Mission Possible: A Boxy 1984 Caprice Classic

[101Volts]

Thanks.

As for the new tires, they throw off the odometer. But what should I calculate by? I read at one source that I should calculate by 1.09%, and yet Automobile-Catalog says the tires are 1.2% larger than stock.

Stock: P205/75R15
New: 225/70R15

Source 1: http://www.1010tires.com/Tools/Tire-...5R15/225-70R15

Source 2: http://www.automobile-catalog.com/ti...automatic.html

[digital rules]

Use a GPS if you have one or can borrow one to calibrate the odometer/speedometer.

[101Volts]

Originally Posted by digital rules

Use a GPS if you have one or can borrow one to calibrate the odometer/speedometer.

Now I have another reason to buy one. Thanks for that.

[digital rules]

You can also use mile markers along the highway, but would need at least 100 miles to dial in an accurate number.

[101Volts]

Originally Posted by digital rules

You can also use mile markers along the highway, but would need at least 100 miles to dial in an accurate number.

Thanks. I have access to a highway and to the time, It's just a matter of doing it.

[101Volts]

OK, Fill-up day.

Not much to say about the mods - I pumped the tires to 45 Hot now. But now I need to find what the actual mileage is VS odometer. I multiplied the 408 miles by 1.15 (To go in-between 1.09 and 1.2) which got 468.6 Miles and between 21 and 22 MPG on this last fill-up. That's in the neighborhood of 35 PSI in the tires for the whole tank.

I will say the car coasts a lot more now, at 45 PSI Hot.

I'm still thinking of changing the fan. And what else is, the fan in the Mercury we got is constant too, not on-demand so that may be changed some time.

[cRiPpLe_rOoStEr]

Originally Posted by 101Volts

I'm still thinking of changing the fan. And what else is, the fan in the Mercury we got is constant too, not on-demand so that may be changed some time.

So, replace the fans on both. It's a fairly cheap mod and in some circumstances can increase efficiency from 3 to 5%.

[101Volts]

Originally Posted by cRiPpLe_rOoStEr

So, replace the fans on both. It's a fairly cheap mod and in some circumstances can increase efficiency from 3 to 5%.

I understand it reduces warm-up time.

[cRiPpLe_rOoStEr]

Originally Posted by 101Volts

I understand it reduces warm-up time.

It does. And actually it also helps regarding efficiency improvements, since the engine would be wasting less fuel to get into the optimum operational temperature.

[101Volts]

I went on a trip today. The odometer read that I went 104.85 (rounded off) miles, I actually went 107.1 according to Google Maps. So, Multiplying by 1.022 gets close to the actual reading.

This also means the tires didn't make much of a difference MPG wise (For just one tank) to the last ones when run at the same PSI (35) but I did bump these new ones up to 45 Hot at fill-up time, and the previous tires said "35 PSI Max."

... I need to put other mods on than just the tires if I'm going to get past 25 MPG frequently. A new fan does come to mind and I wonder if replacing the air-pollution equipment would be of benefit, if it hasn't been replaced. Surely there are some CATs that are more efficient than there were in 1983.

I do still have the Diesel Conversion in mind (With the proper engine + Manual Transmission and 20 Gallon Diesel Tank = Instant 30+ MPG HWY in my mind.) but I'm thinking of doing some other things first.