P&G does not save fuel
#101
Let's try 500 ft for acceleration at 15 mpg and 2500 ft at 0 mpg per cycle.
#102
.539mi + .174mi = .713mi SO 13mi/ga for .174 = .0133ga & at 100mpg for .539mi = .0053ga
Totals .713mi travel / .0186ga used = 38.33MPG
Thats based on the 13mpg during FLOORING it. ..(I dont have a scan gauge but I doubt you will get THAT)
SO I'll at least say under the right conditions P&G is plausable, but if it DOES work, its by such a small amount that it costs you more in wear and tear on your car. But personally, having seen MPG read outs in rental cars. . .you dont get double digit MPG by flooring it.
#103
[quote=HaveaFit!;343317]
.539mi + .174mi = .713mi SO 13mi/ga for .174 = .0133ga & at 100mpg for .539mi = .0053ga
Totals .713mi travel / .0186ga used = 38.33MPG
Thats based on the 13mpg during FLOORING it. ..(I dont have a scan gauge but I doubt you will get THAT)
SO I'll at least say under the right conditions P&G is plausable, but if it DOES work, its by such a small amount that it costs you more in wear and tear on your car. But personally, having seen MPG read outs in rental cars. . .you dont get double digit MPG by flooring it.
You are choosing a poor model. The published data for a 0-60 mph accel is 9.3 seconds in C&D and R&T; much less 40-60. Why would you waste gas taking 12.5 seconds. I only took 4.78 seconds and then called it 5.
If you take 5 seconds at avg 50 mph the distance is 366 ft.(0.069 mi) To claim .174 miles at even 12 mpg simply isn't going to happen; 18-20 mpg would result at 12.5 seconds to go 40 to 60. My Fit struggles 40 - 60 in 5th and is very inefficient.
Also 100 mpg is too much consumption for coasting with the engine off. I did calculate on the engine being off for calculations which of course has no consumption. In my test I coasted with the engine idling just to make the test easier on my vehicle but that would not have affected coast down time. So I get .069 miles + your .539 miles is .608 miles on .0069 gal (10 mpg) or 88 mpg.
Like I said you have to use realistic model to get realistic results.
Besides Jr showed us all Sunday how well P&G works. It 'bought' him a win when it counted. The TV camera showed Jr very well using P&G.
P&G works but is a pain inthe butt on the street as well as dangerous.
.539mi + .174mi = .713mi SO 13mi/ga for .174 = .0133ga & at 100mpg for .539mi = .0053ga
Totals .713mi travel / .0186ga used = 38.33MPG
Thats based on the 13mpg during FLOORING it. ..(I dont have a scan gauge but I doubt you will get THAT)
SO I'll at least say under the right conditions P&G is plausable, but if it DOES work, its by such a small amount that it costs you more in wear and tear on your car. But personally, having seen MPG read outs in rental cars. . .you dont get double digit MPG by flooring it.
If you take 5 seconds at avg 50 mph the distance is 366 ft.(0.069 mi) To claim .174 miles at even 12 mpg simply isn't going to happen; 18-20 mpg would result at 12.5 seconds to go 40 to 60. My Fit struggles 40 - 60 in 5th and is very inefficient.
Also 100 mpg is too much consumption for coasting with the engine off. I did calculate on the engine being off for calculations which of course has no consumption. In my test I coasted with the engine idling just to make the test easier on my vehicle but that would not have affected coast down time. So I get .069 miles + your .539 miles is .608 miles on .0069 gal (10 mpg) or 88 mpg.
Like I said you have to use realistic model to get realistic results.
Besides Jr showed us all Sunday how well P&G works. It 'bought' him a win when it counted. The TV camera showed Jr very well using P&G.
P&G works but is a pain inthe butt on the street as well as dangerous.
#104
[quote=mahout;343262]Never tried. Is that needed?
#106
well I have to fess up. as an engineer, P&G made zero sense and that was also the thought shared by a number of other Sr engineers that deal in the Thermal world in large power gen facilities. So that was why I stated the thread.
I was shown based by examples and some very simple math it did work.
I ate some crow. yummm
As an eco-man, yesterday and today I did some P&G, but not the classic way. I just ran up and down and various peak speeds of 60 to 70 and than coasted in neutral (eng on) to the point I may get in the way on I-95. It works and is good for at least 5mpg was my 1st blush at this. Real big for me was the ride home. No decent host in sight, so I just slugged along at 55 and watched my avg fall from 51 to 47. Then the host arrived and I 1 sec drafted. Than I started P&G and 1 sec+++ drafting and by the time I exited 15 miles later, I worked the avg back up to 51.
I may have a chance at a 55mpg tank real soon.
I also got tougher or more stubborn and decided no A/C today. Think my new set point for that is visible sweet on my face lol
I was shown based by examples and some very simple math it did work.
