What, no 800 Mile Club??? Members welcome here! :)

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
So I was all excited tonight, looking forward to coming home so I could post up my entry into the 800 mile club, only to find that either I'm missing something or there doesn't seem to be one???

2001 GLS 5-Speed TDI Jetta ALH with Kerma PP520 injectors/nozzles and Frank06 cam, totally stock tune.

Took in 16.8 gallons after 807.3 miles driven, mostly 71mph interstate cruising for my work commute, random A/C use as needed for about 1/3 of this tank, quite a bit of random aggressive driving, a few momentary "highway pulls" in excess of 3k rpm's (a.k.a. >100mph), a handful of unintentional "burn-outs" during traffic entry from a stop (upgraded cam, no ASR/ESP), and absolutely no intention or expectation of such decent economy when this tank began.

NOTE: Switched back from 18" BBS RC wheels to stock MkIV AVUS' 2 tanks ago and went from a consistent 38-40mpg highway over the past 10k miles on the BBS wheels (mostly 71mph cruise control) with mpg's varying mildly within that economy range depending on driving agression and A/C use, to an immediate jump up to 43mpg with A/C ON the whole time on the very next tank with otherwise identical driving speeds/habits, which was immediately followed by this unexpected 48mpg >800 mile tank with that same driving style/pattern but only some random A/C use...

So now I'm considering trying 65mph or maybe 60mph cruising and as little A/C use as possible just to see if 50mpg or better and 900 miles might actually be possible for me with calmer driving habits and this particular car.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Congrats! It looks like the latest TDI generations since about 2010 have really managed to get their stock highway economy back up to the stock MkIII/MkIV territory or even better in some cases and I've heard there are aftermarket tuning options to significantly improve/increase their city economy back into the 40's if it's in an area where emissions testing isn't a factor.

I thought about posting my 800 mile entry in the 700 mile club thread but on a ALH MkIV TDI 700 miles isn't hard to reach and isn't some major special accomplishment for a totally stock ALH when driving at posted speed limits, at least in a 5-speed manual (never had an automatic myself), especially if you've got some highway miles in the mix or you do pretty much all highway driving (like me) and you actually take an extra couple minutes at the fuel pump to fill your tank up to its' capacity when refuelling (apparently 17 U.S. gallons on the MkIV's).

This is my second 2001 GLS 5-Speed MkIV TDI, my first one had 234k miles on it when I got it, this one had 138k when I got it, and my experience between 2 of them showed me that 700 miles is almost a given from these cars with mostly highway 70mph regular driving, no slow driving or hyper-mile tactics needed... The key for the ALH MkIV's to hit 700 on a tank is to actually fill your tank to capacity and to trust your Low Fuel light to typically allow 50-80 more miles of driving after it comes on, seriously.
Granted I do nearly all highway and the "city" speed limits in my area are almost all 40-50 mph without tons of traffic lights except near the shopping malls so even my city driving isn't loaded with idle time or slow speeds which helps put my TDI into a somewhat better than typical city economy range for easily allowing it to reach and greatly exceed 700 miles per tank most of the time.

I came out of "drive it like you stole it" Turbo/Twin-Turbo Supras and I6 and V8 Lexus' for well over a decade into two different '01 TDI's back to back, still drive the TDI's pretty agressively, put bigger fuel injector nozzles in both, and did a Frank06 cam to this one after the factory original timing belt idlers seized and bent valves at 140k thanks to the previous owner's cheap-skate belt-only original timing belt service, and 675 miles is still a crappy tank for me in either of those ALH MkIV TDI's with some mods. I'm still on the factory stock tune due to a stock TDI clutch that still works fine, but that may finally change in the near future which I'm told should improve performance and help with economy also...

Plus there's a 900 Mile club thread in the economy section so it just seemed like the 800's should have a place too, and although Dozenspeed posted several possibilities (one that's MkV specific, two of which have almost no posts and stop in '02 and '06, one that's in TDI101 instead of TDI Fuel Economy) my searches for "800 Mile" never revealed those for whatever reason which is why I started this one.

