Congrats to COZX2 on the 100+ MPG fill!
 

(Apologies if this is a repeat topic - I've been scarce around GS the last week or so...)

Nice going on the 102 mpg fill up!

https://www.gassavers.org/garage/viewgaslog/239

https://www.gassavers.org/gaslog/chart.php?id=239

I'd be lying if I said I wasn't hoping to be the first to cross the 100 mpg barrier (in a gasoline powered non-hybrid) and grant zpiloto one of his 2007 predictions, but I just haven't been using the car enough to beat you to it. :)

There is some hope for my current tank, according to the SG, but I'm only at around 70 miles or so since the end of May.

I don't mean to diminish the achievement of Serge with his smart fortwo who was the first here to break the 100 mark, but it's worth cheering when one of the regular GS participants does it too.

My hat's off!

Woooot Wooot!! and Daaaaang thats like 1300 miles to a tank!???Wowzers!
Gratz gratz Gratz!

Amazing FE. His gas log shows some substantal gains, and all in the right direction. My question to COZX2 is how much of the improvements he has gained are from aero mods and how much are from driving techniques. For instance, I'm curious what kind of mileage he thinks he would get in level ground at 60mph. Does the car get 60mpg here and the remaining 40mpg are from pulse and glide, EOC cruising, etc?

eather way amazing!!

I'm curious how much his driving altitude of 10,000 feet has on the mileage. Driving in air that is about 30% less dense than that at sea level reduces aero drag by 30% and derates (non-turbo) engine power by 30%. He drives at the altitudes that lightplane pilots fly at to get their best FE.

I threw some numbers into a density altitude calculator and, assuming a constant elevation, barometric pressure, and relative humidity, the difference in density altitude between my driving in the winter at 0F and summer driving at 90F is 6409 feet. So the difference between my driving at 1000 feet elevation in upstate SC and my driving at 10,000 feet in the CO Rockies would be greater than my summer versus winter aero drag. I wonder what kind of mileage I could get driving at 65mph at 10,000 feet?.

Thank you all. I appreciate the comments.

When I joined GasSavers I had just gotten my first 50+ tank. Figured that was a miracle at the time. I owe a lot to the members of GasSavers for their encouragement and ideas. Never dreamed that what has happened could ever be possible.

I had cardboard front end block and rear wheel skirts at that point. I was also engine off neutral coasting on downhills.

I don't drive much on level ground. It's largely upgrade or down, some more severe than others. The downgrades are great and I never thought I could balance the upgrades in to make close to this average.

I have recently observed that I can maintain 75-80 mpg at 65 mph on one of my most level sections. I did remember to check again (same stretch) when on my return trip. Was very close but had some variation during the 4 mile stretch, probably due to slight variations in terrain.

This last tank was all trips to and from my place of business. Even though there is an 1860 ft. elevation drop there are two mountain passes on this trip. Hard pulls. I take advantage of the downgrades to maximize neutral engine off coasting. Then I return home by the same route. Very little coasting in this direction. I have to average 145-160 mpg going because I only average 55-60 mpg on my returns. This recent tank I started before 6 AM to avoid the winds which pick up by 7:30. Unless it's after dark when I come home, I'm almost always battling some wind.

ScanGauge II has helped me immeasurably with my driving. You can see that in my gaslog.

That being said, I have since made significant aero improvements that translated into better FE. I think I have had my driving stabilized enough, long enough, to make this statement. I am very careful to avoid going backward from gains I have made. CO ZX2

Would you have any idea as to the % FE gains on each mod? Hate to ask for all your secrets, but I'd be really interested to know for example which ones were more successful then others. Since I drive in pretty heavy traffic where it would be hazardous to do pulse and glide, or EOC, the fact that you can get 75-80mpg at 65mph in a car rated at 25mpg on level ground is more impressive to me then the 100mpg you are currently getting with driving techniques.

Basjoos. Good to hear from you.

When I first joined GasSavers there was this guy in South Carolina posting tanks of 80-90 mpg. His name was Basjoos. Other members felt like his terrain was the place to be, calling it 'Basjoos Country'. I thought 'o man, would I like to be there'. Amazing how things can turn around.

Regarding your calculations, I recently found an aircraft site that cited 14% air drag difference 1000 ft. versus 10,000 ft. I would agree that the power drop is 30-35%. I am not very sure that should be considered an advantage.

Also remember that my 10,000 ft. terrain contains little flat ground. You do well on flat ground but have made comments yourself about how much even slight upgrades kill your mileage. Slight upgrades graduate into major uphills here. One mile straight up to get to Denver, then another mile straight up to get to me. I, too wonder what kind of mileage you could get while TRYING to drive constant 65 mph at 10,000 feet. My car must not have known about the altitude advantage till 6-8 months ago. My best for 4 years had been 43 mpg.

Might be worth the trip. Whatever the results, we could have some fun. Lots of scenery, old homesteads from the mid 1800s, 80s max summer temps, 10% humidity, few mosquitoes and trout fishing.

I'm not going to raise a big stink about it, but I don't believe those numbers for one minute.

Two or three weeks ago when he was passed (3rd place or so I believe) at 87 mpg I said to myself... oh just give it some time... he'll somehow be ahead of that leaderboard in just a few weeks. Big surprise there it is. I am not going to say that he isn't getting good fuel economy, because there are some great mods there, but nothing will convince me THAT car is getting THAT good of MPG.

Not a questioning bunch here I see.

radish: if you consider the sum total of the extreme mods to the car (remember: gearbox; ECU; major aero; never a cold start, & more) + driving technique + elevation + terrain + competitive nature of the owner, 100 mpg doesn't seem that much of a stretch.

Ultimately we have to take each member at his word on fill data. But based on what I've learned about CO & his car, I don't have much trouble believing it.

MetroMPG: I agree 100%. Look at the pictures of the testing equipment that CO is using. The guy is just plain hardcore. He is a leader, and is paving his own path. I for one believe his numbers and think that he is someone that the members of gassavers.org should strive to emulate.

Keep up the good work!!! I knew that your first 100 mpg fill would be coming in soon!

I feel in this forum you have to take a person at his or her word. CO has helped me alot by giving away some of his secrets. He is always ready to help. I would like to have a scan gauge to check things out more, but alas no OBDII.

Using the gauge stack for checking his mods is something no one else has even attemted to my knowledge. Lots of thought goes into his testing.
Look at what his attack plan is, check everything and question everything. If it doesn't help off it comes! CO puts alot of thought into what he does and does not do!

His background can only be a plus also. A year ago I would not believe it either but I do NOW. Look at what some of the claims people get with their Prius. It can't all be because it's a hybrid. Lots of it is driving skill.
Thats my two cents.

Agreed!! Absolutely amazing on the 100+ MPG.....but well worth it, considering the amount of thought/planning/execution of the existing mods. Keep with it, and help out all of us straining to hit the high, high peak of 30 MPG!!

Radish, dont be too quick to judge. A few weeks ago I HATED mr 85mph CO. (Nothing against you CO, it was pure jealousy talking :) ) Look at him... he was getting SWEET gas mileage in a car that actually looks normal. He did what apeared to be a few mods that I was actually envious of and wished that I was able to do. (I actually plan on increasing psi and adding high flow air filter so far, but thats a far cry from all the aero stuff that CO did.)
Butthen I realized that CO has to work pretty hard (harder than I am willing to) to get the mpg he gets. I now appreciate and RESPECT what he is able to achieve in his car. Id love to see his car one day and get some ideas. (Too bad I live in the NY area) I'll never get half the mpg he gets using my 98 Camry but thats because I will prob never put the same dedication and effort he does into his car. I was ecstatic to get up to 593 miles in one tank this morning. I cant wait to update my garage this morning.
Also you have to understand that he has some advantages that some of us dont have as in his terrain which he uses to his advantage. 10,000 feet is a very high altitude and even CO has told us that he has a nearly 2 mile descent on one route.
I doubt that CO is lying, but if he is, it doesnt hurt me. I just appreciate that hes a cool person willing to share his ideas and make me (all of us) a better mpg driver.
CONGRATS CO, keep it up !!

A stink has been raised :mad:

I've been called a liar on another site for the mpg I get, not cool :thumbdown: . How do they know? They don't, so it is out of line to say otherwise. I know I'm not lying every time I fill my car and I'm sure CO is the same way. I believe this site is for sharing ideas and helping each other get the best FE out of thier situation. CO is very helpful whenever I've needed tips on techniques or aero mods. He's pm'd me on several occasions to give me pointers or advice.

I am also part of the « questionning bunch » Radis atomique. I don't beleive almost anything I read here... even my own experiments.... except when I get convinced, and to do so, I must prove my mind full of preceding experience that this last result is feasible or possible.

Being a skeptic by nature ( and a scientific by experience), reading these extreme performances by basjoos, CO and others, I thought, as a new member, that GS was -- if not a joke -- a nice place for dreamers ! I myself did many experiments on the best way to achieve best FE by driving techniques alone, and I must say I cannot extend FE much more in this same path. ( 105 MPG on a full tank). There seem to be a wall right there ! But these experiments and real life FE driving opened my mind to accept new experiments done by CO ZX2 ( and thus his results).

CO ZX2 seem like an impossible reality ! Gaining around 20 mpg just adding front wheel skirts ? What the hell contains the air in Colorado ? some ether? or nerve gaz out of powerplant chimneys altering the brain ? Or else ..... I have a lot to learn from his experience ! Since I beleive you're all honest people ( like me !) then I must applaud these achievements !

My car achieved 105 mpg just with acute basic driving techniques ( no possible P&G or EOC). This is due to an efficient small diesel engine and light weight car. I tought first that would be impossible with a ford gas heavyer mover. But the ZX2 has better aerodynamics than my car, which is kind of a square box. Improving the fairing of the ZX2 makes it even better. My gosh, if ever I enter this fairing business, I might go up to 150 mpg ???

Here are a few interrogations :

1- Is it really possible to improve by so much FE, just by pulsing and gliding ? I always tought constant low speed was the best for FE, low because of wind and constant because of acceleration draining more energy than gliding is gaining ( I mean not loosing). The only thing that convinced me was that acceleration is made at better engine efficiency ( not applicable to my diesel since lean burn is the norm for FE in dsl). ( P&G must then be better for some cars only). But really that much improvement ??

2- Downgrades never balance upgrades : My experience shows me that we never gain going down what we lost going up. A stopwatch on a bicycle demonstrate it. The wind effect must make the difference, since the energy gain down equal the energy lost up. It is even worse in a car considering the overall inefficiency of the ICE. How can you have so good results in CO mountains ? I always tought flatland was the perfect FE gainer.

3- Fairing vs driving techniques : While basic engineering ( mostly more efficient engine and transmission ) is king in improving FE, fairing to reduce drag is certainly the second most important factor as speed increase. Going to the extreme like basjoos' lunar car must improve by a good margin, but just a few additions like wheel covering and small skirts .... can they do such a difference ?

Since this topic was aiming at congratulating CO ZX2, well I am very happy Old reliable is first on the top 10 most efficient... We'll learn from your experiments.

-------------------

CO ZX2
You can't do that!!! ;)

Actually, you CAN!!!
Great Job and keep up the good work. :)

atomicradish-

I am a total believer. I reached 46mpg with some tape, pumped up tires and driver technique, in the cool wet early spring, in a relatively inefficient car. I thought the best I could ever do was 40mpg.

COZX2 has performed extensive mods and has a instant feedback device that, I am sure, he uses to ekk out every possible bit of motion.

It is fun really, challenging and I am sure he is trying for more. I am hoping that I can challenge his numbers.....I just need some time!!!

Congratulations COZX2!!!

BeeUU

It's freaking awesome you got 100mpg, but it would be even better if it can be real world driving IE not taking off alternator. The aero mods rock and the driving technique but on the alternator it's allmost like cheating it's something you need that you take off to get better mileage until your battery dies.

But still the mileage you got before the alternator was off is amazing.

korax123, Thanks. I only had the alternator off the car once for 6 miles. While it was off wired it with a switch. I guess some of my posts I did say alternator off, I meant switched off. All the miles in my recent tank were to my place of business and back, pretty real world.

atomicradish -

CO ZX2 has been questioned before but he has proven his case to us over and over again. In my opinion his auto-performance background has dovetailed nicely into the work he has done on the car. He has exploited his car, his knowlege, and his environment to the fullest.

