///// TDI economy Challenge : 60 MPG at 60 MPH /////

[Andyinchville1]

Hi All,

A friend of mine and I made a friendly wager awhile back (well maybe not so friendly since $$ and pride are on the line ... HA).

Anyways, I was telling him how great our little cars were MPG and performance wise and one thing lead to another next thing I know I was telling him I bet my car could get 60 MPG at 60 MPH with only minor mods if I put my mind to it ( historically I had gotten 2 tanks back to back at 56 MPG and even hit 57 a couple times without really trying ... just regular driving) so I figure how hard could it be to get 4 more MPGs? (maybe 5 needed for good measure! ).

Some ground rules were set :

1) No drafting - for safety
2) No pulse and glide / EOC coasting / etc .... min highway speed to be 60 MPH
3) No push cars .... yeah he knows how I think !
4) No being towed .... I was too fast to OK the no push car thing and my grin gave me away on this one .... hmmm ... easy $$ is not to be had!
5) No roll backs or trailering of car ....sigh he got me again! (he didnt say anything about flying or shipping via train but I am fair and a good sport! ).
5) MPG's done over 500 miles on 1 tank (continuous drive or within 48 hours) to keep from cheating down 1 hill and claiming stupid good mpg.
6) Car to be a regular daily driver (no gutting out to save weight or anything too crazy (ref show on TV where doors / windows removed to save weight),
7) car to be street legal and no more illegal than it is if it is currently illegal ... basically car to be relatively the same as now in other words.

Fairly basic , yet hopefully still alot of loopholes to be exploited to help win the bet!

So far the only mods I have are in my signature ....

Some tricks up my sleeve that have not been installed yet are :

1) UPS Let me know my Profi Diesel 3" TIP arrived Wednesday .... Girlfriend to pick it up for me tonight ....

2) PD 150 Airbox - been gathering dust waiting for the TIP to arrive ( I have the PD 150 Pipe already BUT when I saw the Profi diesel one , I figured whay go with the smaller looking one?!? I NEED mpg's - Dual airboxes and BHAF may have to wait for a bit if this is good enough (I may plumb in a sensitive gauge to see what the current restriction is .... other than a spring loaded filter restriction gauge anything I can run that is sensitive ?..... I'd try to install before modding to see what, if any, improvements there are).

3) Came from Japan the other day (yes.... Rice meets Kraut ... interesting combo.... but not a good sounding dinner!) .... Volk TE 37 Gravels weighing in at a disappointingly heavy 12 lb 2 oz according to the UPS store (fed ex store called it 14 lbs , my digital Bathroom scale called it 12 LBS). .... Did I get Obese ones ? are the shipping stores trying to cheat me for extra $$ shopping (I took it to the stores to weigh pretending to want to ship it out to get an accurate weight on the rims figuring my bathroom scale may not be super accurate) I had read that they weigh 8 lbs OR was that LBS minus the "L" .... Hmmmm , well if I loose that will be my excuse!

4) After getting centering rings (I have to measure what I need unless somebody knows for sure) and new lug bolts I am having Hankook Kinergy ST735 tires put on (P215 75R15) .... the extra 2% OD should net me 1 more MPG at least ..... hopefully (2% OD at 50 nets 1 more and I am or can be above 50 w/o AC on (he forgot about AC not having to run! BUT it would be nice to win with AC on).

I'm on my wear bars now somewhat so hopefully this other stuff can be figured out and get here before cords start showing up ! .... Well, I do have a back up vehicle but I hate only getting only 40 MPG!

5) Other than some of my other thoughts are on my threads on this forum ..... anything else than can help (I want to try to win without cheating if possible)?

Other weight savings he won't notice are:

1) Braille or Anti Gravity battery

2) Carbon Fiber hood ( painted (gulp) for stealth).... fenders are surprisingly light so those in carbon fiber probably wont help much.

3) Removal of the rear seat back and replace with 1/4 plywood (not sure that would save too much weight tho BUT the thickness saved would make for more storage space on the floor

4) I don't think I will mess with replacing glass with poly carb , deleting sound deadening, gutting doors, acid dipping the frame etc because the $$ are not that great and this is my daily driver ...

Oh the other thing is .... he drives Prius so we CANNOT let him win! HA

Andrew

 

[Decreppo]

This sounds awesome! Good luck to you and keep us posted with how everything goes. The way you drive is probably more important than anything else.

As for weight savings, have you taken out the spare tire yet? That should help. Your new tires may actually hurt MPG for the first several thousand miles while they break in. Worn out tires actually have less rolling resistance.

 

[CleverUserName]

Increasing tire diameter doesn’t add MPGs unless you need to compensate for an excessively low final drive ratio. After correcting for Speedometer error, taller tires are actually heavier and require more fuel to turn, not less.

FYI There was a guy who hypermiled a stock 2014 Cruze diesel at 60 mph on a 1000 mile run and his average was 67+ MPGs. I think it was actually 67.3.

 

[Decreppo]

That’s good info on the tire diameter. The taller final drive ratio is what I was aiming at for my reasoning behind taller tires working better. Looks like the OP already bought his set so he won’t need to worry about that.

 

[IndigoBlueWagon]

Honestly I don't think this is difficult in a stock TDI. The previous (and original) owner of my B4 Passat regularly got 67+ MPG at 57 MPH. He did have larger diameter tires but that was the only mod. A/C off, windows up, flashers on.

 

[DonL]

Best I have done is around 56 mpg. Drafting at one car length per 10 mph is safe and WILL make a difference. My latest trip into New Mexico I ran 65 to 70 mph and AC on most of the time. I got 50 mpg or better. I did not draft because you have a hard time finding a truck going that slow. I got caught in the traffic coming out of Burning Man once. 45 mph from Gerlach to Fernley, after dark so AC was off. The fuel guage did not move. If I was going all out, I would find a flat area around Nebraska/Iowa/Kansas and drive 50 mph. I would probably also get rear ended.

 

[Seatman]

Just use the UK gallon and you'll be fine lol

60mpg in a stock ALH is no problem over here anyway. I always averaged about 50 mpg at fill up but that included spirited driving as well as towns etc but to get that average I had to be getting over 60 mpg some times.

 

[Andyinchville1]

HI,

From about 11:45 PM yesterday until about 9:30 AM today I drove a couple routes on a courier run... mostly highway / 2 lane country roads ... very little stopping but some city with stoplights at / near the the 3 stops.

My fuel mileage of late had been pretty horrible (sub 50 mpg so it led me to believe something was wrong with the car (my thoughts were maybe slight retarding in the timing due to belt stretch, I do have a slight boost leak, maybe wearing of injectors etc ..... being sub 50 mpg for so many tanks I began to wonder if 60 MPG was even remotely attainable.).

Despite some slow speed driving (which may have actually helped fuel mileage since I was able to stay in 5th gear pretty much all the time) , several stops etc, and since it was cool out no AC usage (I even had to blend in some heat to make it comfortable!) I did manage close to 56 MPG on the tank.

So even with my potential issues above, the car still knocked out pretty good mileage ( I realize now maybe I have not been driving as many higher speed / long distance runs so that was probably the issue behind my string of horrible sub 50 MPG tanks (I'll have to update my fuelly ....I have a good number of receipts I have not put in yet).

Anyways, This got me to thinking about a few things ....

While the goal is to get 60 MPG at a minimum of 60 MPH (the constant speed / min speed was to reduce driving factors and make it more about the actual car itself) , my original intention was to make the car good enough to be able accomplish this all by itself (without relying on driving tactics / hypermileing , or terrain BUT seeing that the best I have gotten was back to back 56 MPG tanks and others have gotten better mileage at times maybe I NEED to incorporate that in the game plan as well.... 5 MPGs or so extra is a long way to go.

In the past, I had done some dedicated runs that stretch 500+ miles per day (yes brutal , day in day out, BUT it was the same run every day so mods could be proven out since the routes were the same and changes could be seen between runs .... I have not done those runs in awhile so it's hard to gauge things tank to tank now unless I write detailed trip notes for the tank (almost too much like work!).

With that, since i have until March 2023 to get this done .... here are some thoughts I have on doing the MPG run ...