So many TDI Owners also like to post that they reached X00 miles but never say how they drove, what typical speeds they drove, how many gallons it required, or the mods status of their cars (if modded at all) that may have helped them achieve it.

I think it'd be nice and helpful to TDI noobs or the TDI curious crowd to get some real-world feedback rather than seeing so many 53mpg, 56mpg, 62mpg posts and deciding to take the TDI plunge only to find 33-42mpg themselves and wonder what they're doing wrong or what might be wrong with their TDI...
For example, I have 2 TDI buddies who kept telling me I was doing something wrong with my 39-43mpg economy tank after tank for a year to their typical 45-53mpg economy ranges in the same ALH based TDI's when we all had the same basic mods including Kerma PP520 nozzles. Turns out they both run 45psi tire pressures and TPMS (to my un-monitored 32-35psi) and one of them normally drives 5-10mph under posted interstate speeds and tries to hyper-mile a lot and the other lives out in the boonies with 45-55mph speeds the whole time and maybe 3-4 stop signs and a short signal light for his 24 mile drive to work vs my 50 mile each way 70mph interstate work commute. I started setting my cruise at 60mph for a whole tank and got 45mpg, imagine that...
But even at 70mph for my commute, on a truly full MkIV tank with upgraded nozzles I can consistently achieve 700 miles without trying which only comes to 42mpg in my car. That's why I was so happy to reach 800 and achieve 48mpg with my same commute in the same car with my same "Turbo Supra" driving habits.
My IQ is 2.8-3.2 typical when I check it, 3.0 set/targeted (hammer mod), my TDI Timing is just below the top line on the graph with the proper engine selected in the pull-down menu (injection pump sprocket adjusted), I put the stock TDI AVUS wheels back on the car at 40psi all around for the past 2 tanks, I added a skid-plate near the beginning of the 48mpg 900 mile tank, and I used the A/C only as needed on the 800 mile tank with cooler weather for the past 2 weeks...
My previous tank on the AVUS' yielded 43mpg with the same changes as above except no skid-plate and A/C ON the WHOLE time and the same driving speeds/style.

Before that I was on 18" BBS RC wheels at 40psi for the past 6 months and was consistently getting 38-40mpg per tank depending on A/C use and driving aggressiveness. Got one 37.8mpg with lots of idling and lots of "beating on it" hard driving and constant A/C use, and one 40.8mpg while driving slow and easy without A/C while deliberately trying to get 700 mile tanks back but 38-40mpg was what it was consistently doing on the larger/wider/heavier BBS wheels regardless of my driving speeds/style.
So I put the AVUS' back on and deliberately used A/C always and still instantly saw >700 miles and 43mpg on the very next tank with no other changes.

Now I'm torn between looks and driving distance... grrr...
I'm going to hang in the "slow lane" and slow it down to 5-10 below posted interstate limits and avoid A/C and see if 900 miles becomes possible for me in this car on the stock MkIV TDI AVUS wheels, and if I succeed in joining the 900 mile club the BBS RC wheels are getting sold. If I can't do it they might go back on the car...

Still... finally, 800 miles! Woo Hoo!!! :)
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
That one looks good actually, thanks!
Good mix of all gen's and more details per poster and such.

Let's migrate this on over to there...
 

jay_fyp

Veteran Member
Joined
Oct 29, 2004
Location
New Jersey
TDI
2015 Golf TDI 6MT 2004 Jetta TDI (PD) 5mt R.I.P - 2013 Golf TDI 6mt - 2004 Golf TDI (PD) 5MT
Congrats! It looks like the latest TDI generations since about 2010 have really managed to get their stock highway economy back up to the stock MkIII/MkIV territory or even better in some cases and I've heard there are aftermarket tuning options to significantly improve/increase their city economy back into the 40's if it's in an area where emissions testing isn't a factor.
You're correct in that statement. And also the mk6 has a super solid engine. It's just unfortunate about the possible HPFP problem. Once that is completely sorted out (which in time will be, 2micron being the leader so far) , I don't see why any of the predecessors are any better. There are plenty CRs climbing way into the high mileage category with little or zero issues and with awesome mpgs. I got way off topic of breaking 800 miles, congrats.
 

PressEnter[]

Veteran Member
Joined
Feb 5, 2013
Location
Saratoga Springs, NY
TDI
2013 Jetta 6M
I've been keeping track of the HPFP issue to some extent, and if someone knows different, let me know...but I haven't heard of a single 2013 that's had the fuel pump fail yet.
 

jay_fyp

Veteran Member
Joined
Oct 29, 2004
Location
New Jersey
TDI
2015 Golf TDI 6MT 2004 Jetta TDI (PD) 5mt R.I.P - 2013 Golf TDI 6mt - 2004 Golf TDI (PD) 5MT

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
WOW! 800+ miles IS impressive, guys. My best so far was 615+ miles, but my car doesn't have the tank capacity of what you guys do. I don't think I can catch up to the 800 mile cars.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Your 2002 Jetta has the same tank as my 2001 Jetta, so yes you can, especially if your car is not modified (mine has a few performance mods, actually!).

You just need to learn how to literally fill it up all the way and you'll find that although it doesn't effect the economy you can drive at least 100 miles extra or more per tank...

Look into "ventectomy" for more information although I still haven't done it to my car yet, I just carefully push and hold the vent lever with the pump nozzle tip (takes some practice) and pump slow to reduce foaming and pump 'till there's clear fuel all the way up to the lip of the neck and sitting there (not creeping down) with no more foam before I call it full...

I regularly pump 15.8 - 16.6 gallons in and I've pumped 16.9 gallons in several times, although I hadn't ever gotten 800 miles from it before, and two buddies have pumped 17.1 gallons, one in a '03 Golf, the other in a '00 Golf (totalled) and his new '03 Jetta 1.8T wagon with an ALH and '01 Jetta sedan tank swapped into it. So I know the '00 - '03 G/J TDI tank size is the same.

After seeing your sig showing 43.9 mpg average and doing the math to multiply that mpg by your tank's true capacity (try 16.8 gallons instead if you want to be safe) then you'll actually find that you should've easily be in the 700 mile club in your Jetta by now...
Notice that 43.9x17.0=746 miles that your car would be averaging with your stated average mpg's on a truly full tank and you'll also find/learn that the low fuel light typically has 60-80 drivable miles on it which takes some getting used to, and no you won't hurt your fuel pump on a 2002 because it's not electric and it's in the engine bay, not in the tank so it's not cooled by being submerged in a tank full of fuel. Many cars have that issue where the fuel pump dies prematurely from riding the low fuel light a lot, especially gassers, but not the ALH based MkIV TDI's...

If you've ever gotten 47mpg in your 2002, had you filled your tank all the way you might've gotten into the 800 mile club by now, really.

Give it a try, get a feel for it, and enjoy your accomplishments once you succeed.
 
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Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
That sounds encouraging, zukikat! I'm currently driving the A6, my dad's driving the Jetta. He tends to speed and the mpg is creeping lower hahah. My personal record was 49.1 mpg(calculated by fuelly). I get printouts at the gas station to keep track of the numbers. I don't think I've ever tried to fill it to the brim. I keep reading that if you do that the charcoal canister will end up getting fuel in it and end up failing fast and throw lights and it gets messy. Typically I stop adding fuel when the pump stops. I don't keep pushing it. I'll check out the ventectomy procedure. I am kind of weary of running my tank super low in fear of getting air into the lines. I've read it's a big problem and tough to clean out, not to mention expensive. I think that I can get more economy out of it(and prolly like 1-3hp) after I perform the intake manifold cleaning. I'm sure the fact that it's only a 4 speed auto doesn't help my mpg all THAT much. I'm confident that if I had a 6 speed manual under it, I could get closer to 55 as is with the dirty intake. Honestly, from what I've been told, my car is awesome on mileage for an auto, but I KNOW I can get a couple more mpg out of it consistently. The biggest factor has been driving style/habbit. I noticed keeping the motor at around 2000rpm has been great. Staying 50-55 mph has kept nicer mileage on it. Getting closer to 70 mph would be nice, but the mpg figure drops quite drastically. 1 mpg is not a big deal, but it changes by 5-7. I think if I can get more fuel into the tank and driving like a grandma continuously and possibly getting a frost heater to start with a warm motor would help. Another thing I have to keep forcing myself to do is to stop obsessing over the mpg figure and look at the diminishing returns line closer. There's no sense for me to spend $5000 improving tank capacity and getting fiberglass or carbon fiber components in order to save $3 per tank. It'd take me 50 years to see half that money returned. Thanks for the tips, man! I'll see what a ventectomy is.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
At 49.1mpg you'd have been in the 800 mile club if your tank had been full.

charcoal canister, on a diesel??? no worries there... on the Audi, yes. MkIV TDI, no.
Anyone feel free to correct me if I'm wrong on that but I'm pretty darn sure there are no diesel fuel vapors to collect with a charcoal canister.

on a gas car "over-filling" -can- cause such problems but again, those types of worries like electric in-tank fuel pumps and emissions charcoal canisters and such don't matter on our ALH powered MkIV TDI's.

I've run my previous TDI MkIV and this one down to just under 17 gallons many many times and haven't had any "air in the line" problems from it yet. I've never run mine dry, but I've had my share of "loss of prime" issues from the car sitting parked with old cracked injector return lines and bad pump seals and such on each of my two TDI's when I first got them so I've had to re-prime my lines more than once until I found and fixed the problems, and I know my current car's previous owner ran it out of fuel more than once, and it wasn't a big expensive ordeal although she had to pay someone to re-prime her lines so the car would start again.

Yes, your automatic has a bigger injection pump and one less gear than the manual cars but it sounds like you're still managing to get stellar economy out of it anyway.

I didn't notice any power increase with my intake manifold cleaning, and trust me I'd notice that (agressive driver), but it did seem to improve my economy a little bit, although mine was so clogged a #2 pencil wouldn't fit into the intake opening at all (hadn't ever been cleaned in 149,950 miles since new) and the car still ran and drove totally normal.

Ironically, as for the 6-speed, lately I'm rivaling one of my 6-speed buddies and beating the other with a stock 5-speed car at the moment, we have no idea how it's happening and I'm not actually trying...
Add that to your "diminishing returns" list, sadly...
The 6-Speeds make about 4k rpm's difference in top gear at 70mph so I'm theorizing that since I somehow got 48mpg without trying on my last tank and I'm on track for it to happen again on this tank driving at 70mph, if I slow down about 10mph on my commute I may cross into the low 50's for mpg's and get close to the 900 mile club. I was going to try it on this tank since my last one was my first 800 mile tank, but I got a work emergency call the morning after I refuelled and had to get there in a hurry so that call blew my chances of a 900 mile effort on this tank and that emergency situation lasted 2.5 days.
Both of my 6-speed swapped buddies have 2 different transmission models and both see about the same results from them. They're now saying they really like it but it'll never pay for itself in fuel savings and it's expensive to do the swap so it's not actually worth it if you're doing it for the savings...
I was seriously considering it myself because I don't like how close together the first 3 gears are on the manual 5-speed and I thought the 6-speeds would give me taller ratios in the lower gears so I could stay in each of them them longer (higher speed per gear) but apparently the 6-speed is basically geared like the stock 5-speed with an extra overdrive position which wasn't really what I was looking for and my stock clutch is still working properly so I decided it wasn't worth the extra unnecessary cost and work to possibly gain a few more mpg's and maybe 50-75 more miles per tank.
Again, I'm sure there are those who have done that swap that will justify/defend it as the greatest mod ever but at 65-70mph with minor basic modifications or a stock car it's typically not like some magic 200+ mile per tank increase by having that extra gear...
I see owners in the 800 mile club with a stock ALH MkIV that used a gallon less than my car with a few minor mods did to get there which is 2mpg better for a 35 mile extra available driving range beyond what mine did. Not a huge difference.
Heck 5mpg extra x17 gallons only gets 85 more miles... 10mpg x17 gallons is 170 miles and I doubt a 6-speed swap itself will ever provide a 10mpg increase.
Return on investment vs diminishing returns.
Pardon the minor rant... :)

