Random thoughts thread

[ichitaka05]

Originally Posted by OmarGC

You just made me want some ube ice creme from this photo... I hate you, I'll be moving back to Japan soon. Actually got a job offer there 2 months ago, but passed it up for reasons I can't disclose :/

ah~ you should at least go on vacation there. you won't regret it

[Want.FR-S]

Originally Posted by serialk11r

Are you serious? I can always hear their electric circuit whine.

Originally Posted by Dimman

I had to wear an earpiece in one ear and there were some very attractive women that worked there, too. So there were other environmental issues. But 3 times, only Prius(es?).

Since there are plenty of noise on the road, I wonder how loud the EV car needs to be so that people are aware of their presence.

That said, I wonder if there would be a situational noise maker implemented on the EV car that can make different level of noise based on the surrounding area. Heh, maybe we will have a quieter street if all the vehicles on the road are powered by Electricity.....

[blur]

All these RC threads got me thinking... wouldn't it be awesome to fabricate a front engine-RWD chassis with a rotary engine like this

Then put an RX8 shell over it....

[ame="http://www.youtube.com/watch?v=lDrxVb9AK5Y&feature=related"]Wankel 30 R/C engine - YouTube[/ame]

[wrxgoose]

i need to find a car that's:
more than 25 years old
has decent storage

any ideas? its so i don't have to deliver pizzas in the BRZ when i get it

[ftc~brz]

Why?

http://m.youtube.com/#/watch?client=...has_verified=1

[M-17]

Man I hate it when my muscles get really sore the next day from the gym, especially when my abdominals and obliques are bitching all day.

[Giccin]

Originally Posted by M-17

Man I hate it when my muscles get really sore the next day from the gym, especially when my abdominals and obliques are bitching all day.

Laugh M laugh!

:>

[serialk11r]

Hmmm @Dimman so I have been listening to CBR250RR and CBR600RR clips all day for the past week...

[ame="http://www.youtube.com/watch?v=yN2hag8J1rY&feature=related"]CBR250RR On Limiter 20,000RPM - YouTube[/ame]
In case anyone isn't aware of how crazy this is.

I am revisiting the faux V8 sound pipe idea again. I listened a bit more carefully and determined that the last 33% of the rev range is where it counts. That CBR250RR for example when he rolls onto full throttle it happens at 2/3 of the rev range, as the pitch goes up a fifth at the limiter (sorry, I'm a musician lol). That's really the only place where a car needs to scream. At low rpm a nice bass-y burble is the most you can ask for, unless you have 12 cylinders onboard.

So I get shivers when that CBR250 hits about 18-19k. To replicate that I'd need at least 9000rpm, and have the resonance pipe essentially double the frequency. If I have an engine good for about 9500rpm, that would do the trick. Now exhaust doesn't actually flow through said resonance pipe but the exhaust heat should affect at least some portion of the resonance pipe...

9000rpm=150 rev/s = 300 exhaust events per second. The resonance pipe needs to be 1/4 the length that the sound waves in the exhaust travel in 1/300 s. At 400m/s speed of sound (corresponds to 150C effective pipe temperature...seems reasonable), this is 32.5cm. At 6000rpm 48.75cm would be required. If the pipe can be cooled so that the speed of sound is closer to the usual 340m/s, maybe 360m/s, then the pipes can be shrunken to 29.25cm and 43.87 cm.

[Asterisked Accolade]

"He opened his hand and from his glowing, sparking palm thundered a microscopic force that plowed into me like a freight train. It ripped me off my feet, threw me into the air and sent me crashing through wall after wall of half-destroyed buildings. I rolled to a stop in the lobby of a hotel, against a mound of debris and bodies. I was dripping blood and in completely over my head. Every minute movement ached like a Babe Ruth swing with a thousand-pound sledge. Blood ran down my face from my forehead as I propped myself against the mound of rubble behind me. Looking through the holes my flailing body created in the walls in front of me, I closed my eyes and whispered, 'God, if you're really there. . .I need to know.' I coughed blood and gritty dirt and flinched in agony. '. . .Wade, please.' I could hear The Obelisk leveling buildings around me; they crashed to the city streets and the quakes rattled the chandeliers in the lobby. '. . .someone, just let me know I'm not alone-- let me know there's a way out of this.' My heart skipped a beat and I trembled in fear as a horrifyingly familiar voice answered from the chaos, 'There is. . .no way out, human.''' - William Bernard Hendriks, White Rook III: Exodus

[serialk11r]

Okay! I just wasted 4 hours making this:
http://www.mediafire.com/?r1fa8m605d9yjia

Grabbed this video:
[ame="http://www.youtube.com/watch?v=tAFRvkNX58I&hd=1"]Honda S2000 Invidia Exhaust - YouTube[/ame]

Cut out the first gear run, overlayed it once perfectly out of phase for 6000 and 9000rpm, sounded like any old muffler. Overlayed twice with fade in/out at 6000rpm and 9000rpm, not convincing but for one moment I heard that glorious sound, so I kept trying.

The file "2 valve" has 3 overlays, one is perfectly out of phase at a bit over 6000rpm, one at about 7500 (it's hard to tell how much lol), one at 9000. Simulates what would happen if there were 2 butterfly valves in an appropriately sized tube for perfectly out of phase resonance at a bit over 6000rpm, with both valves open at 6000, first one closing gradually until 7500, second closing gradually until fully closed at 9000. This gives 3 points where the engine sounds like it has 2 times as many cylinders as it really does.

Then the "3 valve" file has 4 overlays, at about 6000, 7000, 8000, 9000 simulating triple butterfly valves actuated in the same manner. If you ignore the air rushing through pipe making a sound that's not quite right, I think it sounds pretty close to a V8! In real life the butterfly valves would end up spaced apart only 5cm, so it would be an even smoother change. I think I'm going to have to actually do this to my car.

File "original invidia s2k clip" is self explanatory.

[Dimman]

Serial, where would the butterflies need to be positioned from a temperature point of view?

This may turn into a big theory vs practical exercise due to heat issues of the valves and however you actuated them.

On a side note, you may end up doing some research into Inconel. Please share your findings!

[serialk11r]

Originally Posted by Dimman

Serial, where would the butterflies need to be positioned from a temperature point of view?

This may turn into a big theory vs practical exercise due to heat issues of the valves and however you actuated them.

On a side note, you may end up doing some research into Inconel. Please share your findings!

The butterflies would be furthest away from the exhaust stream, closest one will be 30cm. I'm thinking aluminum tube with heatsinking at the junction. 120 degree Y junction for even sound.

[Wesley]

Sometimes dogs are brown.

[S2kphile]

I'm soo hungry right now that I want a Banh Mi Sandwich. For those that don't know:





Or I'd settle for this too: