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Speed costs money
by
scrounger
on 02 Dec, 2021 14:58
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A few weeks ago I had rotated the pressure diaphragm on the top of fuel pump. Had read where turning the diaphragm on the base will enrichen the mixture as the cone is offset.
The car immediately was stronger from off idle on up. I went on to adjust the boost controller to give one more pound of boost on top. Of course with more fuel means less mileage. Had a chance to refill the car and was rewarded with a rather unimpressive 37mpg.
So went into the boost diaphragm and turned it down a quarter turn.
At 3.20 a gallon I want more economy than 37, At one point I was getting over 50mpg every tank at 60 mph. This tank I kept it at 73. Am willing to spend some for more low speed acceleration (as it were on an idi diesel.) Probably will be another month before I learn anything.
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#1
by
ORCoaster
on 02 Dec, 2021 20:07
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It has always been an either-or proposition, Power or Economy. Big honking V-8 or tiny straight four-banger.
But with the addition of electric motors, we now have the desired compromise. You can still get economy if you want and if you want to get out of the way those motors work really well for that.
If you have that front-wheel drive going then add a motor to the rear and a few batteries somehow and enjoy the extra kick.
Dial down the enhancement cone? Well, I guess, our diesel is at 3.89 here so yeah. Might be time to adjust that black smoke coming from the tailpipe.
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#2
by
scrounger
on 02 Dec, 2021 21:06
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Ah Make your caddy a hybrid. Still 37 at 73 isn't too bad for a 35 year old car. You could probably just start by moving ahead with the electric motor and let the clutch out.
Someplace I saw a video of honda car that was powered by two riders on a tandem bicycle. The driver of the car would shift into a desired gear and the riders would move the car forward. At maybe 3 miles per hour.
When I was an endurance bicycle racer I calculated that for the entire 24 hours, I averaged 75 watts of power. That was output power, I went 344 miles. No relevance to the discussion but the study of numbers is fascinating none the less.
I don't have an visible smoke but then again don't look in the mirror with my foot on it at full throttle, high rpm.
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#3
by
srgtlord
on 02 Dec, 2021 23:39
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I think Im only getting 30mpg nowadays but then again I leave a nice cloud of black smoke upon acceleration
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#4
by
ORCoaster
on 02 Dec, 2021 23:47
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I don't have visible smoke but then again don't look in the mirror with my foot on it at full throttle, high rpm.
Yessss, the eyes should be on the road in the direction the vehicle is headed when developing those conditions. You might try to find one of those fancy Roundabouts and just do a quick circle to see just how much black is behind you.
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#5
by
scrounger
on 03 Dec, 2021 00:00
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SL
Do you think that the excess fuel helps performance or does it move more of the combustion later in the power stroke and ultimately out the exhaust.
I don't generally race anyone but don't let them pass me in curves. Maybe smoke would be good there.
In the late 70s - early 80s I was roadracing motorcycles, Yamaha 350 two stroke twins. Our face shields were always covered in oil by the end of a race. Although there was not that much visible smoke, A little but no one was rolling. Nice thing was that bugs didn't stick that well. I still have two of my bikes
I think the nearest roundabout is 80 miles away. My wife won't drive this car mainly because it needed the shifter rebuilt and she became frustrated with it. Will have to find a way to see how much is blowing but is turned down a bit now.
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#6
by
srgtlord
on 03 Dec, 2021 11:49
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Definitely more power
Although I didnt set this up intentionally the pump is stupid advanced in timing. I swore i would reset it 3 years ago and never did. I like the extra pep in its step
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#7
by
Dakotakid
on 04 Dec, 2021 14:35
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In the last 3 weeks, I have been driving Mk. II's (personally well rebuilt and ported and KKK 24 turbo'ed) (two of them) at least 165 miles per day. I live up in the northern plains and wind and hills and fuel at 30 cents MORE than you are paying (I need to find a parked locomotive).
I drive to get places.....not "nursing a 12-pack fashion"driving). Fair amount of wide-open stuff from time-to-time. With loose calculations, I am about 36-37 range. My fuel here is now "winterized"....what-the-hell EVER that means. I run some 20 wt. hydraulic fluid in my fuel for lubricity and "cushioning." I have run hyd. fld. for over 30 years....no ash....no problems.
I rebuild my own injectors and set these at 2650 lbs and get atomization out 15 feet when I have them set on the chinko tester (outdoors with my eyes and body behind and parallel to the equipment). (Still looking for a volunteer to stand out there with a lit cigarette!) (Would burn...not flash).
I suspect with wimpier pressure settings and new injectors and lesser timing advance, I could maybe get a little more per gallon.
I have NEVER gotten the big-stud numbers so many of these key-board punchers proclaim. I live at higher elevation. I real-world drive to get to where the hell I was supposed to be an hour ago.
Furthermore, my ported ALH cars don't do what the blow-hards say either. Again, I have no time to wimp along.
You are doing fine.
You are also talking to a guy who knew RD 350's and KZ's and GS's (G's and E's).
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#8
by
scrounger
on 04 Dec, 2021 16:22
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I have been trying to massage my vw with more fuel and now less mileage. I drive as well, to get some place but probably drive less than 100 miles a month but only for reasons of getting there.