Of course you're up north and I'm waaaay down south but when I got this car everyone told me the dead (stuck wide open) thermostat was killing my economy but it took 6 months to get the car's title from its' previous/original owner and the car had some safety/mechanical issues when I got it so I ignored the bad thermostat for like 10k miles since it wasn't throwing a CEL even though my Scan Gauge said my temps were only getting up to 135-160f at the warmest point most of the time in city idling and on the interstate, and I was all excited about some big economy increase once I got the title and began doing some of the maintenance stuff because "everyone says a bad thermostat kills your economy", but it didn't make a noticeable difference in my driving distance per tank with the same amount of fuel as before at each fill-up so don't go getting your hopes up about a warmed up engine increasing your economy.
I'm sure many people will dispute that but that was my personal experience and I doubt if it gave me 1mpg improvement if that much, granted again I'm down south and I drive at the posted speed limit and mostly on the interstate (70mph around here) so for those old farts driving 45-55mph everywhere it might've been a huge improvement but for those of us doing normal driving it was a total wash...

I agree that spending so much time and money to try for higher mpg numbers is a diminishing returns game, albeit a fun one at times I'm sure...

and the 700 mile, 800 mile, and 900 mile clubs are a game too... which is a fun one to play for 800 and beyond but not on a regular basis as the necessary driving to attempt the 900 mile club in my car would drive me nuts to have to do on a regular basis...
Heck, just going an entire tank driving 60mph is challenging for me as traffic is flying past at posted speeds or higher and I've almost been rear-ended on the interstate several times by inattentive speeders while I was going slow to try for higher mpg's.
If you live in an area where the posted limits are in a more optimum economy range for these cars then it's no big deal but watching traffic pile up behind you to save a few bucks is more stressful to me than it's worth in what minor savings it gives per fill-up...

One thing that did change on my car on the tank where I ended up in the 800 mile club was that I added a skid plate with around 100 miles on the tank so I'll be curious to try a few more experiments over the next few tanks and see if it contributed to my recent significant economy improvement or not. Obviously being able to not use a/c as the weather cooled off is helping but 5mpg above the previous tank with a/c always on seems drastic. Literally went from 43mpg with a/c on to 48 with it only used for about 1/3 of the tank as-needed and a skid plate added while driving the same agressive way and same posted speeds for the same work commuting on both tanks. If the skid plate did contribute to the major increase then it's totally worth it as it also protects your oil pan in areas with crappy roads and potholes and road debris like we have around here. We'll see how my next few tanks do as my last tank, the 800 mile tank, is my first with the skid plate installed on the car.
NOTE: both of my 6-speed buddies have skid plates and I didn't and they kept insisting my driving habits were keeping my mpg's so low. Now I swapped my wheels back to AVUS' and did 40psi (they run 45psi with TPMS') and added a skid plate and magically I'm right up there in a very similar economy range as them for mpg's in my 5-speed while driving the same as before, at (or slightly over) posted speeds and moderately agressive... Nowdays one of them beats me for mpg's and one of them doesn't usually.

Now the game is on... 900 mile club is my goal as soon as my work schedule allows me to drive slow enough to try for it...
 
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JohnWilder

Veteran Member
Joined
Jul 13, 2013
Location
Breckenridge, TX
TDI
2003 Jetta 5 spd manual
In the last 9K miles of driving I have only gone below 50 mpg once. It is easy with an ALH and driving conservatively. When I discovered you can put 17 gallons in the tank I managed 848 miles before the low fuel light came on!
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
zukikat, thanks for the info. i added the skidplate to my car because it's low and i saw no appreciable/noticible improvement in my mpg numbers.
 

Shawnz

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Joined
Apr 14, 2008
Location
Peoria, AZ (Phoenix)
TDI
'02 Jetta GLS TDI, ex-O1M
I just hit 800 myself, testing the limits of 'empty' on the gauge. There was only 1/2 a needle width between my gauge sitting on 800 miles and the car turned off.



49.9 MPGs (800.5 miles, 16.042 gallons). This was mostly 45 MPH commuting to work and back about 15 miles each way.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Congrats on trying to learn the true range of your TDI and hitting 800 miles in the process!

