wvo'ify my NA or my ECO

[bbob203]

i have two jetta's both 91 model year. One is and ECO the other is N/A. The N/A has 190k miles on it the ECO has 156k miles on it. I'm gonna be installing a 5-6 gallon tank underneath my trunk to hold the diesel and use my stock tank for the oil. what vehicle would it be easier to do it on/ would net best mpg. i do lots of long distance driving and want to save money. ill be installing a used vo control system with hyrdraforce valves. here are some pics of all the stuff that came in the used kit i purchased. not pictured is some sort of in tank heater of some sort i have yet to receive.

[8v-of-fury]

I would say the ECO would net you the best mpg, after all the turbo was originally installed on the ECO models to increase efficiency not power.

[745 turbogreasel]

Whichever one is getting better MPG now.

[ORCoaster]

Does going to WVO drop the MPG by about 12% for everyone?  I know who cares man the fuel is much cheaper.  Just wondering if it is a universal thing or some engine, turbo, transmission combos are better with WVO than others.

[8v-of-fury]

Depends on the transmissions really. Can you crawl under both and get the tranny codes? They are on a machined flat surface right on the very bottom of the transmission bell housing.

[bbob203]

na=awy.    eco=avx.

[8v-of-fury]

ew, both are siht for highway cruising.

[8v-of-fury]

But the AVX will give you a cruising speed of 300rpm less than the AWY.

[bbob203]

yes!! that's all I care about to 

[8v-of-fury]

the ECO will cruise 100 km/h at roughly 2950rpms. A little high, but it will be making some boost too, which is good for economy and efficiency.

[bbob203]

I'm gonna try to track down a couple .71 fifth gears what kind of knowledge can you impart there?

[8v-of-fury]

Would be very beneficial in the AWY trans, but only a 200 rpm drop in the AVX. It will drop the AWY's cruising rpm by about 800 rpm.

The AWY is a 3.94 final drive and .89 5th gear. The AVX is a 4.25 final and .75 5th. So the drop will not be the same in the AVX as it will be in the AWY.

However the gap between 4th and 5th will be substantial. Not overly insane.. If you knew to run 4th up a little bit more then it wouldn't be a problem.. but you wouldn't be able to shift 4th low, or you'd stall it when hitting 5th.

[745 turbogreasel]

Does going to WVO drop the MPG by about 12% for everyone?

Never noticed, but I get a small power gain on veg, - I assume from the advance working better.

[sdwarf36]

Does going to WVO drop the MPG by about 12% for everyone?  I know who cares man the fuel is much cheaper.  Just wondering if it is a universal thing or some engine, turbo, transmission combos are better with WVO than others.

On my TD Jetta , I don't notice that much of a drop-on my 96 powerstroke camper, you can. But 12% seems a bit high.

[ORCoaster]

I was seeing folks going from the high 40's to the low 40's and just did the 42/48 and got the 12% reduction.  My problem is more about set distance between the source of fuel at a decent price and would have to find a way to carry extra WVO to top off the tank when it was hot and running.