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GS500 build thread... cf tanks, internal supercharger, etc

A lot more work than air/fuel mixture went into that 105 RWHP figure though, probably changed a great deal of other stuff around the still operating cylinder too
 
Petelite said:
This is a really really cool project. You're extremely good at fabricating things.

But I also don't think it's going to work as well as we'd like.

If your goal is 20% more power than stock - on half the cylinders - then that means that the single cylinder is going to have make 2.2 times as much power as it had to do before in the same amount of time.

Essentially, your engine has to make 220% more power per cylinder. If you turbocharge a car, it doesn't get 220% more hp than N/A without extremely high levels of boost and an extremely built up engine - something like Ken Block's STIs (which makes 565 hp, not 2.2*300(assumed stock sti hp)=660)

So, you're going to have to force 2.2x as much fuel and air into that single combustion chamber, compress it 9:1 without premature combustion, and then convert that extremely rapid expansion of gas into kinetic energy without mechanical failure of components designed for .45 times as much stress.

I don't think that part will work. But, if anyone can make this run, it's you - it looks like you're really really good at building stuff. And maybe you can get super mpg out of it.

Flamesuit....
Click to expand...

It's worth mentioning that the 20% figure didn't come out of thin air. It's a result of a somewhat similar motor that was done by a guy in France. Same general idea, albeit slightly different execution.

Further, it's important to realize that we're talking about a motor that's very much limited to start with. Going from a carb set up with mechanical ignition to fuel injection with electronic ignition. That change alone should net some significant difference.

220% the air and fuel isn't needed to make 220% the power. There are significant gains to be had by increasing the adiabatic efficiency of the motor without just adding more fuel/air.

Also, stresses on the internals of the motor do not increase linearly as one might expect at first glance. In fact, peak stresses on the bottom end of a properly working motor don't even occur during the combustion stroke. They occur at TDC and BDC when not under combustion. I'm actually more worried about the stresses the compressor may experience when turned "off".
 
Idioteque said:
How did you actually learn to use the machines? Did you have previous experience or did you learn it at the shop you're doing your work at currently?

What's rapid protyping btw?
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I've done computer drafting and 3d modeling since I was young. You have to sculpt things in ways somewhat similar to milling this way, so it helps to visualize how to make them. Also is rather useful for setting up models for the cnc mill.

As for physically using the machines, they offer classes at techschop. I've also taken several modelmaking classes at the academy of art.

Rapid prototyping is exactly that... making prototype models in a quick, efficient manner. A lot of my experience working with composites started there. Making molds, making parts from molds, etc.
 
Petelite said:
I am currently eating my shorts.

But I'm still a skeptic. That thing can't be running on pump gas.
Click to expand...

It's important to realize, when comparing those numbers to other forced induction set ups, that this is like a supercharger without the parasitic drag. On a normal motor, putting a supercharger on may net a 50% increase in power, but what it's really doing is increasing the work output of the motor by 100% and requiring 50% of it to actually operate. Turbos work in a similar fashion. What we're used to seeing is the net power output, not the actual work output increase.





Honestly though, if it doesn't work as planned, so be it. It very well may not. I'm trying it, because I think I can get it to, but I offer no guarantees.
 
mllcb42 said:
:laughing You have every reason to be skeptical. It took a lot of looking at the math and thermodynamic charts before I was convinced.
Click to expand...

And that's where the numbers matter. What not many people know is when a engine is built, there are different sets of numbers it can hit.

Think of a Chevy LS6 motor. From the factory they are 405hp (+- a few), And reliable as a top. That stock motor alone can be pushed WELL over 100hp by just changing a few bolt on items. Some of which has a chance of decreasing the overall life and reliability of the engine. And then there is the cheater method. Strap on the biggest power adder you can (N20, Turbo, Supercharger) whatever, and run for the highest "single run" numbers you can.

ANY motor can be pushed well over 100-200% gain in output. The key question is, for how long.
 
Petelite said:
This is a really really cool project. You're extremely good at fabricating things.

But I also don't think it's going to work as well as we'd like.

If your goal is 20% more power than stock - on half the cylinders - then that means that the single cylinder is going to have make 2.2 times as much power as it had to do before in the same amount of time.

Essentially, your engine has to make 220% more power per cylinder. If you turbocharge a car, it doesn't get 220% more hp than N/A without extremely high levels of boost and an extremely built up engine - something like Ken Block's STIs (which makes 565 hp, not 2.2*300(assumed stock sti hp)=660)

So, you're going to have to force 2.2x as much fuel and air into that single combustion chamber, compress it 9:1 (so effectively a 2.2*9=19.8:1 ratio) without premature combustion, and then convert that extremely rapid expansion of gas into kinetic energy without mechanical failure of components designed for .45 times as much stress.

I don't think that part will work. But, if anyone can make this run, it's you - it looks like you're really really good at building stuff. This build is amazing and maybe you can get super mpg out of it.

Flamesuit....
Click to expand...
except that the STI is already turbocharged. The base model Impreza, with a 2.5L engine of the same basic layout as the STI, is rated at 170hp. The stock STI is rated at 305hp, about 1.8x as much... and it's not hard to bump that up to the range that you're talking about.
 
Been roughing out a design for the rear sets. Allows for a bit of adjustment down for those looking to cruise, and a bit more going up and back. Haven't bothered with heel plates yet or pegs themselves, although I'll likely make pegs that are detachable, but not foldable. They'll be designed so that should the bike fall, the peg will break before the mounting point at the frame.

rearsetshade.jpg


with the peg in stock position:
rearsetstock.jpg


All the way down/forward (Down a half inch, forward a quarter)
rearsetlow.jpg


All the way back/up(Back an inch, up an inch)
rearsethigh.jpg
 
The Baby G was my very first love....this thread is 100% WIN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Amazing job!!!!!!!!!!! :thumbup:ride
 
Subscribed. Very impressive thus far :thumbup HP results shouldn't matter; the execution and delivery are what's exciting.
 
VtownMac said:
The live cylinder runs thru 4 cycles. The "compressor" cylinder discharges every revolution.
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Exactly.

The compressor side is basically acting like a 2 stroke motor. Every time the piston goes down, it sucks in air. Every time it goes up, it compresses air.
 
mllcb42 said:
Exactly.

The compressor side is basically acting like a 2 stroke motor. Every time the piston goes down, it sucks in air. Every time it goes up, it compresses air.
Click to expand...

Maybe I'm too tired but, how are you changing your intake valve timing to open on every downward stroke on the compressor side? If you don't change that your only going to suck as much air as the combustion side right? Your intake valves are going to stay shut as if it were on the combustion stroke, but you have no exhaust valves so then you'll be sucking through your exhaust ports as the piston moves down. The translation should be?

Normaly---------as compressor-------------------------w/normal cams
intake------------intake-------------------------only intake valves open
compression------pump air to - engine side-------all valves normally closed
combustion-------suck air back from engine side--all valves normally closed
exhaust----------pump air back to engine side----exhaust valves open

Right? So your intake valves aren't opening any differently unless I missed something.(there's overlap etc. on valve timing just trying to simplify it)

I know both cylinders aren't on the same stroke at the same time..., I'm just trying to translate how valve states would be relative to the cams(not the other cyclinder) although you have the exhaust side always open now on the compressor side.
 
ekolto said:
Maybe I'm too tired but, how are you changing your intake valve timing to open on every downward stroke on the compressor side? If you don't change that your only going to suck as much air as the combustion side right? Your intake valves are going to stay shut as if it were on the combustion stroke, but you have no exhaust valves so then you'll be sucking through your exhaust ports as the piston moves down. The translation should be?

Normaly---------as compressor-------------------------w/normal cams
intake------------intake-------------------------only intake valves open
compression------pump air to - engine side-------all valves normally closed
combustion-------suck air back from engine side--all valves normally closed
exhaust----------pump air back to engine side----exhaust valves open

Right? So your intake valves aren't opening any differently unless I missed something.(there's overlap etc. on valve timing just trying to simplify it)

I know both cylinders aren't on the same stroke at the same time..., I'm just trying to translate how valve states would be relative to the cams(not the other cyclinder) although you have the exhaust side always open now on the compressor side.
Click to expand...

The stock valves on the compressor side of the motor have been removed completely. The cams have no bearing on the valve actuation of the compressor side of the motor. Instead, external valves have been fitted at the intake and exhaust ports that are activated passively. As the piston moves down, the intake valve opens, filling the cylinder. As the piston moves up, air pressure causes the intake valve to shut and the exhaust valve to open. Piston goes down, exhaust valve shuts, intake valve opens.

dsc00164.jpg
 
Anyone that ever worked on a two stage air compressor has seen this concept working, bet it will have an interesting exhaust note. I have seen GM smog pumps used as blowers also,although on small displacement engines. A small turbo downstream that fed the inlet side of the "compressor" cylinder might make it real wild...
 
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