If the car "turned off" at 16.042 gallons then it appears that either something's up with your fuel system (probably not) or you probably hadn't filled your tank to its' full capacity, losing about 50 miles of further driving distance at 49.9 mpg, although that pic shows your needle still on the upper portion of the E line and mine goes well below that for at least 20-30 miles typically but I'm sure that not all TDI fuel gauges and sender units behave exactly the same.

You probably had a good bit of foam when you pumped for that tank and may not have waited for it to settle all the way out to just fuel at the top of the neck with no foam and make sure it didn't settle back down into the tank? Granted I pump fairly slow, but I keep getting it up to the neck, waiting for the foam to settle, and eventually end up with just plain liquid (takes me maybe 2-3 minutes extra) and even then if you wait a few seconds after you think it's full it may drop back down a few times and I just keep slowly pumping and stopping 'till the foamless liquid stays up at the neck to know it's full which usually is 1/4 to 1/2 gallon or more depending on how slow I ran the pump and whether it's a normal or monster "high volume" diesel nozzle.

Note, I regularly pump mid to upper 16.x gallons into my '01 and your tank is the same size as mine.

Granted I almost always refuel as I'm headed to work so I know the level won't stay that high because I'll be using at least a gallon over the next hour after I leave the station on my drive to work.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
zukikat, thanks for the info. i added the skidplate to my car because it's low and i saw no appreciable/noticible improvement in my mpg numbers.
You're totally welcome, and thanks for the feedback on the skid plate.

I've heard that lowering improves economy mildly but noticeably, although apparently stock ride height appears to be a more optimum "handling" configuration from what several long-time TDI owners have told me.
My buddy with a lowered TDI has a 6-speed so I don't have a good economy comparison for that.

I'm on tank #2 with my skid plate now and this tank's still doing well but I'm expecting "only" upper 700's instead of 800 this time based on the 650 I just reached with about a little under 1/3 tank showing on the gauge, not even close to the LF light zone yet. I did 75mph for two "emergency" work trips but surprisingly I was still at almost 500 miles as the needle came off the 1/2 mark.
The biggest difference over my first tank back on the Avus wheels is that I used the a/c the whole time on the first tank, then added the skid plate and used the a/c a lot less on the second Avus tank and I haven't needed a/c at all on this (third Avus') tank so far which probably made up for my two 75mph work trips...
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
In the last 9K miles of driving I have only gone below 50 mpg once. It is easy with an ALH and driving conservatively. When I discovered you can put 17 gallons in the tank I managed 848 miles before the low fuel light came on!
I'd really like to know more about your car (mods, if any) and how you're driving it if you don't mind sharing with the rest of us, please.
I'm guessing you're either heavily modded and tuned or totally 100% stock?

