Economy at 75mph

What economy are people seeing when driving at insterstate speeds of 75mph? I'm considering a 97 Passat purchase in part because of the fuel economy. However, that EPA number is not derived at 75mph and from what I can tell, the motor will be turning over faster then I'd prefer for the length of stroke. If I used the right numbers, I believe the motor would be running at 2600, where 2200 to 2400 would be much better. At least with the experience I've had with GM and Cummins diesels.

Thank you for your assistance.

I've been averaging 41 with a lead foot aroud town, 75 on the hwy, and upsolute chip, and untill recently a dirty MAF. Thats in a golf; the cofecient of friction in a passat is much better than the golf-way back when i hung around here more th b4 guys were regularrly breaking 50 on the hwy, but i think they were going a bit slower.

I average right at 40 mpg, that is with adjusting for my tires which are larger than stock, 195/60/15. stock tires 185/60/14 gave me a more impressive mpg, but they didn't look cool enough for me. I drive right at about 70-74 mph. 2600 rpm for me is 74 mph and I almost always hit 100 mph on my commute to work over the pasc. river bridge on I-10. BECAUSE I CAN and a tank for me will go right about 525 miles give or take, depending on how many trips i make going over 80 mph. my best tank ever was 600 miles, that was with the stock tires so they do make a difference.
Good luck.

Eric B.

On the 2 97 Passat TDIs that I've owned , with timing changes & the use of taller skinnier tires 48 to 55 mpg can be achieved .

I modified the suspension and put 205/75R14s on the back & 215/75R14s on the front . A change of around .175 / mile ( @ 55 mph on the clock actual 65 mph).

And on my trips accross country @ 70 to 90 mph 48 to 51 mpg is normal for me .

Good Luck,

David

I took a trip to seattle and back (about 300miles each way)all freeway 75mph and got 45 mpg both directions.

However I have been getting 47-49 driving back and forth to work 80% @ 55mph 20% city.
05 NB with 10K miles

I took a trip to Seattle (Everrett) which for me is 140 miles each way, and I did that on two consecutive days. Drove a highway speed of 55 mph, 65 mph, and 75 mph, roughly 35%, 20% and 45%
Also did a couple of days of my normal commute.

That tank gave me 57 mpgUS.

I would think you might be able to get in the low 50's for a steady 75.

On my commute (2x45 mi I5 between Irvine and Oceanside) I get

* 48MPG crusing at 70MPH, with some zips in between
* 44MPG at 75-80MPH, dto.

Running (presumably winterized) ARCO/BP ULSD plus Powerservice, and a drop of twostroke oil from time to time.

Just rest assured it'll likely get far better than any other mid-sized sedan (or wagon!) at 75!

Remember, the TDI is built for the Autobahn....high speeds are where it shines. 80+ MPH is its sweet spot, they love to run! This isn't a big, heavy Cummins diesel...

San Francisco to LA - 400 miles @ 80 mph with the CC - I get just under 49 mpg - 48.6 and 49.75 on two trips. Two people, trunk full, back seat to the tops of the backrests...

I can't complain.

Friday (yesterday and today) Saturday must have been/be slow news day/s for the "lemming news services" to pick up on the AAA's (triple A automobile associations) assertation the EPA estimates does not reflect the "real world" results of the majority of drivers.

This of course has been an egg on the face of those folks who tout and/or own the hybrid. It also calls into question the validity of the claims of those who have ceaselessly whined on about the need for higher mileage fuel standards, etc, etc.!? Now we need to change the standards because the GASSER Toyota Prius drivers don't get any where NEAR the EPA estimates!!!??? Are we now to drop the standards even lower to let the Prius owners get near their published EPA figures????

Kills me for two reasons: 1. this test has has been a known entity even before EPA estimates has been implemented!!!!They have been implement anyway and a long time ago 2. because while the real world results can and do vary; everybody that has any familarity with these tests know that the test is a scientific and REPEAT ABLE test. Whereas real world results are by defintion NOT scientific and repeatable!!!!

The nexus to me; this is where the VW TDI SHINES!! Given the above post with an EPA of 42/49 at 80 mph you get between 48/49/50 mpg?? WOO HOO!!

