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Fuel Mileage? |
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farna
Supporter of TheAMCForum
Moderator Lost Dealership Project Joined: Jul/08/2007 Location: United States Status: Offline Points: 7108 |
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Posted: May/21/2012 at 5:50pm |
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You might have been a *little* harsh, but you followed the "harsh" with good explanations, so we'll forgive you... this time...
![]() Tall/short tires and gear ratio changes follow the same principle. I tried using a 3.08 gear with the AW4 auto. The 4.6L stroker would pull the car up hills at 1700 rpm/70 mph all day, but it was working harder doing it and it showed in gas mileage. The engine wasn't lugging or straining by any means, just working hard. Had air resistance and hills working against it, and not enough gear when in OD, but 70 mph was too fast for direct drive. Wanted 3.31 gears, but got a deal on 3.55 gears for the Jag IRS I'm running. Turns out the 3.31 was only used overseas in five speed cars, only used in some older model XKEs over here, so hard to find in the states. With the 3.55 gears rpm went up to around 2000 @ 70 mph and gas mileage went up 2 mpg on the highway. Engine wasn't working so hard. Might have got another mpg with 3.31, might have only got 1 more... who knows? Too expensive to find out! |
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Frank Swygert
American Motors Cars Magazine www.amc-mag.com |
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vinny
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Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 490 |
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Posted: May/21/2012 at 6:26pm |
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The 2V 232 in my 64 Classic with a T35 and 3:15 gears now gets 19 - 20 MPG US. It seems to have improved a lot with a replacement rocker assy and new timing set.
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bikerfox
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Joined: Aug/03/2009 Location: Cali Status: Offline Points: 1352 |
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Posted: May/21/2012 at 8:15pm |
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The SC (with stock engine and t-10), 3.08:1 diff got 14.14 to LA this weekend on constant 65-70 mph driving. I'm happy!
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Steve
1969 SC/Rambler |
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Thikstik
AMC Addicted
Joined: Mar/20/2008 Location: Alabama Status: Offline Points: 1084 |
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Posted: May/21/2012 at 8:23pm |
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At least we dont have to work hard at having Jaguar mirrors, as long as our cars came with the hooded sport mirror.
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75 gremlin x, jeep 4L headed 258,Clifford cam, intake,header. 390 holley. I want a 282 VAM motor!
AC/PS/PDB. 72 AMX , 304 2bbl, 3speed, now disks...probably will sell, want an automatic /AC. |
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tomj
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Joined: Jan/27/2010 Location: los angeles Status: Offline Points: 591 |
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Posted: May/22/2012 at 1:44am |
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meh. i'm with billd. 99.9% of what goes wrong with, or can be improved on, in an internal combustion engine has been documented, tested, ad nauseum. RTFM, man! A crappy sparkplug/coil/distributor/whatever can hinder good spark, but once it's solidly Good, more Good will not occur. When the fuel/air mixture is solidly ignited, reliably and on time, more spark won't do squat except eat electricity and make heat.
Same goes for every other system/subsystem in the car. There is a lot of boring, plodding, plain old science to be had. Partake of it. There's fun and excitement in getting new experiments to work. Working out the "right" (eg. optimum FOR YOUR CIRCUMSTANCE) gearing and tire size needs regression testing, unless you are lucky enough to find someone else's work that fits your car to a "t". Taller tires help -- when your tires are too small. Taller tires hurt, when tire size is already optimal! And the factories do a pretty good job on ordinary cars. How do you know which is which? Read read read, then document and test. Which means, change tire size, drive 1000 miles, document, compare. That's what racers do, right? Track test, note the effect of small (or large) changes. The proof's in the numbers. |
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1963 American 440 hardtop
195.6 OHV, modded T-96 Twin Stick, 3.78 axle |
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billd
Moderator Group
Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 22780 |
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Posted: May/22/2012 at 1:19pm |
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gee, thanks Frank, I think.............
