2stroke
10-01-2007, 01:27 PM
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2stroke Ok, befor i get blasted for asking , i do have a basic understanding of the diferance in a 2 and 4 stroke engine.
But, could a V8 be converted to a 2 stroke? Maybe with differant crank and cam? Has it ever been done?
If not, why? I dont mean going to mixed gas and such, but just to fire on every down stroke. Sure it would burn twice the gas, but in a race aplication who cares.
Could it be done? Would the power be enough to justify the means?
Scincerly,
LionelC-5
But, could a V8 be converted to a 2 stroke? Maybe with differant crank and cam? Has it ever been done?
If not, why? I dont mean going to mixed gas and such, but just to fire on every down stroke. Sure it would burn twice the gas, but in a race aplication who cares.
Could it be done? Would the power be enough to justify the means?
Scincerly,
LionelC-5
10-01-2007, 02:00 PM
#2
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I don't even know where to begin with this one... 
Two strokes, in general, are only good for light-weight applications where emissions and longevity are not a concern. You could, in theory, build a big 2-stroke and put it in a car; I seem to remember there being some giant diesel 2-strokes that were built for powering trains or something. I also remember talk of a small 6-stroke engine that was effectively combining multiple 2 stroke cycles with a valved head? I think that the economics and the durability issues doomed most of the big 2-strokers. They also limit you on peak power production and response to mods. Modifying an existing 4-stoke V-8 to make it a 2 stroke, however, is a whole different animal. One major problem is the delivery of air and fuel into the cylinders, as well as the removal of exhaust gasses. 2 strokes do not have cam shafts and heads like a 4 stroker does. They rely on reed valves and specially designed exhaust pipes to help draw the gasses in and out of the cylinder. 2 strokes actually compress the air/fuel mixture inside the crankcase, which also creates a lubrication problem. That is why 2 strokes have to mix the oil and gas for lubrication. Throw in other problems like bad fuel efficiency, terrible emissions, and shorter engine life and the experiment is over. The push today is to develop lighter-weight 4 strokes.
Interesting topic though - I'm sure some of the other gurus will chime in with stories of giant 2-strokes performing at the circus, state fair, ect...
It's kinda like the rotary engine - works great on paper only.
Two strokes, in general, are only good for light-weight applications where emissions and longevity are not a concern. You could, in theory, build a big 2-stroke and put it in a car; I seem to remember there being some giant diesel 2-strokes that were built for powering trains or something. I also remember talk of a small 6-stroke engine that was effectively combining multiple 2 stroke cycles with a valved head? I think that the economics and the durability issues doomed most of the big 2-strokers. They also limit you on peak power production and response to mods. Modifying an existing 4-stoke V-8 to make it a 2 stroke, however, is a whole different animal. One major problem is the delivery of air and fuel into the cylinders, as well as the removal of exhaust gasses. 2 strokes do not have cam shafts and heads like a 4 stroker does. They rely on reed valves and specially designed exhaust pipes to help draw the gasses in and out of the cylinder. 2 strokes actually compress the air/fuel mixture inside the crankcase, which also creates a lubrication problem. That is why 2 strokes have to mix the oil and gas for lubrication. Throw in other problems like bad fuel efficiency, terrible emissions, and shorter engine life and the experiment is over. The push today is to develop lighter-weight 4 strokes.
Interesting topic though - I'm sure some of the other gurus will chime in with stories of giant 2-strokes performing at the circus, state fair, ect...
It's kinda like the rotary engine - works great on paper only.
Last edited by JohnnyC; 10-01-2007 at 02:17 PM.
10-01-2007, 02:24 PM
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Originally Posted by JohnnyC
I don't even know where to begin with this one...
