12+ WR increasing low-end power


10 replies to this topic
  • cowboyona426

Posted February 11, 2014 - 02:32 PM

#1

I bought my 06 YZ450F new and have been slowly making it into the bike I want, but last Memorial Day I rode my cousin's 12 WR450F and really enjoyed it.  The one thing I didn't care for was the lack of low end power compared to my YZ (I've been riding YZ 4xx bikes since 00 so I've become very accustomed to it).  His bike had the race ECU and FMF pipe, I'm not sure what he had for mapping.  I'm just curious if the low-end power can be altered enough with the programmer, or if a cam swap would be in order to help get some of the YZ low end bark.



  • Navaho6

Posted February 11, 2014 - 02:48 PM

#2

Yes, the mapping will make a huge difference.  I thought the Aussie map was too soft on the bottom. Woods/Mud maps could be even softer.  You need to ride it with the MX map and Sand map

 

I prefer the FMF map for traction in the woods but have a lot of experimenting to do.  It's fun. 



  • mebgardner

Posted February 12, 2014 - 10:28 AM

#3

Navajo6 is correct.

 

But, he did not mention something else that may be equally as important to you (tho, you did not ask...).

 

These map adjustments appear to have a huge change on "range", or fuel economy. Some quite rightly claim that MPG is a horrible measure of range given the wildly varying terrain and methods we use to play. They claim that operating time is the correct measure.  No matter, choose one and be happy.

 

The point still stands.  Make a map adjustment, and maybe watch your range decrease dramatically. These map changes appear to be much more pronounced in this regard than carb'ed cycles. That's what I currently believe, based on my readings and experiments.



  • cowboyona426

Posted February 12, 2014 - 11:06 AM

#4

Navajo6 is correct.

 

But, he did not mention something else that may be equally as important to you (tho, you did not ask...).

 

These map adjustments appear to have a huge change on "range", or fuel economy. Some quite rightly claim that MPG is a horrible measure of range given the wildly varying terrain and methods we use to play. They claim that operating time is the correct measure.  No matter, choose one and be happy.

 

The point still stands.  Make a map adjustment, and maybe watch your range decrease dramatically. These map changes appear to be much more pronounced in this regard than carb'ed cycles. That's what I currently believe, based on my readings and experiments.

 

I have read up on that some.  Like many things, opinions seem to vary a lot on how certain maps affect the fuel usage of the bike.  I judge range on miles, and I know the stock tank is around 2 gallons, so if I could reasonably get around 40 miles on the stock tank I'd be happy.  That's close to what my 06 was capable of with the stock tank on it.

That being said, does anyone have any input on whether a cam swap would produce the desired change in power delivery while not affecting the fuel usage of the bike?



  • Navaho6

Posted February 12, 2014 - 01:44 PM

#5

This dude should know.  See post # 5 - http://www.thumperta...pionship-wr450/



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  • cowboyona426

Posted February 12, 2014 - 02:19 PM

#6

This dude should know.  See post # 5 - http://www.thumperta...pionship-wr450/

 

Thanks for the link!



  • GP1K

Posted February 12, 2014 - 04:10 PM

#7

Navajo6 is correct.

 

But, he did not mention something else that may be equally as important to you (tho, you did not ask...).

 

These map adjustments appear to have a huge change on "range", or fuel economy. Some quite rightly claim that MPG is a horrible measure of range given the wildly varying terrain and methods we use to play. They claim that operating time is the correct measure.  No matter, choose one and be happy.

 

The point still stands.  Make a map adjustment, and maybe watch your range decrease dramatically. These map changes appear to be much more pronounced in this regard than carb'ed cycles. That's what I currently believe, based on my readings and experiments.

 

It's fairly easy to predict which maps are going to use more fuel on average. And that's the ones with a lot of fuel and retarded timing. Typically the 'slippery/hard pack' type maps. Which is exactly what I started with, and yes my range/mileage dropped noticeably. As I've gotten more used to the bike, and changed the gearing I've backed off on that map, as in less fuel and more ignition advance. So some of that range has come back again.