I ate some crow. yummm
As an eco-man, yesterday and today I did some P&G, but not the classic way. I just ran up and down and various peak speeds of 60 to 70 and than coasted in neutral (eng on) to the point I may get in the way on I-95. It works and is good for at least 5mpg was my 1st blush at this. Real big for me was the ride home. No decent host in sight, so I just slugged along at 55 and watched my avg fall from 51 to 47. Then the host arrived and I 1 sec drafted. Than I started P&G and 1 sec+++ drafting and by the time I exited 15 miles later, I worked the avg back up to 51.
I may have a chance at a 55mpg tank real soon.
I also got tougher or more stubborn and decided no A/C today. Think my new set point for that is visible sweet on my face lol
#107
An update.The info above was bogus. My SG is way off when doing pulse and glide. 17% on the fuel used
My actual millage was less than my best using my proven methods 46.7mpg P&G vss 48.14 my best.
My actual millage was less than my best using my proven methods 46.7mpg P&G vss 48.14 my best.
#108
This duplicates my results as well. I was being fed the same bogus data by my SG. I played around with calibration but that's not the problem; the problem is that it grossly misreports realtime and 'trip' mileage when P&G is employed. I went back to using the cruise control.
#110
By "mileage" I meant MPG. Miles driven has always been very close, within a mile or two.
I tried calibrating the gallons used via the "Fillup" adjustment but that did not change the inaccurate realtime and trip MPG numbers.
I tried calibrating the gallons used via the "Fillup" adjustment but that did not change the inaccurate realtime and trip MPG numbers.
#111
A gas engine has higher efficiencies with a more open throttle than the typical nearly closed throttle at steady state cruise. This inefficiency is due to having to work against a higher vacuum generated by the nearly closed throttle. The P&G technique takes advantage of the higher efficiency of a more open throttle, when combined with fuel cutoff during coast. A six gear tranny with a tall 6th gear would accomplish nearly the same without the speed variations.
Diesels do not have throttle plates and therefore would not benefit from P&G.
Diesels do not have throttle plates and therefore would not benefit from P&G.
#112
For all those on here that have used P&G in a Fit and have results post it.
I have tested it using the method described by one that posted on here and the results for the same or less avg speed was 2mpg less than my normal methods. As far as I have seen I'm the only one in a Fit to show my results based on a full tank of fuel P&G with that change only.
Also please post how you do it and be specific.
Would like to see the moderator that was on my case like a cheap suit show any data from his Fit that show results, because I never see him post any actual results like us that use the cleanmpg site and have ours on the public view,,,,,,,, Without data your just noise
I have tested it using the method described by one that posted on here and the results for the same or less avg speed was 2mpg less than my normal methods. As far as I have seen I'm the only one in a Fit to show my results based on a full tank of fuel P&G with that change only.
Also please post how you do it and be specific.
Would like to see the moderator that was on my case like a cheap suit show any data from his Fit that show results, because I never see him post any actual results like us that use the cleanmpg site and have ours on the public view,,,,,,,, Without data your just noise
#113
A gas engine has higher efficiencies with a more open throttle than the typical nearly closed throttle at steady state cruise. This inefficiency is due to having to work against a higher vacuum generated by the nearly closed throttle. The P&G technique takes advantage of the higher efficiency of a more open throttle, when combined with fuel cutoff during coast. A six gear tranny with a tall 6th gear would accomplish nearly the same without the speed variations.
Diesels do not have throttle plates and therefore would not benefit from P&G.
Diesels do not have throttle plates and therefore would not benefit from P&G.
#114
P&G Is also more suited towards cars that have a good amount of mileage.. over 50k.. it will go thru and clean out your fuel-lines and all that fun stuff.. I just threw some in my RSX type S that has 74k on the ODO.. I have not had much of a chance to test it out though.. we will see what happens.
#115
P&G Is also more suited towards cars that have a good amount of mileage.. over 50k.. it will go thru and clean out your fuel-lines and all that fun stuff.. I just threw some in my RSX type S that has 74k on the ODO.. I have not had much of a chance to test it out though.. we will see what happens.
#116
Paul - For what it is worth:
Honestly, I don't know. I do not have a scan gauge. All my efforts have been learned by trial and error and by reading threads/forums on the internet.
I usually try to count, if I am on flat ground, letting it take anywhere from 5-10 sec to increase 10-15mph to the desired speed and then coast hoping it is twice as long(I usually count that too).
Luck has it, if you can call it that, that most of my drive has hills, so I just reach my desired speed at the peak and coast to like 40-45mph and keep a steady pace up the next hill or maintain 45-50mph up the hill if I can get away with it assuming the flow of traffic will allow me.
In hind sight, I believe you would want to track the distance traveled along with time when pulsing to the desired speed and the same for the glide to the desired speed.
I have tried this once in my wife's CRV with the FCD. I P&G from 30-40mph and I compared the same stretch of road putting the CRV on Cruise control at the P&G's average speed(happened to be 35mph and flat ground) and came up with the same mpg for both P&G and CCcases. That would seem logical to me but I do not have proof of actual improvement.