Two strokes, in general, are only good for light-weight applications where emissions and longevity are not a concern. You could, in theory, build a big 2-stroke and put it in a car; I seem to remember there being some giant diesel 2-strokes that were built for powering trains or something. I also remember talk of a small 6-stroke engine that was effectively combining multiple 2 stroke cycles with a valved head? I think that the economics and the durability issues doomed most of the big 2-strokers. They also limit you on peak power production and response to mods. Modifying an existing 4-stoke V-8 to make it a 2 stroke, however, is a whole different animal. One major problem is the delivery of air and fuel into the cylinders, as well as the removal of exhaust gasses. 2 strokes do not have cam shafts and heads like a 4 stroker does. They rely on reed valves and specially designed exhaust pipes to help draw the gasses in and out of the cylinder. 2 strokes actually compress the air/fuel mixture inside the crankcase, which also creates a lubrication problem. That is why 2 strokes have to mix the oil and gas for lubrication. Throw in other problems like bad fuel efficiency, terrible emissions, and shorter engine life and the experiment is over. The push today is to develop lighter-weight 4 strokes.
Interesting topic though - I'm sure some of the other gurus will chime in with stories of giant 2-strokes performing at the circus, state fair, ect...
It's kinda like the rotary engine - works great on paper only.
Two strokes, in general, are only good for light-weight applications where emissions and longevity are not a concern. You could, in theory, build a big 2-stroke and put it in a car; I seem to remember there being some giant diesel 2-strokes that were built for powering trains or something. I also remember talk of a small 6-stroke engine that was effectively combining multiple 2 stroke cycles with a valved head? I think that the economics and the durability issues doomed most of the big 2-strokers. They also limit you on peak power production and response to mods. Modifying an existing 4-stoke V-8 to make it a 2 stroke, however, is a whole different animal. One major problem is the delivery of air and fuel into the cylinders, as well as the removal of exhaust gasses. 2 strokes do not have cam shafts and heads like a 4 stroker does. They rely on reed valves and specially designed exhaust pipes to help draw the gasses in and out of the cylinder. 2 strokes actually compress the air/fuel mixture inside the crankcase, which also creates a lubrication problem. That is why 2 strokes have to mix the oil and gas for lubrication. Throw in other problems like bad fuel efficiency, terrible emissions, and shorter engine life and the experiment is over. The push today is to develop lighter-weight 4 strokes.
Interesting topic though - I'm sure some of the other gurus will chime in with stories of giant 2-strokes performing at the circus, state fair, ect...
It's kinda like the rotary engine - works great on paper only.
I can see that everything you said follows good reason. But that is not what was trying to ask exactly. I know 4 strokes are more efficient, I have a F225 Yam on my boat.
My real question i guess is why cant you fire on every stroke? no reed valves added or anything like that, just pistons firing eveytime they are on the way down.
Is it a question of getting fuel in and exahust out fast enough?
10-01-2007, 02:44 PM
#4
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Your response indicates that you do not have a good feel for 2 stroke vs. 4 stroke theory. You can’t simply fire the spark plug on your ls1 every time that the piston is at TDC. There will be no fuel present, and you would simply be attempting to burn the remnants of the exhaust charge before the intake stroke. The cycle is:
1) Air intake stroke 2) compression stroke 3) power stroke 4) exhaust stroke.
Four strokes make power by igniting the compressed air / fuel mix near the top of the power stroke, and this happens only once per cycle. The two engines are totally different designs, and are not readily interchangeable.
1) Air intake stroke 2) compression stroke 3) power stroke 4) exhaust stroke.
Four strokes make power by igniting the compressed air / fuel mix near the top of the power stroke, and this happens only once per cycle. The two engines are totally different designs, and are not readily interchangeable.
10-03-2007, 01:31 AM
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Hey Johnny C,
I respectfully disagree on some parts of your 2-stroke description. I think the reason that large 2-strokes never made it was due mainly to fuel consumption and emissions... NVH are also some big reasons that 2-strokes have not been implemented in larger motors...
In the other respects, I feel that the 2-stroke is advantagous to the 4-stroke.
