Mods to increase highway mpg?

[civic94]

I might pump the tired up to 50 psi for the trip. the tires are at 44 now, max sidewall is 44.

i would probably take off the hubcaps too.

I just changed to timing belt and 02 sensor, so it should be running the most efficient possible. the thing that kills the most is the 3000 rpm at 60 mph, feels like the engine is getting alot of wear and tear.

[theholycow]

Pulse & Glide.

My VW is very badly geared for highway driving. Pulse & Glide provides a large increase in highway FE.

[FrugalFloyd]

My xB also turns 3000 rpm at 60 mph. P&G is one of the things I do to pull 50+ mpg on highway trips with that atrocious gearing. Going slower is the other. The xB returns only 32 mpg at 70 mph.

[civic94]

Originally Posted by SentraSE-R

My xB also turns 3000 rpm at 60 mph. P&G is one of the things I do to pull 50+ mpg on highway trips with that atrocious gearing. Going slower is the other. The xB returns only 32 mpg at 70 mph.

Really? I thought the XB should do somewhere at 2500 rpm at 60, since its a 4 sp auto or 5 sp manual. Its rated at 31? mpg highway, and it doesnt look too aerodynamic at all.

[theholycow]

You might assume that more gears means more efficient ratios, but too often they choose instead to keep high gear the same and either tack on a lower gear or make the ratios closer.

Example: My 2008 VW's 5 speed vs. 2008 VW GTI 6 speed...my 5th = GTI's 6th, my 1st = GTI's 1st, just closer ratios. The GTI turns 3000RPM @70MPH just like my Rabbit.

[FrugalFloyd]

The AT xBs have a higher final drive ratio, and turn about 500 rpm less at 60 mph than the MTs. The 1G MT xBs had an original 30/33 EPA city/highway estimate. The current 2008 EPA city/hwy estimates are 26/30 mpg.

The 1G AT xBs had the same city EPA estimates, but their EPA highway mpg estimates are 1 mpg higher originally, and in the 2008 revision (30/34 originally, 26/31 in 2008).

[civic94]

Originally Posted by SentraSE-R

The AT xBs have a higher final drive ratio, and turn about 500 rpm less at 60 mph than the MTs. The 1G MT xBs had an original 30/33 EPA city/highway estimate. The current 2008 EPA city/hwy estimates are 26/30 mpg.

The 1G AT xBs had the same city EPA estimates, but their EPA highway mpg estimates are 1 mpg higher originally, and in the 2008 revision (30/34 originally, 26/31 in 2008).

Thats what I really dont like about many cars, the MT version always have 1 extra gear but overall, its more for performance than FE. I would love to get a first gen XB only it it was a bit more aerodynamic. the current xb has an engine thats too big for the car (not too big but its excessive).

[FrugalFloyd]

My SE-R was an exception, a MT car whose final top gear ratio only differed from its AT counterpart by 4%. My MT xB is something like 14% shorter-geared than the AT xB.

The barn door aerodynamics of my 1G xB are another argument for slow speed driving with it. Speeds over 55 mph kill its mpg.

[IndyFetch]

I would think that if the Geo was turning 3,000 rpm at 60 mph, then it would be turning 4,000 at 80 mph, not 5,000.

My wife had a '95 with a 3-speed auto. It drove well but I hated the transmission. I could not get decent mileage out of it. The only way I could improve mpg was to drive slowly.

[theholycow]

Originally Posted by Fetch

I would think that if the Geo was turning 3,000 rpm at 60 mph, then it would be turning 4,000 at 80 mph, not 5,000.

Could be a really awful non-locking torque converter.