I haven't done this much, but I know if one goes the speed limit on the same leg, (60/65 mph) it is almost a no brainer to EXCEED the EPA estimates of 42/49 to more like 55/60 mpg and beyond!!! So by their own definition does this mean that 55/60 mpg is "NOT THE REAL WORLD"????

Advantage: TDI !!!!

ADVANTAGE: DIESEL !!!

Friday (yesterdayand today) Saturday must have been/be slow news day/s for the "lemming news services" to pick up on the AAA's (triple A automobile associations) assertation the EPA estimates does not reflect the "real world " results of the majority of drivers.

Thisof course has been an egg on the face of those folks who tout and/or own the hybrid. It calls into question also the validity of the claims of those have have ceaselessly whined on about the need for higher mileage fuel standards!? Now we need to change the standards because the GASSER Toyota Prius drivers don't get any where NEAR the EPA estimates!!!???

Kills me for two reasons 1. this has been known every since EPA estimates has been implemented!!!! 2. because while the real world results can and do vary; everybody that has any familarity with these tests know that it is a scientific and REPEAT ABLE test. Whereas real world results are by defintion NOT scientific and repeatable!!!!

The nexus to me; this is where the VW TDI SHINES!! Given the above post with an EPA of 42/49 at 80 mph you get between 48/49/50 mpg?? WOO HOO!!

I havent done this much, but I know if one goes the speed limit on the same leg, (60/65 mph) it is almost a no brainer to EXCEED the EPA estimates of 42/49 to more like 55/60 mpg!!! So by their own definition does this mean that 55/60 mpg is "NOT THE REAL WORLD"????

Advantage: TDI !!!!

ADVANTAGE: DIESEL !!!

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Driving 50 mph on an interstate with a speed limit of 65-75 mph is, IMHO, unsafe. I'm getting 40 mpg or so at highway speeds of 70-75 mph on a 2004 TDI NB w/ 6-speed Tiptronic (highway efficiency 42 mpg per the sticker).

IMO, the EPA should test fuel highway fuel efficiency for 75 mph to better reflect actual speeds at which cars are typically driven. Under the current model, the max speed they test for is 60 mph.

To me the main issue is not safety at 50 mph. (loaded trucks in Europe routinely have averages like this along side Porsche's MB's etc, etc, that routinely zip by at a leisurely far greater speed i.e., 155 plus mph. The issue (which is not easily sound bite able or even graphic) is what oil hammer and I have publically said. The sweet spot of the VW TDI is 80 plus mph. The sweet spot for MOST cars is significantly below that(50-55 plus mph)!! So this whole environmental and save gas, "less speed is more" case that has built up around so called "less than accurate" EPA estimates vs real world has been a bit like a variation of WIZARD of OZ!!!! If I can bea sound bite able, BOGUS!! I frankly think that Toyota getting sued because they followed the EPA protocol, would be unjust and bogus.

To me the main issue is not safety at 50 mph. (loaded trucks in Europe routinely have averages like this along side Porsche's MB's etc, etc, that routinely zip by at a leisurely far greater speed i.e., 155 plus mph. The issue is what oil hammer and I have publically said. The sweet spot of the VW TDI is 80 plus mph. The sweet spot for MOST cars is significantly below that!! So this whole environmental and save gas, "less speed is more" case that has built up around so called "less than accurate" EPA estimates vs real world has been a bit like the WIZARD of OZ!!!! I frankly think that Toyota getting sued because they followed the EPA protocol, would be unjust and bogus.

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How [in what way] is the TDIs sweet spot 80 MPH?

There are MANY ways, but given the title of this thread "Economy at 75 mph", conceptually this is the syllogism. EPA estimates (60/65) (economy class leader) Honda Civic 29/38 mpg vs VW Jetta TDI of 42/49. Which would you expect to get higher MPG? Honda or VW TDI at 75 mph?

So using the SF to LA example of a prior post, I have specifically gone from San Jose to Santa Monica in a driving rain and high winds at 85 mph and gotten 50/51 mpg. If I did the same trip in my Honda Civic, do you think I would 1. get more or less mpg 2. get more or less the EPA estimates of 29/38? 3. which scenario would use LESS fuel?: MORE?