I'm also trying to determine if decel to a stop with the transmission left "in-gear" and clutch engaged 'till you're about to finally stop or if going to neutral when you begin your decel seems to yield more favorable economy results overall.
I'm told that leaving it in gear with clutch still engaged on decel uses no fuel versus coasting at idle which does use fuel although leaving it in gear and clutch engaged on decel reduces coasting distance considerably, at least in my car.
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
You're totally welcome, and thanks for the feedback on the skid plate.
I've heard that lowering improves economy mildly but noticeably, although apparently stock ride height appears to be a more optimum "handling" configuration from what several long-time TDI owners have told me.
My buddy with a lowered TDI has a 6-speed so I don't have a good economy comparison for that.
I'm on tank #2 with my skid plate now and this tank's still doing well but I'm expecting "only" upper 700's instead of 800 this time based on the 650 I just reached with about a little under 1/3 tank showing on the gauge, not even close to the LF light zone yet. I did 75mph for two "emergency" work trips but surprisingly I was still at almost 500 miles as the needle came off the 1/2 mark.
The biggest difference over my first tank back on the Avus wheels is that I used the a/c the whole time on the first tank, then added the skid plate and used the a/c a lot less on the second Avus tank and I haven't needed a/c at all on this (third Avus') tank so far which probably made up for my two 75mph work trips...
I didn't even really see much difference due to weight. Going around with 2 people in the car or pulling out literally everything out of my trunk down to bare metal made no difference for mine. Some fill ups are a bit more and some are a bit less. You can look at my fuelly charts. There's no general improvement that's noticeable after a certain point. The only thing you'd see is mpg changed when the driver changed. That's really it. I drove it stock and you can see more changes in the first few fill ups since i was getting used to the car. Then I changed suspensions around November, just under 2 years ago, but I didn't notice any major drop or improvement. I'm sure there would be a difference if I removed my mirrors, equipped a full undercar panel that's dimpled and calculated to work for the car, went to super skinny tires and installed a single carbon fiber/aluminum racing seat and gutted the car, but in my case I saw no significant mpg change with anything I've done so far.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
I found that the change from the large 2-ton floor jack and my entire "german tools" stash from the timing belt job that were still in my trunk for several months after the job was done actually added a few drivable miles to my commuting per tank once I removed them from the trunk and rear floor boards but I wouldn't call it a major gain or loss, albeit certainly noticeable for my car. In my gas Toyotas of the past it made a much bigger difference when I stopped hauling around my work tool bag (telco/electronics tools) and jack and "work on the cars" tool pile so I was hoping for similar results in the TDI but that doesn't seem to be the case.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
So it's been almost another tank again and unless I manage to do something totally bone-headed in the next 55 miles this is definitely going to be another 800 mile tank, my second ever, and still not actually trying... still setting the cruise on 71mph most of the time and driving agressive as usual.
For the most part this has been a 70mph cruise control tank and I haven't needed any a/c at all, BUT twice I set the cruise on 75mph for 50 miles as I was almost late for two work appointments I couldn't miss, and still somehow this time my LF light didn't come on until a little over 720 miles whereas my previous tank was just a little sooner than 720 and made it past 800 miles.

I'm about 35 miles into the low fuel light already as it came on not long after I left the office, but I'll be surprised if I can't make it all the way back to work with what's left in the tank now (which would cross 800 miles again) without running out along the way.

Now this reeeeally has me wanting to try 55mph or 60mph for a whole tank to try for the 900 mile club and cross 50mpg as the math says it would require 53mpg or better for my car to achieve the 900 mile club.
Barring any more work emergencies, I'll give it a shot once I cross 800 and refuel again, probably tomorrow or friday but maybe next week depending on if I have to go to the office again this week or not. I'll be working on one of the antique Supras which has a full tank of gas so I can probably leave the TDI parked a few days unless I get a work call again this week.
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
I've been wanting to get 50 so badly since i saw 49 hahaha. It's right there. It's so close. I dont think it's doable since its cold now and winter is almost here. Maybe next spring/summer.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Well last winter when I first put my car back together after the TB fail I was getting 45-47mpg and then just a few tanks later spring arrived and I changed wheels to the BBS RC 18's and my economy slowly began its' free-fall into the upper 30's on the interstate...
Now that the weather has cooled enough to not constantly need the a/c and I put the stock Avus' back on I'm back up in the upper 40's driving at posted on the interstate without trying for economy at all.

It really seems to have more to do with sustained driving speeds and a/c use and mods than time of year. Even my gear/rpm choices don't seem to have a drastic effect so far. Like when I first bought a TDI I started out driving gently (at posted speeds though) and shifting at 1,500rpm's for the first several tanks, then switched to 2k rpm's and and got moderately agressive in my driving style and didn't notice hardly any difference in economy, maybe 1mpg, seriously. Now I still generally use the 2k as my base reference but it's not unusual to be more like 2,400 or 1,600 at random with the occasional WOT pull to over 4k for interstate merging or fun or smoking out tail-gaters and I'm getting 45 with a/c always on, 47-48 with it on 1/2 the time or less.

From my personal experiences and observations over the last 2 years, slowing down your highway speeds, reducing or avoiding a/c use, and idling as little as possible seem to be the keys to maximizing economy in these cars, with highway speeds making the most significantly obvious and drastic difference unless your a/c is having problems. I have no real city economy reference at all because my city's speed limits are 40-55mph almost everywhere and I spend so much time per tank commuting to work on the interstate that I have no idea what my car would do as a city stop-n-go commuter-box at all.

