Superstroker1
Veteran
- Joined
- Nov 6, 2005
- Messages
- 29
You've got to be a saint!
Allen,
You are a saint and patient as the day is long! I admire you...this is the very reason I'm speaking to you from Florida! Sure is nice outside...
Maybe I can help with this one.
Do any of you ride a 500cc Snowcross sled?
When I served as crew chief for one of the Skidoo Snowcross Teams, I used to measure fuel specific gravity/volume of fuel used along with the atmospheric conditions at the track and account for every ounce of fuel the sled used per moto. Without going into a long involved technical explanation as to why I did this, I will say that I do understand what kind of fuel mileage a race sled produced. Try 2 miles per gallon!
These 440s made 95hp...Period! Regardless of what you have been told.
A 4-stroke engine, like the PhaZer 500 will get twice the fuel mileage as a similar 2-stroke non-DI engine...the DI engine will probably be a bit more fuel efficient than the carb 2-stroke, depending on who wrote the program for the race course of the day.
The problem is, the 80HP PhaZer engine won't make 95 hp (unless it is further modified for racing) but will be competitive even with less HP due to something you may not have considered???
Linearity in power delivery! This is what eventually replaced 2 strokes in Motocross racing.
Spinning tracks or bike tires does not equate to foreword acceleration...although it looks cool.
Thankfully, the Snowcross race prepared PhaZer will have ALL OF 100HP and Linearity of power delivery to boot.
The problem is, this HP will come at 13,000 RPM and here in lies the reason small displacement 4-stroke twins will never be more fuel efficient than a 2-stroke that is tuned to make similar power.
An engine is an air pump. The higher you spin the engine (RPMs) the more air it consumes and consequently, the more fuel it needs to establish correct stoichiometry (air/fuel ratio for best power).
Now, Yamaha engineers may have been able to build an engine for the PhaZer that would have produced similar performance out on the trail and provided better fuel economy. That would have been a long stroke version of the 500 you will receive in the 2007 PhaZer but you would have lost peak HP.
THANK THE LORD ABOVE THEY DIDN'T!
That engine/stroke combination would have reduced the one thing the 4-stroke has over the 2 stroke...RPM while preserving a greater proportion of torque at low rpm's and a flatter more LINEAR torque curve while doing it!
Soooo,
Since my truck that I use to haul my sleds gets 12 miles to the gallon on the way to the trails...I frankly don't give a rats #*$&@ that my AMAZING little 12,000 RPM PhaZer crotch rocket gets 13 miles to the gallon! As a matter of fact...I think that’s pretty damn good considering!
AGAIN!!!!!!!!!!!!!!!
Thanks Yamaha for delivering the right technology to the sport, with racing success on your mind!
I hated Yamaha in the past for always delivering the "Golf Cart" technology to my snowmobiles, while the others were getting racing technology year after year in their trial sleds!
I'll be DAMED if I'm going to cry about something as foolish as 13 vs. 16 miles to gallon when Yamaha has finally delivered on the philosophy of building MOTOCROSS race bike technology to my snowmobiles!
Please wake up and stop the BS!!!!!!!!!!!!!
We finally convinced Yamaha to give us what we asked for and you cry about 13 mpg???
Allen,
You are a Saint!
Allen,
You are a saint and patient as the day is long! I admire you...this is the very reason I'm speaking to you from Florida! Sure is nice outside...
Maybe I can help with this one.
Do any of you ride a 500cc Snowcross sled?
When I served as crew chief for one of the Skidoo Snowcross Teams, I used to measure fuel specific gravity/volume of fuel used along with the atmospheric conditions at the track and account for every ounce of fuel the sled used per moto. Without going into a long involved technical explanation as to why I did this, I will say that I do understand what kind of fuel mileage a race sled produced. Try 2 miles per gallon!
These 440s made 95hp...Period! Regardless of what you have been told.
A 4-stroke engine, like the PhaZer 500 will get twice the fuel mileage as a similar 2-stroke non-DI engine...the DI engine will probably be a bit more fuel efficient than the carb 2-stroke, depending on who wrote the program for the race course of the day.
