Doin what they say cant be done.

[Sparkeysmall]

so i feel like I'm getting somewhere.... my best tank yet out of this thing. 11.41 mpg avg. and that was with a trip with a friend who wanted to make good time with the A/C on (he paid for the gas, so i didn't complain).



and on the "2000 rpm" sweet spot... I've found my best results, in 90's chrysler products anyway, that 62 mph/1750 rpm is the sweet spot. i read somewhere a long time ago that 1750 rpm was the "brake specific thermal efficient" rpm or something like that. in the jeep my economy always hit the moon when i cruised at 62 mph. and usually rolled around 20-22mpg up to 80 mph. I'm wondering if i should've built up a thread on it... it was simply dropping it an inch and a half and a light pedal... and usually get 19-20 out of it.

anyway, i tried sitting at 2000 rpm for most of the 200 mile trip. and got 11 on the computer before i was back home again. next week ill be heading down there again but will be able to do 55-65 mph and get things up a bit.


and the topper is still together. i notice at highway speeds the tail end lifts off the tailgate about an inch. otherwise all the glue is holding and it hasn't melted in the heat yet, although it was just 70 ish today (warm for february, making me scared this summer is going to be a hot one, or a whole bunch of rain (i like rain))

and i cannot see behind with it on. i might as well just got solid panels... although these where the cheapest i could find per sq ft... but my first idea was a 6mil plastic sheet. $20 to cover it 3 times.... but i didn't want a balloon flailing in the wind behind me, even with tension...


so. im happy with the fact I've broke the 11mpg barrier for a whole tank. or at least 3/4 of it. i did make it 100 miles on a quarter tank once, before the topper, but that was sitting behind a truck...



and another thing. I've gotten some "thats cool"'s and some "what the bleh is that?"... i just say its worth a %20 some improvement in economy...

also, did not have time to drop the ride height down. next weekend for sure. i mean it this time...

one last bit, I'm getting the parts list together for a manual transmission swap. I've made my decision on the nv4500HD. more abundant and cheaper. 6 speeds would be nicer for towing, but 5 is just easier to work with. I've found ebay specials for rebuilt ones for $1500, $2500 for the nv5600... so ill be walking the local junk yards to see if i can get lucky and find a v10 or cummins with all the fixings i need. i could get a used gearbox for $150, rest would be probably $300 more. and a rebuild kit is around $350. so if i could slap a manual transmission behind this motor for less than a grand i would be all kinds of happy. i want to change the transmission as soon as possible. this automatic just does the exact opposite of what i want it to... holds gears too long, and I've set the kick down cable from too tight (stupid high shifts) and even disconnected it. but having it connected and properly adjusted gives the best results. however it shifts gears using a calendar... i can't coax it into the next gear easily without loosing speed and keeping it from going into the next gear. and the overdrive torque converter lock out doesnt kick in until 50 mph, and loosens up as soon as you drop below it. but once it locks up instant mpg goes from 8 to 14 in a snap.

i know its a strong word, but i HATE automatics... with a passion... they're just lazy lazy lazy...

[ECONORAM]

Originally Posted by oil pan 4

Is the SRT10 the 8L or the 8.4L V10?

Per ALLPAR, the Viper truck has an 8.3L V10.

[cRiPpLe_rOoStEr]

Originally Posted by Sparkeysmall

i know its a strong word, but i HATE automatics... with a passion... they're just lazy lazy lazy...

I actually like the comfort provided by automatics, and the fact that a torque converter often stands better under heavy load compared to a conventional clutch, but the much lower technical complexity of a manual transmission also has its advantages when it comes to maintenance and repairs cost.

[Fat Charlie]

I hear people talking about ATs being able to hold up. Fake news people, not true!

[Sparkeysmall]

The only reason an automatic is stronger than a manual transmission is because of the planetary gearsets. The internal load is placed more or less radially into the case. Unlike a manual where the gears are trying to push themselves apart, and helical putting a small load lengthwise through the shaft. But with pumps, solenoids, bands, clutches, numerous heavy planetary gears and the simple fact the engine is never "really" connected to the road unless the torque converter clutch is locked up, its only excuse is to just pedal and go.... Yes a clutch sucks in traffic, let alone changing one every once in a while, but the mechanical efficiency with the ability to better control revs per mile vs torque required to get the job done. Manual all day long.

Anyway. So far im at 3/8 of a tank left and at 270 miles. I would say a good improvement with the topper. Ive got new ubolts on the way so i can drop the suspension down. I was going to just move the lift block to the top of the spring instead but after measuring things out i dont have enough clearence.