These are all NON car related ( more driver / driving / environment based to maximize fuel mileage ( Part 2 will be the car itself BUT the below can have significant impact on overall mileage).

These are easier since no mods / parts required (my thoughts but feel free to comment) ....

1) I have to try to drive the 500 mile loop all at once (less slow time getting to the highway, less warm up time with poor fuel mileage etc).

2) I need to drive it largely late at night to wee hours of the AM (less traffic fewer needs to slow / stop) .

3) I have to plan WHERE to do the run .... I think 500 miles of relatively FLAT / CLOSE to sea level would be best for MPG rather than high altitude and / or hills ( I hear you never really get back good MPGs on the hills / mountains and maybe THIS is why we seem to have such varied MPGs between / among our vehicles .... environment probably is a fairly significant factor in the MPGs.... that is why when we do things to see if it improves our cars , we have to base it on our individual previous history more so than from one car in one area to another car in a different area ?

4) I think the run needs to be done when it is cool out and requires NO ac to be comfortable .... no ac means better MPG's

5) I was thinking maybe if the run was done during the daytime less electric load would be imparted due to not having to use headlight / lights of course the drawback is traffic

So environmentally :

1) where do you think the run should be run ? (admittedly I would like to get / try to get a courier run to do simultaneously ... get paid to drive it BUT realistically that probably won't happen .... gotta hope / try tho right ?... maybe out in the great plains ? down by the eastern coast? go west young man? Any specific highways to run?

2) Any approximate dates to try to run ? (maybe during a holiday so roads are empty ? Sunday night ? .... would prefer NO rain / NO snow.... more resistance / harder to get good MPGs).

3) Times to run ?

4) Any other thoughts on the environmental factors that would be good to consider / do to help maximize MPGs ?

Thanks for your thoughts on this....

 

[CleverUserName]

1. Tape all body seams with blue painters tape. Block the front grill and radiator with cardboard or plastic sheets.
2. Lower the car. A lower profile means less wind resistance.
3. Alignment. An alignment to minimize toe might be required.
4. Tire air pressure should be maximized to limit the footprint and rolling resistance.
5. Remove brake disks. Getting rid of the brakes will also reduce your unsprung weight and boost the MPGs.
6. Use VCDS to cheat. Adjust the speedometer to add 10% to your measured speed and calculated MPGs.
7. Remove accessory belt. No parasitic losses from the alternator, PS pump or A/C.

 

[Mozambiquer]

I do a modified p&g where I am not pushing the clutch or neutral gliding. The reason that works is because on decel the TDI cuts all fuel to the injectors and so it isn't using any fuel at that point. 60 mpg is the goal I have on my caddy build.

 

[ToxicDoc]

As mentioned, fill tires to maximum safe pressure. Narrowest tires that fit.
Drive in the morning before it gets hot so you drive with the windows closed and do not use the AC.
Drive all 500 miles in 1 shot as you mentioned (2 trips more likely since you'll have to eat and pee in an 8+ hour trip). Make sure car is fully warmed before you fuel up and start the count
Route should be flattest possible - no hills. Use interstate in a low-traffic corridor to reduce use of brakes
All non-essential electrical turned off.
Use lowest permissible oil viscosity, synthetic type, and under fill by 1 qt.
Alter timing to benefit mileage
Remove all unnecessary items from car - required documents only, empty trunk, no floor mats, consider no spare tire if your tires are good and you have AAA or equivalent. Reduce washer fluid to half container. I would say empty it and get rid of wipers but that's risking safety for minimal benefit
Remove seats other than driver.
Wash car, vacuum it out, and have it buffed/polished. Seams taped as previously mentioned. Remove antenna
Wear shorts, T-shirt. Carry only basic ID/card/phone.

 

[PradoTDI]

Sounds very interesting, I'll be curious to see how this turns out! Should be doable, I got a 54mpg average over 400+ miles in my stock '97 Jetta once, it was mostly 55-65mph in snow and heavy slush, with about an hour of 20mph backroad. Half the time I was carrying a huge engine hoist too! My brother averaged something like 56 or 57mpg on a 1000+ mile tank in a stock B4V on a drive through southern BC. Part way through he had to fix a leaky injector return hose.