After riding dirt bikes for years, I have come to understand well how a 2-stroke works. It is a brilliant design when you compare it to a four stroke because it gets the job done without any sort of valvetrain and VERY few moving parts. I have ridden both 2-stokes and 4-strokes out in the desert (on dirt bikes) and there is NOTHING that accelerates quite like a 500CC 2-stroke motorcycle. The tin sounding buzz of the exhaust as it fires on every crank stroke is intoxicating!!!
There are very few 2-stroke motors even being made anymore for motorsports. Sure you will find them on weed-wackers and chainsaws, but when it comes to accelerating a piece of macinary as fast as possible, they have become extinct.
Sorry for the long post, I am only 21 and I am saddened that the 2-stroke motor (which has been a part of motorcycle racing for over 40 years) is on the way to permanent retirement and this post just gave me one more chance to keep the ingenious and simple design of the unique 2-stroke motor alive.
Long live the 2 stroke!!!!!!!
PS- Is there anyone else out there saddened by the disappearance of the 2-stroke motor?
I respectfully disagree on some parts of your 2-stroke description. I think the reason that large 2-strokes never made it was due mainly to fuel consumption and emissions... NVH are also some big reasons that 2-strokes have not been implemented in larger motors...
In the other respects, I feel that the 2-stroke is advantagous to the 4-stroke.
After riding dirt bikes for years, I have come to understand well how a 2-stroke works. It is a brilliant design when you compare it to a four stroke because it gets the job done without any sort of valvetrain and VERY few moving parts. I have ridden both 2-stokes and 4-strokes out in the desert (on dirt bikes) and there is NOTHING that accelerates quite like a 500CC 2-stroke motorcycle. The tin sounding buzz of the exhaust as it fires on every crank stroke is intoxicating!!!
There are very few 2-stroke motors even being made anymore for motorsports. Sure you will find them on weed-wackers and chainsaws, but when it comes to accelerating a piece of macinary as fast as possible, they have become extinct.
Sorry for the long post, I am only 21 and I am saddened that the 2-stroke motor (which has been a part of motorcycle racing for over 40 years) is on the way to permanent retirement and this post just gave me one more chance to keep the ingenious and simple design of the unique 2-stroke motor alive.
Long live the 2 stroke!!!!!!!
PS- Is there anyone else out there saddened by the disappearance of the 2-stroke motor?
10-03-2007, 03:13 AM
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me. 2 months ago i called up dealer to see if they had a new banshee for me to buy.. come to find out they quit making them in like 06 or something..Sucks cause banshees the only quad i'll buy
10-03-2007, 04:55 AM
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Hey Johnny C,
I also respectfully disagree on some parts of your 2-stroke description.
GM (Detroit Diesel) made millions of 2 stroke diesel engines which were successful and powered everything from trucks to ships to generators worldwide for decades. Emission rulings ended their reign in the 1980's.
"The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today."
http://people.bath.ac.uk/ccsshb/12cyl/
"HHI is the largest ship engine maker in the world, with a global share of about 35% in marine diesel engines. In 2002, the Engine & Machinery Division produced 132 two-stroke diesel engines totaling 4.3 million brake horsepower (bhp) and 314 fourstroke diesel engines amounting to 606,000 bhp."
Granted none of my examples are gasoline engines.......but none of them have reed valves or mix oil with the fuel. The GM 2 strokes were all supercharged and had 4 normal poppet type exhaust valves per cylinder running off a camshaft. Many were also either single,twin or quad turbocharged. Only compressed air entered the crankcase as the fuel was added by direct injection.
Perhaps the only things stopping a modern overhead valve 2 stroke gasoline engine from being successful are emission targets.
I also respectfully disagree on some parts of your 2-stroke description.
Two strokes, in general, are only good for light-weight applications where emissions and longevity are not a concern. 2 strokes do not have cam shafts and heads like a 4 stroker does. They rely on reed valves and specially designed exhaust pipes to help draw the gasses in and out of the cylinder. 2 strokes actually compress the air/fuel mixture inside the crankcase, which also creates a lubrication problem. That is why 2 strokes have to mix the oil and gas for lubrication.