  • mebgardner

Posted February 14, 2014 - 12:01 PM

#8

It's fairly easy to predict which maps are going to use more fuel on average. And that's the ones with a lot of fuel and retarded timing. Typically the 'slippery/hard pack' type maps. Which is exactly what I started with, and yes my range/mileage dropped noticeably. As I've gotten more used to the bike, and changed the gearing I've backed off on that map, as in less fuel and more ignition advance. So some of that range has come back again.

 

I'm curious about this part of the stmt:

 

"And that's the ones with a lot of fuel and retarded timing."

 

... the "retarded timing" part of the statement.

 

You believe that retarding timing decreases MPG / range?  I don't.  I believe that, *up to a point*, it (increasingly retarding timing) increases the engine's ability to make power with a (same) given fuel charge and atmosphere.  I believe this, and I also believe that modern engine control attempts to retard ignition to be as close to the point of detonation as possible, for this exact reason (It's why they use a "knock sensor").  If you can make more power with a given amount of fuel and air, then you can decrease the commanded power (your foot's command), for a same-power / same work need, and then use less fuel.

 

Now you have more range.

 

Increasingly advancing ignition (again, up to a point) has the opposite effect. Less work is performed by the "air pump", because it has less "push" (performs less work for a given air/fuel charge) against the piston, because the "push point" is later in the air pump cycle.

 

So, that's why I respectfully disagree.

 

It's also why, when you look at the "Max Range" FI map development work I'm documenting (under "Maps Only" thread), I'm not increasing ignition advancement. Not yet, and not if I dont have to...



  • GP1K

Posted February 14, 2014 - 02:47 PM

#9

I'm curious about this part of the stmt:

 

"And that's the ones with a lot of fuel and retarded timing."

 

... the "retarded timing" part of the statement.

 

You believe that retarding timing decreases MPG / range?  I don't.  I believe that, *up to a point*, it (increasingly retarding timing) increases the engine's ability to make power with a (same) given fuel charge and atmosphere.  I believe this, and I also believe that modern engine control attempts to retard ignition to be as close to the point of detonation as possible, for this exact reason (It's why they use a "knock sensor").  If you can make more power with a given amount of fuel and air, then you can decrease the commanded power (your foot's command), for a same-power / same work need, and then use less fuel.

 

Now you have more range.

 

Increasingly advancing ignition (again, up to a point) has the opposite effect. Less work is performed by the "air pump", because it has less "push" (performs less work for a given air/fuel charge) against the piston, because the "push point" is later in the air pump cycle.

 

So, that's why I respectfully disagree.

 

It's also why, when you look at the "Max Range" FI map development work I'm documenting (under "Maps Only" thread), I'm not increasing ignition advancement. Not yet, and not if I dont have to...

 

I meant the + fuel part of that equation, not the - ignition part. It's just that on the 'muddy/slippery' type maps you see out there, that's how they tend to be, and they get lousy mileage/range in exchange for that fluffier bottom end.

 

So no, I wasn't saying the retarded ignition affects mileage, the added fuel does. Some of those maps are +5 to +7 on the fuel side, which seems like a lot considering the "FMF" map is like +2 to +4.

 

I'll check out the other thread as I'm curious to see your work on the max range map. FWIW, I started out with the 'woods/tight trail' map (which is - fuel and - ignition) as that's pretty much all I ride, but didn't really like it. Then I switched to the 'muddly/slippery' map, (even more - fuel and - igition). It was definitely softer on the bottom and easier to manage on tight single track, but the range was bad, IIRC my idiot light would come on at 40 miles tops.

 

I added an IMS 3.0 gallon tank to extend the range and just rode it like that for awhile. Then as I got more used to the bike, I started playing around the mapping again, namely backing off on the fuel, and adding a little ignition. I'd need to go pull my map to get the exact numbers, but IIRC I'm close the "FMF" map on fuel (+2 to +4) but with less ignition, a little retarded or near zero. The range definitely got better, it's a little more snappy off the bottom, but still on the softer side. The bike starts fine now, except when in gear, pretty much have to be in neutral to start it.