So in terms of public policy, if the Honda uses more fuel shall it be required to go a much lower speed say 45-55 mph to attempt to match my VW Jetta 50 mpg consumption at 85 mph?????

I drove my Golf, with a kayak on the roof rack, to Ocean city and back, mostly around 75 MPH. I got 46 MPG on that tank. My worst tank was with four people in the car, driving through the moutains in western MD/PA at speeds of up to 105 MPH. I got 43 MPG on that tank.

Long highway trips (which I rarely take in my Golf) and flat roads with steady speeds would surely result in higher mileage than that. Your mileage may vary, of course.

To that I say WOO HOO! I would also say this car continues to amaze me or I am easily amuzed

On a recent 606 mile leg of a 2900 mile trip, I fueled at and went from Durango, CO. (up thru Moab Utah hooking up with I 75 west to hook up with I 15 S) to Las Vegas NV. The trip time was 7 hrs including two 15 min stops! I fueled at the 584 miles and took on 12.1 gal of fuel for 48 mpg!!???

Someone asked why 80 MPH+ is the TDI's sweet spot. It has to do with the engine's efficiency at a certain RPM, and since the TDI has an abundant amount of torque at a relatively low RPM, it can sustain high speeds in a higher gear with ease. The PD adds an even bigger advantage in that it seems to rev smoother and faster thus broadening the power band even more!

Our 2004 Passat, once it slips into 5th gear and the convertor locks up, is turning 3000 RPM at 98 MPH! And it will pull a hill like it it's not even there without a hint of a drop on the tachometer. On level ground, at 80 MPH, the MFA reports and instant MPG of around 44 MPG, and it feels like you could get out and walk it is so smooth!

In contrast, a 2004+ Lexus ES330 (I pick this car because I am familiar with them) is wound up to about 3200 RPM at 80 MPH, and its aluminum V6 is whining like a chainsaw...you definitely can tell you are going fast..and its instant MPG meter shows around 19 It, too, uses a 5 speed automatic. Not sure about the acuracy of the mileage meter, but our Passat is running about 2-3% optimistic. Even taking that into account, there really isn't any other mid-sized sedan sold in the US that can claim what the Passat does, unless you include the MB E320 CDI at nearly double the cost.

The TDI is just a magnificent little engine!

Someone asked why 80 MPH+ is the TDI's sweet spot. It has to do with the engine's efficiency at a certain RPM, and since the TDI has an abundant amount of torque at a relatively low RPM, it can sustain high speeds in a higher gear with ease. The PD adds an even bigger advantage in that it seems to rev smoother and faster thus broadening the power band even more!

Our 2004 Passat, once it slips into 5th gear and the convertor locks up, is turning 3000 RPM at 98 MPH! And it will pull a hill like it it's not even there without a hint of a drop on the tachometer. On level ground, at 80 MPH, the MFA reports and instant MPG of around 44 MPG, and it feels like you could get out and walk it is so smooth!

In contrast, a 2004+ Lexus ES330 (I pick this car because I am familiar with them) is wound up to about 3200 RPM at 80 MPH, and its aluminum V6 is whining like a chainsaw...you definitely can tell you are going fast..and its instant MPG meter shows around 19

It, too, uses a 5 speed automatic. Not sure about the acuracy of the mileage meter, but our Passat is running about 2-3% optimistic. Even taking that into account, there really isn't any other mid-sized sedan sold in the US that can claim what the Passat does, unless you include the MB E320 CDI at nearly double the cost.

The TDI is just a magnificent little engine!

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I can see it now... "But officer, I was just trying to keep my engine running where it likes to run "

You're right that the Passat will be turning 2600 RPM at an indicated 78, which is probably right around 75. Most VW speedos are about 3% optimistic.

If I can keep my Jetta wagon to 75 it gets about 48. It's hard for me to get through a tank w/o getting in some pretty heavy stop and go traffic where I live, so my numbers are a bit lower than some here.