It's kinda like the rotary engine - works great on paper only.
It's kinda like the rotary engine - works great on paper only.
"The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today."
http://people.bath.ac.uk/ccsshb/12cyl/
"HHI is the largest ship engine maker in the world, with a global share of about 35% in marine diesel engines. In 2002, the Engine & Machinery Division produced 132 two-stroke diesel engines totaling 4.3 million brake horsepower (bhp) and 314 fourstroke diesel engines amounting to 606,000 bhp."
Granted none of my examples are gasoline engines.......but none of them have reed valves or mix oil with the fuel. The GM 2 strokes were all supercharged and had 4 normal poppet type exhaust valves per cylinder running off a camshaft. Many were also either single,twin or quad turbocharged. Only compressed air entered the crankcase as the fuel was added by direct injection.
Perhaps the only things stopping a modern overhead valve 2 stroke gasoline engine from being successful are emission targets.
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10-03-2007, 11:26 AM
#10
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Hey Johnny C,
I also respectfully disagree on some parts of your 2-stroke description.
GM (Detroit Diesel) made millions of 2 stroke diesel engines which were successful and powered everything from trucks to ships to generators worldwide for decades. Emission rulings ended their reign in the 1980's.
Perhaps the only things stopping a modern overhead valve 2 stroke gasoline engine from being successful are emission targets.
I also respectfully disagree on some parts of your 2-stroke description.
GM (Detroit Diesel) made millions of 2 stroke diesel engines which were successful and powered everything from trucks to ships to generators worldwide for decades. Emission rulings ended their reign in the 1980's.
Perhaps the only things stopping a modern overhead valve 2 stroke gasoline engine from being successful are emission targets.
I said: "I seem to remember there being some giant diesel 2-strokes that were built for powering trains or something."
"Throw in other problems like bad fuel efficiency, terrible emissions, and shorter engine life and the experiment is over."
We both agree that some big 2 strokes have been built with success, and that emissions doomed them.
10-03-2007, 12:24 PM
#11
There's a generator at my roomates work that is one of those Detroit Deisel engines referenced above...twin supercharged and twin turbocharged...it's really quite the piece of machinery to look at...it's only used as a backup generator though, so I've never seen it running.
10-03-2007, 01:18 PM
#12
i wouldn't say 2-strokes have shorter engine life.
From personal experience having or had a few 1960's era outboards, 10 to 18hp, I run them wide open all the time and they refuse to die. Bearings and piston rings can last a very very long time provided you use adequate 2-stroke oil and don't go crazy lean/rich on the AF ratio. I would even argue if you could somehow standardize the comparison that piston rings and cylinder walls of a 2-stroke engine being oil premixed or injected (with today's 2-stroke oil) would last longer than a 4-stroke.
http://www.keveney.com/twostroke.html
the basic problem you have already stated, how do you get air/fuel in and exhaust out on every stroke. That's why we have 4-strokes.
2-strokes cannot have an overhead intake & exhaust valve, there's no way on every up/down stroke to expel exhaust and suck in air simultaneously. So when you asked can a V-8 be converted to a 2-stroke, assuming you mean LS1 for V-8, no. Not without modifying the engine block which I think falls outside the realm of conversion.
But for all out power, I would think a 2-stroke engine is the way to go. Combine that with no camshaft, pushrods, or valvetrain, you can simplify things greatly and provided you design you pistons and intake/exhaust system correctly you should make more power per given displacement over a 4-stroke. How many cylinders you want to use in a V or inline configuration is arbitrary. And with direct injection technology hitting the market for gasoline engines, I wonder if that can offset emissions problems with 2-strokes now that you can manually inject your fuel into the cylinder rather than suck it in with air.
******'a, I was lucky last year in that I ponied up for a 2006 yamaha 25hp outboard that I had to order for my raft... that's rated for 15hp
Everything is going 4-stroke and it sucks! The outboards are heavier, produce less power especially at lower rpms and they're not even cheapier. And everything is so much simpler with 2-strokes. What i would really like to do is a fuel consumption comparison of my 25hp 2-stroke vs a 15hp 4-stroke.