  • grayracer513

Posted February 14, 2014 - 05:08 PM

#10

I'm curious about this part of the stmt:

 

"And that's the ones with a lot of fuel and retarded timing."

 

... the "retarded timing" part of the statement.

 

You believe that retarding timing decreases MPG / range?  I don't.  I believe that, *up to a point*, it (increasingly retarding timing) increases the engine's ability to make power with a (same) given fuel charge and atmosphere.  I believe this, and I also believe that modern engine control attempts to retard ignition to be as close to the point of detonation as possible, for this exact reason (It's why they use a "knock sensor").  If you can make more power with a given amount of fuel and air, then you can decrease the commanded power (your foot's command), for a same-power / same work need, and then use less fuel.

 

Now you have more range.

 

Increasingly advancing ignition (again, up to a point) has the opposite effect. Less work is performed by the "air pump", because it has less "push" (performs less work for a given air/fuel charge) against the piston, because the "push point" is later in the air pump cycle.

 

So, that's why I respectfully disagree.

 

For one thing, there is no knock sensor in the WR EFI system.  Where such systems are used, they attempt to retard the timing only when a knock is detected.  Otherwise, the system tries to run the timing as far advanced during cruise operation as possible because advancing the timing generally improves fuel economy, not the other way around. 

 

The reason is that under light throttle application, the density of the incoming AF charge is very low due to the nearly closed throttle and resulting high intake manifold vacuum (or low manifold absolute pressure, if you like).  This lower pressure also reduces the dynamic compression, and the spark must be advanced quite a little bit to make up for that if there is to be any significant pressure brought to bear against the piston as it starts down.  Timing is indeed "everything".  This is also the reason for the existence of the vacuum advance unit on older automobiles that were so equipped.  If the vacuum advances the spark, which it does, and if vacuum is higher in cruising than at heavy throttle, which it is, what do you suppose is happening?  Ignition timing at full throttle on a V8 with 4"x3.5" nominal bore stroke dimensions runs in the neighborhood of 32-35 degrees, depending on a number of things.  At a cruise, it can be as high as 65-70 degrees BTDC.

 

You're entirely wrong on your analysis of the theory involved except for the "up to a point" part.  Actually, that should be "either way from optimum".  Advancing or retarding the spark from the optimum point for any given situation will negatively impact fuel economy and power.   Nevertheless, unless it pings at  a cruise, retarding the timing will pretty much always cut into your mileage.



  • mebgardner

Posted February 15, 2014 - 07:28 AM

#11

For one thing, there is no knock sensor in the WR EFI system.  Where such systems are used, they attempt to retard the timing only when a knock is detected.  Otherwise, the system tries to run the timing as far advanced during cruise operation as possible because advancing the timing generally improves fuel economy, not the other way around. 

 

The reason is that under light throttle application, the density of the incoming AF charge is very low due to the nearly closed throttle and resulting high intake manifold vacuum (or low manifold absolute pressure, if you like).  This lower pressure also reduces the dynamic compression, and the spark must be advanced quite a little bit to make up for that if there is to be any significant pressure brought to bear against the piston as it starts down.  Timing is indeed "everything".  This is also the reason for the existence of the vacuum advance unit on older automobiles that were so equipped.  If the vacuum advances the spark, which it does, and if vacuum is higher in cruising than at heavy throttle, which it is, what do you suppose is happening?  Ignition timing at full throttle on a V8 with 4"x3.5" nominal bore stroke dimensions runs in the neighborhood of 32-35 degrees, depending on a number of things.  At a cruise, it can be as high as 65-70 degrees BTDC.

 

You're entirely wrong on your analysis of the theory involved except for the "up to a point" part.  Actually, that should be "either way from optimum".  Advancing or retarding the spark from the optimum point for any given situation will negatively impact fuel economy and power.   Nevertheless, unless it pings at  a cruise, retarding the timing will pretty much always cut into your mileage.

 

I am thoroughly ashamed of myself. For all these years, I thought I understood this, and now to find that I did not.

 

Thanks for taking the time to help me.

 

To GP1K, I apologize.

 

Kind Regards,

Bob






 
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