quote Originally posted by 30+mpg: The settings for toe, caster and camber all have ranges. On a stock 2M4, what value within each spec will yield the lowest rolling resistance?

Here are the specs from the allignment rack at work. Sorry it took me so long to get them for you

FRONT Spec. Tot.
Left Camber .50 .80
Right Camber .50 .80
Cross Camber 1.00
Caster 5.0 2.00
Cross Caster 2.00
Total Toe .30 .10

REAR
Camber -1.00 .25
Total Toe .30 .20

Hope this helps, sorry it took so long.

Riiiiiight, I can see that those numbers clearly represent ranges. The orginal question is what specific value within each range is the best for mileage.

I have the ranges listed in the '86 service manual, a Haynes manual & a Chilton's manual already.

34 mpg on the last tank of 87 octane and 33.75 on the previous tank. I've boosted my cruising speed by a couple of mph to boot!
Faster AND Farther!

More data points, for what they're worth:

Based on averaging several cross-country highway trips, and averging many trips around town, recording and calculating the mileage whenever the notion stikes me...

1986 V6 SE 4-sp Muncie, City: 22 Hwy: 30
1987 V6 GT 5-sp Getrag, City: 22.5 Hwy: 32

1987 3.1 Cavalier/Getrag City: ?? Hwy: 26
This car probably can do better.

1986 V6 SE Auto: No idea (not licensed).

1988 Duke 5-sp Isuzu, City: Awful, maybe 18.
Hwy: Never tried it.
Clutch slips, engine never tuned. Car seems to have been abused by previous owner(s).

Just for fun I thought I would interject. It would seem that logically, your wheel alignment should run dead true to the road. That would mean that caster doesn't enter the equation unless you drive on curvey roads a lot. Assuming highway conditions, camber should be as close to zero as possible, simple enough. Toe-in (front and rear)on the other hand needs to be true at velocity, meaning you have to account for deflection of the system at speed. This will vary from car to car, based on the condition of suspension components and such, so the answer to your question is EXPERIMENTATION! You will need to measure more accurately the milage to know if you are going in the right direction adjustmentwise. I recommend picking a long section of road for repetition and measuring the fuel injector "rms" voltage with a voltmeter at the same speed and other variable conditions. I did this on a car and it was pretty fun "in a nerdy sort of way".

Low tech, start at dead nuts straight alignment, check mileage, and give toe-in adj a couple cranks in one direction and see how it affects mileage. Note: this may adversly effect handling if you go outside the mfg specs, but I feel I have to say that in case you drive off a cliff.

Not many cliffs in southeast Kansas. Fewer in western KS.

For comparison.... (All averaged over many tanks...)

87 DIS L4 TH125

I get right about 26-27 city. I've gotten as high as 32-33 highway.

One way to increase MPG is change the finals in the TH125. That will knock off some launch torque. Read Gear Ratio and Tires in my cave.

The AOD (440whatever) units often have lower first gear and finals than TH125. The OD high gear makes up for the lower finals on the highway. So these may not deliver more MPG w/o some changes.... You would however launch quicker.

Theoretically, If you put the same ratio finals as you now have in the TH125 into a 440...
You'd still launch quicker in traffic because of lower 1st gear.
You'd get higher MPG because you'd be over driven on the top end.

Just what ratios are available for the 440 I don't know. You might not want exactly the same ratio as the TH125. You may want it geared slightly lower to keep RPM up a bit more than calculated above. The engines of most cars are tuned to work best in a certain narrow band of RPM. If you get too far bellow 2000RPM it could hurt engine efficiency. I don't think 1900 should be a problem. Hard to say w/o a whole lot of data I don't have right now.

As far as highway driving goes, It doesn't take a huge amount of power to keep a car rolling once it gets up there... Of course the faster you go you'll always eat more power and thus fuel.

Technically swapping tires can change MPG... You would have to also recalibrate the speedometer accordingly to see it. This is a bit tricky... If you swap in too large a tire, you could loose MPG to drag and loss of gearing.

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11-Sept-01, The day the world as we knew it ended.

sounds like you're out for the ultimate mpg - I've always found that running hi octane fuel gave me the best mpg - as much as 1 or 2 more than regular. Also, Texaco works best; chevron next best. Experiment with 92 octane and different brands. I'll bet you pick up 1 or 2 mpg more !

Higher octane = 5% increase in mileage with greater that 5% increase in fuel cost? Not cost effective.

Well, my quest for better mileage is about to come to a welcome halt. I'm in the process of moving. In about a week, instead of 37 miles from work, I'll be about 7 blocks! This is a 2.5 minute drive so why do it? I'll be back to riding my 3 speed Hercules bicycle to work as I did from '93 to '00. During some of those years I only used 4 to 6 tanks of gas for a whole year. I will be reclaiming about 9 hours a week of personal time. I'll get home faster by not traveling any farther than I have to. LOL

A 299.1 mile trip used 8.86 gallons last week for an average of 33.76 mpg while crusing at 65 mph.

I'm getting around 30 city/highway combo. I have about a 12 mile drive to work, about 7-8 miles are expressway. I have 88 2.5 with 5 speed with 60 sries tires.

My 88 coupe will get ~35mpg at 55mph, but here in california we never drive that. ~28mpg at 80mph (95% highway) is what I get day in and day out. Around town, only about 20mpg, but I'm not really babying it. it's an isuzu 5spd with 205-55-16 tires on grand am wheels.
Don't know what the 88 Formula does - haven't had it long enough.

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88 4cyl 5spd & 88 Formula 5spd

[This message has been edited by nick2x88 (edited 02-01-2003).]

Gas mileage certain does vary... In my experience it is an oddity to get less than 30MPG; six miles highway and 4 miles city, one-way. I took the 88 Coupe on a trip recently for teacher training, a little over 350 miles, single tank of fuel. I drove a steady 70MPH and got 35 miles to the gallon.

God damn it my v6 gets about 9 mpg and feels rich because it feels a little weak and all this from a car with less then 60k miles on it.

Anybody try z max yet or that turbo air cleaner insert thing??

Most recent trip with passanger got 32mpg.