Regarding EPA figures, I think part of the problem here is that most people don't know how to drive for efficiency. I hardly drive slow but have gotten between the EPA city and highway figures in every car I've owned since I can remember. That includes a Toyota Camry V6 automatic (EPA 18/24, regularly got 22-26, even driving at 80 MPH on trips); an Audi A4 Quattro stick (EPA 17/26, usually got 22-24); A Toyota Previa SC (18/24; got 18 even in pure short trips around town driving); and a Toyota MR2 Spyder (26/30, never got less than 30, even driving to NY at 90-100 MPH--I wasn't driving).

The 02 Jetta TDI 5-speed is rated 42-50. I typically get 44 in truly mixed driving. If someone gets 35 or 40 in a Prius or Civic Hybrid they've got a lead foot.

I think there is nothing wrong with the EPA estimates, afterall they are just estimates. Isn't it funny how the EPA fuel economy ratings come into question once fuel has become "expensive"? The same test has been used for many, many years.

Basically consumers need to be able to think for themselves and know that an estimate is an estimate. I personally always take the worst-case senario when dealing with someones estimate.

Even taking that into account, there really isn't any other mid-sized sedan sold in the US that can claim what the Passat does, unless you include the MB E320 CDI at nearly double the cost.

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I've recently done an eighty mile run with a E320 CDI at 80+ MPH and the driver couldn't believe I could keep up with him, he'd keep looking over in disbelief as if a "jetta" couldn't hang with him... then I led for about 20 miles, he must have realized I was in a TDi... when he passed me to lead he smiled and gave me the thumbs up..
This was still a 40+ mpg tank!!
I luv this car!!

With the speed limits here in the U.S. you can surely keep up with the CDI, but no chance on the Autobahn where you can drive the CDI at 225Kmh/140MPH constant without a problem.

Only when you drive the thing completely empty remeber to take bit of a rest before refuling it with Diesel that is being stored at ~10-15 degC.
That´s one of the very few ways people kill their CDIs in Germany - by running very cold fuel into their well-heated fuel pumps after a longer chase

I thought our Golf needed to 'strech his legs' and so we did a Houston, TX - Orange Park, FL - Houston run this weekend (1700miles). Most of it we spent at or around 80mph (real! about 84-85 indicated) and we got around 39-41 mpg. The low end on the way back since we drove the night and all the freeways were open, no LEO's...

I have no complaints.

There's no getting around the fact that the faster go, the more wind resistance you have to deal with. And the penalty grows exponentially.

I made a roundtrip from the Seattle area to western Idaho and back last week.

I drove the same way in both directions but on the way east I had a substantial tail wind.

I set the cruise control on 75-76 mph which yields a GPS verified 71-72 mph.

With a ~15 mph tail wind, (which is kind of like driving 57 mph) I got almost 56 mpg.

On the way back it was dead calm and I got 49 mpg.

I'm not complaining about 49 mpg in dead calm conditions. I just point out that when you go faster and have to push more air out of the way, it's gonna cost you. Exponetially.

At highway speeds air drag is dependent on the square of the car velocity. For example, to compare the air drag difference between going 65 mph versus 80 mph the equation would look like this; (80 X 80) / (65 X 65) = 1.51. So going that extra 15 mph increases the air drag force by 51%. For the complete math details see;

http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Dynamics/Forces/DragForce.html

In a Passat 2004 SW-From Virginia Beach, VA to Charleston,S.C., high winds and a surfboard on top: 33.5 mpg @75-80. From Charleston, S.C. to Virginia Beach, much less wind, still with a surfboard: 36.7 mpg @ same speed.

Long highway trips with my 96 Passat have yielded as low as 38 at 85 (GPS Indicated) but at 75 get a pretty consistent 41-43.

Thanks for the formulas BoboBear. Been looking for those.

I've also found the 75 mph mark to be where my millage starts to fall away quickly if I go faster.

i recently bought a 00 beetle and drive between 150-200 miles mostly highway a day. i live in MI and at this time am getting only 35-36mpg. no ck engine lights or excess smoke. is this typical? any ideas on how to improve? thanks for your help

i recently bought a 00 beetle and drive between 150-200 miles mostly highway a day. i live in MI and at this time am getting only 35-36mpg. no ck engine lights or excess smoke. is this typical? any ideas on how to improve? thanks for your help

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How fast do you drive? Any hills? Auto or manual?