From personal experience having or had a few 1960's era outboards, 10 to 18hp, I run them wide open all the time and they refuse to die. Bearings and piston rings can last a very very long time provided you use adequate 2-stroke oil and don't go crazy lean/rich on the AF ratio. I would even argue if you could somehow standardize the comparison that piston rings and cylinder walls of a 2-stroke engine being oil premixed or injected (with today's 2-stroke oil) would last longer than a 4-stroke.
http://www.keveney.com/twostroke.html
the basic problem you have already stated, how do you get air/fuel in and exhaust out on every stroke. That's why we have 4-strokes.
2-strokes cannot have an overhead intake & exhaust valve, there's no way on every up/down stroke to expel exhaust and suck in air simultaneously. So when you asked can a V-8 be converted to a 2-stroke, assuming you mean LS1 for V-8, no. Not without modifying the engine block which I think falls outside the realm of conversion.
But for all out power, I would think a 2-stroke engine is the way to go. Combine that with no camshaft, pushrods, or valvetrain, you can simplify things greatly and provided you design you pistons and intake/exhaust system correctly you should make more power per given displacement over a 4-stroke. How many cylinders you want to use in a V or inline configuration is arbitrary. And with direct injection technology hitting the market for gasoline engines, I wonder if that can offset emissions problems with 2-strokes now that you can manually inject your fuel into the cylinder rather than suck it in with air.
PS- Is there anyone else out there saddened by the disappearance of the 2-stroke motor?
Everything is going 4-stroke and it sucks! The outboards are heavier, produce less power especially at lower rpms and they're not even cheapier. And everything is so much simpler with 2-strokes. What i would really like to do is a fuel consumption comparison of my 25hp 2-stroke vs a 15hp 4-stroke.
10-03-2007, 02:35 PM
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in theory two strokes should produce double the power of a 4 stroke of equal size because with a two stroke you have a power stroke every 360 degrees of crank rotation compared to 720 degrees of a 4 stroke
now we know that two-strokes are not suitable to automobiles because of emissions and nvh etc etc but think about this...
my 700cc snowmobile produces about 140 horsepower
that is 200 hp/liter and about 135 ft lbs tq per litre this may be some ricer math but think about it in terms of a 5.7 litre engine producing 1140 hp and 770 ft/lbs of tq all well before 8000 rpm and all of this being done with pump gas N/A do you want one just for fun? i know i do!
now we know that two-strokes are not suitable to automobiles because of emissions and nvh etc etc but think about this...
my 700cc snowmobile produces about 140 horsepower
that is 200 hp/liter and about 135 ft lbs tq per litre this may be some ricer math but think about it in terms of a 5.7 litre engine producing 1140 hp and 770 ft/lbs of tq all well before 8000 rpm and all of this being done with pump gas N/A do you want one just for fun? i know i do!
10-03-2007, 02:53 PM
#14
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To give you an example to appreciate the mighty little two stroke.
Watch the Daytona Superbike race sometime. On the back stretch there is a chicane corner where the riders really have to scrub off the speed.
This was put there back in the early 80's during the days of Eddie Lawson and Kenny Roberts. It's because of the old Yamaha 350Z and the 750cc two stroke animals that they made for a while. The tire technology back then was poor at best. Riders were destroying tires on the back stretch from the HP these little engines produced.
The chicane was made to save lives.
I had the pleasure of working in autoracing as a machinist once about 14 years ago. I talked to a guy who used to work for Chet Herbert. He made reference once to a billet two stroke piston port top fuel motor that was blown and running nitrometh and alky.
It made one half pass (full tilt and then shut down at mid track) and NHRA told them to never bring it to another track. Now, I have no idea if this story is true or not, but knowing the minds of drag racers, I'd say its plausible.