Regarding my adjustments The boost pin is offset. A cam that can be rotated to adjust the baseline but whos main purpose of giving more fuel under boost. It has a pin follower that drives through a lever down to the main fuel screw.
I had first rotated the diaphragm so that the pin pushes out a bit further against the cone shaped cam. I think that ajusts the fueling no matter whether on boost or off.
Car ran better but mileage was worse.
I turned the diaphragm cam assembly back half way and after a drive to town could really feel less low rpm torque.
I returned it to settings that I had initially done on the first post of this thread.
But see two other areas of adjustment that I might try. The spring preload on the diaphragm spring, a threaded wheel under the diaphragm and load spring. i could turn it it clockwise and reduce the preload allowing the motor to get fuel faster as the boost comes up. There is also a stop added in, a nylon spacer can be reduced or eliminated to allow the cam to drop down further to a thinner part of the cam allowing enrichment only when the boost is higher Maybe getting acceleration when you need it and less fuel when you want to cruise. I can see by the wear pattern on the cam that there is plenty of room for the diaphragm to move further.
any thoughts?
Tks.
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#9
by
libbydiesel
on 10 Jan, 2022 09:49
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I have been trying to massage my vw with more fuel and now less mileage. I drive as well, to get some place but probably drive less than 100 miles a month but only for reasons of getting there.
Regarding my adjustments The boost pin is offset. A cam that can be rotated to adjust the baseline but whos main purpose of giving more fuel under boost. It has a pin follower that drives through a lever down to the main fuel screw.
I had first rotated the diaphragm so that the pin pushes out a bit further against the cone shaped cam. I think that ajusts the fueling no matter whether on boost or off.
Car ran better but mileage was worse.
I turned the diaphragm cam assembly back half way and after a drive to town could really feel less low rpm torque.
I returned it to settings that I had initially done on the first post of this thread.
But see two other areas of adjustment that I might try. The spring preload on the diaphragm spring, a threaded wheel under the diaphragm and load spring. i could turn it it clockwise and reduce the preload allowing the motor to get fuel faster as the boost comes up. There is also a stop added in, a nylon spacer can be reduced or eliminated to allow the cam to drop down further to a thinner part of the cam allowing enrichment only when the boost is higher Maybe getting acceleration when you need it and less fuel when you want to cruise. I can see by the wear pattern on the cam that there is plenty of room for the diaphragm to move further.
any thoughts?
Tks.
You've got gasser thinking on the brain. On a diesel, for a given cruising load and a given timing of injection, there is not any adjustment you can make to the 'mixture' that will result in any fuel economy savings. Period. Trying to do so, you will chase your tail endlessly and never get any positive results.
Get rid of the gasser 'mixture' thinking!
You CAN turn down MAX fuel, blow less smoke, reduce performance and realize some fuel economy savings. You can also simply press less hard on the accelerator pedal so that you don't spend time in the max fuel zone for the same results. However, no amount of fiddling with the fueling for cruising will result in any fuel economy benefit. All it will do is change the required position of your right foot for a given cruising load!
Adjust your boost enrichment for an even amount of smoke at max fuel on/off boost. Then turn down the max fuel until the smoke clears. Trying to go beyond that is just an exercise in tail chasing.
Other things that CAN affect fuel economy for a given load, are timing, dynamic advance, weight of oil, transmission gearing, transmission lube, dragging brakes, wheel alignment, etc, etc, etc...
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#10
by
scrounger
on 11 Jan, 2022 23:56
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Yes I may have gas thinking on my mind. Generally to get good mileage I use a light throttle use as little turbo or as much vacuum (in a non turbo gasser) and try to get it into top gear as soon as possible.
Using this technique, we commuted in our jetta for several years about 150 miles each way. Usually keeping the speed at 55-65mph and got about 50 mpg regularly. Using almost no boost and little foot feed, pretty much letting everyone pass us. Carrying two adults 5, 50 pound dogs and supplies. About half interstate type and half 2 lane. As far as I know it was in stock vw tune. 'It generally felt pretty gutless
Never saw any black smoke. There are many on this list that tune for or by smoke. Probably moving their power up above the stock torque peak, the point of the highest efficiency. They have more power and I would say less mileage.
Even in this day and age of higher fuel prices it doesn't sound like many attempt to get really great mileage. I know that with as few miles as I drive there is very little motivation to get that last few mpg out of it. I can drive our v8 truck if I want to burn a lot of gas which I don't unless I need it for hauling.
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#11
by
libbydiesel
on 13 Jan, 2022 14:19
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My prior post was not motivated by any lack of desire, interest, or enthusiasm for 'tuning for mileage'. My statement that it is impossible to get better fuel economy through changes in cruising speed fueling was based instead on the physics of diesel operation. The injection pump is the 'mixture adjustment'. At the mid-range (cruising) fueling, increasing fuel increases power output, decreasing fuel lowers power output. You can fiddle with screws on the pump, but if adjusting fuel quantity is all you do, then when you are back on the road cruising in the same gear at the same speed, you will be burning the same amount of fuel. Your foot may be higher or lower from the floor, but the fuel quantity for a given load will be the same. There are some injection pump fueling adjustments that can make a big difference in both performance and/or economy, but those changes come at the max fuel range and are often the same as simply pressing less hard. The best tune you can get for fuel economy and performance is an even amount of fueling across rpms and boost pressures.