INDIAN 741 Supercharged...See you in 2011

[jl222]

 
  THATS impressive

  JL222

[Rex Schimmer]

Octane,
One of the things that you probbly don't need to be really concerned about is quick throttle response, you are running at Bonneville not on a drag strip. That being said, I would think that the larger the volume of your plenum the less the pulsations of the blower and the engine inlet track will affect the steady state pressure in the plenum. I would think that going 5 of even 10 times the engine volume would have a greater affect on dampening the blower and engine plusations. If you want to see what is happening you will need an electronic pressure transducer and the ability to look at the transducer output at a rate probably at least once every milisecond (1000 time per second) this will really tell you what is happening. At this sample rate you will be able to see all of the events that you are concernd with, i.e. blower pulsations and inlet pulsations. Trying to use some sort of water or fluid column to visually look at the plenum pressure is only an indication of the average pressure in the plenum and not the instantaneous pressure.

You have a situation where the blower is injecting chunks of air at a rate of 2 chunks every revolution of the blower and the engine is inhaling 2 chunks of air every revolution of the engine, but not at the same rate or frequency as the blower so there is no doubt that there is a very big possibility of some sort of dynamic resonance that could occure  between the blower output and the engine intake all of which you probably do not want to happen. The larger the plenum volume the less this will happen. So my vote is that if you see some sort of problem related to this blower/engine pulsation interaction go to a larger plenum.

In reality you will probably just go with what you have, it will run like a "stripped a$$ ape" and you will have tons of fun!!

See you at the salt!!

Rex

[wobblywalrus]

Rex and others have the good answers to your questions, especially about the gauge.  My mention of dyno experiences are just to give an idea about a useful tool and method.

We are definitely looking forward to seeing the Indian and hearing it run.  Its a beauty.   

[jl222]

  Rex do you know of any data recorders that test at that speed?

   JL222

[Rex Schimmer]

Jl222,
I have a small 2 channel recorder that will go to 10,000 times a second cost a couple of hundred bucks. PM me at rexschimmer@gmail.com and I will try to dig up the info. I think that I have a couple of pressure transducers also, which are actually more expensive than the data recorder!

Rex

[oz]

Its Just Soooo Pretty I reckon thats the best looking Indian I have ever seen.

[octane]

Thank you OZ , and thanks all, for your input
and for your kind words.

Mmmmmmm; this whole plenum volume thing;
I really don't know.
Rex I understand what you're saying, but 10 times the cylinder volume.?!
That's one mighty plenum ; 6 liters or close to 1½ gallon !!!
I don't know these things but I'd be inclined to take into account
Panic's warning that if the plenum is too big, ".... gas speed will decay ..... causing fuel drop-out"

I've see all sorts of set-ups from some rather long intakes/plenums,
like Max's blown double-Vincent, and these magnificent old drag bikes

   

   


...to no plenum at all;
(BTW this is a 650cc Triumph, with the exact same blower as mine)





...and interestingly the bolt-on blower kit from MAGNACHARGER for H.D.'s
doesn't have much, if any, plenum to speak of.







So for now I can't really do anything, but go by what I've read,
which is up to 200% of cylinder-volume and see how it works out.
We'll see.
.

[octane]

SO:
..back to work !

Last welding, mods, etc. on the frame done, so it's been sandblasted:



Will paint it tonight or tomorrow.

Engine disassembled for the xxx'th time




...doing the final little things like replacing all the cylinder-studs





..before final ( as IF) engine assembly.



Blower drive is just about ready:






...just need the thingy that 'locks' the belt-wheel and the extended sprocket-thingy together.

[panic]

..

[Super Kaz]

octane,
1st of AWESOME JOB !
#1 Fuel Tank size ? Riding to the Line,then running a Pass{Long or Short Course?} Then the Long ride back to the Pit's or Hopefully Impound area? Is a Long Way ! I know the hard way. You also better wear a CUP/JOCK Support if you ever want to use it again ! Rigid and Rear set's@ Bub = PAIN IN THE NADS!:mrgreen:
Good Luck and Go FASTER!
SEE YA ON THE SALT,
Kaz................

P.S

Whats your Day Job ?

As you could be a Custom Bike Builder Easily !

[octane]

Thanks Panic
....but I'm afraid I don't get the "..300 f/s this gives a diameter of 1.6".." part ?

octane,
1st of AWESOME JOB !
#1 Fuel Tank size ?

