Exhaust gases speed up as they enter the turbine housing..... smaller area, and accelerate at the exit of the housing(nozzle effect of the housing), and slow once again as they impinge on the turbine blades.



once the exhaust gases enter the turbine, pressure can be assumed to be atmospheric.

 

[HoleshotHolset]

I knew someone with more fluid dynamics experience than me would chime in!



Cool! good stuff to keep in mind.....



Matt

 

[work2muchplay2little]

Re: Basic Fluid Dynamics

Originally posted by Diesel Freak

if a fluid under steady flow conditions travels from a pipe of 1"in diameter to a pipe of 2" in diameter..... its velocity drops to 1/4 it's original. and vice versa.





Exhaust gases speed up as they enter the turbine housing..... smaller area, and accelerate at the exit of the housing(nozzle effect of the housing), and slow once again as they impinge on the turbine blades.



once the exhaust gases enter the turbine, pressure can be assumed to be atmospheric.

A practical example would be the standard garden hose. Turn it on full blast with an open end and it goes what, 2-3 feet and hits the ground. You put a spray nozzle on the end and force that water through a much smaller opening than the end of the hose and it accelerates and sprays a heck of a lot further with more pressure. But there is a trade-off in flow rate as it drops with the increase in pressure and smaller orifice.

 

[HoleshotHolset]

I guess I dismissed the obvious garden hose relationship to fluid flow..... the fact that exhaust gas is a 1400°F and is gaseous and not a constant flow, but a pulse-flow is what made me think that it is so different than regular fluid dynamics... .

 

[Animal]

Re: Basic Fluid Dynamics

Originally posted by Diesel Freak

if a fluid under steady flow conditions travels from a pipe of 1"in diameter to a pipe of 2" in diameter..... its velocity drops to 1/4 it's original. and vice versa.

Diesel Freak,



Isn't that 1/5 not 1/4. Buy doubling the diameter don’t you get 5 times the volume?

 

[Diesel Freak]

Re: Re: Basic Fluid Dynamics

Originally posted by Animal





Diesel Freak,



Isn't that 1/5 not 1/4. Buy doubling the diameter don’t you get 5 times the volume?

Going from 1" to 2":



pi x r^2



(3. 14x. 5^2)/(3. 14x1^2)



. 25/1



when going from a pipe of diameter 1 inch to a pipe of diameter 2 inch (id) flow area increaces by 4 and velocity drops by a factor of 4... . this is an ideal situation where friction plays no role. I have not accounted for the head loss coefficient (k) of the pipe reducer.

 

[Powder Extreme]

Well, with all these calculations, can somebody tell me how I can shove a flux capacitor in there to really see some boost?



But seriously, I'm still debating trying this. From what I can find out, it seems the hy-9 might choke the system down too much.



Hey Greg, you've got new turbos, maybe your nasty nine would work for what we're tryin to do??



Here's some more food for thought. What about driving the hy-9 with only half the cylinders, then to the B-1 and the other 3 cylinders going straight to the B1?? Would the HY spool to slow to accomplish the very little lag I want? I realize it would be a plumbing nightmare, but what the heck.



Jerry

 

[HVAC]

That's a no no

Your engine would be unbalanced. The three barrells blowing the B1 would have less back pressure then the three blowing the HY.

 

[Jetpilot]

You also would have less air driving both turbos (1/2). I don't think you would spool either turbo effectively.



Doug

 

[JTroiano]

What about a super charger in front of a big turbo? You could have it driven to make boooost at almost idle and then have a by-pass if it can't keep up with the big turbo. This would give you zero lag and you could have the power of that huge turbo. The super chargers use a little bit of HP but not to much. Just a thought. No Lag.

Jon T

 

[HVAC]

Lag?

Until going to slicks for May Madness my problem was traction, not lag



Twin turbos can be made to hit hard and fast for individual applications.

 

[Powder Extreme]

Jon T, I asked that same question awhile ago. It was deemed too ineffecient.



"split turbos" I was wondering if it wouldn't be good for the motor because of one side having more backpressure, but most wastegates only dump one side of the cylinders anyway. Is that okay because it is usually for just a short time?



HVAC, I think I need to sit down and talk to you about building a system. I already have a Kwikspool B-1, an HY-9, and an HX 35 with 12,14 & 16 cm housings, the 16 is not wastegated. Is it feasible to build a low lag, ~450hp setup with what I've got, or do I need to buy a different turbo from you. PM me if you like, I'd really appreciate your input. Thanks.



Jerry

 

[csutton7]

Powder Extreme--I'm betting that you'll need to fork over some cash for a bigger turbo, so get ready---chris

 

[JTroiano]

I thought we were past being efficeint? I can't believe that a super charger uses more than maybe 10 HP to run it. Mercedes uses one with an AC type clutch. It could be cycled off when the turbo is spooled up. I don't think it would be that much harder to make than putting twin turbo's in.