Point is, Two strokes make some scary power compared to displacement.
Last example, then I'll shut up.
I enjoy 3D aerobatic RC planes even though I suck at it really bad and crash allot. The power to weight ratios on the giant scale models allows for aerobatic maneuvers that are impossible in a full size aircraft. A 3D plane cannot pull into a climb from a dead hover. The RC ones can. Kinda cool.
Long live the two stroke!
Watch the Daytona Superbike race sometime. On the back stretch there is a chicane corner where the riders really have to scrub off the speed.
This was put there back in the early 80's during the days of Eddie Lawson and Kenny Roberts. It's because of the old Yamaha 350Z and the 750cc two stroke animals that they made for a while. The tire technology back then was poor at best. Riders were destroying tires on the back stretch from the HP these little engines produced.
The chicane was made to save lives.
I had the pleasure of working in autoracing as a machinist once about 14 years ago. I talked to a guy who used to work for Chet Herbert. He made reference once to a billet two stroke piston port top fuel motor that was blown and running nitrometh and alky.
It made one half pass (full tilt and then shut down at mid track) and NHRA told them to never bring it to another track. Now, I have no idea if this story is true or not, but knowing the minds of drag racers, I'd say its plausible.
Point is, Two strokes make some scary power compared to displacement.
Last example, then I'll shut up.
I enjoy 3D aerobatic RC planes even though I suck at it really bad and crash allot. The power to weight ratios on the giant scale models allows for aerobatic maneuvers that are impossible in a full size aircraft. A 3D plane cannot pull into a climb from a dead hover. The RC ones can. Kinda cool.
Long live the two stroke!
10-03-2007, 05:09 PM
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There's a generator at my roomates work that is one of those Detroit Deisel engines referenced above...twin supercharged and twin turbocharged...it's really quite the piece of machinery to look at...it's only used as a backup generator though, so I've never seen it running.
http://www.youtube.com/watch?v=7iRPjtLrsU8
World Speed Record
http://www.youtube.com/watch?v=kFJYqILwa1U
Burnout
http://www.youtube.com/watch?v=DmDzR9lbju4
10-03-2007, 06:00 PM
#16
2-strokes are a done deal. Everyone looks at peak power and that screaming 2 strokes can make so much power but I think the biggest problem with 2 strokes is they have no usable power. You always have to be in the power band to go anywhere. That is the main reason motocross has gone to 4 stroke, well that and they dont have to rebuild them all the time, them guys were always rebuilding the top ends of 2 strokes to keep em going. But back to the usable power thing, them guys were always shifting and having to slip the clutch in corners to get any drive out. Now they can just keem em a gear high and power out faster then they ever could with a 2 stroke. If you ask me I'd take a lightweight high reving 4 stroke over a 2 stroke anyday. I have a YFZ450 quad and after riding with a few guys and being around banshees and everything I wouldnt give it up for a 2 stroke anyday. In the sand I can beat modded banshees all day long with just a pipe and intake. Another good example are snowmobiles. You will see them eventually being phased out for 4 stroke sleds. They already are. The technology with 4 strokes nowadays succeeds anything you can do with 2 strokes and they still last twice as long. If you just into dragging in the sand and stuff sure a big cc 2 stroke will scream but thats all you got, something to go straight, I can take my YFZ and hang with most bikes in a drag in the sand and the next day I can take it to the motocross track and jump 80ft jumps all day long. To me i just dont see anything advantages in 2 strokes. Sorry if I offended anyone here i know some people are still die-hard 2 stroke fans.
10-03-2007, 07:30 PM
#17
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Your response indicates that you do not have a good feel for 2 stroke vs. 4 stroke theory. You can’t simply fire the spark plug on your ls1 every time that the piston is at TDC. There will be no fuel present, and you would simply be attempting to burn the remnants of the exhaust charge before the intake stroke. The cycle is:
1) Air intake stroke 2) compression stroke 3) power stroke 4) exhaust stroke.