 

[Andyinchville1]

HI All,

Been a little negligent on this thread BUT I have taken a few steps towards weight loss to help with better MPGs.

I have read that reducing 100 lbs can increase fuel mileage 1 to 2 percent ... while 1 or 2 percent may not sound like alot ..... 2 percent of 50 MPG is another 1 MPG!

NOTE : All weights were done on my digital bathroom scale so it's not necessarily certified ... I didn't think about it until now (literally) BUT I will see how accurate my scale is by using some weights I have but know by varying my foot placement on the scale I can get different results with the most consistent numbers being gotten with my feet are spread out towards the edges.

In the past , I figured I could get better numbers by going to Fed Ex and UPS to see how heavy my new wheels were but the difference between the 2 scales at the 2 different places was 2 lbs !! ugh .... you'd think they would have really accurate scales but NOT since the numbers did not match (or maybe 1 was accurate and 1 was not) who knows but you figure commercial places should have accurate scales since they charge by weight and dimensions.

Anyways, I cleaned out the car ... It's amazing how many partially filled drinks there were floating around inside ... easily probably 2 quarts worth ! I cleaned out other misc things too (extra clothes ... yes I keep them in the car usually because on my occasional long drives I sometimes sleep in the car when tired so if it is cold out it's good to have extra warm stuff), extra tools, paperwork , extra clipboards (from when I think I brought it home for the might so I bring another with me when I head out in the AM only to find 2 other clip boards already inside ! ....Anyways, I cleaned out my small personal stuff .... Not alot of weight but every bit adds up to get to the magic 100 lb mark. (admittedly that was the other day and I did not weigh everything).

While I want to reduce weight , I am not going too crazy with weight reduction to where it makes the car louder or colder/ hotter inside ( I thought I could simply wear ear plugs BUT I tried that experiment and it isn't real comfortable or convenient so gotta keep the sound proofing and carpet and headliner / insulation....

Same with nixing the AC , power steering, and heater core ..... not really doable if one wants to be comfortable in a daily driver that I literally spend hours in the car daily ( I have half though maybe buying a project car specifically for gutting out as a max effort MPG monster BUT time is sometimes at a premium .... maybe when I become independently wealthy!

I did look into noise cancelling technology ( I know they make headphones BUT I really don't want the hassle of wearing that and it may draw unnecessary attention from law enforcement if they see that on while driving.....

I was hoping to find a noise cancelling system that could use speakers like car stereo so the noise can be abated without need for headphones or earplugs .... I have not neen able to find such a system yet ... If that was doable I would consider gutting out since the weight of the sound deadner would probably weigh more than the noise cancelling system .... maybe.

On a more practical front and what I have done so far (and plan to do) .....:

1) I removed the lower rear seat cushions and headrests ( I run the car as a 2 seater with the rear seat back folded down for cargo space).... I'll have to find and weigh these pieces ......... weight savings unknown at this time.

while the seat cushions and headrests were relatively light , the rear seatbacks ARE (or at least FEEL) quite heavy .... I have not unbolted them yet until I make a replacement to keep the flat floor (see next paragraph).

My plan for that is to remove that and use 3/8 plywood (framed and hinged with 1x2) to replace them ... That SHOULD save weight , keep a flat floor AND increase storage area under the flat floor since the seat back is fat while the 3/8 plywood and 1x2 framing is thin.

It would be nice to have a full sheet of carbon fiber flooring instead of the plywood BUT I imagine that would be some $$ ....

I have to keep the flat floor for cargo and sometimes I do sleep in back on long trips so it is nice to have a flat bed of sorts.

Weight savings of the future plywood seat back mod currently unknown (I may try this this weekend if it isn't rainy since I have no garage to work out of ......... Weight savings of this mod unknown at this time

2) I replaced the full size spare tire (michelin MXV4 Plus tire on avus wheel .... combo weight 36.2 lbs) with a full size Michelin Defender T + H tire on a 15x6 Volk Gravel wheel ( combo weight 31 lbs) for a savings of about .........5.2 lbs

(on a serious MPG run I could omit the spare , the jumper cables, the tool kit , the extra safety supplies *like flares , triangles , car jack, 4 way lug wrench with 2 foot galvanized breaker bar extension for the 4 way jack, spare water jugs , snacks).