Honestly, I don't know. I do not have a scan gauge. All my efforts have been learned by trial and error and by reading threads/forums on the internet.
I usually try to count, if I am on flat ground, letting it take anywhere from 5-10 sec to increase 10-15mph to the desired speed and then coast hoping it is twice as long(I usually count that too).
Luck has it, if you can call it that, that most of my drive has hills, so I just reach my desired speed at the peak and coast to like 40-45mph and keep a steady pace up the next hill or maintain 45-50mph up the hill if I can get away with it assuming the flow of traffic will allow me.
In hind sight, I believe you would want to track the distance traveled along with time when pulsing to the desired speed and the same for the glide to the desired speed.
I have tried this once in my wife's CRV with the FCD. I P&G from 30-40mph and I compared the same stretch of road putting the CRV on Cruise control at the P&G's average speed(happened to be 35mph and flat ground) and came up with the same mpg for both P&G and CCcases. That would seem logical to me but I do not have proof of actual improvement.
#117
[quote=HaveaFit!;343317]
.539mi + .174mi = .713mi SO 13mi/ga for .174 = .0133ga & at 100mpg for .539mi = .0053ga
Totals .713mi travel / .0186ga used = 38.33MPG
Thats based on the 13mpg during FLOORING it. ..(I dont have a scan gauge but I doubt you will get THAT)
SO I'll at least say under the right conditions P&G is plausable, but if it DOES work, its by such a small amount that it costs you more in wear and tear on your car. But personally, having seen MPG read outs in rental cars. . .you dont get double digit MPG by flooring it.
Sorry, but P&G is very plausible. Lets say I did get 13 mpg accelerating for .174 miles so thats .013 gal. I'd say 100 mpg is low for idling, more like 200 mpg based on minimum fuel required at600 rpm no load. So by your rationale thats .00265 gal. The total is .0156 gal on which I traveled .713 miles for a total of 45 mpg. But even if your numbers were right 38 mpg is quite a bit higher than a CRX SiR that gets typically 25 to 28 mpg. The CRX SiR is a long way from a Fit but it was the only manual on hand and it is handicapped by having a 4.88 diff.
We do have a Civic HX that normally gets 40 to 45 mpg and when we get time we'll duplicate P&G with it.
Sorry but P&G is very plausible in our tests.
PS how many of the rental cars had 1600 cc engines and weighed 2100 lb. Any of those big V6's and V8's pulling 4000 lb better not get 13 mpg accelerating. In fact they are lucky to get 13 mpg overall. But with P&G they might get 20 mpg.
.539mi + .174mi = .713mi SO 13mi/ga for .174 = .0133ga & at 100mpg for .539mi = .0053ga
Totals .713mi travel / .0186ga used = 38.33MPG
Thats based on the 13mpg during FLOORING it. ..(I dont have a scan gauge but I doubt you will get THAT)
SO I'll at least say under the right conditions P&G is plausable, but if it DOES work, its by such a small amount that it costs you more in wear and tear on your car. But personally, having seen MPG read outs in rental cars. . .you dont get double digit MPG by flooring it.
We do have a Civic HX that normally gets 40 to 45 mpg and when we get time we'll duplicate P&G with it.
Sorry but P&G is very plausible in our tests.
PS how many of the rental cars had 1600 cc engines and weighed 2100 lb. Any of those big V6's and V8's pulling 4000 lb better not get 13 mpg accelerating. In fact they are lucky to get 13 mpg overall. But with P&G they might get 20 mpg.
Last edited by mahout; 07-18-2008 at 04:54 PM.
#118
I'm not buying it. Lets say you can coast twice as far as it takes you to accelerate back up to speed. If you are getting 10mpg from 40-65mph and 100mpg 65-40mph, and using the distance of 10 miles accellerating and 20 miles coasting. . .the gas you would use accellerating would be 1 gal. Coasting would use .2gal for a total of 1.2gal in 30 miles. Thats 25mpg. I can get more then that at a steady 70mph! I call BS!
If you want bias why didn't you chose they are equal?
#119
mahout. Please STOP telling Fit owners P&G works when flooring it on the pulse. It works poorly for sure. I have been talking to the Fit owners that are getting the BEST Eco out of any Fit owners and they all agree. Furthermore I take great records and I tried what was suggested here and it was not as good as my best other methods. 46 vss +48mpg
P&G ONLY works well (according to the Pros) with easy acceleration to speed and FAS on the glide.
On a Fit no matter what you do, the best MPG is by:
no more than 2/3rd throttle,
2000 rpm shifts and less than 60mph to name a few things
If you have a SG keep the LOD under 80
P&G ONLY works well (according to the Pros) with easy acceleration to speed and FAS on the glide.
On a Fit no matter what you do, the best MPG is by:
no more than 2/3rd throttle,
2000 rpm shifts and less than 60mph to name a few things
If you have a SG keep the LOD under 80