Thanks Kaz!
..and thanks for asking about the tank.
I had completely forgotten to check the size (embarrassing)

Did it right away now.
Now half a tank is 5 liters ( yep; the tank hasn't been welded yet, as you can see)



..so if my time back at school wasn't totally wasted; the tank holds 10 liters = 2.64172052 US gallons

Riding to the Line,then running a Pass{Long or Short Course?} Then the Long ride back to the Pit's or Hopefully Impound area? Is a Long Way ! I know the hard way.

Short course, so let me figger that out: approx. 5,5 miles to the course, 5 mile course, 5,5 returning = 11 miles. / 17,7 km.

2.64 : 11 = 0.24 gallon to run one mile

Being European that doesn't mean a thing to me so:

10 liters : 17,7 km = 0.56 liter to run one km.

You also better wear a CUP/JOCK Support if you ever want to use it again ! Rigid and Rear set's@ Bub = PAIN IN THE NADS!:mrgreen:

Yeah; I'm aware of that, but because the bike is as short as it is, it's not quite as bad as it looks.
That's probably bad enough..ha ha...so I've been experimenting with a different shaped seat that improves the situation somewhat.

Good Luck and Go FASTER!
SEE YA ON THE SALT,
Kaz..............

Whats your Day Job ?

As you could be a Custom Bike Builder Easily !

Thanks!
I work free lance, and right now I don't 'work'
so technically my 'day job' is building this bike

.-)


.

[Rex Schimmer]

I agree with Panic regarding fuel drop out from high volume but my thinking was more along the line of increasing volume by say adding a -8 or -10 fitting to the end of your plenum and then connecting any additional volume to this fitting. The idea is getting the volume to provide capacitance to the system, which will modify the resonance of the inlet tract,  not increase the size of the inlet tract to a point that the inlet charge velocity drops so low that the fuel falls out of suspension. I have a mid 80s Yamaha two stroke dirt bike and they added inlet tract volume this way to dampen the intake track resonant frequency and also broaden the resonant curve.

Rex

[jl222]

I agree with Panic regarding fuel drop out from high volume but my thinking was more along the line of increasing volume by say adding a -8 or -10 fitting to the end of your plenum and then connecting any additional volume to this fitting. The idea is getting the volume to provide capacitance to the system, which will modify the resonance of the inlet tract,  not increase the size of the inlet tract to a point that the inlet charge velocity drops so low that the fuel falls out of suspension. I have a mid 80s Yamaha two stroke dirt bike and they added inlet tract volume this way to dampen the intake track resonant frequency and also broaden the resonant curve.

Rex

  Yea Rex I was wondering if that would help I added one of those ''boost bottles'' to my 465 yamaha back in the early 80s also and it made a big difference in response

     JL222

[octane]

Mmmmm; not for a supercharged four-stroke engine, I believe.

At least not according to
Maurice Brierley, who in his book,  "Supercharging Cars and Motorcycles"
says that such a thing serves a useful function on a standard car
but in case of using it in the pressure manifold of supercharged engines
he calls it "quite comprehensible".

"...the inlet pipe is subject to regular pulsations caused by
the intermittent 'gulp' of each cylinder on it's induction stroke.
The frequency of these pulsations depends on the number
of cylinders, and on the RPM of the engine.
The latter is variable.
In case of the production car the closed ended
buffer chamber serves to produce 'aerodynamic fungus'.
This prevents the disposition of of liquid fuel on the walls of the bend...
...it is necessary to avoid this deposition in the interest of equable
distribution of the mixture to various cylinders...
...One of the reasons why one choke per cylinder is used
on high-performance un-supercharged engines is that the necessity
for this is avoided and equable distribution is assured without having to
make a compromise with the volumetric effeciency and hence the specific
power output...


... the inclusion of a buffer end
which is in effect a resonance chamber is to be avoided
in the case of a supercharged engine, where there is in any
case no excuse for it's use.
In case of a supercharged twin cylinder engine with one inlet stroke
per revolution there are 6000 pulses per minute inflicted on the pressure manifold
at 6000 RPM (which is 100 pulses per second), at 3000 RPM
it will be 50 pulses per second, and so on.
It can therefore be seen that a wave formation (similar to sound waves)
is forced on the pressure inlet pipe with frequency depending on the
number of cylinders and RPM.
In any given engine since the frequency varies with the RPM it is most
important that the pipe work does not include anything in the nature
of a possible resonance chamber design....

....it may often be easy and convenient but can sometimes
result in unwanted harmonics in the system..."

[panic]

..