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Old 07-23-2016, 06:21 PM   #56 (permalink)
EcoModding Lurker
Join Date: Jun 2010
Location: Henry, VA
Posts: 69

The Little Car - '00 Chevrolet Metro
90 day: 91.08 mpg (US)

The Big Car - '94 Chevrolet Caprice Wagon
90 day: 44.9 mpg (US)
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Thanked 127 Times in 33 Posts
Some responses to some of the thoughts and questions that have been shared...

Originally Posted by Frank Lee View Post
How much ratio change do you think is needed? Perhaps swapping on a set of smaller diameter wheels and tires will do the trick. It might look funny but then again the skirts might hide it. Put air shocks or air bags on the rear to level it out again- helps with the load, aero, and looks.
Originally Posted by Vigo View Post
As far as swapping the axles out, my first thought would be to use a rwd transfer case with a very mild low range (~2:1) and no front driveshaft. With your current tire size, 5th gear, and rear gear, a ~2:1 low range would have you doing about 2000rpm @ 55 mph, which sounds ideal for towing since you'll have abundant torque and probably not want to go much faster anyway. I'm not sure how this would fit under the car, but without a front driveshaft to worry about you could probably rotate it to suit with a little work. Seems like a more permanent solution than a 'theoretically quick'-change rearend. If you only used it rarely you wouldn't even need to make the shifter very convenient. Even jacking up the car and shifting the T-case by hand would be less effort than a rearend change, by far. I know you've already considered this but unless it requires a completely different main case for the nv3500 or major floorboard mods, it seems like the simplest long-term solution to me.
Yes, both of these solutions could theoretically work. But the problem with leaving the 2.14 ratio 7.5" axle in the car, and getting lower gearing though another means (such as an auxiliary transmission or smaller tires) is that the 7.5" axle really isn't up to handling the weight, torque loads, or braking of serious towing. It's fine for hauling passengers, but I wouldn't want to use it for much else.

Even the 8.5" axle that came in the car from the factory has it's limitations. GM used the same rear end in 1/2 pickups and SUVs, and it's been known to fail towing at full capacity (6000 lbs. plus). The 9.5" rear will make the drivetrain pretty much bulletproof, and give me better rear brakes than stock.

And smaller tires would have a lower load rating and lower ground clearance--both major drawbacks for towing.

Originally Posted by Vigo View Post

I'm also curious if you've recorded any highway travel with no P&G or EOC and what it does under more or less 'normal' steady-state highway driving?
I posted about this car on the GM Wagon forum, and they had the same question.

This car would go 32 MPG pretty consistently with the automatic and 2.56's. So with the manual and 2.14's, I'm guessing it would do around 35 MPG highway with no EOC.

Running a tank with no EOC would ruin my 90-day average, though.

Originally Posted by serialk11r View Post

If I were you though, I'd just go with a 2.74 final drive instead of the transfer case or a swappable diff, because your rpms are so low that you might actually do better P&Ging at a higher rpm. As you mention, you are already using 5th gear to pulse, why not just have 6th gear be like 5th and get a shorter 1st at the same time?
5th gear is the highest gear. It's a five-speed transmission, so no 6th gear.

Originally Posted by serialk11r View Post
I cannot believe you went with manual steering on that car...makes me feel like a wimp for struggling to turn my steering wheel with the engine off.
Originally Posted by autoarcheologist View Post
Did the S10 steering gear help the massive front end wander?
The manual steering really isn't bad at all, especially with the skinny, overinflated, LRR tires. My wife drives this car at least as much as I do, and she doesn't have any issues.

Originally Posted by autoarcheologist View Post
If you do decide to tow close to 5000 lbs you should firm up the rear suspension, a Panhard bar would be a great addition.
In "towing mode," this car will have a rear sway bar (which it does not have stock), heavy duty shocks front and rear, heavy duty rear springs, and tires with a higher load rating. I would also plan to use weight distribution and sway control if towing that much. Hopefully it will be just fine.

Originally Posted by LioNiNoiL View Post
Nice work Hoss, very nice.
Thirty-five years ago, I had an over/under/direct drive
auxilliary transmission in my old Jeep, made (I think)
by Gear Vendors (now defunct) that worked really well
for towing. It was a lot more convenient than swapping
pumpkins when I needed to pull a trailer.
A GV overdrive would be cool. There are only two problems. First, I wouldn't have the range of gearing that I will get with the two axles. And second, it would almost double the cost of the whole project.

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