LOL Steve/biker - geesh, I was pulling a 2,000 pound trailer with my 4x4 and got 14-14.8 going to Indiana - once I left the hills of Iowa. On the way back, not so great....... well, someone shoved a car full of parts onto my trailer while I wasn't looking and stuffed parts in the back seat and box of my pickup. Actually, Steve, I'm funnin' ya - that's NOT BAD for that car at that speed. I've be PLEASED if my Javelin approached that. 12-13 mpg just kills me when I must buy premium just to get by. My Eagle (SX/4) does a range of 19-24 when COMMUTING, which is a mix of 2/3 40 mph and 1/3 in town stop and go. On the highway, 55 mph, I've approached an average of 30. Driving REALLY fast (for an Eagle, that is) I get 19. 65 it's mid 20s. The tires on it are a tad smaller than factory spec - reason is I have the lower profile, same size, but a 60% not a 65% The speedometer is thus about 1 mph off at highway speeds - the speedometer says 65 but the GPS says 64. Yes, that skews the MPG numbers a bit. I want to put the correct size tires on it, a bit taller is how that would end up, as the small diameter tires look too small for the large wheel openings in an Eagle, and that would put my speedometer readings about right if my math is right. How will that impact MPG? I guess I'll find out...... I found that how I drive the car has huge impact - like farna said earlier, my best mileage with the truck or Eagle is speeds under 65. Once I cross that, it drops. We did 65-70 with the Jeep to Overland Park and back last week - and got about 21 mpg - that's with the rear seats folded down and 5 very large rolls of quilters cotton batting in the back. (squeezed into place I might add) Not bad for a SUV/brick on the highway. I suspect had we slowed to 65 or less we'd have gotten 22+, we've done it before. I note that Iowa's move from 65 to 70 has cost me in fuel costs - of course it's my choice to drive that fast. doc seriously all we can do is "generalize" as your car is unique, the engine and drivetrain combo is unique, the condition of the engine and car is unique, and like tom said above - you've reached the sweet spot in ignition already, forget the "cool" or fancy stuff - Tim Allen was wrong - "MORE POWER" won't always help. How do we know if taller tires will help or hurt? All we can do is warn that taller MAY hurt, it's no guarantee - and explain why. If your engine is already working hard, the taller tires will make it work harder and get you less MPG. Here's another direct comparison - 2 identical (nearly) 1982 Eagle SX/4 cars. One has a 6, the other a 4. The 4 tops out at about 18 mpg. The 6 does much better. the 4 is over-worked, but gee, smaller engine, smaller carb, less weight, fewer cubes to burn fuel, it should do much better, right? No - it's worked too hard. The 6 is working about right. I IMPROVED my MPG when I decided to drive my baby eagle differently - I decided to not upshift so soon, and to not use 5th so often.... so now I hardly ever hit 5th gear unless I top 55. My mileage improved, even though I've been using lower gears. It's similar to taller tires...... I was working the engine harder, and/or, the engine was now running slower and was below it's most efficient spot. |
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DocCreer
AMC Addicted
Joined: Oct/03/2009 Location: Portland Oregon Status: Offline Points: 1426 |
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Posted: May/23/2012 at 2:00am |
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Well my dad's old 91 accord got 23mpg highway,and my Rambler is getting 21 highway right now after doin the electric fan conversion,so im pleased!
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69 440 sedan (totalled,junked)
69 440 wagon (sold to forum member. 73 Waggie (Gone) 78 Plymouth Volare Wagon 225,auto,(daily driver) 61 American Super(The Last Amc) |
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nickleone
AMC Apprentice
Joined: Oct/04/2008 Location: westminster co Status: Offline Points: 157 |
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Posted: Jun/13/2012 at 1:10pm |
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Just back from th 2012 Hot Rod Power Tour. Denver to Detroit to finish at Arlington TX, to Denver CO. Corrected milage 4050 mi. Average MPG for the trip 20.1.
About 250 mi per quart of oil LOL. In 2010 on the HRPT our 401 73 Gremlin got 11 mpg.
Combo of highway and state and county roads.
1962 Rambler Cross Country SW. 196 ohv 3 on column.
On the way to Detroit somewhere in Indiana we tore the carb apart in the hotel room to cure flooding. No real cause, put it back on in the rain and it ran the rest of the week without problems.
Nick Edited by nickleone - Jun/13/2012 at 1:12pm |
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nick
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farna
Supporter of TheAMCForum
Moderator Lost Dealership Project Joined: Jul/08/2007 Location: United States Status: Offline Points: 7108 |
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Posted: Jun/14/2012 at 8:48am |
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That's a heck of a trip in a well worn 62 Classic! Decent gas mileage, the oil consumption is why I assume "well worn". The only thing that made me finally stop trips like this with a 196 was the water pump. Took me a week to get the correct one the last time. If it went out on the road... So I got something I could put a 232/258 in, and ended up with a 4.0L EFI instead.
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Frank Swygert
American Motors Cars Magazine www.amc-mag.com |
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nickleone
AMC Apprentice
Joined: Oct/04/2008 Location: westminster co Status: Offline Points: 157 |
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Posted: Jun/14/2012 at 2:33pm |
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Farna,
We are palnning a rebuild. We have a set of 60 over pistons. Comp cams and others will do a regrind. Looking at a full flow oil filter and some more carbs for the manifold.
We ran out of time before the HRPT to get much done. It took 3 months to get the title, mostly because of the PO not returning a certified letter in the correct time frame.
Nick
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nick
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