Compressing intake air

[tallguy]

Two questions for now . . .

Why would turbocharging be advantageous in land speed racing,
compared to supercharging?

Since a supercharger or turbocharger takes power to run, and this
power comes from the primary engine(s), has anybody used or seriously
considered using a battery-powered electric motor, or an air motor
powered by compressed gas, or even an additional powerplant such as a
small internal-combustion engine to power a supercharger or turbocharger
of a land speed vehicle's primary engine?

I know this would add weight and complexity, but maybe it would be
worth it, to keep the output of the primary engine used only for driving
the vehicle. 

[tortoise]

I know this would add weight and complexity, but maybe it would be
worth it, to keep the output of the primary engine used only for driving
the vehicle.  

If it were deemed legal, it would be worth it.

[kiwi belly tank]

You can only hook up so much power on the salt, blower's or turbo's can deliver more than you can use. I'm at the end of another 18hr day on the streamliner & you're over thinking the situation.
  Sid.

[tallguy]

Good point, Sid.  I've known for awhile that the traction available on the salt
is roughly half of what a paved road offers. 

Having acknowledged that, is it legal to have spoilers that are adjustable
during a run, in order to provide more downward force to the drive wheels,
at least in the earlier part of the run?

If there's excess horsepower available from the engine, why not use some
of it to "hookup" to the ground?

[dw230]

Section 4.FF of your rulebook tells us that superchargers must be mechanically driven and powered by the primary engine.

Moveable spoilers or wings are OK to use, haven't seen one work successfully yet.

DW

[tauruck]

What about the Wright Flyer?.

[kiwi belly tank]

Good point, Sid.  I've known for awhile that the traction available on the salt
is roughly half of what a paved road offers. 

Having acknowledged that, is it legal to have spoilers that are adjustable
during a run, in order to provide more downward force to the drive wheels,
at least in the earlier part of the run?

If there's excess horsepower available from the engine, why not use some
of it to "hookup" to the ground?

If you could hook it up, it wouldn't be excess.
DW gets to see all the $hit that is legal & actually works, he is "Mr Impound".
  Sid.

[Seldom Seen Slim]

Well, I would think you could run a separately-powered air blower of some type using a lawnmower (or big V8, or whatever) engine -- if and only if you're running in a class where multiple engines are allowed.  that is -- not only the drive engine is counted when they say "mutliple" engines -- all of 'em!

This has been discussed a handful of times here.  Go searching and I expect you'll find some good information.  Ditto moveable airfoils.

Ditto, for that matter, dang near any subject you can imagine.  The accumulated knowledge here is amazing.

[floydjer]

Google Mickey Thompson Thermo-charger

[Grant Borman]

Turbochargers are able to remove heat energy from the exhaust and use that to turn the compressor wheel. It also adds some back pressure but not enought to make it less efficient than a supercharger.  Both systems present packaging constraints and that's why not every one uses a turbo.

Might want to look into the turbonique axle and supercharger. Technically these use a separate combustor and would not be legal under most lsr engine classes.

Not very many classes have records held by fully developed turbocharged engines so I'm not sure if it would be worth it to investigate into alternative supercharging methods from a cost perspective.

Good luck

[bbarn]

I have heard rumors that it takes 200 HP to run a large set of turbos and significantly more to drive a supercharger. I know that is a fairly wide open statement, it really would depend on the turbo size, the target boost, the CFMs..., just for arguments sake, let's say that number is pretty close to 200HP. (If it is not, I will gladly take the corrections to the numbers and some data to back it up!  )

I would think that by the time you put the weight on to run a pony motor of 200 HP and package it all in, you would be further ahead to just plumb the "compressor" in a traditional fashion. Additionally, if the rules allowed a pony motor to drive the compressor, I would assume that the total displacement of any and all motors would be considered in determining the class.

Several years ago, on another thread I raised the idea of using a turbine engine (APU/GPU) and using the bleed air from it as a charging source. You can get a 200 HP APU in a small form factor that could easily be packaged into a vehicle. This would mean that there is no turbo/supercharger, only the excess compressed air from the turbine engine. The problem is, even if it were legal, you would have to run in the omega class, so there is no real gain from the exercise.

Fun mental exercise though...

[dw230]

Slim/all,

The deal on multiple engines is that they are allowed in specific classes only. To use a second or third engine to run a supercharger for this purpose you must get approval from the committee and the Board of Directors. If you are considering using the displacement of the second engine to meet a class the engine must be a part of the drive train and contribute to the propulsion of the vehicle.

See rule 2.A

DW

[jl222]

 There was a turbocharger company just outside Carpenteria Ca. that was making electric motor powered turbo chargers
  '' centrifugal impeller'' not sure of name, Turbodyne maybe.

  I was told by a so called expert it couldn't be done, and it skipped my mind to have him to look up next time he exited
the car wash. Now that some CFM

           JL222

[Sumner]

I have heard rumors that it takes 200 HP to run a large set of turbos and significantly more to drive a supercharger. I know that is a fairly wide open statement, it really would depend on the turbo size, the target boost, the CFMs..., just for arguments sake, let's say that number is pretty close to 200HP. (If it is not, I will gladly take the corrections to the numbers and some data to back it up!  )..

It can vary a lot depending.....

According to Borge Warner's MatchBot  for the two turbos on the Stude at the 1200 HP level the turbo shaft HP is 66 HP at 11 lbs. boost, but that is a 572 that makes a lot of the HP na.  At a 1400 HP level they claim about 90 HP at 14 lbs. of boost ....

http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20hooley-construction-2013-1-a.html

Now if you go to the little 180 cu. in. motor I'm building and are trying to make 700 HP with the same turbo they claim 144 HP to make 30 lbs. of boost.

So it is going to depend a lot on how hard the turbo has to work to reach the boost levels you want,

Sum

[wobblywalrus]

Many years ago my brother and I discussed an electric supercharger for the Triumph.  Battery driven, it was.  It sure was a workable idea in theory and my brother knows what he is talking about.  An electric supercharger is way more safe and mild than some of the other goofy things we race.  There are other venues than the SCTA.