PS - I do admit that if you read it for the first time, it's hard to believe. But, keep reading.

CarloSW2

Yup, what Carlos said X2. If you run the numbers, you can see that 100mpg at an average speed of ~40mph is possible with a car like that.

Assuming (approximations) Cd=.25 from mods, A=2m^2, Crr=.007, W=12000N, and ro=.85. We get that at ~40mph=18m/s the car needs ~3kW=4hp on average. Minimum BSFC for most engines is ~250g/kWh, so the best mileage this car could get would involve using ~750g of gasoline per 40 miles. Or, since a gallon of gas weighs ~6lbs, or ~2700g, assuming he has the conditions available to run the engine at peak efficiency, he should be at ~110mpg@40mph. The thing is, his drag coefficient may be less than .25, and the CRR may be less than .007, especially with all the tires at 60psi, so until I see otherwise, I'm won't call BS. What he's getting squares pretty well with a car/route optimized for efficiency. If he started claiming 150mpg, then yeah, it's BS, but the physics pans out.

Thanks.
 

MetroMPG, thanks for putting this thread up. I, too, expected you or basjoos to be the first to post a 100 mpg tank on gasoline. And you very probably would have been first except for the time spent on ForkenSwift. I thank you for the thousands of posts you have made to date and your huge contribution to GasSavers success.

To all who have made comments on this thread: I appreciate your interest and kind words. Most of you seem to realize that the good fortune that has befell Old Reliable and me did not just happen, it did take a lot of work, a lot of thinking, an unrelenting desire to improve, and a lot of help and encouragement from fellow GasSavers members.

Hopefully I can pass on some of what I have learned in the spirit that prevailed here when I had questions to ask.

To try and answer questions that have been asked here, I will post later tonight with a detailed good faith estimate of what I feel my car mods have proven to be worth in FE. Searching my notes and working at it now.

Thank you all again. GasSavers is a great place to be.

Hey CO, great job! What are all those dials/gauges in that black box. I think that what you've done is such a great controversy, I hope it brings more people to greater success in their FE. Its so much fun to tell non gassavers about you and your car and hear them scoff... and then actually consider it.

Yeah, you're right, in comparing 1000ft to 10,000ft, aero drag drops 15% and ICE power drops 32%. But (assuming your ICE adjusts air/fuel ratio to compensate for altitude) that power drop would result in improved ICE efficiency since the ICE is having to operate at a higher throttle setting (less pumping losses) to get the same power output. Your high mileage is a result of your driving skills and aero mods, but the low air pressure driving environment also is a factor. If you were driving an Insight, you'd probably be getting 160mpg.

When they chose Oklahoma to run last summer's Insight marathon, at the time I was thinking that if they had run it on some fairly level, low trafficked roads on the Colorado Plateau in SE CO or southern UT on the plateau at 8000 to 11,000 feet, they could have gotten better mileage that they did in OK.

I'm pretty sure pumping losses remain consistent at different altitudes because I read that oxygen content is proportional to altitude as well. So, if there's 15% less air density that'll help w/ aerodynamic drag, but pumping losses remain the same because the proportion of air to everything else remains the same.

Living in a mountainous area myself, I believe everyone is completely overhyping the benefits of driving in mountainous terrain.

Before you can coast off a hill, you must also drive up it. There is a lot of wasted energy when climbing mountains. As well, when you go back down them, you cannot fully maximize your potential energy because if you value your life and driving record, you'll use your brakes to keep from dying.

Personally I would have thought you to be the most likely to reach the 100 mpg plateau. How are his techniques that much different from any one elses?

Metro, I believe it was you yourself who said that there is must be a maximum MPG for each car. Just look at the numbers - 274% above EPA - yours is only 108%.

I just have a hard time believing that. As I said earlier, I don't want to judge him too harshly. He has made a lot of fine improvements, and I'm glad for him. I do believe he is getting good mpg, but I think the temptation to stretch the numbers for each upgrade has to be there.

I have to admit, the mpg figures COZX2 has given and some of the others on the top ten seem a little high, but I am willing to take the man at his word. I am interested in seeing his breakdown of mods and the FE improvements they make. It will help me decide which ones I want to do on my car so hopefully I can at least beat the EPA figures on my car.

Depends on the grade and mods. I'm guessing that CO ZX2 is setup so that he can engine off coast in gear, or N. While EOC'ing in gear is wasteful compared to out of it in terms of time, it's still using no fuel, so whatever the peak mileage is it can still be attained, just at a proportionally lower speed than it could be attained using P&G. In fact, P&G generally bites compared to long enough mountains because by using it, the car can't warm up totally and ends up running through the enriched cycle/inefficient portion of the BSFC map a significant amount of time. In fact, in all my experience, climbing mountains with steepish grades in EFI manuals generally helps because efficiency is way greater than in the flats, something like 50-100% better, and when I'm going down the other side in gear, I'm using no fuel as long as I'm above the idle fuel cut. :thumbup:

Value of mods in FE.
 

I list my mods and my estimate of the effect they have had on my FE. This is not intended to be a guide for anyone, just my statement of what I have done and how they relate to my car. A little hard to give completely separate figures for each mod as some are intertwined and depend on others for best results. I will use 43 mpg as a baseline as that was my best measured tank in 4 years before any mods and normal driving. Note that 43 mpg is considerably over EPA before any mods. I have evaluated a number of mods that didn't pass the test. No gain, they are not here anymore. Keeps me from accumulating a bunch of useless mods.

1. I will start with the first 2 mods I ever did. I completely covered and sealed the grille area and installed quickie rear skirts, also sealed. The first tank with these mods produced 11 mpg over my previous best. There was some engine on neutral coasting involved here but not to a large extent. Much later I found that these mods also were effective in reducing negative pressures at the rear of the car, something I was not fully aware of when the mods were first installed. Shortly afterwards is when I joined GasSavers.

2. ScanGauge II woke me up considerably. Changed my driving forever. Very valuable in making me aware of real time mpg and other engine functions that would lend themselves to improvement. I will group engine off neutral coasting and pulse and glide (my idea of a true glide is engine off in neutral) in with SG. I believe these items, developed over time, have produced (conservatively) 20 mpg for me.

3. I will list the following items together because they are so intertwined and dependent on each other. Combined I estimate 22 mpg benefit from items below.

a. Partial belly pan, bumper to front tires and under engine (placed my engine temps and AIT temps into a more consistent efficiency range, especially in frigid weather). I have recently discovered the belly pan also has a profound effect on my measured wake pressures at the rear of the car. Additions to this pan proved detrimental to wake pressures and were promptly removed. The pressure/flow gauges have enabled me to identify and correct turbulence all around the car. I have managed to reduce the negative pressures at the rear of car to near zero. Sources that I have read cite that negative pressures and turbulence at the rear may produce as much as 85% of total aero drag. Have also read that a Ford Taurus pushes 6 tons of air per mile out of the way at 60 mph. These are astounding figures.

b. Wheel spats(4) to deflect air around tires. Front fender skirts. Air dam and recent extension of it. I have recently realized the cumulative effect of these mods on the wake pressures measured with the pressure/flow gauges I acquired in February. These gauges have made these mods' effects easier to identify and explain than I was able to do before.

4. I will group the following miscellaneous items together to try and shorten this report a bit. I consider each of these mods stand-alone that have their own distinct advantages. Combined, my estimate is 15 mpg benefit as I use them optimally.

a. Cold startup aids, engine block heater, coolant heater, engine compartment insulation.

b. Alternator off switch.

c. Fairly recent transmission gear change reducing my engine rpm 7%. I will mention that I have another home/modded gearset that will lower my engine rpm an additional 22%. Have not used these yet. I have a camshaft in the works as a complement to this lower rpm range. I am fairly certain camshaft will be needed to provide additional torque at the lower engine speed. These items will probably constitute my next major attempt at increased mileage.

d. Also recent, ECU fuel trim range adjustments.

e. More recent, select disconnection of knock sensor to allow additional ignition timing. Especially helpful in my quest of better upgrade mileage.

f. Injector kill switch mounted on gearshift lever. Instantly kills engine without fumbling with ignition switch. Everything else stays on that ignition switch controls. No fuel can be consumed when this is switched off. Makes EOC infinitely easier. I can shut the engine down, slide into neutral, turn the switch back on and bump start when ready by putting back in gear, all while keeping my eyes on the road.

g. B.F. Goodrich TA Touring tires with real decent LRR rating. I use 60 psi in all 4 tires, wear patterns look great. Spun smooth wheel discs.

h. I keep thinking of one more thing I should mention. I have a manual switch for my radiator fan, I have not had it turned on at all in the last 8 months. I have found that my engine is more efficient at temps 210-225 degrees. Rejected heat is lost energy, I strive to retain as much as practical. A great help when EOCing in keeping engine temps from dropping too far.

Hope this is an adequate picture of my mods and what they did for me. They are here for anyone to consider as they see fit.

Whew lots of work for alot of gain. Thanks for sharing. Curious is the gear set changes your own work or did you find available pre built parts.
Engine running hotter is a new concept to lots of people. Remember the days of lowering the thermostate temp. We were going the backwards to todays metods. Getting the car up to temp. fast is the way to go. Most new cars are built that way.
Also your fan mod. is of intrest. Corvettes now have a 98% duty cycle fan that comes on only as needed as fast as needed. Suspect lots of veh. use this today. Thanks again for sharing. I think your supporters out weigh your skeptics. Way to go!

Thanks, minic6, I posted my gearset info into a thread started by another member. You will find 3 of my posts there:
https://www.gassavers.org/showthread.php?t=3094

I kyped the idea from my friend Tom, an engineer in Michigan. There is a link to his site that shows great pics. Made from stock gears from another Escort trans. I paid $200 for precision grinding of the gears, $55 for the used trans and my brother did the welding. Custom cut gears would probably cost more than my car is worth. Hope all this info is of some use.

have you considered any weight reduction? Also, how do your pressure gauges work, that must be what the black box is in your photos?

I have thought of weight reduction, but not seriously. I do not want to rip my car apart which would be necessary for any meaningful reductions.

My gauges direct read air pressure as the car is moving. I read the gauges inside the car at 60 mph. All windows and vents have to be tightly closed and fans turned off in cabin. Assists me in spotting problem areas of turbulence and flow. Gauges are zeroed to atmospheric pressure at rest. I use 3/16 in. plastic tubing taped to various spots on the car. I have started using all 6 at once to minimize the place tubing, start, accelerate to 60 mph, stop, change tubing position then repeat over and over. Saves a lot of time and gas. Recently started testing on my regular driving trips instead of special test only sessions. What can be learned from these gauges has been my biggest discovery ever.

so you are looking for pressure differences within the cabin?

I can but have not. I am using only to pick up pressure readings on the outside of the car at this time. Gauges compare outside pressures to the atmospheric pressure inside the cabin. I could use the gauges to read the pressure effect of window(s) down, vents open, fans on, etc.

My main focus has been to reduce the negative pressures at the rear of the car. As the car moves forward at speed, punching a hole in the air, vacuum (if you will) forms at the rear because the punched hole does not fill in at the rear as fast as it is occuring. This created vacuum is trying to pull the car backwards. Experts cite 85% of total aero drag is caused by this vacuum and turbulence at the rear of the car.

Have you found that the front air dam on your car decreases the pressure under the car? Before banned, F1 cars used to have skirts to cause downforce (and probably increased drag) to allow higher cornering speeds. I have seen several cars on Gassavers using air dams on the front or lowering the car, but have thought that it would be better to improve the flow of air under the car then try to reduce the amount of air flowing under the car.

Have not got around to checking the undercar pressures much. With the reduction in negative pressures at the back of the car, that has to outweigh most all other factors. With no skirts at the body sill I would not expect to see significant low pressures underneath. I will test it more in the future.

Has any of this given you any ideas for you own car?

I've been trying to figure out how to wire up switches to interrupt my injector signal grounds which appear to run from the injectors up to the driver's side near the injector resistor. I'm thinking the brown, red, light blue, and yellow need to be cut into and a switch added there. I also think the green/white wire to my alternator may be the one to interrupt which signals the alternator that the battery is charged. I'm not really up for the aero mods yet. I have to make sure it looks alright, but most importantly that it won't fly off. I don't understand how you route those little tubes to outside the car without creating some kind of air leak.