3) I had my new wheels and tires installed .....

I went from Hankook Kinergy 205 75 R15 tires on Avus wheels to 215 75 R15 Hankook Kinergy tires on 15x7 Volk Gravel Wheels.....

I had weights the rims but seem to have misplaced the paper it was on .... paperwork is disorganized sadly

I believe the new wheels were each 5 LBS lighter (avus vs volk) BUT I think the larger tires were 3 LBS heavier so the net loss of weight was about
2 lbs per wheel or ......................8 LBS total weight loss

Yes, I realize there is extra weight further out (the tires) BUT so far I think the extra diameter (2% over my last tires) is helping more than the extra width and aero loss (section width of the wider tires) is hurting ...

I have not had the chance to drive to PA recently but hopefully that run will be soon so I can see MPGs on that trip since i have info from the last times I went out there to see if the tires help or hurt but my guy says help .... FWIW at 60 mph my scan gauge reads about 1900 RPM so if peak MPG happens at peak torque (I have read that is 1900 RPM) then I am right on peak at the stipulated 60 MPH run BUT I think the car "feels" better at about 2000 RPM (I can;t recall the MPH at that RPM tho .....).

4) I plan on Nixing the side mirrors and running "mini's" .....

Literally a 3" convex mirror and a small 1"x2" regular mirror to pass inspection (you have to have the "regular" mirror to pass .... convex alone won't pass).

I mainly use my wide view rear view mirror for driving anyways (it can literally see pretty much everything behind me unless I am piled high with stuff inside than I have to use the side mirrors and I basically use convex all the time then .... convex is handy for parking too ... you can see the lines on the ground / curb etc).

This mod should save some weight BUT more importantly give an aero edge.

5) I am getting my headliner fixed so it has to come out shortly ......

While that is out I will see what is under there and I will be removing the roof racks (a little weight saved , a little aero improvement , PLUS in times of civil unrest just one less thing a protester can hang onto or keep a molotov cocktail from simply rolling off your roof faster.

I may remove the rear side airbags if present BUT I don't want to trip any error lights so may have to research that first .....

5) I am seriously looking into a lightweight battery (lithium type) and carbon fiber hood ..... Anybody running these now ? How much weight was saved ?

6) I thought about carbon fiber front fenders BUT at $800 to $ 900 each the weight savings was really NOT that great ( I felt how light a factory front fender was when I swapped mine out due to the over the fender rust and I cannot imagine being much lighter than even with carbon fiber).

7) Tho expensive , the A arms and Subframe seem cool .... see link below

Tubular Racing Subframe (MK4 FWD) : USRT | Real cars, Real Roads, Real Fast!

USRT Tubular Racing Subframe (MK4 FWD) - Our newest Tubular Racing Subframe substantially increases grip on FWD cars! It reduces front-end roll and keeps the tires planted flatter to

usrallyteam.com

I may do the A arms when mine need to be refreshed (probably about 150K from now) ..... subframe seems cool too and maybe one of those"while the mechanic is in there anyways ....." things.

8) On a negative note (or positive weight gain).... some mods I've also done or will do ....

Atlas skid plate adds I think 19 lbs .... sadly may need for protection

Whiteline Rear Sway Bar I think added about 16 lbs ... this does make the car feel better so it'll stay

Profi Diesel TIP is quite heavy and probably heavier than stock .... I went to a welding shop and asked if they could make a duplicate but in aluminum and they quoted a price of $800 .... ouch so I guess not..... freer breathing should offset weight I think (hope!)

Kerma 3" turbo back exhaust (straight through) weighs the same as the factory system .... net 0 ...... would be nice if some of it could have been aluminum ( I was reading up on that but it seems aluminum only after the cat would be best due to heat weakening aluminum).

Titanium Lug Bolts - Light and I think a full set is $165 .... I think there was a potential negative to titanium but I can't remember the article ... something about it weakening if it is exposed or in contact with something BUT I cannot recall what.

Any other ideas ?

Andrew