ADVrider

Go Back   ADVrider > Bikes > Old's Cool > 2 smokers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-06-2014, 09:57 PM   #1
Sp4rks OP
Gnarly Adventurer
 
Joined: Aug 2013
Location: Texas
Oddometer: 243
Crazy idea, Forced Induction 2 stroke implications.

Seriously, think about it, it's a theoretical quadruple displacement advantage over a naturally aspirated 4 stroke. 2 strokes already have a theoretical double displacement(125 2t=250 4t, in theory). Now, lets say, we add in one additional atmosphere of pressure(30lbs of boost, yeah, crazy number, just go with it). Now, instead of 125 2t=250 4t, it's 125 2tFI(FI being forced induction)=500 4tNA(NA being naturally aspirated). Here that KTM, get to work on it. I want my 160hp sub 200lb. Obvious problems are exploding engine(KTM 125sx makes peak hp at 12000RPM, I can't imagine that the engine could take much more), and carbs not being able to compensate(DFI, maybe?). And probably about a million other reasons that I didn't think of when the idea for this post popped into my head while I was watching a video about forced induction.

But then again, the possibility of a sub 220lbs 160 HP motorcycle is kinda neat. Even in cars, a 2.0 liter car makes around 150hp, if it was a forced induction 2 stroke, 600hp.

Alright KTM(from the guys that brought you 100hp dirt bike, 180hp naked bike, 150hp Adventure bike, and hilariously aggressive 125 2 strokes) R/D, get to work. Time to show those 4 choking bastards whats up(I joke, I joke).

Again, this is just an idea that popped into my head and I thought I'd share. Cheers.
__________________
2002 KTM 125sx:
Acerbis Uniko handguards, KTM Powerparts skidplate, FMF Shorty Exhuast, FMF Fatty Expansion Chamber, Renthal Sprockets, Renthal Chain, Pirelli Hard Terrain tires, SDG Seat, Acerbis and UFO plastic.
Sp4rks is offline   Reply With Quote
Old 01-07-2014, 12:18 AM   #2
brianwheelies
Iron toocus
 
brianwheelies's Avatar
 
Joined: Aug 2005
Oddometer: 3,533
The engine in the Aprilia SR50 Ditech is direct injection using an onboard compressor(crank driven piston) to inject the air and fuel into the combustion chamber. It is providing forced induction.

High Gain Tuning did a turbo SR50.

With direct injection and a turbo it would be extremely efficient and powerful.
__________________
Quote:
Originally Posted by JohninVT View Post
Adding a turbo or supercharger doesn't automatically turn an engine into a Palestinian alarm clock.
brianwheelies is offline   Reply With Quote
Old 01-07-2014, 10:25 AM   #3
dhallilama
Gnarly Adventurer
 
Joined: Apr 2012
Location: Portland, OR, USA
Oddometer: 387
check out some of the turbo'd two stroke snow mobiles... some crazy swedes and their drag machines.

i've ridden one, it flat out scared the shit out of me.

not a ton of turbo two stroke stuff out there, i'm guessing lots of tuning headaches and such... but i want to try it. i've turbo'd enough other things.

__________________
current: '89 suzuki gsxr 750 '77 yamaha IT250 '67 harley xlh chopper (3) suzuki jr50 '62 bird mini
project: '96 husqvarna wxc250 '69 harley xlh resto '31 ford
dhallilama is offline   Reply With Quote
Old 01-07-2014, 10:49 AM   #4
WIsixfitty
ceiling unlimited
 
Joined: Aug 2006
Location: west of road america
Oddometer: 2,134
going back to the snowmobile world they have been turboing two-strokes for thirty years plus. Mostly western mountain riders as they need the help at altitude.

To this day the applications are well made, make big power and are reliable.
__________________
sideways and smiling
WIsixfitty is offline   Reply With Quote
Old 01-07-2014, 03:13 PM   #5
Twotaildog
Old Poop
 
Twotaildog's Avatar
 
Joined: Dec 2002
Location: upstate Nebraska
Oddometer: 1,259
Quote:
Originally Posted by Sp4rks View Post
...Now, lets say, we add in one additional atmosphere of pressure(30lbs of boost, yeah, crazy number, just go with it). ...
Interesting idea. Just wanted to point out that 30 psig boost is a little more than two additional atmospheres of pressure. Depending on your elevation, of course.
Twotaildog is offline   Reply With Quote
Old 01-09-2014, 06:34 PM   #6
concours
WFO for 41 years
 
concours's Avatar
 
Joined: Dec 2008
Location: Kensington, NH USA
Oddometer: 5,386
Turbo charging two strokes is like smoking in a Nitro Glycerin factory. The whole design of a two stroke relies on exhaust having no backpressure, and rather pressure waves tuned (expansion chamber) to extract the gases. A turbo puts a BIG restriction, and adds pressure on the other side... It's a PRECARIOUS balance... I've towed a couple melted turbo's off the lake, heard of every one built melting down. SUPERCHARGE if you insist on force feeding.
__________________
Too much is just barely enough.....

