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

[mllcb42]

Mllcb42: Any thoughts as to how well the tank will survive a crash? I would be interested for race use, but I need to confirm that it would withstand some pretty severe abuse, and wouldn't pose a fire or surface hazard in the event of a major get-off.

That's the whole reason for the use of kevlar in the lay up. Carbon under impact will crack and shatter. Kevlar may crack, but won't separate. Think of the difference between normal glass and safety glass.


If you're really worried about it, a bladder could be run as well.

 

[Sharky]

awesome thread. I don't think you'll due much more than stock, but it is a fun idea. Tests your tuning and fabrication skills.
So far well done.
Wear safety glasses when you start it up (perhaps a welding hood just in case)

 

[mllcb42]

awesome thread. I don't think you'll due much more than stock, but it is a fun idea. Tests your tuning and fabrication skills.
So far well done.
Wear safety glasses when you start it up (perhaps a welding hood just in case)

I don't expect peak hp to be that much more than stock. I do expect a much broader torque curve and far better fuel economy.

 

[Asphaultnaut]

oh and in anticipation, when you get running videos, please make 'em available for download for those of us with blocked Youtube access?

I wanna know what this will sound like near redline.

 

[Alexey]

I want to make a comment about something that was said earlier in the thread. If I'm repeating someone else's comments, apologies.

So this is regarding parasitic losses of the supercharger. Yes, it's true that in this project there is no "new" part that gets added to the motor, but when we talk about the supercharger overhead, we have to remember that it's no longer a 500 -- it's a 250 single now with a supercharger that happens to be driven directly instead of a chain or what have you. But the fact remains that some of the energy the single will produce, must go toward driving the supercharger (other cylinder). Yes, there are some efficiency gains in terms of better coupling of "engine" and "supercharger", but physics tells you that there's no free lunch here: the air still has to be compressed in the supercharger and it takes a certain amount of energy.

On the plus side, thermodynamics tells us that the supercharger cylinder will generate some heat because all it's gonna be doing is compressing air at 2-stroke rate. That means that while there probably won't be the same temperature parity across the head gasket as you'd see on a stock GS500 motor, it won't be as though one side is hot and the other cold. So, while another energy loss, this may help some with the gasket and head longevity.

 

[Asphaultnaut]

remember though, that with the added boost from the supercharger, more fuel can be added while keeping the ratio correct. So you're gaining energy in the hot cylinder from the increased amount of kaboom you're shoving in, and not from air compression.

It's like pumping gasoline with a hand pump. The energy you get by lighting it is a hell of a lot more than you expended pumping it out of a barrel. As opposed to pumping that gasoline into something like a hydraulic cylinder and using that pressure to lift something.

by sleeving or boring out the pump side, or using thicker or thinner pistons, he can change the ratio of work needed to drive that compressor as well. Experimentation potential is pretty epic here.

I expect parasitic losses to compression to be more than compensated for if the concept can be made to function properly. Starting the motor could be an interesting proposition.

Only issue I have so far, is development time spent on rearsets when the concept motor has yet to prove it's concept

I want to make a comment about something that was said earlier in the thread. If I'm repeating someone else's comments, apologies.

So this is regarding parasitic losses of the supercharger. Yes, it's true that in this project there is no "new" part that gets added to the motor, but when we talk about the supercharger overhead, we have to remember that it's no longer a 500 -- it's a 250 single now with a supercharger that happens to be driven directly instead of a chain or what have you. But the fact remains that some of the energy the single will produce, must go toward driving the supercharger (other cylinder). Yes, there are some efficiency gains in terms of better coupling of "engine" and "supercharger", but physics tells you that there's no free lunch here: the air still has to be compressed in the supercharger and it takes a certain amount of energy.

On the plus side, thermodynamics tells us that the supercharger cylinder will generate some heat because all it's gonna be doing is compressing air at 2-stroke rate. That means that while there probably won't be the same temperature parity across the head gasket as you'd see on a stock GS500 motor, it won't be as though one side is hot and the other cold. So, while another energy loss, this may help some with the gasket and head longevity.

 

[Alexey]

remember though, that with the added boost from the supercharger, more fuel can be added while keeping the ratio correct. So you're gaining energy in the hot cylinder from the increased amount of kaboom you're shoving in, and not from air compression.

It's like pumping gasoline with a hand pump. The energy you get by lighting it is a hell of a lot more than you expended pumping it out of a barrel. As opposed to pumping that gasoline into something like a hydraulic cylinder and using that pressure to lift something.

by sleeving or boring out the pump side, or using thicker or thinner pistons, he can change the ratio of work needed to drive that compressor as well. Experimentation potential is pretty epic here.

I expect parasitic losses to compression to be more than compensated for if the concept can be made to function properly. Starting the motor could be an interesting proposition.

Sure, I totally agree that it should be a net gain over a normally aspirated 250. No doubt.

Only issue I have so far, is development time spent on rearsets when the concept motor has yet to prove it's concept

The man's gotta fund the project somehow. Most of us wish we had that kind of fabrication kung fu.

 

[auntiebling]

awesome thread, awesome project

Mllcb42: Any thoughts as to how well the tank will survive a crash? I would be interested for race use, but I need to confirm that it would withstand some pretty severe abuse, and wouldn't pose a fire or surface hazard in the event of a major get-off.

zoran ran one on his race sv650 that tygaboy made. lined with something after final assembly, that wasn't a bladder. i don't know what kind of crash you're expecting, but if your bike does catch fire the tank will burn too as the resins are flammable regardless of how you isolate the fuel from the tank material.

for those that haven't seen it: tryaboy's carbon tank project for zoran

 

[Whisky_Richard]

I read through just about the whole thread... but any reason you didn't just leave the valves in the pumping cylinder and just grind the lobes off the cam?

Forgot to mention: Sweet project! Looks like a ton of fun. Reminds me of my senior design project, SAE's Supermileage vehicle.

 

[wrexallen]

I have the biaxial carbon here for doing cylinders. I'm more concerned about the safety of doing a carbon peg. Crash and it won't bend, it'll shatter, leaving some sharp pieces attached to the bike next to your leg. I could use kevlar like I did in the tank, but why? Some shiny carbon pegs would likely end up all scratched to hell with minimal use, so you lose the aesthetic reasoning in a hurry.

I gotcha. I was think more of an aluminum core wrapped in CF. It would scuff up, eventually, but still think would look pretty sharp. And they're easy to make. You could make several sleeves

 

[mllcb42]

I read through just about the whole thread... but any reason you didn't just leave the valves in the pumping cylinder and just grind the lobes off the cam?

If I were to leave the valves in the cylinder and grind down the lobes on the cam, the valves would stay sealed shut. No air would flow in and out at all.

 

[mllcb42]

Only issue I have so far, is development time spent on rearsets when the concept motor has yet to prove it's concept

Concurrent project for another class I'm taking. Both need to be done by the same deadline, so I'm multitasking...


and they will help pay for the project.

 

[mllcb42]

Aluminum is on its way for the rear sets. Bought enough to make 3 sets.

Last night I placed the cf reinforcement for the fuel pump in the bottom of the tank and set some studs down through the tank

Now waiting for ups to show up with the tank sealer so I can start sealing the inside of the tank.

 

[Asphaultnaut]

my mistake. i thought it was just for the bike project.

sounds like he's getting decent interest in the tank

The man's gotta fund the project somehow. Most of us wish we had that kind of fabrication kung fu.

 

[mllcb42]

my mistake. i thought it was just for the bike project.

sounds like he's getting decent interest in the tank

I'm making them for my bike, as a project for one of my classes. Selling them to help fund the rest of the bike certainly doesn't hurt though

 

[mllcb42]

So I'm sitting here shopping online for some polystyrene foam so I can start prototyping the air tank for the bike. Can't find it anywhere. Look out the window, and a box truck from Bob's Foam Factory pulled up to the neighbor's house. Guess who carries the foam I need?

 

[Stormdragon]

Serendipity.

 

[Maddevill]

I vote this guy for "BARF OFFICIAL EGG HAID"!!!

 

[mllcb42]

Sealant showed up yesterday in the mail.

It'll get a couple coats with the halves separated, then a little added after the tank is sealed to coat the edge.

 

[mllcb42]

started working on the air tank today. This is just a rough shape for a plenum. Volume is about 3 times that of a single cylinder. This is the proper size plenum design for a forced induction application.

A whole lot more pictures to follow from today's work when I upload them off the other camera.