[cRiPpLe_rOoStEr]

Originally Posted by Sparkeysmall

The only reason an automatic is stronger than a manual transmission is because of the planetary gearsets. The internal load is placed more or less radially into the case. Unlike a manual where the gears are trying to push themselves apart, and helical putting a small load lengthwise through the shaft.

That's also true, but I was refering to the coupling. I've already seen more clutch packs damaged under heavy loads than torque converters damaged under the very same conditions.

[Sparkeysmall]

another record. 13 mpg over 200 some miles all highway. my mostly city average has been around 11.5 mpg.

and I've found the speed and rpm that makes the miles skyrocket with this truck. around 56 mph at 1550 rpm. i can keep the instant gauge well into and over 18-25 while steadily cruising on a level road, without a draft. anywhere else and the truck gets no further than 14. at 1550 rpm i can get a lot of usable torque without hurting economy too much. so that rpm must be this engines most efficient brake specific fuel consumption rpm. i tried looking around for a bsfc map for the 8.0 v10's and got nowhere...

I've been thinking about getting one of those plug in power programmers. from all the reviews its either gained a few hp or a few mpg's, depending on the tune you flash the computer with. kinda pricey though at $350 or so for a so-called "good one". then again for the $1000 (probably more) transmission swap i want to do it might be cost effective. but, from what I've googled, the v10's with a manual get 18+ without trying, so perhaps some math needs to be done...


with 10 mpg baseline and $2 a gallon.

price per mile at 10 mpg; $.20

price per mile at 12 mpg; $.17

price per mile at 15 mpg; $.13

price per mile at 17 mpg; $.12

price per mile at 20 mpg; $.10

price per mile at 22 mpg; $.09

price per mile at 24 mpg; $.08

price per mile at 26 mpg; $.07

current savings per 300 miles.... with aerotopper and grill block...

at 12 avg; $9

possible savings with tuner. estimated at 15 mpg; $21

possible savings with manual transmission estimated at 18-20 mpg; $24-30

possible savings with tuner and manual transmission, estimated 20-22; $30-33

while lowered a few inches, manual trans, tuner and some other bits at 24-26; $35-39


so. as i sit right now, to make what i already have into the truck pay itself off, it will take another 1500 miles or so to be in the black.

with the transmission swap at an estimated $2000 finished, and a $350 tuner, rolling at 24 mpg, would take around 9,000 miles to pay itself off.

i probably did some math wrong there somewhere, i am no wizard. but it all sounds about right.

so it would take about a year for all my planed mods to pay themselves off. which isn't too bad as i plan to drive this truck for a good while.


i just had another thought, if i waited to too all this work, vs doing it all asap, what would the total fuel costs be.

at 12 avg, over 10,000 miles; $1700
at 24 avg, over 10,000 miles; $800

dollars spent with fuel and all planned mods; $3500 ish
dollars spent as i sit right now; well, $1700...


hmm......

how about over 100,000 miles... $2 a gallon.

as i sit now; $17,000

with mods; $10,000, including the transmission and bits.



so after looking at things long term, doing the swap would be beneficial. and the inevitable cost of fuel going up in the future, would save even more.


fuel costs alone.....

how about $3 a gal, over 100,000 miles?

now; $25,000
with mods; $12,500
at 26; $11,500


$4 a gallon?

now; $33,300
with mods; $16,600
at 26; $15,384


$5 a gallon?

now; $41,600
with mods; $20,883
26; $19.230




i need to get busy...

[oil pan 4]

I say always expect gas prices to go up, never bet on the gas price going lower.

[ECONORAM]

Sparkey, I don't think I asked before. Are you able to get 100% gasoline where you live? If so, it's about 30 cents more/gallon here, but seems to help. I just switched the wife's car over, and the first tank was 3mpg higher. Not sure that will hold up, but might be worth investigating if you don't have to drive 200 miles to get it.

[ThermionicScott]

Originally Posted by ECONORAM

Sparkey, I don't think I asked before. Are you able to get 100% gasoline where you live? If so, it's about 30 cents more/gallon here, but seems to help. I just switched the wife's car over, and the first tank was 3mpg higher. Not sure that will hold up, but might be worth investigating if you don't have to drive 200 miles to get it.

On that, you need to make sure you're not just spending too much money for the MPG bragging rights. I can get non-ethanol gas at a couple local stations, but the price differential would blow away any savings I'd get from 2-4% higher FE.