concours screwed with this post 01-09-2014 at 06:45 PM
concours is offline   Reply With Quote
Old 01-09-2014, 09:24 PM   #7
tHEtREV
Captain Awesome
 
tHEtREV's Avatar
 
Joined: Apr 2007
Location: Middle Park, Brisbane, Australia
Oddometer: 7,481
There is a bit of a discussion on the subject down the bottom of this page, and the next one. http://advrider.com/forums/showthrea...297308&page=58
__________________
tEAM iDIOT.
"Far to the general now, and without great final hope of victory, he has nothing to lose. And it must above all have rabies. For the moment, it dominates this special."
Joan Barreda
tHEtREV is offline   Reply With Quote
Old 01-10-2014, 12:58 AM   #8
Duck_Pilot
Retired Roadracer
 
Joined: Jun 2007
Location: Denver 'Burbs, Colorado, USA.
Oddometer: 5,667
Lotsa theory here.....

....... little practical experience. You'll never get a 2-1 horsepower advantage over a 4T engine of the same displacement. 2 reasons:

1 - Scavenging will not seal a combustion chamber as well as poppet valves.

2 - The faster an engine spins, the more power potential. Even with power-valve exhaust, chamber tuning will limit powerband more than cam profiles/overlap will. Feeding that beast enough air and fuel for peak power will make that much worse.

Reliability is the devil you are dancing with, trying to artificially aspirate a 2T engine. The entire system NEEDS to be sealed tight, from throttle valve to exhaust tip. Pressurizing adds more heat than cases, gaskets and seals are designed for. Expect short life and expensive repairs.
__________________
" A man that can have patience, can have what he will." - Benjamin Franklin

"Man cannot imagine how life could be more difficult or complex. But Congress can." - Cullen Hightower

Honestly, I *do* like Socialists. They just need a little tartar sauce.
Duck_Pilot is offline   Reply With Quote
Old 01-10-2014, 07:26 AM   #9
joexr
Beastly Adventurer
 
Joined: Jan 2011
Location: S.E.
Oddometer: 3,773
With blown , forced induction and direct injection you wouldn't need typical 2-stroke cylinder ports. You could have poppet valves in the head and a FULL powerstroke. No premix or oil injection.
joexr is offline   Reply With Quote
Old 01-10-2014, 01:27 PM   #10
Tim McKittrick
Beastly Adventurer
 
Joined: Dec 2003
Location: Wasilla Alaska
Oddometer: 1,705
See Detroit diesel.
Tim McKittrick is offline   Reply With Quote
Old 01-10-2014, 01:36 PM   #11
joexr
Beastly Adventurer
 
Joined: Jan 2011
Location: S.E.
Oddometer: 3,773
You mean the 2-stroke turbo-diesel?
joexr is offline   Reply With Quote
Old 01-10-2014, 02:43 PM   #12
concours
WFO for 41 years
 
concours's Avatar
 
Joined: Dec 2008
Location: Kensington, NH USA
Oddometer: 5,386
Quote:
Originally Posted by joexr View Post
You mean the 2-stroke turbo-diesel?
Nope. That would be a 2-stroke SUPERCHARGED diesel. Later in life, they added a turbo in ADDITION to the supercharger. Now, defunct, they were, at one time, a HOT new alternative to the pokey old diesels that came before.
__________________
Too much is just barely enough.....
concours is offline   Reply With Quote
Old 01-10-2014, 10:43 PM   #13
darmst6829
Gnarly Adventurer
 
Joined: Jul 2006
Location: Redmond WA
Oddometer: 367
Quote:
Originally Posted by Sp4rks View Post
Seriously, think about it, it's a theoretical quadruple displacement advantage over a naturally aspirated 4 stroke. 2 strokes already have a theoretical double displacement(125 2t=250 4t, in theory).

Again, this is just an idea that popped into my head and I thought I'd share. Cheers.

My buddy Herb super charged a Kawasaki Bighorn with a vacuum cleaner impeller and belt drive off the ignition flywheel. From what he told me it ran hard for about 60 seconds.
__________________
David Armstrong
Member
VME
Seattle
darmst6829 is offline   Reply With Quote
Old 01-11-2014, 08:45 AM   #14
chollo9
Screwed the Pooch
 
chollo9's Avatar
 
Joined: Jul 2003
Location: Silk Hope, NC
Oddometer: 1,405
DKW, in the 1930s:






A later version:


__________________
"It's not that I don't like people...I just find I am happier when they're not around"
chollo9 is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 01:10 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014