Four strokes make power by igniting the compressed air / fuel mix near the top of the power stroke, and this happens only once per cycle. The two engines are totally different designs, and are not readily interchangeable.
1) Air intake stroke 2) compression stroke 3) power stroke 4) exhaust stroke.
Four strokes make power by igniting the compressed air / fuel mix near the top of the power stroke, and this happens only once per cycle. The two engines are totally different designs, and are not readily interchangeable.
apparently your not familiar with some ford and a lot of import systems. On alot of ford and import systems, (such as toyota) the ignition system works off what they call, WASTE SPARK, for reduced emissions. it fires every time the piston reaches TDC. and with the advent of VVTI(variable valve timing and ignition) its a basic thing now. ever wondered why they allways say they have the lowest emissions? because it fires on the exhaust stroke to burn ANY unburned fuel
10-05-2007, 02:02 AM
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apparently your not familiar with some ford and a lot of import systems. On alot of ford and import systems, (such as toyota) the ignition system works off what they call, WASTE SPARK, for reduced emissions. it fires every time the piston reaches TDC. and with the advent of VVTI(variable valve timing and ignition) its a basic thing now. ever wondered why they allways say they have the lowest emissions? because it fires on the exhaust stroke to burn ANY unburned fuel
dude you are sorely sorely misguided
i dont know how you think a waste spark system decreases emissions.... think of what would need to happen for that to even work.... lets say you inject way to much fuel (which isn't a problem with computer controlled cars anyway) by the time your done with the power stroke there ISN'T ANY OXYGEN LEFT! so it would be impossible to burn any more fuel. Toyota might say its for emissions to convince people that their vehicles are more green than the others guys but its pure propaganda...give yourself a pat on the back you fell for it
the reason a waste spark system even exists is because of simplicity. every manufacturer has been doing this for years. take for example the 3.8 in a buick grand national way back in the 80's 3 coil packs with two terminals on each coil, thats a waste spark setup. any 3800 since then has 3 double terminal coils. same with a lot of the 3.1 and 3100 motors and of course the same goes for the 3400 The northstar 4.6 litre engine uses 4 double terminal coils because its waste spark. This is not done for emission purposes its done because its cheaper and easier 3 coils instead of 6 or four coils instead of 8
10-05-2007, 04:50 AM
#19
2-strokes are a done deal. Everyone looks at peak power and that screaming 2 strokes can make so much power but I think the biggest problem with 2 strokes is they have no usable power. You always have to be in the power band to go anywhere. That is the main reason motocross has gone to 4 stroke, well that and they dont have to rebuild them all the time, them guys were always rebuilding the top ends of 2 strokes to keep em going. But back to the usable power thing, them guys were always shifting and having to slip the clutch in corners to get any drive out. Now they can just keem em a gear high and power out faster then they ever could with a 2 stroke. If you ask me I'd take a lightweight high reving 4 stroke over a 2 stroke anyday. I have a YFZ450 quad and after riding with a few guys and being around banshees and everything I wouldnt give it up for a 2 stroke anyday. In the sand I can beat modded banshees all day long with just a pipe and intake. Another good example are snowmobiles. You will see them eventually being phased out for 4 stroke sleds. They already are. The technology with 4 strokes nowadays succeeds anything you can do with 2 strokes and they still last twice as long. If you just into dragging in the sand and stuff sure a big cc 2 stroke will scream but thats all you got, something to go straight, I can take my YFZ and hang with most bikes in a drag in the sand and the next day I can take it to the motocross track and jump 80ft jumps all day long. To me i just dont see anything advantages in 2 strokes. Sorry if I offended anyone here i know some people are still die-hard 2 stroke fans.
The pipe dictates the powerband on a 2-stroke. The powerband is usable, you just have to set it up to what you want to do. The only reason 2-strokes are being phased out is because the EPA doesnt want them around anymore for emission reasons. Simple physics dictates that a two stroke will always make more power than a four stroke with same displacement assuming equal technology.