Of course that's based on me and my friends' lightly modded cars.
Kerma PP520 Nozzles, various levels of intake/intercooler/MAF upgrading, and their 6-speeds vs my 5-speed and their personal choices of different Malone tunes based on their current mods vs my still stock tune on whatever cheap aftermarket clutch the original owner put in my car at only 107k miles on the car.

and both of them told me my cam upgrade was a bad economy choice that would cause a fairly large drop but my power band is much wider and far more predictable and power and torque come on a good bit sooner than on the stock cam and I'm still right up there with them for mpg's again now that I swapped out my big 18" BBS wheels back to stock Avus'.

If memory serves correctly, at this point have 12k miles experience in this car on the stock cam and wheels with the Kerma nozzles until the TB shredded on the interstate thanksgiving night last year, 10k with cam and BBS wheels on the new TB starting the last week of January this year when I finished the full TB/head install (and added a bigger e-bay intercooler and partially customized big metal 1.8T "pancake pipe" to the car during reassembly), then 2k after that with the upgraded cam and back to stock wheels starting a few weeks ago, plus the 6k I put on my first TDI that was all stock except these same nozzles I bought for it and added immediately and then a PD150 TIP (that got destroyed in the crash) which I installed within 2 weeks of buying that car which got totalled in a 45mph head-on crash less than 3 months after I bought that car.

As I've said earlier, I'm trying to offer my experiences and compare notes with some of the super-high mpg guys to learn more about what really matters, what sort of matters, how much each thing seems to matter (alone or in combination with other changes), and what's just plain TDI urban legend...

I haven't found the bottom of the ideal speed/economy balancing window or the top of it yet myself but 45-55 seems to be the window for the 1.9 ALH's from what I've read and observed so far.

I'm about to try experimenting with that if my job would stop needing me there asap and screwing up my mpg speed tests...
 
Last edited:

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I did this just last week:

I make about twice stock power, typically drive between 70 and 80 on the highway. This tank included a fair number of short trips to and from work and lots of local driving.

I got a new Rocketchip Stage 4+ at TDIFest, and I think the fueling and boost profiles are really helping my FE. Vent is removed on the tank: I put in 16.3 gallons on this fill.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Aftermarket "tunes" do often seem to have significant effects on fuel economy.
I really want to get a tune but the extra torque (and my driving style) would kill my clutch pretty quickly so right now the roughly $1k it'd cost me for the clutch and a tune, doing all the work myself, is a bit more out of my budget than I'm willing to spend on the car right now just to gain a little more fuel cost savings, especially when my current clutch is still working fine on my current setup. If it were clutch time or I had some spare cash laying around, then hell yeah, but for the time being I just live with it as-is...

I assume you're still running a stock 5-speed transmission, or do you have different 5th gear or 6-speed swap? (if you don't mind sharing the details, of course...)
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Stock 5-speed with a .71 5th gear which is a very small step up from stock. Drops revs about 150 RPM at 70. Of course the clutch is not stock, in fact I'm on my 5th clutch in this car, but one was a mistake.

I started modding this car in '03 with a tune, then nozzles (and clutch), then breathing mods, 11mm pump, lift pump, and finally a turbo upgrade at 177K. Despite the power it makes fuel economy has changed little.
 

zukikat

Veteran Member
Joined
Jan 7, 2012
Location
Greater New Orleans area
TDI
2001 Jetta GLS, 2003 Jetta GLS Wagon
Your replacement .71 5th gear looks pretty close to the 6th gear in a 6-speed swap based on those rpm's at that speed, and that's the type of economy one of my 6-speed buddies is getting with his stock turbo, upgraded 6-Speed clutch/flywheel, PP520 nozzles, "Old-Man Intake" TIP, bigger intercooler (same IC I now have), bigger intake snorkel, (stock maf), 3 Bar MAP sensor, and Malone Stage 3 Custom tune with "dynamic idle", off the top of my head anyways. :)

I'll have to remember to check with you at clutch time! :)
 
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