The problem is, the 80HP PhaZer engine won't make 95 hp (unless it is further modified for racing) but will be competitive even with less HP due to something you may not have considered???
Linearity in power delivery! This is what eventually replaced 2 strokes in Motocross racing.
Spinning tracks or bike tires does not equate to foreword acceleration...although it looks cool.
Thankfully, the Snowcross race prepared PhaZer will have ALL OF 100HP and Linearity of power delivery to boot.
The problem is, this HP will come at 13,000 RPM and here in lies the reason small displacement 4-stroke twins will never be more fuel efficient than a 2-stroke that is tuned to make similar power.
An engine is an air pump. The higher you spin the engine (RPMs) the more air it consumes and consequently, the more fuel it needs to establish correct stoichiometry (air/fuel ratio for best power).
Now, Yamaha engineers may have been able to build an engine for the PhaZer that would have produced similar performance out on the trail and provided better fuel economy. That would have been a long stroke version of the 500 you will receive in the 2007 PhaZer but you would have lost peak HP.
THANK THE LORD ABOVE THEY DIDN'T!
That engine/stroke combination would have reduced the one thing the 4-stroke has over the 2 stroke...RPM while preserving a greater proportion of torque at low rpm's and a flatter more LINEAR torque curve while doing it!
Soooo,
Since my truck that I use to haul my sleds gets 12 miles to the gallon on the way to the trails...I frankly don't give a rats #*$&@ that my AMAZING little 12,000 RPM PhaZer crotch rocket gets 13 miles to the gallon! As a matter of fact...I think that’s pretty damn good considering!
AGAIN!!!!!!!!!!!!!!!
Thanks Yamaha for delivering the right technology to the sport, with racing success on your mind!
I hated Yamaha in the past for always delivering the "Golf Cart" technology to my snowmobiles, while the others were getting racing technology year after year in their trial sleds!
I'll be DAMED if I'm going to cry about something as foolish as 13 vs. 16 miles to gallon when Yamaha has finally delivered on the philosophy of building MOTOCROSS race bike technology to my snowmobiles!
Please wake up and stop the BS!!!!!!!!!!!!!
We finally convinced Yamaha to give us what we asked for and you cry about 13 mpg???
Allen,
You are a Saint!
Re: You've got to be a saint!
The 2007 Yamaha Phazer is Throttle Body Fuel Injected (FI) not Direct Injection (DI). You may have been confused – being in Florida (wouldn’t mind being there as well – no snow here) – as Yamaha outboards use DI – pretty high tech DI as they use more pump pressure than anyone. I think the pump ramps up to about 700 psi before it squirts.
DI, like Diesel is directed into the crank case – on the Yamaha as well – but designed so none escapes out the exhaust. They build the high pressure to get better fuel atomization.
You kept track of fuel – well….after exhausted thinking
I can only come up with – you wanted to be sure no one was stealing it? 
I agree with most of what you said about the Phazer power.
Superstroker1Superstroker1 said:
The 2007 Yamaha Phazer is Throttle Body Fuel Injected (FI) not Direct Injection (DI). You may have been confused – being in Florida (wouldn’t mind being there as well – no snow here) – as Yamaha outboards use DI – pretty high tech DI as they use more pump pressure than anyone. I think the pump ramps up to about 700 psi before it squirts.
DI, like Diesel is directed into the crank case – on the Yamaha as well – but designed so none escapes out the exhaust. They build the high pressure to get better fuel atomization.
You kept track of fuel – well….after exhausted thinking
I can only come up with – you wanted to be sure no one was stealing it? I agree with most of what you said about the Phazer power.
Superstroker1
Veteran
- Joined
- Nov 6, 2005
- Messages
- 29
Actually, you're confused...
I know the PhaZer is TBFI
Try reading my note again...you'll get it!
I was comparing 2-stroke carb to 2-stroke DI.
The sun is very warm here in FLA...
Thank you.
I know the PhaZer is TBFI
Try reading my note again...you'll get it!
I was comparing 2-stroke carb to 2-stroke DI.
The sun is very warm here in FLA...
Thank you.
